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1. s ssssssesss 70 VAG Standards deer ir Pe RI 71 GO Eq ipiment ian ERE Ree EE eI cute chests 72 8 1 Standard equipment bic dede atn Dee ea eee 72 8 2 Optional accessories ci Tego Mei ee tario eee Ry get 72 8 2 1 C 4 current clamp 8 2 2 C 5 current clamp 8 2 3 C 6 current clamp 8 2 4 C 7 current clamp 8 2 5 F t F 2 F 3 c rrent clamps i ah s 79 9 Other information ss essmenanemnzzwezaaazaa ann na tnra natn aaa wana anna awa aa az nan 81 9 1 Cleaning and maintenance einen nnne nnne 81 9 2 icu m NER 81 9 3 Dismantling and dispose 81 9 4 Man facturer EORR 81 1 General Information 1 General Information 1 1 Safety PQM 700 Power Quality Analyzer is designed to measure record and analyse A power quality parameters In order to provide safe operation and correct meas urement results the following recommendations must be observed e Before you proceed to operate the analyzer acquaint yourself thoroughly with the present man ual and observe the safety regulations and specifications provided by the manufacturer e Any application that differs from those specified in the present manual may result in a damage to the device and constitute a source of danger for the user e PQM 700 analyzers must be operated only by appropriately qualified personnel with relevant certificates authorising the personnel to perform works on electric systems Operating the ana lyzer by
2. Waveforms Event waveforms for voltage and current Recording activation mode manual starting at the first detected event scheduled four defined time periods Measurement points 1 single user configuration Recording time Depending on the configuration Memory Built in 2 GB micro SD memory card Memory Model Linear Security Key lock to prevent unauthorized access 1 Averaging times shorter than 10 seconds are in fact equal to a multiple of the mains period 200 ms 10 12 cycles 1 s 50 60 periods 3 s 150 180 periods 5 s 250 300 cycles 2 Urmsc1 2 and lRus 1 2 are RMS values for one period refreshed every half period 68 PQM 700 Operating manual 3 Averaging periods min max 200 ms 1 s 3 s 5s are in fact equal to a multiple of the mains period 200 ms 10 12 cycles 1 s 50 60 periods 3 s 150 180 periods 5 s 250 300 cycles Recorded parameters Minimum value Instanta neous value Maximum value RMS phase phase to phase depending on the type of system voltage Urms RMS phase to phase voltage Urms only 3 phase wye with N and split phase systems RMS current laus Frequency f Voltage crest factor CF U Current crest factor CF Unbalance factors for negative and positive se quence symmetrical components negative posi tive zero voltage Uo U1 U2 uo u2 Unbalance factors for negative and positive
3. d wt 5 RZE o Oo Di X OPTIONAL Voltage input terminals Current input terminals Wiring diagram 3 phase wye without neutral conductor current measurement using Aron method 2 Operation of the analyzer L1 A L1 Gi QZ L2 B gt GZ B L3 C Ee M epo 6860 Voltage input terminals Current input terminals Fig 12 Wiring diagram a system with transformers in wye configuration Transformer Load Voltage inputs Current inputs Fig 13 Wiring diagram a system with transformer in delta configuration 22 PQM 700 Operating manual 27 Key Lock Using the PC program the user may select an option of locking the keypad after starting the process of recording This solution is designed to protect the analyzer against unauthorized stop ping of the recording process To unlock the keys follow these steps e press three times in a row cop button in steps of 0 5 s and 1 s e then press GD button within 0 5s to 1s When buttons are pressed the user hears the sounds of inactive buttons after completing the whole sequence the meter emits a double beep 2 8 Sleep mode PC software has the feature that can activate the sleep mode In this mode when the user starts recording the meter turns off LEDs after 10 seconds From this moment the following options are available e immediate triggering after LEDs are turned off LOGG LED bli
4. 2 Operation of the analyzer 2 Operation of the analyzer 2 1 Buttons The keyboard of the analyzer consists of two buttons ON OFF qu and START STOP e To switch on the analyzer press ON OFF button START STOP button is used to start and stop recording 22 Switching the analyzer ON OFF e The analyzer may be switched on by pressing button Green ON LED indicates that analyzer is switched on Then the analyzer performs a self test and when an internal fault is detected ERROR LED is lit and a long beep 3 seconds is emitted measurements are blocked After the self test the meter begins to test if the connected mains configuration is the same as the configuration in analyzer s memory and when an error is detected ERROR LED flashes every 0 5 seconds When ERROR LED flashes the analyzer still operates as normal and measurements are possible The criteria used by the analyzer for detecting a connection error are as follows deviation of RMS voltage exceeding 15 of nominal value deviation of the phase angle of the voltage fundamental component exceeding 30 of the theoretical value with resistive load and symmetrical mains see note below deviation of the phase angle of the current fundamental component exceeding 55 of the theoretical value with resistive load and symmetrical mains see note below network frequency deviation exceeding 10 of the nominal frequency Note To detect a phase error the fundamenta
5. 18 28 C lt 85 non condensing e Technical data test range e frequency range e maximum allowable continuous current e accuracy sine wave 0 100 A AC 40 Hz 3 kHz 100 A AC 50 60 Hz Basic uncertainty 0 5 0 1 mV lt 2 1 0 0 2mV unspecified Frequency Phase error 45 65 Hz 40 Hz 1 kHz ratio 5mV AC 1 AAC output impedance 110 type of insulation double according to IEC 61010 1 measurement category according to IEC 61010 1 III 300 V e dimensions 100 x 60 x 26 mm e weight approx 160 g e maximum diameter of tested cable 024 mm e length of clamp cables 1 5m e operating temperature 0 C 50 C e relative humidity lt 85 non condensing e electromagnetic compatibility IEC 61326 78 PQM 700 Operating manual 8 2 5 F 1 F 2 F 3 current clamps F 1 F 2 and F 3 flexible clamps Rogowski coil are used to measure the alternating current of frequencies up to 10 kHz in the 1 A 3000 A range The only difference between the F 1 F 2 and F 3 flexible clamps is the coil size The electrical parameters are identical The output signal if voltage proportional to the derivative of the measured current with the sen sitivity equal to 38 83 mV 1000 A for 50 Hz and 46 6 mV 1000 A for 60 Hz Fig 29 F 1 clamp Fig 31 F 3 clamp Fig 30 F 2 clamp The output signal is supplied by a 2 meter lead with a pin adapted for the socket in the meter The arrow loc
6. Transducers defined by user Impedance of measurement in puts 14 MO CMRR Current input terminals gt 70 dB 50 Hz Number of inputs 4 3 phases neutral not isolated galvanically Nominal input voltage 1 Vnus Peak input voltage Analog passband 3dB Input Impedance CT clamps 100 kQ Flexible clamps 12 4 kQ Measurement range without transducers Flexible clamps F 1 F 2 F 3 1 3000 A 110000 A peak CT clamps C 4 C 5 1 1000 A 3600 A peak CT clamps C 6 0 01 10 A 36 A peak CT clamps C 7 0 100 A 360 A peak Transformers defined by user CMRR 7 2 Sampling and RTC Sampling and RTC 60 dB 50 Hz A D converter 16 bit Sampling rate 10 24 kHz for 50 Hz and 60 Hz Simultaneous sampling in all channels Samples per period 204 8 for 50 Hz 170 67 for 60 Hz PLL synchronization 40 70Hz Reference channel for PLL L1 Real time clock 3 5 ppm max approx 9 sec month in the temperature range of 20 C 55 C 62 PQM 700 Operating manual 7 3 Measured parameters accuracy resolution and ranges 7 3 1 Reference conditions Tab 5 Reference conditions Reference conditions Ambient temperature 23 C 2 C Relative Humidity 40 60 Voltage unbalance lt 0 1 for unbalance factor of negative sequence applies only to 3 phase systems External continuous magnetic
7. itive direction if it is flowing from the source to the receiver Such clamp orientation is required for a correct power measurement Fig 25 C 4 clamp Note Currents above 1200 A must not be measured The measurement time for currents above 1000 A shall be limited as follows Current range 1x 1000A 1000 A lt I lt 1200 A Operation mode continuous 15 minute measurement then 30 minute break 1 For frequency f lt 1 kHz Limitation of maximum current for continuous operation for frequen cies above 1 kHz according to the relationship leon 1000 A f kHz Warning Do not use the device on non insulated conductors with a potential of more than 600 V in relation to the earth and a measurement category greater than III e Reference conditions e Temperature 20 26 C e Humidity 20 75 RH e Conductor position conductor centered in jaws e Sinusoidal current frequency 48 65 Hz e Harmonics content lt 1 e Current DC component none e Continuous magnetic field earth field lt 40 A m e Alternating magnetic field none e Conductors in direct vicinity no flowing current 73 8 Equipment e Technical parameters 8 2 2 The C 5 clamp is used to measure the alternating and direct current without interrupting the circuit with the flowing current The measuring range is 1400 A for DC and 1000 A AC The output signal is voltage proportional to the meas ured current The clamp has one 1000 A measuri
8. tion Unit Method of calculation Voltage True RMS where U is a subsequent sample of voltage Ua n M 2048 for 50Hz and 60 Hz Voltage DC component M 1 Uapc 2 Ui 1 i where U is a subsequent sample of voltage Ua M 2048 for 50Hz and 60 Hz Frequency number of full voltage periods Us counted during 10 sec period clock time divided by the total duration of full periods Current True RMS where liis subsequent sample of current la M 2048 for 50Hz and 60 Hz Current constant compo nent 1 M l pc 3 li i 1 where liis a subsequent sample of current la M 2048 for 50Hz and 60 Hz Active power 1 M P SH Uili i 1 where U is a subsequent sample of voltage AA liis a subsequent sample of current la Budeanu reactive power M 2048 for 50Hz and 60 Hz 40 QB gt Dun sin h h 1 where Unis h th harmonic of voltage Ua N In jest h th harmonic of current a qnis h th angle between harmonic U and In Reactive power of funda mental component Q Ul sin 9 where U is fundamental component of voltage Ua N h is fundamental component of current la gi is angle between fundamental components U and li Apparent power S Uanuslanus Apparent distortion power Sy 45 U Budeanu distortion power Dg 52 P Qi Power Factor PF TS If PF 0 then the load is of a generator type If PF gt O then the l
9. The arithmetic average AVG is calculated according to the formula N 1 AVG x X i 1 where e Xiis subsequent parameter value to be averaged e Nis the number of values to be averaged 39 6 Power Quality a guide 6 Power Quality a guide 6 1 Basic Information The measurement methodology is mostly imposed by the energy quality standards mainly IEC 61000 4 30 This standard introducing precise measurement algorithms ordered analyzers mar ket allowing customers to easily compare the devices and their results between the analyzers from different manufacturers Previously these devices used different algorithms and often the results from measurements on the same object were completely different when tested with different de vices The factors behind growing interest in these issues have included wide use of electronic power controllers DC DC converters and switched mode power supplies energy saving fluorescent lamps etc that is widely understood electrical power conversion All of these devices had a ten dency to significantly deform the supply current waveform The design of switched mode power supplies widely used in household and industrial applications is often based on the principle that the mains alternating voltage is first rectified and smoothed with the use of capacitors meaning that it is converted to direct voltage DC and then with a high frequency and efficiency is converted to required output volta
10. Us Uc Operator mag indicates vector module A 1 v3 Si ED po m a le 2 2 j 1 v3 g 2169 7 Voltage unbalance factor for zero component 2 52 Uo ug 100 U Voltage unbalance factor for negative sequence _ U2 1009 U ii uz 36 Current zero sequence PQM 700 Operating manual 1 b 3 lar Ini Ici Io mag Ip where Jai IB1 Ic are vectors of fundamental compo nents for phase currents la Ip Ic Operator mag indicates vector module RMS value of positive current sequence 1 L ga algi t aile l mag I where lar s1 Ic are vectors of fundamental current components la lp lc Operator mag indicates vector module RMS value of negative current sequence 1 b 3 lu Pl alc 1 mag 12 where Jai ls1 Ici are vectors of fundamental compo nents for phase voltages la le Ic Operator mag indicates vector module Current unbalance factor for zero sequence H io 7 100 Current unbalance factor for negative sequence d i 7 100 5 4 3 phase wye and delta network without neutral conductor 3 phase wye and delta network without neutral conductor Parameters RMS voltage and current DC components of vo tage and current THD flicker are calculated as for 1 phase circuits instead of the phase voltages phase to phase voltages are used Symmetrical components and unbalance factors ar
11. Y Par OT i 1 Piot i dla Pj lt 0 0 dla Prop i gt 0 Poor 0 Ptot 1 where iis subsequent number of the 10 12 period measure ment window Pia i represents total active power Piot calculated in i th measuring window T i represents duration of i th measuring window in hours 5 Calculation formulas Total Budeanu reactive energy consumed and supplied EQB tot EQB tot EQB tot gt QBtot COT I i 1 QBtot i dla Qgtoc i gt 0 0 dla Qgtot i lt 0 m EQB tot gt QBtot OT 0 i 1 lQstot i dla Qpioc i lt 0 0 dla Qgtoc i 0 QBtot i QBtot I where iis subsequent number of the 10 12 period measure ment window GBtot i represents total reactive power Qaia calculated in ith measuring window T i represents duration of i th measuring window in hours Total reactive energy of fundamental component consumed and supplied Eatstot Ea1 tot Eq1 tot gt Hier OT i 1 Qitor D dla Qytoc i gt 0 0 dla Qiror i lt 0 m Eq1 tot p Qior COT CL i 1 lQitot i dla Qitot i lt 0 0 dla Qytor 0 Q1tot i Qitor where iis subsequent number of the 10 12 period measure ment window Qitor i represents total reactive power Qitot calculated in ith measuring window T i represents duration of th measuring window in hours Total apparent energy Estot 3 SOTO i 1 where iis subsequent num
12. e ratio 100 mV AC 1 A AC e frequency range 40 Hz 10 kHz e insulation type double according to IEC 61010 1 measuring category acc to IEC 61010 1 Ill 600 V e protection rating acc to IEC 60529 IP 40 with open jaws IP 30 e dimensions 135 x 50 x 30 mm e weight about 240 g e jaws opening 21mm e open jaws height 69 mm e maximum measured conductor diameter 220 mm e clamp lead length 1 5m e operating temperature 10 C 55 C e humidity lt 85 RH e height lt 2000 m e electromagnetic compatibility IEC 61000 6 3 2008 IEC 61000 6 2 2008 8 Equipment 8 2 4 C 7 current clamp C 7 Clamps are used to measure alternating currents in net works of low and medium power within the range up to 100A The output signal is a voltage proportional to the measured current at the sensitivity of 5 mV A It is introduced via a cable length 1 5 m ended with a plug suitable for a socket in the meter The arrow marked on one of the clamps indicates the direction of current flow It is assumed that the current flows in the positive di rection if it flows from the source to the receiver This orientation of clamps is required for the correct power measurement Attention Do not use non insulated clamps for conductors with a potential exceeding 300 V with respect to the ground and in systems with the measurement category higher than III Fig 28 C 7 clamp e Reference conditions e temperature e relative humidity
13. lt 2 5 lt 2 e ratio 1mVAA e frequency range DC 5 kHz e output impedance 100 Q e DC zero adjustment range 10 A e noise DC up to 1 kHz lt imVp p or 1 Ap p DC up to 5 kHz lt 1 5mVp p or 1 5 Ap p 1 Hz up to 5 kHz lt 0 5mVp p or 0 5 Ap p e Additional errors e caused by current frequency 65 440 Hz 296 440 1000 Hz 5 1 5 kHz 4 dB e caused by battery voltage lt 1 A V e caused by temperature lt 300 ppm C or 0 3 10 C e caused by relative humidity in the10 85 range 0 596 8 Equipment e caused by position of 220 mm conductor DC up to 440 Hz 0 596 DC up to 1 kHz 196 DC up to 2 kHz 396 DC up to 5 kHz 1096 e caused by a parallel conductor with the 50 60 Hz AC at 23 mm from the clamp e common mode rejection ratio e Other data insulation type protection rating acc to IEC 60529 power supply operating time with alkaline battery dimensions weight clamp lead length operating temperature humidity height electromagnetic compatibility 8 2 8 C 6 current clamp The C 6 is used to measure the alternating cur rent with frequencies up to 10 kHz in the 10 mA 10 A range The output signal is voltage proportional to the measured current with the 100 mV A sensitivity The output signal is supplied by a 1 5 meter lead with a pin adapted for the socket in the meter The arrow located on one of the jaws indicates the current flow direction It is assume
14. u Uo 100 Dm u U2 100 2 U where uo zero sequence unbalance U negative sequence unbalance 55 6 Power Quality a guide Uo zero sequence symmetrical component U positive sequence symmetrical component U2 negative sequence symmetrical component The most convenient method to calculate the symmetrical components and unbalance is using the complex number calculus The vectors parameters are amplitude of the voltage current fun damental component and its absolute phase shift angle Both these values are obtained from FFT 6 7 Detection of voltage dip swell and interruption Voltage dips swells and interruptions are the mains system disturbances during which the RMS voltage significantly differs from the nominal value Each of the three states can be detected by the analyzer when the event detection is activated and when the user defines the threshold values Voltage dip is a state during which the RMS voltage is lower than the user defined voltage dip threshold The basis for the dip measurement is Upwsa2 that is the one period RMS value refreshed every half period Voltage dip definition according to the IEC 61000 4 30 standard The voltage dip starts at the moment when the Unus voltage decreases below the dip thresh old value and ends at the moment when the Unusu2 voltage is equal to or greater than the dip threshold value plus the voltage hysteresis The dip threshold is specified at 909
15. 12 period val Negative sequence unbalance fac tor for voltage max 0 0 20 0 Basing on 10 12 period val Negative sequence unbalance fac tor for current max 0 0 20 0 Basing on 10 12 period val Short term flicker Pst max 0 20 Basing on 10 minute value Long term flicker Pr max 0 20 Basing on 2 hour value Active power P min max Depending on the con figuration Basing on 10 12 period val ue for consumed and supplied power Reactive power Q min max 67 Depending on the con figuration Basing on 10 12 period val ue for consumed and supplied power 7 Technical specifications Apparent power S min max Depending on the con figuration Basing on 10 12 period value Distortion power D Apparent dis tortion power SN min max Depending on the con figuration Basing on 10 12 period value Power Factor PF min max 1 Basing on 10 12 period value Displacement power factor cosq DPF min max 0 0 1 Basing on 10 12 period value tang min max 0 10 Basing on 10 12 period value Active energy Ep max Depending on the con figuration Exceedance checked every 10 12 periods for consumed and supplied energy Reactive energy Eo max Depending on the con figuration Exceedance checked every 10 12 periods for consumed and supplied energy Apparent energy
16. 5 2 THD Total Harmonic Distortion THD is the most widely used measure of waveform distortion Two versions of this factor are applied in practical use e THD THD F or simply THD total harmonic distortion referred to the fundamental com ponent e He THD R total harmonic distortion referred to the RMS value In both cases THD is expressed in percent The definitions are given below Vna Ah THD x 100 A n A THDg V2inz2 An x 100 Apus where A RMS of the hth order harmonics A RMS of the fundamental component Arms RMS waveform Limitation of the number of harmonics used to calculate THD is conventional and is caused mainly by measuring limitations of the device Because the PQM 700 is capable of measuring the harmonic components up to the 40 order the harmonics up to the 40 order are used to calculate THD Please note that when the waveforms are very distorted the two definitions presented above will give significantly different results THDR may not exceed 100 but there is no such limit for THDF and it may go up to 200 or higher Such case can be seen when measuring very distorted current The voltage harmonic distortion usually does not exceed a few percent both THDr and THDR for example the limit according to EN 50160 is 8 THDF 6 6 Unbalance Unbalance is term related to three phase systems and can refer to e supply voltage unbalance e load current unbalance e receiver unba
17. 55 C Storage temperature range 30 C 60 C Humidity 10 90 with posible condensation Ingress protection according to EN IP 65 60529 Reference conditions Ambient temperature 23 C 2 C Humidity 40 60 Dimensions 200 x 180 x 77 mm without cables Weight approx 1 6 kg Display 5 LEDs indicating operational status Data memory removable micro SD memory card 2 GB as standard option of ex tending up to 8 GB optional 7 13 Safety and electromagnetic compatibility Safety and EMC Compliance with IEC 61010 1 Measurement Category IV 300V pollution class 2 according to IEC 61010 1 Insulation Double acc to IEC 61010 1 Electromagnetic compatibility IEC 61326 70 Immunity to radio frequency interferences PQM 700 Operating manual IEC 61000 4 3 sinusoidal modulation 80 AM 1kHz 80 1000MHz 10V m 1 4 2 0 GHz 3 V m 2 0 2 7 GHz 1 V m Immunity to electrostatic discharge IEC 61000 4 2 Air discharge 8 kV Contact discharge 4kV Immunity to conducted disturbances in duced by radio frequency fields IEC 61000 4 6 sinusoidal modulation 8096 AM 1kHz 0 15 80MHz 10V Immunity to a series of electrical fast tran sients bursts IEC 61000 4 4 Amplitude of 2kV 5kHz Surge immunity IEC 61000 4 5 Amplitude 2kV L L Emission of radiated RF disturbances IEC 61000 6 3 30 230MHz 30dB uV m at 10m 230 1000MHz 37dB uV
18. Analysis 2 Communication with a PC is possible via USB connection which provides the transmission speed up to 921 6 kbit s 1 3 Power supply of the analyzer The analyzer has a built in power adapter with nominal voltage range of 90 460 V AC 127 460 V DC The power adapter has independent terminals red cables marked with letter P power To prevent the power adapter from being damaged by undervoltage it automatically switches off when powered with input voltages below approx 80 V AC 110 V DC To maintain power supply to the device during power outages the internal rechargeable battery is used It is charged when the voltage is present at terminals of the AC adapter The battery is able to maintain power supply up to 2 hours at temperatures of 20 C 55 C After the battery is 8 PQM 700 Operating manual discharged the meter stops its current operations e g recording and switches off in the emergency mode When the power supply from mains returns the analyzer resumes interrupted recording Note The battery may be replaced only by the manufacturer s service de partment 1 4 Tightness and outdoor operation PQM 700 analyzer is designed to work in difficult weather conditions it can be installed directly on electric poles Two bands with buckles and two plastic fasteners are used for mounting the ana lyzer The fasteners are screwed to the back wall of the housing and bands should be passed throug
19. Es max Depending on the con figuration Exceedance checked every 10 12 periods Total harmonic distortion for volt age THD F max 0 100 Basing on 10 12 period value Total harmonic distortion for cur rent THD F max 0 200 Basing on 10 12 period value Voltage harmonic amplitudes max 0 100 or absolute values Basing on 10 12 period value Independent thresholds for all harmonics in the range of 2 40 Current harmonic amplitudes max 0 200 or absolute values 7 5 1 Event detection hysteresis Event detection hysteresis Range Basing on 10 12 period value Independent thresholds for all harmonics in the range of 2 40 Calculation method Hysteresis 0 10 See section 4 7 7 6 Range A Inrush current measurement in 0 1 steps Resolution A Basic uncertainty 0 100 Inom 0 1 1 Inom e voltage and current measurement is carried out every 75 period in all channels averaging set to 75 period e measurement time up to 60 seconds 7 7 Recording Recorder Averaging time 15 35 10 s 30 s 1 min 10 min 15 min 30 min Special mode 75 period for recording waveforms with a limited recording time up to 60 sec e g inrush current Averaging min max for Unus period period 200 ms 1 s 3 s 5 s Averaging min max for ous period period 200 ms 1 s 3 s 5 s
20. Inom 7 3 4 Frequency Frequency Ranges and conditions Resolution Basic uncertainty 40 70 Hz 0 01 Hz 0 05 Hz 10 Unom s Unus lt 120 Unom 7 3 5 Harmonics Ranges and condi tions Harmonic n DC 1 40 grouping harmonics sub groups acc to IEC 61000 4 7 Unus amplitude 0 200 Unom 0 01 Unom 0 15 Unom if m v lt 3 Unom 5 m v if m v 2 3 Unom acc to IEC 61000 4 7 Class I Inus amplitude Depending clamps 0 0196 Inom 0 5 Inom H m v 1096 Inom used see specifica 5 of m v if m v 2 10 Inom tions for ous acc to IEC 61000 4 7 Class I Voltage THD R 0 0 100 0 0 1 5 n 2 40 for Unus 2 1 Unom Current THD R 0 0 100 0 0 1 5 n 2 40 for Joe 2 1 Inom Phase angle voltage 180 180 0 1 Phase angle current 180 180 0 1 Harmonics Resolution Basic uncertainty 7 3 6 Power and energy Conditions Power and energy for power and energy Resolution Basic uncertainty 80 Unom S Unus 120 Unom Active power 2 kon S Rus lt 5 Inom depending on Active energy coso 1 Unom and Inom 5 Inom S IRMS S Inom coso 1 5 Inom S ous lt 10 Inom cos 0 5 10 Inom s IRms S Inom cos 0 5 Reactive power 2 kon S IRMs lt 5 Inom depending on Reactive energy sino 1 Unom and Inom 5 Inom lt IRMs lt Inom sino 1 5 Inom ous lt 1096 Inom sino 0 5 10 Inom lt IRMs lt Inom sino 0 5 1096 Inom s IRMs lt In
21. a neutral conductor terminals L1 N 2 phase split ohase Split phase with a neutral conductor terminals L1 L2 N 3 phase wye with N 3 phase wye with a neutral conductor terminals L1 L2 L3 N 3 phase delta Three phase delta terminals L1 L2 L3 N shorted with L3 3 phase delta Aron Three phase delta terminals L1 L2 L3 N shorted with L3 with two cur rent clamps 3 phase wye without N 3 phase wye without neutral conductor terminals L1 L2 L3 N shorted with L3 3 phase wye without N Aron 3 phase wye without neutral conductor terminals L1 L2 L3 N shorted with L3 with two current clamps 7 10 Supported current clamps Types of supported current clamps F 1 Flexible clamps Rogowski coil perimeter 120 cm measuring range 3000 A Rus F 2 Flexible clamps Rogowski coil perimeter 80 cm measuring range 3000 A nus F 3 Flexible clamps Rogowski coil perimeter 45 cm measuring range 3000 A nus C 4 CT AC clamps measuring range 1000 Arms 1 mV A G CT AC DC clamps with Hall sensor measuring range 1000 Arms 1 mV A C 6 CT AC clamps for low currents measuring range 10 Arms 1 mV 10 mA C 7 CT AC clamps measuring range 100 Anus 5 mV A 7 11 Communication Communication USB Max bitrate 921 6 kbit s Compatible with USB 2 0 7 12 Environmental conditions and other technical data Environmental conditions Operating temperature range 20 C
22. accuracy in difficult measuring environments The analog integrators must also include the systems protecting the inputs from saturation in case DC voltage is present on the input A perfect integrator has an infinite amplification for DC signals which falls with the rate of 20 dB decade of frequency The phase shift is fixed over the whole frequency range and equals 90 Theoretically infinite amplification for a DC signal if present on the integrator input causes the input saturation near the power supply voltage and makes further operation impossible In practi cally implemented systems a solution is applied which limits the amplification for DC to a specified value and in addition periodically zeroes the output There are also techniques of active cancella tion of DC voltage which involve its measurement and re applying to the input but with an opposite sign which effectively cancels such voltage There is a term leaky integrator which describes an integrator with finite DC gain An analog leaky integrator is just an integrator featuring a capacitor shunted with a high value resistor Such a system is then identical with a low pass filter of a very low pass frequency Digital integrator implementation ensures excellent long term parameters the entire procedure is performed by means of calculations and aging of components drifts etc have been eliminated However just like in the analog version also here we can find the saturatio
23. after triggering it is lit continuously e threshold triggering The user must first press GC button to enter recording stand by mode in this case pressing button does not trigger the recording process immediately the normal recording starts automatically after exceeding any threshold set in the settings LOGG flashes every 1 second in stand by mode and after triggering it is lit continuously Stopping the recording process e recording ends automatically as scheduled if the end time is set in other cases the user stops the recording using button C or the software e recording ends automatically when the memory card is full e after finishing the recording when the meter is not in the sleep mode LOGG LED turns off and the meter waits for next operator commands e ifthe meter had LEDs turned off during the recording process then after finishing the recording no LED is lit pressing any button activates ON LED 2 5 2 Inrush current measurement This function allows user to record half period values of voltage and current within 60 sec after starting the measurement After this time the measurements are automatically stopped Before the measurement set aggregation time at 72 period Other settings and measurement arrangements are not limited 2 5 3 Approximate recording times The maximum recording time depends on many factors such as the size of the memory card averaging time the type of system number of recorded parame
24. been adopted after tests carried out on a representative group of people What causes flicker Most frequently the reason is the voltage drop as a result of connecting and disconnecting large loads and some level of flicker is present in the majority of mains systems Disregarding the unfavorable effect on humans described above flicker does not need to be and usually is not a symptom of malfunctioning of our installation However if a rather abrupt and unexplainable flicker level increase is observed in the mains increase of Ps and Py this should not be ignored under any circumstances It may turn out that the flicker is caused by unsure connections in the installation increased voltage drops on connections in the distribution panel for example will result in higher voltage fluctuations on the receivers such as light bulbs The voltage drops on connections also cause their heating and finally sparking and possibly a fire Periodical mains tests and described symptoms can turn our attention and help find the source of hazard 6 4 Power measurement Power is one of the most important parameters defining the properties of electrical circuits The basic magnitude used for financial settlements between the supplier and the consumer is electric energy which is the power multiplied by time A few different power types can be found in electrical engineering e active power designated as P and measured in watts e reactive power desig
25. cross section which is available for the electrons which means that the conductor resistance is increasing Consequently the higher the current har monics the higher effective cabling resistance for this harmonics and this inevitably leads to more power losses and heating A classic example connected with this effect is related to neutral conductor in three phase sys tems In a system with little distortion little unbalance and a balanced or slightly unbalanced re ceiver the current in neutral conductor has the tendency of zeroing it is much smaller that RMS phase currents Such observation has tempted many designers to obtains savings by installing the 51 6 Power Quality a guide cabling in such systems with neutral conductor of a smaller cross section than in phase conductors And everything went well until the appearance of odd harmonic orders which are multiples of 3 third ninth etc Suddenly the neutral conductor began overheating and the measurement showed very high RMS current Explanation of this phenomenon is however rather simple In this example the designer did not take into consideration two circumstances in systems with distorted waveforms the higher harmonics might not zero in the neutral conductor and quite to the contrary they may sum up and secondly the skin effect and high harmonic currents additionally contributed to the neutral conductor heating Let us try now to answer two basic questions What is
26. field lt 40A mDC lt 3A m AC for 50 60 Hz frequency DC component of voltage and current none Waveforms sinusoidal Frequency 50 Hz 0 2 or 60 Hz 0 2 7 3 2 Voltage Voltage Ranges and conditions Resolution Basic uncertainty Urus AC DC 20 Unom lt Unus lt 120 Unom 0 01 Unom 0 5 Unom for Unom 2 100 V Crest Factor 1 10 1 1 65 for 690 V voltage 0 01 5 for Urms 2 10 Unom 7 3 3 Current Ranges and condi Current ions Irms AC DC Resolution Basic uncertainty Input path without clamps 0 1V 0 3 6Vp p 0 01 Inom 1 Inom Flexible clamps F 1 F 2 F 3 0 3000 A 0 01 Inom Additional uncertainty 10 kAp p 1 2 taking into account additional error due to the position CT clamps C 4 0 1000 A 0 01 Inom Additional uncertainty 3600 Ap p 0 1 10 A 3 0 1 A 10 A 3 50 A 1 5 200 A 0 75 1000 1200 A 0 5 CT clamps C 5 0 1000 A 0 01 Inom Additional uncertainty 3600 Ap p 0 5 100 A lt 1 5 1 A 100 800 A lt 2 5 800 1000 A AC lt 4 800 1400 A DC lt 4 CT clamps C 6 0 01 Inom Additional uncertainty 0 01 0 1 A 3 1 mA 0 1 1 A 2 5 1 12 A 196 7 Technical specifications CT clamps C 7 0 0196 Inom Additional uncertainty 0 100A 0 5 0 02A 45 65Hz 0 100A 1 0 0 04A 40 1000Hz Crest Factor 1 10 1 3 6 for Inom 5 for ous 2 1
27. g and 11 order are the opposite sequence harmonics meaning that they generate the torque which counteracts normal motor direction of rotation which can cause heating unnecessary energy losses and reduced efficiency The last group are the zero sequence components such as the 3 6 and 9 which do not generate torque but flowing through the motor winding cause additional heating Based on the data from the table it is easy to note that the series 0 is repeated for all successive harmonic orders The formula which links the sequence with order is very simple and for k being any integer Sequence Harmonic order positive 3k 1 negative 3k 1 0 zero 3k The even order harmonics do not appear when a given waveform is symmetrical in relation to its average value and this is the case in majority of power supply systems In a typical situation the measured even order harmonics have minimum values If we consider this property it turns out that the group of harmonics with the most undesirable properties is the 3 9 15 zero sequence and the 5 11 and 17 negative sequence The current harmonics which are multiples of 3 cause additional problems in some systems In 4 wire systems they have a very undesirable property of summing up in the neutral conductor It turns out that contrary to other order harmonics in which the sum of instantaneous current values is zeroed the waveforms of these harmon
28. in the power grid Later the curve was used to design equipment sensitive to voltage fluctu ations as the reference range in which the equipment must operate properly Finally the curve began to be widely used in the analyses of power supply quality in terms of disturbances such as swell dip interruptions The vertical axis of the graph presents voltage in percent of the nominal value whereas the horizontal axis presents time in logarithmic scale The middle part of the graph between curves represents the area of the correct operation of the device The area above represents high voltage conditions that may damage the device or trigger over voltage protection while the area under the curves represents a situation of low voltage in mains which may disconnect the power supply or temporary power shortage resulting in incorrect operation of the equipment 57 6 Power Quality a guide Voltage U 500 400 ANSI ITIC Hi 300 200 140 120 110 100 80 70 0 100us ims 3 10ms zs 100ms 05s 1s 10s Time Fig 21 Voltage tolerance curves ANSI ITIC and CBEMA As shown in the graph on Fig 21 there is a relationship between the voltage value and the duration of the disturbance For example voltage swell of 200 U nom and with duration of 1 ms in typical cases does not result in failure or malfunctioning point between curves but an interference of such
29. interested parties an actual view of energy transmission effectiveness Have we not mentioned before that the reactive power is only one of the nonactive power components which influence the power factor reduction Indeed it seems that instead of tang we should use the power factor PF which takes into account also other issues Unfortunately if the present regulations leave no choice than the correct reactive power meas urement seems a key matter Now a question should be asked whether the reactive energy meters ensure correct readings in the light of the controversies described above And what do such widely used meters really measure One can attempt to look for answers to these questions is the standard on such meters IEC 62053 23 Unfortunately to our disappointment we will not find there any reference to measure ments in non sinusoidal conditions the calculation formulas relate to sinusoidal conditions we can read in the standard that due to practical reasons non sinusoidal waveforms have been ex cluded The standard does not give any measurement criteria which would allow checking the me ter properties at distorted voltage and current waveforms As a surprise comes also the fact that the older standard IEC 61268 already withdrawn defined the test which involved checking the meas urement accuracy at 10 of the third current harmonic The present situation leaves the choice of measuring method to the meters designers which un
30. lanus max I Where the operator expresses the highest abso lute value of current 4 samples i 2048 for 50 Hz and 60 Hz Short term flicker calculated according to IEC 61000 4 15 Long term flicker 31 where Psri is subsequent i th indicator of short term flicker 5 Calculation formulas Active energy consumed and supplied Ep PTO i 1 _ PD dla P i gt 0 Po 0 dla P i lt 0 EE E POTO i 1 IP dla PGi lt 0 FO f 0 dla P i gt 0 where iis subsequent number of the 10 12 period measure ment window P i represents active powerP calculated in i th measur ing window T i represents duration of i th measuring window in hours Budeanu reactive energy consumed and supplied Egg 9 Qg OT Q dla Qz i gt 0 0 dla Qg i lt 0 Eos A Ge OT C i21 _ Gest dla Qs i lt 0 0 60 0 dla Qp i 0 05 0 where iis subsequent number of the 10 12 period measure ment window Qa i represents Budeanu active power QB calculated in ith measuring window T i represents duration of i th measuring window in hours Reactive energy of fun damental component consumed and supplied Fas Q4 OTO QO dla Q gt 0 0 dla Q i lt 0 Ea 9 OTO IQ G dla Q 1 lt 0 0 dla Q i gt 0 00 ao where iis subsequent number of the 10 12 period measure ment window Oil represents reactive power of fundame
31. meas uring method One can only wait impatiently for the next version of the standard which let s hope will define the measuring and testing methods much more precisely also for non sinusoidal conditions 6 4 5 Apparent power Apparent power S is expressed as the product of RMS voltage and RMS current S UI As such the apparent power does not have a physical interpretation it is used during designing of transmission equipment In terms of value it is equal to maximum active power which can be supplied to a load at given RMS voltage and current Thus the apparent power defines the maxi mum capacity of the source to supply usable energy to the receiver The measure of effective use of supplied power by the receiver is the power factor which is the ratio of active power to apparent power In sinusoidal systems peat Use E XN 7s In non sinusoidal systems such simplification is however not allowed and the power factor is calculated on the basis of actual ratio of active power and apparent power PF S In one phase systems the apparent power is calculated as shown in the formula above and there are no surprises However it turns out that in three phase systems calculation of this power is equally difficult as calculation of reactive power Of course this is related to actual systems with non sinusoidal waveforms which additionally can be unbalanced The tests have shown that the formulas used so far can give errone
32. method is used in power quality analyzers Example In order to calculate the 3 harmonic component in the 50 Hz system use the 150 Hz main spectral line and neighboring 145 Hz and 155 Hz lines The resultant amplitude is calculated with the RMS method 27 4 Design and measurement methods 47 Event detection The PQM 700 analyzer gives a lot of event detection options in the tested mains system An event is the situation when the parameter value exceeds the user defined threshold The fact of event occurrence is recorded on the memory card as an entry which includes e parameter type e channel in which the event occurred e times of event beginning and end e user defined threshold value e parameter extreme value measure during the event e parameter average value measure during the event Depending on the parameter type you can set one two or three thresholds which will be checked by the analyzer The table below lists all parameters for which the events can be detected including specification of threshold types Tab 4 Event threshold types for individual parameters Parameter Interruption Dip Swell Minimum Maximum U RMS voltage e DC voltage Frequency e Voltage crest factor D e Voltage negative sequence unbalance Short term flicker Pst e Long term flicker Pit e RMS current e e Current crest factor Current negative sequence unbalance Active power e e Q1 QB Reactive power
33. mode up to 1000 Ain continuous mode up to the 1 kHz frequency 74 75 PQM 700 Operating manual e Limitation of maximum current for continuous operation for frequencies above 1 kHz ac cording to the relationship Lan 1000 A f KHz Switching on To switch on the clamp put the switch in the 1 mV A position Green LED indicates the correct operation If after switching the LED is not lit or goes off replace the battery DC zero indication correction Make sure the jaws are closed and there is no conductor inside them Then connect the clamp to the analyzer and launch the Sonel Analysis 2 software in the instantaneous values viewing mode check if the measurement point is correctly configured for meas urement with the C 5 clamp Press the knob and turn until the DC current indication is zero Reference conditions e Temperature 18 28 C e Humidity 20 75 RH e Battery voltage 9V 0 1V e Conductor position conductor centered in jaws e Current direct DC or sinusoidal AC f lt 65 Hz e Continuous magnetic field earth field 40 A m e Alternating magnetic field none e Conductors in direct vicinity no flowing current e Technical specification e Accuracy 800 1000 A AC 800 1400 A DC Basic uncertainty lt 1 5 1A lt 2 5 lt 4 1 as of measured value Current range 0 5 100A 100 800 A e Phase error 45 65 Hz Current range 10 200A 200 1000 A Phase error
34. of positive sequence components of phase to neutral voltages UA Us Uc ope 1 43 1e 120 q a e Aa YE 1 3 2 1gj240 a e 2 a Fig 18 shows a graphical representation of determination of this component As we can see from the definition the vector of positive sequence component equals one third of the sum of the summands Ua alle a Uic Operators a and a are unit vectors with angles 120 and 240 The procedure is as follows turn the voltage vector Us by 120 counterclockwise multiply by a and add to the vector Ua Then turn the vector U c by 240 and add to the previous sum of vectors As a result you get the vector 3U The vector U is the symmetrical positive sequence component Let us note that in case of a perfect symmetry equal voltages and angles the positive sequence component is equal in terms of value to the phase to neutral voltages The positive sequence component is a measure of similarity of the tested set of three phase vectors to the symmetrical set of positive sequence vectors Analogously the negative sequence component is a measure of similarity to the symmetrical set of negative sequence vectors The zero sequence component exists in the systems in which the sum of three voltages or currents is not equal to zero A measure of the system unbalance which is widely used in the power generation is the negative sequence and zero sequence unbalance formulas are for the voltage
35. off Removing the card during the operation of the analyser may result in the loss of important data 1 General Information Mounting space for fasteners for bands for mounting the analyzer on a pole or positioning catches for mounting the analyzer on a DIN rail c v pu o o o i o OL Mounting space for DIN rail bracket y LLU Fig 2 The rear wall of PQM 700 analyzer Recorded parameters are divided into groups that may be independently turned on off for re cording purposes and this solution facilitates the rational management of the space on the memory card Parameters that are not recorded leave more memory space for further measurements PQM 700 has an internal power supply adapter operating in a wide input voltage range 90 460 V AC 127 460 V DC which is provided with independent cables terminated with ba nana plugs An important feature of the device is its ability to operate in harsh weather conditions the analyzer may be installed directly on electric poles The ingress protection class of the analyzer is IP65 and operating temperature ranges from 20 C to 55 C Uninterrupted operation of the device in case of power failure is ensured by an internal re chargeable lithium ion battery The user interface consists of five LEDs and 2 buttons The full potential of the device may be released by using dedicated PC software Sonel
36. on the type of disturbance in the system and the user s expectations for the final data analysis A frequent situation is that we know only that there is a problem in the mains and the measurements with the analyzer will only help us identify the cause In this situation it is better to use shorter averaging times e g 10 seconds and activate the recording of minimum and maximum values for the voltages and currents it is advisable in such situation to set the shortest possible time for determining the maxi mum and minimum value i e half the period Short time averaging will give more precise diagrams of changes of parameters over time and minimums and maximums will be detected and recorded Recording with short averaging times is performed mostly for limited time primarily due to rapid growth of data the air of such recording is identifying the possible cause of a problem and not a long term analysis Recording with a short averaging time may be sufficient to evaluate the performance of the mains and disturbances in it However equally detailed information can probably also be obtained with longer times in minutes but with activated recording of minimum and maximum values and event detection An important advantage in this situation is that the volume of recorded data is much smaller which means faster data retrieval and analysis 60 PQM 700 Operating manual On the other hand the power quality tests are usually made according to the
37. phenomenon known as the Hall effect and include a Hall sensor In brief the effect is the production of voltage across an electrical conductor through which the current is flowing and which is placed in a magnetic field The voltage is transverse to the field induction vector The clamps based on this phenomenon can measure the DC and AC current component The conductor with current located inside the clamps generates a magnetic field which concentrates in an iron core In the core slot where both clamp parts are joined placed is a semiconductor Hall sensor and its output voltage is amplified by an electronic circuit supplied from a battery This clamp type usually has the current zero adjustment knob To adjust the current zero close the jaws no conductor inside and turn the knob until the DC indication is zero In the area of AC DC measurement clamps Sonel S A offers the C 5 clamp with rated range of 1000 A AC 1400 A DC This clamp has a voltage output and for 1000 A rated current it gives a 1 V voltage signal 1 mV A 41 6 Power Quality a guide 6 2 3 Flexible current probes Flexible Current Probes are based on a totally differ ent physical principle than the current transformer Their principal part is a so called Rogowski coil named after German physicist Walter Rogowski It is an air core coil wound around a conductor with current Special design of the coil allows leading out its both ends on the same side thus facilita
38. re entry PIN When within 30 sec of connecting a PC to the device no data exchange occurs between the analyzer and the computer the analyzer exits data exchange mode and terminates the connection Notes e Holding down buttons E and cop for 5 seconds results in an emergency setting of PIN code 000 e If you the keys are locked during the recording process this lock has a higher priority first the user would have to unlock buttons to reset the emergency PIN This is described in chapter 2 7 USB is an interface that is continuously active and there is no way to disable it To connect the analyzer connect USB cable to your PC USB slot in the device is located on the left side and is secured with a sealing cap Before connecting the device install Sonel Analysis 2 software with the drivers on the computer Transmission speed is 921 6 kbit s 15 2 Operation of the analyzer 2 5 Taking measurements 2 5 1 Start stop of recording Recording may be triggered in three ways e immediate triggering manually by pressing GP button after configuring the meter from a PC LOGG LED is lit e Scheduled triggering according to time set in the PC The user must first press button to enter recording stand by mode in this case pressing Gy button does not trigger the recording process immediately the meter waits for the first pre set time and starts automatically LOGG LED flashes every 1 second in stand by mode and
39. unauthorised personnel may result in damage to the device and constitute a source of danger for the user e The device must not be used for networks and devices in areas with special conditions e g fire risk and explosive risk areas e Itis unacceptable to operate the device when itis damaged and completely or partially out of order its cords and cables have damaged insulation e Do not power the analyzer from sources other than those listed in this manual e If possible connect the analyzer to the de energized circuits e Opening the device socket plugs results in the loss of its tightness leading to a possible damage in adverse weather conditions It may also expose the user to the risk of electric shock e Repairs may be performed only by an authorised service point Measurement category of the whole system depends on the acces sories used Connecting analyzer with the accessories e g current clamps of a lower measurement category reduces the category of the whole system Note e Do not unscrew the nuts from the cable glands as they are perma nently fixed Unscrewing the nuts will void the guarantee e Do not handle or move the device while holding it only by its ca bles PQM 700 Operating manual 1 2 General characteristics Power Quality Analyzer PQM 700 Fig 1 is a high tech device providing its users with a com prehensive features for measuring analysing and recording parameters of 50 6
40. voltage and current harmonics for the PQM 700 analyzer without clamps and transducers Tab 6 Phase error in the PQM 700 analyzer depending on the frequency Phase difference error Frequency range 0 200 Hz 200 500 Hz 500 Hz 1 kHz 2 2 4 kHz Error 1 2 59 bo 15 The phase error caused by used transducers and clamps can be usually found in their technical documentation Such being the case we need to estimate the resultant phase error between the voltage and the current for a given frequency caused by all elements of the measuring circuit cur rent and voltage transducers clamps and the analyzer The phase uncertainty of the harmonics active power measurements can be calculated according to the following formula LrAg Bu 100 1 2 96 cosp 0 On the other hand the phase uncertainty of the harmonics reactive power measurements can be calculated according to the following formula in g A P Bun 100 1 857 96 sing 0 In both formulas p means the actual phase shift angle between the current and voltage com ponents and Ap means the total phase error for a given frequency The conclusion which can be drawn from these relationships is that power measurement uncertainty for the same phase error very clearly depends on the displacement power factor between current and voltage It is shown in Fig 24 65 7 Technical specifications Example Calculation of measurement uncertaint
41. 0 Hz power net works and power quality in accordance with the European Standard EN 50160 The analyzer is fully compliant with the requirements of IEC 61000 4 30 2009 Class S The device is equipped with four cables terminated with banana plugs marked as L1 L2 L3 N The range of voltages measured by the four measurement channels is max 1150 V This range may be extended by using external voltage transducers Buttons Serial number Ce gt Input ratings AC adapter inputs Current clamps inputs NJ L1 L2 L3 N Voltage measurement inputs L1 L2 L3 N Fig 1 Power Quality Analyser PQM 700 General view Current measurements are carried out using four current inputs installed on short cables termi nated with clamp terminals The terminals may be connected to the following clamp types flexible claps marked as F 1 F 2 F 3 with nominal rating up to 3000 A differing from others only by coil diameter and CT clamps marked as C 4 range up to 1000 A AC C 5 up to 1000 A AC DC C 6 up to 10 A AC and C 7 up to 100 A AC The values of nominal measured currents may be changed by using additional transducers for example using a transducer of 100 1 ratio the user may select C 6 clamps to measure currents up to 1000 A The device has a built in 2 GB micro SD memory card Data from the memory card may be read via USB slot or by an external reader Note SD card may be removed only when the analyzer is turned
42. 1 thy I A q 3 Ua Up Ed SE ey Uca Ve 18 where la Ib lo are RMS currents for individual phases line or phase In is the RMS current in neutral conductor Ua Ub Uc are RMS phase to neutral voltages and Ua Ubc Uca are RMS phase to phase voltages Se calculated in this manner includes both the power losses in the neutral conductor in four wire systems and the effect of unbalance 6 4 6 Distortion power Ds and effective nonfundamental apparent power Sen During the discussion on reactive power it was proved that the distortion power according to Budeanu cannot be used at large voltage and current distortions and three phase systems unbal ance a paradox of distortion power which is not a measure of actual distortion Despite this fact however this power is often used by energy quality specialists and manufacturers of systems for reactive power compensation It must be clearly said that this parameter has given relatively good results only in conditions of slight distortion of voltage and current waveforms The IEEE 1459 2000 standard lists this definition of power however just like in case of Budeanu reactive power it has a non removable defect and it is recommended to discard it entirely Instead of Dg another value has been proposed which is a much better characteristics of total distortion power in a system nonfundamental apparent power Sen The Sen power allows a quick estimation whether a load works in co
43. 6 of Unom During the voltage dip the analyzer remembers the minimum recorded voltage this is called the residual voltage Ures and is one of the parameters characterizing the dip and the average voltage value maximum swell RMS4 value Swell threshold hysteresis hysteresis hysteresis interruption threshold minimum dip and interruption value Fig 19 Voltage swells dips and interruptions Interruption is a state during which the Unus voltage is lower than the specified interruption level The interruption threshold is usually set much below the voltage dip level at about 1 10 of Unom The interruption starts at the moment when the Unus voltage decreases below the interrup tion threshold value and ends at the moment when the Urmsi1 2 voltage is equal to or greater than the interruption threshold value plus the voltage hysteresis 56 PQM 700 Operating manual During the interruption the analyzer remembers the minimum recorded voltage and the average voltage value Swell is a state of increased voltage The swell threshold is usually set at the level close to 110 of Unom PhaseA The swell starts at the mo t ment when the Urmsc1 2 voltage gt increases above the swell thresh EMS RMS RMSyp old value and ends at the mo RMS 2 D RMS4 2 ment when the Urmsi1 2 voltage is equal or less than the swell threshold value minus the voltage hysteresis During the interrup Phase B tio
44. EN 50160 In this case the analysis is carried out over a longer period of time e g 7 days and therefore the chosen averaging time is also long 10 minutes Please note that there is no single best setting for both the averaging time and other parameters or event thresholds Each mains system is different and so are the goals of the mains tests There fore the optimal configuration of the analyzer may require several approaches and will also depend on the experience of the operator 61 7 Technical specifications 7 Technical specifications e Specifications are subject to change without prior notice Recent revisions of technical documen tation are available at www sonel pl e Basic uncertainty is the uncertainty of a measurement instrument at reference conditions specified in Tab 5 e Provided uncertainties apply to PQM 700 without additional transformers and clamps e Abbreviations e m v reference measured value RMS RMS value n harmonic order current harmonics 7 1 Inputs Voltage input terminals Unom nominal voltage Lem nominal current of clamps 6p additional uncertainty of error in the measurement of the phase between voltage and Number of inputs 4 L1 L2 L3 N 3 measuring channels not galvanically isolated Maximum input voltage 760 Vrms Peak input voltage 1150V Range of measured DC voltages 1150 V Analog passband 3dB 12 kHz
45. M 700 analyzer calculates the active power directly from the integral formula using sampled voltage and current waveforms M 1 P 2 Uil i 1 where M is a number of samples in the 10 12 period measuring window 2048 for the 50 Hz and 60 Hz system U and l are successive voltage and current samples 6 4 2 Reactive power The most popular formula for reactive power is also correct only for one phase circuits with sinusoidal voltage and current waveforms Q Ulsing Interpretation of this power in such systems is as follows it is an amplitude of AC component of instantaneous power on the source terminals Existence of a non zero value of this power indi cates a bidirectional and oscillating energy flow between the source and the receiver Let us imagine a one phase system with sinusoidal voltage source which load is a RC circuit As under such conditions the elements behavior is linear the source current waveform will be sinusoidal but due to the properties of capacitor it will be shifted in relation to source voltage In such a system reactive power Q will be non zero and can be interpreted as an amplitude of energy oscillation which alternately is collected in the capacitor and returned to the source Capacitor active power equals zero However it turns out the energy oscillation seems only an effect and that it appears in particular cases of circuits with sinusoidal current and voltage waveforms and is not the cause of reacti
46. S Apparent power e e D SN Distortion power e e PF Power factor D e coso Displacement power factor e e tano tano D e Ep Ep Active energy consumed and supplied D Ea Ea Reactive energy consumed and supplied e Es Apparent energy e THDr U Voltage THDr e Voltage harmonic amplitudes Una Uno order n 2 40 THDF Current THDr Ira Current harmonic amplitudes Mpeg order n 2 40 Some parameters can take positive and negative values Examples are active power reactive power power factor and DC voltage As the event detection threshold can only be positive in order to ensure correct detection for above mentioned parameters the analyzer compares with the threshold their absolute values 28 PQM 700 Operating manual Example Event threshold for active power has been set at 10 kW If the load has a generator character the active power with correct connection of clamps will be a negative value If the measured absolute value exceeds the threshold i e 10 kW for example 11 kW an event will be recorded ex ceeding of the maximum active power Two parameter types RMS voltage and RMS current can generate events for which the user can also have the waveforms record The analyzer records the waveforms of active channels voltage and current at the event start and end In both cases six periods are recorded two be
47. The use of Hann weighting window which reduces the undesirable spectral leakage has been permitted but is limited to the situations when the PLL has lost synchronization The IEC 61000 4 7 defines also the required accuracy of the synchronization block the time 1 25 Current sensing for energy metering William Koon Analog Devices Inc 4 Design and measurement methods between the sampling pulse rising edge and M 1 th pulse where M is the number of samples in the measuring window should equal the duration of indicated number of periods in the measuring window 10 or 12 with maximum allowed error of 0 03 To explain it in simpler terms let s use the following example For nominal frequencies the measuring window duration is exactly 200ms If the first sampling pulse occurs exactly at time t 0 the first sampling pulse of the next measuring window should occur at t 200 0 06 ms 60 us is allowed deviation of the sampling edge The standard also defines the recommended minimum frequency range at which the above mentioned synchronization system accuracy should be maintained and specifies it as 5 of rated frequency that is 47 5 52 5 Hz and 57 63 Hz for 50 Hz and 60 Hz mains respectively The input voltage range for which the PLL system will work correctly is quite another matter The 61000 4 7 standard does not give here any concrete indications or requirements The PQM 700 PLL circuit needs L1 N voltage above 10 V for
48. Unbalanced Conditions For the first time Budeanu s definition of reactive power has been listed as not recommended which should not be used in new reactive power and energy me ters Many magnitudes have been also divided into the part related to the current and voltage fun damental component first harmonics and the part related to remaining higher harmonics In most cases it is recognized that the usable part of energy is transmitted by the 50 60Hz components with much smaller and often harmful participation of higher harmonics The standard also introduced a new magnitude nonactive power N which represents all non active components of power N yS P Reactive power is one of the components of nonactive power N In one phase systems with sinusoidal voltage and current waveforms N equals Q hence the nonactive power does not have any other components In three phase systems this is true only for symmetrical sinusoidal systems with a balanced purely resistive load Other nonactive power components are related to concrete physical phenomena According to the professor Czarnecki s theory which is one of the best in explaining the physical phenomena in three phase systems the power equation in such systems is as follows S P D Q D D is the scattered power which appears in the system as a result of changing load conductance with frequency Hence presence of reactive elements in the system may cause the scatter
49. actor is often underestimated though as a form of justifica tion it can be said that this theory had not been refuted for 60 years Seconaly in the 1920s there were no measuring instruments which could give insight in individual voltage and current harmonic components and it was difficult to verify new theories Thirdly distorted voltage and current wave forms i e with high harmonics contents are a result of revolution in electrical power engineering which did not start before the second part of the last century Thyristors controlled rectifiers con verters etc began to be widely used All these caused very large current distortion in the mains and consequently increased harmonic distortion Only then were the deficiencies of the Budeanu s theory felt Finally fourthly the scientific circles related to power utilities were aware of the fact that industrial plants had invested a fortune in the measuring infrastructure energy meters Each change is this respect could bring about huge financial consequences However slow changes became visible in the views of electrical engineers With time as non linear loads were more and more frequent and the waveforms more and more distorted the limita tions of used formulas could no longer be tolerated A very significant event was the 2000 publication by IEEE of the standard 1459 called Defini tions for the Measurement of Electric Power Quantities Under Sinusoidal Non Sinusoidal Bal anced or
50. age output a shunt resistor is located in the clamps Such current transformer has a few characteristic proper ties It can be used to measure very large currents and its power consumption is low The magnetizing current causes some phase shift tenth of a degree which can result in some power measure Fig 16 Current ment error particularly when the power factor is low Another dis transformer clamp with advantage of this clamp type is also the core saturation phenom voltage output enon when very large currents are measured above the rated range Core saturation as a result of magnetizing hysteresis leads to significant measurement errors which can be eliminated only by the core demagnetization The core becomes saturated also when the measured current has a significant DC component An undeniable disadvantage of such clamp is also its considerable weight Despite such drawbacks the CT clamps are presently the most widely used non invasive alter nating current AC measurement method The following CT clamps can be used with the PQM 700 analyzers to measure alternating cur rents e 0 4 rated range 1000 A AC e C 6 rated range 10 A AC e C 7 rated range 100 A AC 6 2 2 AC DC measurement clamps There are situations when it is necessary to measure the current DC component In such case the clamps must be based on different principle of operation than a traditional current transformer The clamps in this case use the physical
51. amplitude which lasts for half period of the mains may be have very adverse effects the point above two curves Generally it is accepted that in a typical situation events occurring in the power grid when it comes to the value of the mains voltage should fit in the middle area of the graph between curves and then they should not lead to malfunction or damage to the connected equip ment Equipment manufacturers especially power adaptors often use this pattern while designing their products in order to ensure their reliable operation and maintaining proper output voltage Note however that the curve represents typical cases and cannot be a guarantee of correct oper ation for each device as tolerance for interferences is very different ITIC curve is the successor of the CBEMA curve developed by ITI in 1994 and later modified to its present form in 2000 This curve has the form of two broken lines and is also known as ANSI curve as it was adapted by ANSI American National Standards Institute Both curves are pre sented in Fig 21 Sonel Analysis software provides the ability to modify the characteristic points of the curves allowing user to adjust them to individual requirements 58 PQM 700 Operating manual 6 9 Averaging the measurement results Mains monitoring over a longer period of time means that a huge amount of data needs to be collected If analysis of such data is to be possible at all it is necessary to introduce the
52. ange of configurations including a multitude of measured parameters make PQM 700 analyzer an extremely useful and powerful tool for measuring and analysing all kinds of power supply systems and interferences occurring in them Some of the unique features of this device make it distinguishable from other similar analyzers available in the market Tab 1 presents a summary of parameters measured by PQM 700 depending on the mains type 11 1 General Information Tab 1 Measured parameters for different network configurations 3 phase triangle Network type 3 phase wye with channel Parameter out N aramete L31 TOT RMS voltage Voltage DC component RMS current Current DC component Frequency Voltage crest factor Current crest factor Active power Reactive power Distortion power Apparent power Power Factor Displacement power factor tgo tangent Factor Voltage Total harmonic JEM distortion Current Total harmonic ui distortion Active energy con Eee ER sumed and supplied Eat Ear Reactive energy con EaB EaB sumed and supplied Es Apparent energy Voltage harmonic am Uu Unio plitudes Current harmonic am plitudes is Symmetrical compo U I nents and unbalance EMO Ub factors Pst Pit Flicker factors coso Ju Jan Explanations L1 L2 L3 L12 L23 L31 indicate subsequent phases N is a
53. asuring window for 50 Hz and 60 Hz this fulfills the requirement of Fast Fourier Transform that the number of samples subjected to trans formation equals a power of 2 A very important thing is to maintain a constant synchronization of sampling with the mains FFT can be performed only on the data which include a multiple of the mains period This condition must be met in order to minimize a so called spectral leakage which leads to falsified information about actual spectral lines levels The PQM 700 meets these requirements because the sampling frequency is stabilized by the phase locked loop PLL Because the sampling frequency can fluctuate over time the standard provides for grouping together with the harmonics main spectral lines also of the spectral lines in their direct vicinity The reason is that the components energy can pass partially to neighboring interharmonic components There are two grouping methods e harmonic group includes the main spectral line and five or six neighboring internarmonic com ponents on each side e harmonic subgroup includes the main spectral line and one neighboring line on each side 26 harmonic subgroup order 1 0 50 0 1 harmonic subgroup order 2 100 2 PQM 700 Operating manual harmonic subgroup order 3 FFT output 150 frequency Hz 3 harmonic order Fig 15 Determination of harmonic subgroups 50 Hz system The IEC 61000 4 30 standard recommends that the harmonic subgroup
54. ated on the closing unit indicates the current flow direction It is assumed that the current is flowing in the positive direction if it is flowing from the source to the receiver Such clamp orientation is required for a correct power measurement Warning Do not use the device on non insulated conductors with a poten tial of more than 1000 V in relation to the earth and a measure ment category greater than III e Reference conditions e Temperature 18 22 C e Conductor position centered in relation to the clamp loop e Continuous magnetic field earth field lt 40 A m e Alternating magnetic field none e External electric field none Technical specification e Rated measuring range 1 A 3000 A 10000A peak for 50 Hz e Input output ratio 38 83 mV 1000 A 50 Hz 46 6 mV 1000 A 60 Hz e Basic uncertainty 1 in the 1 A 3000 A range e Linearity 0 2 e Additional error caused by conductor position 2 max e Additional error caused by external magnetic field 0 5 max e Additional error caused by temperature 0 07 e Output impedance 30 0 400 mm 79 8 Equipment e Remaining data insulation type measuring category acc to IEC 61010 1 protection rating acc to IEC 60529 coil diameter closing unit diameter maximum coil circumference internal coil diameter closed clamp weight clamp lead length operating temperature electromagnetic compatibility double accordin
55. ber of the 10 12 period measure ment window Stot i represents total apparent power Stor calculated in i th measuring window T i represents duration of i th measuring window in hours 34 PQM 700 Operating manual 5 3 3 phase wye network with N conductor 3 phase wye network with N conductor parameters not mentioned are calculated as for single phase Parameter Name Designa tion Method of calculation Total active power Prot Prot Pa Pg Pc Total Budeanu reactive power QBiot QBtot QBa Qeg QBc Total reactive power acc to IEEE 1459 Qi 20 H singt where U1 is the voltage positive sequence component of the fundamental component I11 his the current positive sequence component of the fundamental component git is the angle between components U and h Effective apparent power S 3Uele where 2 3 U4 Ug Uc Han Upc Uca de 18 I4 Ig Ic ly le S Effective apparent distor tion power Sen 4 S Ser where Se1 3Ue1le1 2 3 Um Ug Uc User Ugci Uca Ue1 18 Iga Igi le Iva lei 3 Total Budeanu distortion power DBtot Dgtot Dga Des Dac Total Power Factor PF tot Total displacement power factor COS Quot DPFeot 1 COS Prot DPFrot 3 008 Pa Loose COSPc Total tangent p tangrot Qtot tanProt 5
56. catches in addition to fasteners for mounting the analyzer on a pole which should be installed to increase the stability of the mounting assembly These catches have special hooks that are supported on the DIN rail SS X LFS TEJ Fig 4 The rear wall of the analyzer with fixtures for mounting on DIN rail 10 PQM 700 Operating manual 1 6 Measured parameters PQM 700 analyzer is designed to measure and record the following parameters e RMS phase and phase to phase voltages up to 760 V peak voltages up to 1150 V e RMS currents up to 3000 A peak currents up to 10 kA using flexible clamps F 1 F 2 F 3 up to 1000 A peak values up to 3600 A using CT clamps C 4 or C 5 up to 10 A peak values up to 36 A using C 6 clamps or up to 100 A peak values up to 360 A using C 7 clamps crest factors for current and voltage mains frequency within the range of 40 70Hz active reactive and apparent power and energy distortion power harmonics of voltages and currents up to 40th Total Harmonic Distortion THDr and THDa for current and voltage power factor cosq tang unbalance factors for three phase mains and symmetrical components flicker Ps and Pr inrush current for up to 60 s Some of the parameters are aggregated averaged according to the time selected by the user a
57. ctive nonfundamental apparent power Sen 50 6 4 7 lo gend 6 5 Into e 6 5 1 Harmonics characteristics in three phase system 6 6 UnDalance ib rb a a esr eH rs epi Me E eager 6 7 Detection of voltage dip swell and interruption 6 8 CBEMA and ANSI cumves senten nnne nn nennt 6 9 Averaging the measurement results eene 7 7 1 7 2 7 3 Measured parameters accuracy resolution and rangesS 63 7 3 1 Reference conditions 7 3 2 Voltage 7 3 8 EDITI RETE 7 3 4 Frequency iot i haie twoi nia uen 64 7 3 5 Harmonie eech Hi see tdt dete La y NE ED PI e Dey tabled ins 64 7 3 6 Power and energy tiina kaiia 64 7 3 7 Estimating the uncertainty of power and energy measurements 7 3 8 STEE ce en O ences du s Ee cu Edict etd 7 3 9 Bere 7 4 Event detection voltage and current RMS 7 5 Event detection other parameters 7 5 1 Event detection hysteresis 7 6 Inrush current measurement 7 7 Recording eee 7 8 Power supply and heater 7 9 Supported networks 7 10 Supported current clamps sss eene nnne nnne nnns T Communication nb nieder ert e Geer 7 12 Environmental conditions and other technical data 70 7 13 Safety and electromagnetic compatibility
58. d that the current is flowing in the positive direction if it is flowing from the source to the receiver Such clamp orientation is required for a correct power measurement measuring category acc to IEC 61010 1 maximum measured conductor diameter 10 mA A caused by the 400 A m 50 Hz external magnetic field on the centered conductor 1 3A gt 65 dB A V 50 400 Hz double according to IEC 61010 1 IIl 600 V IP 30 9 V battery 6LR61 6LF22 NEDA 1604 about 120 h 237 x 97 x 44 mm about 520 g 239 mm 1 5m 10 C 55 C lt 85 RH lt 2000 m IEC 61000 6 3 2008 IEC 61000 6 2 2008 Fig 27 C 6 clamp Warning Do not use the device on non insulated conductors with a potential of more than 600 V in relation to the earth and a measurement category greater than III 76 77 Reference conditions e Temperature e Relative humidity e Conductor position e Sinusoidal current frequency e Harmonics content e Current DC component e Continuous magnetic field e Alternating magnetic field e Conductors in direct vicinity Technical specification PQM 700 Operating manual 20 26 C 20 75 conductor centered in jaws 48 65 Hz lt 1 none earth field lt 40 A m none no flowing current e Accuracy Current range 6 odd Phase error 0 01 0 1 A lt 3 1 mA not specified 0 1 1A lt 2 5 5 1 12A lt 1 3 1 as of measured value
59. e an integrating circuit generally the flexible probes comprise a Rogowski coil and an analog integrator circuit characteristic battery powered module On the integrator output available is the voltage signal proportional to measured current and suitably scaled for example 1 mV A Another problem connected with the Rogowski coil is its sensitivity to external magnetic fields A perfect coil should be sensitive only to the fields closed within its area and should totally suppress external magnetic fields But this is a very difficult task The only way to obtain such properties is very precise manufacture of the coil with perfectly homogenous windings and impedance as low as possible It is the high precision which causes a relatively high price of such probe The PQM 700 analyzer can be used with the following flexible probes from Sonel S A e F 1 with coil circumference 120 cm e F 2 with coil circumference 80 cm e F 3 with coil circumference 45 cm All these probes have identical electrical parameters The peak current which can be measured after connecting to PQM 700 is about 10 kA the limitation is due to the properties of the input channels and not the probe itself 6 3 Flicker In terms of power quality flicker means a periodical changes of the luminous intensity as a result of fluctuations of voltage supplied to light bulbs The flicker measurement function appeared in the power quality analyzers when it turned out tha
60. e calculated as in 3 phase 4 wire systems Parameter Name Designa tion Unit Method of calculation Phase to phase voltage Uca Uca V Uca Uag Unc Current l2 Aron measuring circuits le A b h 13 Total active power 37 1 M M Prot ER Uiacli gt Vacha i i i 1 where Uiac is a subsequent sample of voltage Ua c Uigc is a subsequent sample of voltage Us c la is a subsequent sample of current la lg is a subsequent sample of current je M 2048 for 50Hz and 60Hz 5 Calculation formulas Total apparent power Se 3l T where Uag Ugc Uca Ue 9 I Ig IG ez 3 Total reactive power Bu deanu and IEEE 1459 Q N 53 P Total Budeanu distortion power Dgtot 0 Effective apparent distor tion power Sen S Ser where Ser 3Ue1le1 Uag Usci Ucar Ver 9 dla In lea a 0 Total Power Factor Prot PFtot S e Active energy consumed and supplied m Ep tot gt Paoc OT i 1 Pas pu dla Pg gt 0 Stop 0 dla Bal lt 0 m Ep_tot gt Pto OT i 1 Pas PES dla Ball lt 0 Eon 0 dla Bal gt 0 where iis subsequent number of the 10 12 period measure ment window Pall represents total active power Piot calculated in i th measuring window T i represents duration of i th measuring window in hours Total apparent en
61. ear receiver such as widely used switched mode power supplies i e for computers receives power from a perfect generator of si nusoidal voltage For the time being let us assume that the impedance of connections between the generator and the receiver is zero The voltage measured on the receiver terminals will have sinus oidal waveform absence of higher harmonics this is imply the generator voltage The receiver current waveform will however include harmonic components a non linear receiver often takes current only in specified moments of the total sinusoid period for example maximum current can take place at the voltage sinusoid peaks However the receiver does not generate these current harmonics it simply takes current in a variable or discontinuous way The whole energy is supplied only by the generator In the next step we can modify the circuit by introducing some impedance between the gener ator and the receiver Such impedance represents the resistance of cabling transformer winding etc Measurements of voltage and current harmonics will give slightly different results What will change Small voltage harmonics will appear and in addition current frequency spectrum will slightly change When analyzing the voltage waveform on the receiver one could notice that original sinusoidal waveform was slightly distorted If the receiver took current mainly at voltage peaks it would have visibly flattened tops Large current take
62. eceivers are described with many various magnitudes and indicators This section can shed some light on this area As already mentioned the lack of standardization of measurement methods has caused signif icant differences in values of individual mains parameters calculated with various devices Efforts of many engineers resulted in IEC 61000 4 30 standard concerning power quality For the first time this standard and related standards provided very precise methods mathematical relations and required measurement accuracy for power quality analyzers Compliance with the standard in par ticular the class A should be a guarantee of repeatable and almost identical measurement results of the same magnitudes measured with devices from different manufacturers 40 PQM 700 Operating manual 6 2 Current measurement 6 2 1 Current transformer clamps CT for AC measurements CT Current Transformer Clamp is just a transformer converting a large current in primary wind ing to a smaller current in secondary winding The jaws of typical current clamp are made of a ferromagnetic material such as iron with the secondary winding wound around The primary wind ing is a conductor around which the clamp jaws are closed hence Le Le most often it is one single coil If the 1000 ampere current flows through the tested conductor in the secondary winding with 1000 coils the current will be only 1 A if the circuit is closed In case of clamps with volt
63. ed power In this equation reactive power Q appears when there is a phase shift between the voltage and current harmonics D means the unbalanced power which is a measure of unbalance of a three phase receiver 46 PQM 700 Operating manual This component explains the situation in which an unbalanced three phase load of a purely resistive character results in the power factor less than one Such load does not have the reactive power Q and still the results from the power triangle S P Qare totally different the Budeanu s power theory with its distortion power could not explain this situation either in a purely resistive load the distor tion power Dg equals zero An attempt to connect the IEEE 1459 2000 standard with the Czarnecki s power theory leads to the conclusion that nonactive power conceals at least three separate physical phenomena which influence the reduced effectiveness of energy transmission from the source to the receiver i e reduction of the power factor P P Se P2 D 2 Q2 D In the IEEE 1459 2000 standard reactive power known as Q has been limited to the fundamen tal component for both one phase and three phase systems Q Uil sing In three phase systems only the positive sequence component is taken into consideration Qi 3UTH singy Correct measurement of this power requires the same phase rotation sequence i e phase L2 delayed by 120 in relation to L1 phase L3 delayed by 240 in relation
64. ed with real time clock in the following manner When the clock measures a successive full multiple of the averaging period the instantaneous 10 12 period measurement is added as the last to the average value k th measurement in Fig 22 Simultane ously the ending averaging period is given a time stamp which relates to its end The next 10 12 period measurement is the first in a consecutive averaging period Averaging with times less than 10 seconds is somewhat different Although they are all ex pressed in time units 200 ms 1 s 3 s 5 s in reality they are measured in multiples of the mains period For example selecting of a 3 second averaging period means averaging in the time equal to 150 180 mains periods fifteen 10 12 period measurements 59 6 Power Quality a guide 3 second interval x timestamp 3 second interval x 3 second interval x 1 actually it is a 150 180 cycles interval Fig 23 Determining the averaging intervals shorter than 10 seconds with the 3 second averaging The method of average values determination for such periods is shown in Fig 23 Here we do not have synchronization with the real time clock When a defined number of 10 12 period meas urement is collected the instantaneous averaging period is closed and a new one starts The time stamp corresponds to the end of the interval Averaging of measurement results leads to the loss of extreme values smoothing of results In cases
65. ent and provider of service during and past the warranty period SONEL S A ul Wokulskiego 11 58 100 widnica Poland tel 48 74 858 38 60 fax 48 74 858 38 09 E mail export sonel pl Web page www sonel pl Note Service repairs must be performed solely by the manufacturer 81 Notes 82
66. er definition issues in order It was even more necessary as the voices had been ap pearing in scientific circles for many years that the power definitions used so far may give erroneous results Most of all the controversies related to the definition of reactive and apparent power and also distortion power see below in one and three phase systems with non sinusoidal current and voltage waveforms In 1987 professor L S Czarnecki proved that the widely used definition of reactive power by Budeanu was wrong This definition is still taught in some technical schools and it was proposed by professor Budeanu in 1927 The formula is as follows QB gt Unln sin Pn n 0 where U and are voltage and current harmonics of order n and o are angles between these components As after this magnitude has been introduced the known power triangle equation was not met for circuits with non sinusoidal waveforms Budeanu introduced a new magnitude called the distor tion power Dp S P Q5 Distortion power was to represent in the system the power appearing due to distorted voltage and current waveforms For years reactive power had been associated with energy oscillations between the source and the load The formula indicates that according to Budeanu s definition the reactive power is a sum of reactive power of individual harmonics Due to the sing factor such components can be positive or negative depending on the angle betwee
67. ergy Estot A SOTO i 1 where iis subsequent number of the 10 12 period measurement window Se i represents the total apparent power Se calculated in i th measuring window T i represents duration of i th measuring window in hours 38 PQM 700 Operating manual 5 5 Methods of parameter s averaging Method of averaging parameter Parameter Averaging method RMS Voltage RMS DC voltage arithmetic average Frequency arithmetic average Crest factor U I arithmetic average Symmetrical components U I RMS Unbalance factor U calculated from average values of symmetrical components RMS Current RMS Active Reactive Apparent and Distortion Power arithmetic average Power factor PF calculated from the averaged power values cose arithmetic average tano calculated from the averaged power values THD U I calculated as the ratio of the average RMS value of the higher harmonics to the average RMS value of the fundamental component for THD F or the ratio of the average of RMS value of higher harmonics to the average value of RMS value for THD R Harmonic amplitudes U RMS The angles between voltage and current harmonics arithmetic average Active and reactive power of harmonics Note arithmetic average RMS average value is calculated according to the formula RMS 1 N GERS bx
68. ess nel OPERATING MANUAL POWER QUALITY ANALYZER PQM 700 CE SONEL SA ul Wokulskiego 11 58 100 widnica Poland Version 1 2 03 02 2015 GG IRELE ULLE 296 CONTENTS 1 General Information 112 2 2 meresenzzzawezaanenanaweza zwan nina aaa anna own za anna aa az AAAA 6 1 1 Ir mL 6 1 2 General characteristics o te edd eei AAA sd 7 1 3 Power supply of the analkzer sessi 8 1 4 Tightness and outdoor operation seen 9 1 5 Mounting on DIN rail irte teretes 10 1 6 Measured parameters 5 cete a e re reet 11 1 7 Compliance with standards sessi 12 2 Operation of the analyzer eeesessie sienne enean na natnra natn nana an Seen 14 2 1 Isl nop p 14 2 2 Switching the analyzer ON OFF sessi nnne nns 14 2 3 P roo zza poi PO ad A OAZA A KI A dlo 15 2 4 PC connection and data transmission esses 15 2 5 Taking measurements eie iiem nne t nnne nn 16 2 5 1 Start stop of recording w ehe een e HER ERU iet 16 2 5 2 Inrush current measurement sessi seien nnne nnns nnne nnns nnne 16 2 5 8 Approximate recording times eeeeeaeae aaa eee eene nnne nnne nnne nnn 16 2 6 Measuring arta nmdements eau ea aa eee nnne nnne nnne nnne 17 2 7 A Bor MER 23 2 8 Sleep MOJE ui n A Re b e RD e pave R
69. fore the start end of the event and four after start end of the event The waveforms are recorded in an 8 bit format with 10 24 kHz sampling frequency The event information is recorded at its end In some cases it may happen that event is active when the recording is stopped i e the voltage dip continues Information about such event is also recorded but with the following changes no event end time extreme value is only for the period until the stop of recording average value is not given only the beginning waveform is available for RMS voltage or current related events In order to eliminate repeated event detection when the parameter value oscillates around the threshold value the analyzer has a functionality of user defined event detection hysteresis It is defined in percent in the following manner 29 for RMS voltage events it is the percent of the nominal voltage range for example 296 of 230 V that is 4 6 V for RMS current events it is the percent of the nominal current range for example for C 4 clamps and absence of transducers the 296 hysteresis equals 0 02x1000 A 20 A for remaining parameters the hysteresis is specified as a percent of maximum threshold for example if the maximum threshold for current crest factor has been set to 4 0 the hysteresis will be 0 02x4 0 0 08 5 Calculation formulas 5 Calculation formulas 5 1 One phase network One phase network Parameter Designa
70. fortunately leads to significant differences in reactive energy indications in the presence of high harmonic distortion level Older electromechanical meters have characteristics similar to that of a low pass filter higher harmonics are attenuated in such meters and the reactive power measurement in the presence of harmonics is very close to the value of reactive power of the fundamental component Electronic meters which are more and more popular can perform the measurement with various methods For example they can measure active and apparent power and then calculate the reac tive power from the power triangle square root from the sum of both such powers squared In reality in the view of the IEEE 1459 2000 standard they measure the nonactive power not the reactive power Another manufacturer may use the method with voltage waveform shift by 90 which gives a result close to the reactive power of the fundamental component 48 PQM 700 Operating manual The higher the harmonics content the higher difference in readings and of course as a con sequence other fees for measured energy As it has been signaled before the reactive power measurement in unbalanced three wire sys tems with traditional meters is subject to an additional error caused by creation of a virtual zero inside the meter which has little to do with actual zero of the receiver On top of that the manufacturers usually do not give any information about the applied
71. g to IEC 61010 1 III 1000 V IP 65 15 5 mm 30 mm F 1 120 cm F 2 80 cm F 3 45 cm F 1 360 mm F 2 235 mm F 3 120 mm F 1 about 410 g F 2 about 310 g F 3 about 220 g 2m 20 C 80 C IEC 61000 6 3 2008 IEC 61000 6 2 2008 80 PQM 700 Operating manual 9 Other information 9 1 Cleaning and maintenance Note Use only the maintenance methods presented by the manufacturer in this manual Clean the analyzer casing with a wet cloth using generally available detergents Do not use any solvents and cleaning media which could scratch the casing powder paste etc Clean the leads can with water and detergents then wipe dry The analyzer electronic system is maintenance free 9 2 Storage When storing the device observe the following recommendations e disconnect all leads from the analyzer e thoroughly clean the analyzer and all accessories e recharge the battery from time to time to prevent total discharging 9 3 Dismantling and disposal Used electric and electronic equipment should be collected selectively i e not placed with other types of waste Used electronic equipment shall be sent to the collection point according to the Used Electric and Electronic Equipment Act Before sending the instrument to the collection point do not dismantle any parts by yourself Observe local regulations on disposal of packages and used batteries 9 4 Manufacturer The manufacturer of the equipm
72. ge Such a solution however has an undesirable side effect Smoothing capacitors are recharged by short current pulses at moments when the mains voltage is close to peak value From power balance rule it is known that if the current is taken only at short intervals its crest value must be much higher than in case it is taken in a continuous manner High ratio of current crest value to RMS value a so called crest factor and reduction of power factor PF will result in a situation in which in order to obtain a given active power in a receiver in watts the power supplier must supply power greater than the receiver active power this is a so called apparent power expressed in volt amperes VA Low power factor causes higher load on the transmission cables and higher costs of electricity transfer Harmonic current components accompanying such parameters cause additional problems As a result the electricity suppliers have started to impose financial penalties upon the customers who have not provided sufficiently high power factor Among entities that may be potentially interested in power quality analyzers are power utility companies on one hand they may use them to control their customers and on the other hand the power consumers who may use the analyzers to detect and possibly improve the low power factor and solve other problems related to widely understood power quality issues The power source quality parameters as well as the properties of r
73. ge fundamental component Then the signal is sent to the phase locked loop circuits as a reference signal The PLL system generates the frequency which is a multiple of the reference frequency necessary for clocking of the analog to digital converter The necessity to use the phase locked loop system results directly from the requirements of the IEC 61000 4 7 standard which describes the methodology and admissible errors during the meas urements of harmonic components The standard requires that the measuring window being the basis for a single measurement and evaluation of harmonics content is equal to the duration of 10 periods in the 50 Hz mains systems and 12 periods in the 60 Hz systems In both cases it corre sponds to about 200 ms Because the mains frequency can be subject to periodical changes and fluctuations the window duration might not equal exactly 200 ms and for the 51 Hz frequency will be about 196 ms The standard also recommends that before the Fourier transform to separate the spectral com ponents the data are not subject to windowing operation Absence of frequency synchronization and allowing the situation in which the FFT is performed on the samples from not the integer number of periods can lead to spectral leakage This phenomenon causes that the spectral line of a har monic blurs also to a few neighboring interharmonic spectral lines which may lead to loss of data about actual level and power of the tested spectral line
74. ges We need to take account of the fact that at given voltage values at terminals and currents flowing into such black box there is an infinite number of variants of receiver internal structure which will give us identical measurement results of voltage and current values visible outside the black box Then how is it possible that there are reactive power meters intended for measurements in three wire systems and the mains analyzers which allow the reactive power measurement under such circumstances In both cases the manufacturers use the trick which involves an artificial creation of a reference point virtual neutral terminal N Such point can be created very easily by connecting to the termi nals of our black box a wye connected system of three resistors of the same value In no case should a measuring instrument mislead the user and such approximation can be 47 6 Power Quality a guide allowed only after a clear reservation that the indicated value is not a result of actual measurement but only an approximated value 6 4 4 Reactive power and reactive energy meters Reactive energy meters are devices unknown to the household users who for settlements with energy suppliers use the meters of active energy expressed in Wh or kWh Household users are in a comfortable situation they pay only for usable energy and do not have to think what the power factor is in their installations In contrast to the first group the industria
75. h the resulting gaps J J NN NN L 4 Ke Li u GU Fig 3 Fasteners for bands for mounting the analyzer on a pole The ingress protection class of the analyzer is IP65 and operating temperature ranges from 20 C to 55 C Note A In order to ensure the declared ingress protection class IP65 the fol lowing rules must be observed e Tightly insert the stoppers in the slots of USB and micro SD card e Unused clamp terminals must be sealed with silicone stoppers At ambient temperatures below 0 C or when the internal temperature drops below this point the internal heater of the device is switched on its task is to keep the internal temperature above zero when ambient temperatures range from 20 C to 0 C 9 1 General Information The heater is powered from AC DC adapter and its power is limited to approx 10 W Due to the characteristics of the built in lithium ion rechargeable battery the process of charging is blocked when the battery temperature is outside the range of 0 C 60 C in such case Sonel Analysis software indicates charging status as charging suspended 1 5 Mounting on DIN rail The device is supplied with a bracket for mounting the analyzer on a standard DIN rail The bracket must be fixed to the back of the analyzer with the provided screws The set includes also positioning
76. ics are in phase with each other which causes adding of the phase currents in the neutral conductor This can lead to overheating of such conductor partic ularly in the distribution systems in which this conductor has a smaller cross section than the phase conductors and this was widely practiced until recently Therefore in systems with non linear loads and large current distortions it is now recommended that the cross section of neutral conductor is larger than that of the phased conductors In the delta systems the harmonics of these orders are not present in the line currents provided these are balanced systems but they circulate in the load branches also causing unnecessary power losses Character of individual harmonics as shown in the table is fully accurate only in three phase balanced systems Only in such systems the fundamental component has the exclusively positive sequence character In actual systems with some degree of supply voltage unbalance and the load 53 6 Power Quality a guide unbalance there are non zero positive and negative sequence components The measure of such unbalance is so called unbalance factors And this is due to this unbalance of the fundamental component and additionally the differences in amplitudes and phases of the higher harmonics that also these harmonics will have the positive negative and zero sequence components The larger the unbalance the higher the content of remaining components 6
77. in 23 3 Sonel Analysis 2 softWare eese eese eee n nett rani nn nani nn nn 23 4 Design and measurement methods cerei nen 24 4 1 Ve Ee GEET 24 4 2 Eeler 24 4 2 1 Digital Isole gm 24 4 3 Signal sampling ii ci aia o Diei A ded eror 4 4 PLL synchronization 4 5 Frequency measurement 4 6 Harmonic components measuring method 26 4 7 Event detection ied onn ee Ee e 28 5 Calculation formulas essei ei essen neni tn nana nana nn nana anna nana nana nana 30 5 1 One phase network AAA 30 5 2 Split phase netWork ic ra t ee Re E E it 33 5 3 3 phase wye network with N conductor een 35 5 4 3 phase wye and delta network without neutral conductor 37 5 5 Methods of parameter s averaging sss 39 6 Power Quality a guide eei eeee seii ei senten inna nn nan 40 6 1 Basic Information toii ata e ete signe te avene dap inue 40 6 2 Current meagsurerment isses innen aaa aaa n tnnt nnnnn 41 6 2 1 Current transformer clamps CT for AC measurements sss 41 6 2 2 AC DC measurement clampe esses eene 41 6 2 3 Flexible current probes 6 3 FUCK E i A ee be 6 4 Power measurement 6 4 1 Tee 6 4 2 REACIVE e TEE 6 4 3 Reactive power and three wire systems 6 4 4 Reactive power and reactive energy meters 6 4 5 Palo oigo 6 4 6 Distortion power Dg and effe
78. ith the frequency of power supply voltage in the reference channel This frequency equals 10 24 kHz for the 50 Hz and 60 Hz mains systems Each period includes then about 205 samples for 50 Hz systems and about 170 samples for 60 Hz systems A 16 bit analog to digital converter has been used which ensures 64 fold over sampling 3 decibel channels attenuation has been specified for frequency of about 12 kHz and the am plitude error for the 2 4 kHz maximum usable frequency i e the frequency of 40th harmonics in the 60 Hz system is about 0 3 dB The phase shift for this frequency is below 15 Attenuation in the stop band is above 75 dB Please note that for correct measurements of phase shift between the voltage harmonics in relation to current harmonics and power of these harmonics the important factor is not absolute phase shift in relation to the basic frequency but the phase coincidence of voltage and current circuits The highest phase difference error for f 2 4 kHz is maximum 15 Such error is decreasing with the decreasing frequency Also an additional error caused by used clamps are transducers must be considered when estimating the measurement errors for harmonics power measurements 44 PLL synchronization The sampling frequency synchronization has been implemented by hardware After passing through the input circuits the voltage signal is sent to a band pass filter which is to reduce the harmonics level and pass only the volta
79. l component of the measured se quence must be at least equal to 5 of the nominal voltage or 1 of the nominal current If this condition is not fulfilled the correctness of angles is not verified e When the meter is switched on and detects full memory MEM LED is lit measurements are blocked only read out mode for current data remains active e When the meter is switched on and fails to detect the micro SD card or detects its damage ERROR and MEM LEDs are lit and measurements are blocked Note The ERROR and MEM LEDs behaves the same way when a new microSD card has been inserted to the analyzer s slot To format the card to be usable with PQM 700 analyzer the START STOP button must be pressed Ana lyzer will then confirm start of formatting process with 3 beeps All the data on the card will be erased If the formatting finishes successfully the ERROR and MEM LEDs will switch off and the analyzer will be ready for further operation e f the connection test was successful after pressing aD the meter enters the recording mode as programmed in the PC e To switch the analyzer OFF keep button pressed for 2 seconds when no button or recording lock are active 14 PQM 700 Operating manual 23 Auto off When the analyzer operates for at least 30 minutes powered by the battery no power supply from mains and it is not in the recording mode and PC connection is inactive the device automat ical
80. l consumers are obliged in their contracts and some times under pain of financial penalties to keep the power factor at an appropriate level The EN 50160 standard gives some guidelines for the power quality requirements and defines the quality parameters which should be met by energy supplier Among these parameters are among others mains frequency RMS voltage total harmonic distortion THD and allowed levels of individual voltage harmonics Besides EN 50160 requirements there is often an additional condi tion the supplier does not need to comply with those requirements if an energy consumer does not ensure the tang factor below some threshold agreed value which can be changed in the contract between the energy supplier and consumer i e 0 4 and or exceeds the agreed level of consumed active energy The tang is defined as a ratio of measured reactive energy to the active energy in a settlement period Going back for a while to the power triangle in sinusoidal systems we can see that the tangent of the phase shift angle between the voltage and the current is equal to the ratio of reactive power Q to active power P Consequently the requirement to maintain the tang below 0 4 means nothing else but only that maximum level of measured reactive energy may not exceed 0 4 of the measured active energy Each consumption of reactive energy above this level is subject to addi tional fees Does the knowledge of tang calculated in this manner give both
81. lance In three phase systems the voltage current unbalance occurs when values of three compo nent voltages currents are different and or the angles between individual phases are not equal to 120 The receiver unbalance occurs when impedance values of individual receiver branches are not equal These phenomena are particularly dangerous for three phase motors in which even a slight voltage unbalance can cause current unbalance that is many times larger In such situation the motor torque is reduced heat losses in windings increase and mechanical wear is faster The un balance also has an unfavorable effect on power supply transformers The most frequent reason of unbalance is uneven load on individual phases A good example is connecting to three phase systems of large one phase loads such as railway traction motors The PQM 700 is capable of measuring the voltage and current unbalance with a symmetrical components method This method is based on the assumption that each set of three unbalanced 54 PQM 700 Operating manual vectors can be resolved to three groups of vectors positive sequence negative sequence and zero sequence Uj ale Se 3U Un Uis Fig 18 Example of determination of positive sequence component As an example let us use the calculation of voltage positive sequence component 1 Ut 3 Wa aU a Us where U is the vector of positive sequence component Uia De Uic are vectors
82. ly turns off to prevent discharging the battery The analyzer turns off automatically also when the battery is fully discharged Such an emer gency stop is preceded by activating BATT LED for 5s and it is performed regardless of the current mode of the analyzer In case of active recording it will be interrupted When the power supply returns the recording process is resumed 24 PC connection and data transmission When the meter is switched on its USB port remains active In the read out mode for current data PC software refreshes data with a frequency higher than once every 1 second During the recording process the meter may transmit data already saved in memory Data may be read until the data transmission starts During the recording process the user may view mains parameters in PC instantaneous values of current voltage all power values total values for three phases harmonics and THD unbalance phasor diagrams for voltages and currents current and voltage waveforms drawn in real time When connected to a PC button Gy is locked but when the analyzer operates with key lock mode e g during recording cop button is also locked To connect to the analyzer enter its PIN code The default code is 000 three zeros The PIN code may be changed using Sonel Analysis 2 software When wrong PIN is entered three times in a row data transmission is blocked for 10 minutes Only after this time it will be possible to
83. m at 10m Emissions of conducted interferences 7 14 Standards Standards IEC 61000 6 3 Levels for a quasi peak detector 0 15kHz 0 5MHz 66dBuV 56dBuV 0 5MHz 5MHz 56dBuV 5MHz 30MHz 60dBuV Measurement Methods IEC 61000 4 30 Class S Measurement Accuracy IEC 61000 4 30 Class S Power Quality EN 50160 Flicker IEC 61000 4 15 Harmonics IEC 61000 4 7 Safety IEC 61010 EMG IEC 61326 Quality standard 71 design construction and manufacturing are ISO 9001 compliant 8 Equipment 8 Equipment 8 1 Standard equipment The standard set of equipment supplied by the manufacturer includes Permanently fixed cables 2 2 m with banana plugs 6 pcs K01 crocodile clip black 3 pcs WAKROBL20K01 K02 crocodile clip blue WAKROBU20K02 red crocodile clip 2 pcs WAKRORE20kK02 mains plug with banana inputs L1 and N for connecting the analyzer to a socket in order to charge the battery and or carry out data transmission from a PC WAADAAZA software for data reading and analysing Sonel Analysis 2 USB cable WAPRZUSB 2 GB microSD card meter case L 5 WAFUTL5 band for mounting the device on a pole 2 pcs WAPOZOPAKPL bracket for mounting the analyzer on DIN ISO rail with stabilizing connectors WAPOZUCH3 connectors for bands used for mounting the device on a pole 2 pcs WAPOZUCHA built in battery operating manual g
84. measurement for current channel In TOT is the total value for the system 1 n 3 wire networks the total reactive power is calculated as inactive power N J S P see discussion on reactive power in section 6 4 3 1 7 Compliance with standards PQM 700 is designed to meet the requirements of the following standards Standards valid for measuring network parameters e IEC 61000 4 30 2009 Electromagnetic compatibility EMC Testing and measurement techniques Power quality measurement methods IEC 61000 4 7 2002 Electromagnetic compatibility EMC Testing and Measurement Techniques General Guide on Harmonics and Interharmonics Measurements and Instrumentation for Power Supply Systems and Equipment Connected to them e JEC 61000 4 15 2011 Electromagnetic compatibility EMC Testing and Measurement Techniques Flickermeter Functional and Design Specifications EN 50160 2010 Voltage characteristics of electricity supplied by public distribution networks 12 PQM 700 Operating manual Safety standards e IEC 61010 1 Safety requirements for electrical equipment for measurement control and laboratory use Part 1 General requirements Standards for electromagnetic compatibility IEC 61326 Electrical equipment for measurement control and laboratory use Requirements for electromagnetic compatibility EMC The device meets all the requirements of Class S as defined in IEC 61000 4 30 The summar
85. mechanisms which will reduce the data size to the values acceptable by both humans and machines Lets us take the example of EN 50160 compliant power quality measurements The basic mains test period is one week If all 200 millisecond RMS values were to be remembered we would get 3 024 million measurements Processing of such amount of data would be time consuming and difficult Therefore the averaging concept has been introduced which involves recording one value per a specified time interval for the analysis purposes For the EN 50160 standard such time interval is 10 minutes In such case the analyzer calculates an average 10 minute value on the basis of about three thousand 200 millisecond values approximately because in reality the conventional 200 millisecond value is a 10 12 period value synchronized with the mains frequency Each aver age voltage value is recorded every 10 minutes which gives only 1008 measurement results Fig 22 presents the method according to which the PQM 700 analyzer determines the average values at averaging intervals equal to or greater than 10 seconds with the 10 minute averaging time This method meets the requirements specified in IEC 61000 4 30 2009 RTC 10 min tick i e 14 10 00 10 min interval x I timestamp 10 min interval x 1 Fig 22 Determining the averaging intervals equal to or longer than 10 seconds with the 10 minute averaging The average values are synchroniz
86. n the analyzer remem bers the maximum recorded voltage and the average voltage value RMS RMSyz RMS4 2 The hysteresis for all three Fig 20 Determination of the Uer Value states is the same and it is a user defined percent of nominal voltage Unom Events detection hysteresis parameter The analyzer remembers the event start and end time with a half a period accuracy The minimum voltage dip interruption and swell duration is half a period The Unus values are determined during 1 period when the fundamental voltage component passes the zero and they are refreshed every half period independently for each voltage channel This means that these values will be obtained at different times for different channels Fig 20 shows the method of the RMS4 determination with two voltage phases Information about the fundamental component s passing the zero is obtained by FFT RMS4 2 RMSq 2 HS vo 6 8 CBEMA and ANSI curves CBEMA curve was first proposed in the 70 s of the last century by the organization that gave the curve its name Computer and Business Equipment Manufacturers Association now Infor mation Technology Industry which associated manufacturers of computer and office equipment The curve was developed as a guide in the construction of power supply adapters and at the be ginning it was a graph showing the tolerance of equipment to the size and duration of the disturb ances
87. n at such moments results in larger voltage drops on the system impedance A part of the ideal sinusoidal voltage is now dropped on this impedance A change in the current spectrum is a result of slightly different waveform of voltage supplied to the receiver The example described above and flattened tops of the sinusoid are very frequent in typical systems to which switched mode power supplies are connected 52 PQM 700 Operating manual 6 5 1 Harmonics characteristics in three phase system In three phase systems the harmonics of given orders have a particular feature which is shown in the table below Order Frequency Hz Sequence positive negative 0 zero The row Sequence refers to the symmetrical components method which allows the resolution of any 3 vectors to three sets of vectors positive sequence negative sequence and zero sequence more in the part related to unbalance Let us use an example Assuming that a three phase motor is supplied from a balanced 4 wire mains RMS phase to neutral voltage values are equal and angles between the individual funda mental components are 120 each Sign in the row specifying the sequence for the 1 harmonics means the normal direction of the motor shaft rotation The voltage harmonics for which the sign is also cause the torque corresponding with the direction of the fundamental component The harmonics of the 23 5th
88. n problem and without a suitable counteraction the digital integration may become useless It should be remembered that both input amplifiers and analog to digital converters have a given finite and undesirable offset which must be removed prior to integration The PQM 700 analyzer firmware includes a digital filter which is to remove totally the DC voltage component The filtered signal is subjected to digital inte gration The resultant phase response has excellent properties and the phase shift for most critical frequencies 50 and 60 Hz is minimal Ensuring the least possible phase shift between the voltage and current components is very important for obtaining small power measurement errors It can be proven that approximate power 24 PQM 700 Operating manual measurement error can be described with the following relationship Power measurement error z phase error in radians x tan q x 100 where tan g is the tangent of the angle between the fundamental voltage and current components From the formula it can be concluded that the measurement errors are increasing as the displace ment power factor is decreasing for example at the phase error of only 0 1 and cosq 0 5 the error is 0 396 Anyway for the power measurements to be accurate the phase coincidence of volt age and current circuits must be the highest possible 43 Signal sampling The signal is sampled simultaneously in all eight channels at the frequency synchronized w
89. n the harmonics of voltage and current Hence a situ ation is possible when total reactive power Qs will be zero at non zero harmonic components Ob servation that at non zero components total reactive power can according to this definition be zero is a key to a deeper analysis which finally allowed proving that in some situations Qscan give quite surprising results The research has questioned the general belief that there is a relation be tween energy oscillations and Budeanu reactive power Qs One can give examples of circuits in which despite oscillating character of instantaneous power waveform reactive power according to Budeanu is zero Over the years the scientists have not been able to connect any physical phe nomenon to the reactive power according to this definition Such doubts about the correctness of this definition of course also cast shadow on the related distortion power Dg The scientists have started to look for answers to the question whether the distortion power Dg really is the measure of distorted waveforms in non sinusoidal circuits The distortion is a situation in which the voltage waveform cannot be put on the current waveform with two operations change of amplitude and shift in time In other words if the following condition is met u t Ai t 7 the voltage is not distorted in relation to the current In case of sinusoidal voltage and load which is any combination of RLC elements this condition is al
90. nated as Q unit is var e apparent power S unit is VA These three types of power are the most known but there are also other types At school we are taught that these three power types make up a so called power triangle which properties are expressed by the following equation P Q S This equation is however correct only for systems with sinusoidal voltage and current wave forms Before a more detailed discussion about the power measurement individual types of power should be defined 6 4 1 Active power Active power P is a magnitude with precise physical meaning and it expresses the ability of a system to perform a given work It is the power most desired by the energy consumers and it is for this supplied power that the consumer pays the supplier in a given settlement period the problem of fees for additional reactive power is discussed separately see below It is the active power and consequently the active energy which is measured by electric energy meters in each house hold Basic formula to calculate the active power is as follows 43 6 Power Quality a guide t T P u t i t dt t where u t instantaneous voltage value i t instantaneous current value T period for which the power is calculated In sinusoidal systems the active power can be calculated as P Ulcosg where U is RMS voltage lis RMS current and gis the phase shift angle between the voltage and the current The PQ
91. nd may be stored on a memory card In addition to average value it is also possible to record minimum and maximum values during the averaging period and to record the current value occur ring in the time of measurement The module for event detection is also expanded According to EN 50160 typical events include voltage dip reduction of RMS voltage to less than 90 of nominal voltage swell exceeding 110 of the nominal value and interruption reduction of the supplied voltage below 596 of the nominal voltage The user does not have to enter the settings defined in EN 50160 as the software provides an automatic configuration of the device to obtain energy measurement mode compliant with EN 50160 The user may also perform manual configuration the software is fully flexible in this area Voltage is only one of many parameters for which the limits of event detection may be defined For example the analyzer may be configured to detect power factor drop below a defined value THD exceeding another threshold and the 9th voltage harmonic exceeding a user defined percentage value Each event is recorded along with the time of occurrence For events that relate to exceeding the pre defined limits for voltage dip swell interruption and exceeding minimum and maximum current values the recorded information may also include a waveform for voltage and current It is possible to save two periods before the event and four after the event A very wide r
92. nditions of small or large harmonic distortion it is also a basis for esti mating the static values and active filters or compensators Sen S2 S Se1 3le Vex where Effective current and effective voltage of the fundamental component ley and Uer respectively are calculated similarly to and Ue but instead of RMS phase to neutral or phase to phase voltages the effective voltages of fundamental components are substituted 50 PQM 700 Operating manual Sy 45 UL where U and are effective values of fundamental components of phase to neutral voltage and current 6 4 7 Power factor True Power Factor or Power Factor TPF or PF is the value which takes into account also the presence of higher harmonics For sinusoidal systems it is equal to Displacement Power Factor DPF popular cosq Hence DPF is a measure of phase shift between the fundamental voltage and current compo nents P U L cos yin DPF Sy Uh COSQy111 he general formula for True Power Factor is PF S In case of a purely resistive load in a one phase system the apparent power is equal to active power in terms of value and reactive power equals zero so such load fully uses the energy po tential of the source and the power factor is 1 Appearance of reactive component inevitably leads to reduction of energy transmission effectiveness the active power is then less than apparent power and the reactive power is increasi
93. ng In three phase systems the power factor reduction is also influenced by receiver unbalance see discussion on reactive power In such systems correct power factor value is obtained using the effective apparent power S that is the value defined among others in the IEEE 1459 2000 standard 6 5 Harmonics Decomposition of periodic signal into harmonic components is a very popular mathematical operation based on Fourier s theorem which says that any periodic signal can be represented as a sum of sinusoidal components with frequencies equal to multiples of basic frequency of such signal Time domain signal can be subjected to Fast Fourier Transform FFT to receive amplitudes and phases of harmonic components in the frequency domain In a perfect situation voltage is generated in a generator which at output gives a pure sinusoidal 50 60 Hz waveform absence of any higher harmonics If the receiver is a linear system then also current in such situation is a pure sinusoidal waveform In real systems voltage and current wave forms can be distorted hence in addition to the fundamental component there must be harmonics of higher orders Why is the presence of higher harmonics in the system not desirable One of the reasons is the skin effect which involves pushing out the electrons from the center of conductor towards the surface as the current frequency is increasing As a result the higher the frequency the smaller the effective conductor
94. ng range with the 1 mV A sensitivity DC zero adjustment knob and accuracy Current range per den Phase error 0 1 10A 396 0 1A not specified 10 50A lt 3 EEN 50 200 A lt 1 5 lt 1 5 200 1000 A lt 0 75 lt 0 75 1000 1200A lt 0 5 lt 0 5 1 as of measured value e input signal for max current 1VAC e ratio 1mV ACA A AC e frequency range 30 Hz 10 kHz e insulation type double according to IEC 61010 1 e measuring category acc to IEC 61010 1 IIl 600 V e protection rating acc to IEC 60529 IP 40 with open jaws IP30 e dimensions 216 x 111 x 45 mm e weight about 640 g e jaws opening 53 mm e open jaws height 139 mm e maximum measured conductor diameter 252 mm e clamp lead length 1 5m e operating temperature 10 C 55 C e relative humidity lt 85 e height lt 2000 m e electromagnetic compatibility IEC 61000 6 3 2008 C 5 current clamp LED power supply indicator The output signal is supplied by a 1 5 meter lead with a pin adapted for the socket in the meter The arrow located on one of the jaws indicates the current flow direction It is assumed that the current is flowing in the positive direction if it is flowing from the source to the re ceiver Such clamp orientation is required for a correct power measurement e Overload e Direct current DC e Alternating current AC IEC 61000 6 2 2008 Fig 26 C 5 clamp up to 3000 A continuous
95. nks every 10 sec signalling the recording process e triggering by event after LEDs are turned off LOGG LED blinks every 30 sec in stand by mode and when the recording process starts LOGG LED starts to blink every 10 sec e scheduled triggering after LEDs are turned off LOGG LED blinks every 30 sec in stand by mode and when the recording process starts LOGG LED starts to blink every 10 sec In addition to the above cases e if the user interrupts the recording process by pressing SA then LEDs are lit unless the next recording is triggered e if the analyzer finishes the recording process due to the lack of space on the memory card or due to a completed schedule the LEDs remain off Pressing any button shortly activates ON LED and possibly other LEDs e g MEM depending on the state and activates desired feature if available 3 Sonel Analysis 2 software Sonel Analysis 2 is an application required to work with PQM 700 analyzer It enables the user to configure the analyzer read data from the device real time preview of the mains delete data in the analyzer present data in the tabular form present data in the form of graphs analysing data for compliance with EN 50160 standard reports or other user defined refer ence conditions independent operation of multiple devices e upgrade the software and the device firmware to newer versions Detailed manual for Sonel Analysis 2 is available in a separate d
96. nt may be measured by the Aron method which uses only two clamps that measure linear currents l and lis ls jest current is then calculated using the following formula l2 li l3 This method can be used in delta systems Fig 10 and wye systems without a neutral conduc tor Fig 11 Note As the voltage measuring channels in the analyzer are referenced to N input then in systems where the neutral is not present it is necessary to connect N input to L3 network terminal In such systems it is not required to connect L3 input of the analyzer to the tested network It is shown in Fig 8 Fig 9 Fig 10 andFig 11 three wire systems of wye and delta type 17 2 Operation of the analyzer In systems with neutral conductor the user may additionally activate current measurement in this conductor after installing additional clamps in In channel This measurement is performed after activating in settings the option of Current in N conductor Note In order to correctly calculate total apparent power Se and total Power Factor PF in a 4 wire 3 phase system it is necessary to measure the current in the neutral conductor Then it is necessary to activate option Current in N conductor and to install 4 clamps as shown in Fig 7 More information may be found in sec 6 4 5 Pay attention to the direction of current clamps flexible and CT The clamps should be installed with the arrow indicating the load directi
97. ntal compo nent Q calculated in th measuring window T i represents duration of i th measuring window in hours 32 Apparent energy 5 2 Split phase network PQM 700 Operating manual Ey 3 SOTO i 1 where iis subsequent number of the 10 12 period measure ment window S i represents apparent power S calculated in i th measuring window T i represents duration of i th measuring window in hours Split phase network parameters not mentioned are calculated as for single phase Parameter Name Designa tion Unit Method of calculation Total active power Prot w Prot Pa PB Total Budeanu reactive power QBtot QBtot QBa QBB Total reactive power of fundamental component Qrtot Q1tot Q14 Has Total apparent power Stot Stot Sa Sp Total apparent distortion power Dua Ntot Sna Sup Total Budeanu distortion power DBtot Dear Dea Des Total Power Factor PFtot Prot PFrot 5 tot Total displacement power factor COSQtot DPFeot 1 COS Prot DPFrot 2 cos Q4 cosqg Total tangent o tangrot Qtot Prot where Quot Oper when Budeanu method was chosen Qtot Qitot when IEEE 1459 method was chosen tanQtot Total active energy con sumed and supplied 33 m Ep tot gt Proc OTM i 1 Pj dla Pro i gt 0 0 dla Pj4 i lt 0 m Ep_tot
98. oad is of a receiver type 30 Displacement power fac tor PQM 700 Operating manual cos DPF cos Pu 91 where ou is an absolute angle of the fundamental com ponent of voltage Ua n is an absolute angle of the fundamental component of current A Tangent p Q tang P where Q Qs when Budeanu method was chosen Q Q when IEEE 1459 method was chosen Harmonic components of voltage and current method of harmonic subgroups according to IEC 61000 4 7 x harmonic 1 40 Total Harmonic Distortion for voltage referred to the fundamental compo nent 40 U2 h 2 h THDU 4 7 x 100 1 where Unis h th harmonic of voltage Ua N U is fundamental component of voltage au Total Harmonic Distortion for voltage referred to RMS 40 U2 h 2 h THDUg x 100 ARMS where Uh is h th harmonic of voltage Ua w Total Harmonic Distortion for current referred to the fundamental compo nent Ys THDI x 100 T where lais h th harmonic of current la I is fundamental component of current la Total Harmonic Distortion for current referred to RMS Yea lh THDIp x 10096 ARMS where lais h th harmonic of current la Voltage crest factor max U CFU UARMS max U Where the operator expresses the highest abso lute value of voltage Us samples i 2048 for 50 Hz and 60 Hz Current crest factor max I CFI
99. ocument also downloadable from the manufacturer s website www sonel pl 23 4 Design and measurement methods 4 Design and measurement methods 4 1 Voltage Inputs The voltage input block is shown in Fig 14 Three phase inputs L1 L2 L3 have common refer ence line which is the N neutral input Such inputs configuration allows reducing the number of conductors necessary to connect the analyzer to the measured mains Fig 14 presents that the power supply circuit of the analyzer is independent of the meas uring circuit The power adapter has a nominal input voltage range 90 460 V AC and has a separate terminals Supply The analyzer has one voltage range with voltage range 1150V 4 2 Current inputs The analyzer has four independent current inputs with iden tical parameters Current transformer CT clamps with voltage output in a 1 V standard or flexible clamps probes F 1 F 2 and F 3 can be connected to each input A typical situation is using flexible clamps with built in elec tronic integrator However the PQM 700 allows connecting the Rogowski coil alone to the input and a digital signal integration Fig 14 Voltage Inputs and integrated AC power 4 2 1 Digital integrator adapter The PQM 700 uses the solution with digital integration of signal coming directly from the Rogowski coil Such approach has allowed the elimination of the analog integrator problems connected with the necessity to ensure declared long term
100. oltage and current RMS Unus voltage dips interruptions and swells Range Resolution Basic uncertainty URvs 1 2 0 0 120 0 Unom 0 01 Unom 1 Unom Detection thresholds Set by the user in percentage riod or absolute values Event detection based on the measurement of Urmsi1 2 1 period RMS refreshed every 7 pe Duration hh mm ss ms Y2 period One period Waveform record Inus current min max Two periods before event 4 204 8 170 67 50 Hz 60 Hz s Range periods after the event amples per period Resolution total of 6 cycles Basic uncertainty IRMS 1 2 0 0 100 0 Inom 0 01 Inom 1 Inom Detection thresholds Set by the user in percentage on the measurement of lnust1 or absolute values Event detection based 2 1 period RMS refreshed every 75 period Duration hh mm ss ms 7 period One period Waveform record 7 5 Event detection Parameter Two periods before event 4 periods after the event total of 6 cycles 204 8 170 67 50 Hz 60 Hz s other parameters Range amples per period Detection method Frequency min max 40 70 Hz percent age or absolute value Detection based on 10 sec measurement acc to IEC 61000 4 30 Voltage crest factor min max 1 0 10 0 Basing on 10 12 period val Current crest factor min max 1 0 10 0 Basing on 10
101. om sing 0 25 Apparent power 2 Inom S IRms lt 5 Inom depending on Apparent energy 5 Inom IRMS S Inom Unom and Inom 2 52 62 4 2 02 62 4 2 52 62 4 2 o 62 4 2 o 62 4 2 o 62 4 2 o H 62 4 2 o 62 4 2 o 62 4 PQM 700 Operating manual Power factor PF 0 1 50 Unom lt Urms lt 150 Unom 10 Inom S Irms lt Inom Displacement power 0 1 factor cosq DPF 50 Unom S Urus lt 150 Unom 10 Inom s InMs lt Inom 1 See sec 7 3 7 7 3 7 Estimating the uncertainty of power and energy measurements The total uncertainty of active and reactive power and energy measurements and the harmonics power is based on the following relationship additional time measurement uncertainty is omitted in case of energy as much smaller than other uncertainty types pg Sun rd EN Kr where 6dp q uncertainty of active or reactive power measurement oun total uncertainty of voltage harmonic amplitude measurement analyzer transducers n total uncertainty of current amplitude measurement analyzer transducers clamps Opn additional uncertainty caused by the error of phase measurement between the voltage and current harmonics The y uncertainty can be determined if we know the phase shift angle for a given frequency ranges Tab 6 presents the phase difference error between the
102. on It may be verified by checking an active power meas urement in most types of passive receivers active power is positive When clamps are incorrectly connected it is possible to change their polarity using Sonel Analysis 2 software The following figures show schematically how to connect the analyzer to the tested network depending on its type Transformer Receiver OPTIONAL n OOOO Current input terminals Voltage input terminals Fig 5 Wiring diagram single phase 18 19 PQM 700 Operating manual Transformer Receiver Voltage input terminals Current input terminals Transformer Receiver OPTIONAL 9151610 Current input terminals Voltage input terminals Fig 7 Wiring diagram 3 phase wye with a neutral conductor 2 Operation of the analyzer Transformer Receiver OPTIONAL Voltage input terminals Current input terminals Fig 8 Wiring diagram 3 phase wye without neutral conductor gosiunia MMB rare i HET Wo i d E IH iO 1 ie DX o ZG C oO 6 I A gt Voltage input terminals Current input terminals Fig 9 Wiring diagram 3 phase delta 20 21 Transformer PQM 700 Operating manual Receiver OPTIONAL Voltage input terminals Current input terminals Fig 10 Wiring diagram 3 phase delta current measurement using Aron method Transformer Fig 11
103. ous results if the system is unbalanced As apparent power is a conventional magnitude and does not have a physical inter pretation determination which of proposed apparent power definitions is correct could be difficult Yet the attempts have been made based on the observation that the apparent power is closely related to the transmission losses and the power factor Knowing the transmission losses and the power factor one can indirectly specify a correct definition of apparent power The definitions which have been used so far include arithmetic apparent power and vector ap parent power The test have shown however that neither the arithmetic definition nor the vector definition give correct value of the power factor The only definition which did not fail in such a situation was the definition proposed as early as in 1922 by German physicist F Buchholz Se 3U I It is based on RMS current and voltage and the power is called an effective apparent power hence the index e in designations in three phase systems Those effective voltage and current 49 6 Power Quality a guide values are such theoretical values which represent voltage and current in an energetically equiva lent three phase balanced system Consequently the key issue is to determine the Ue and le The IEEE 1459 standard gives the following formulas In three wire systems l p 1 E gt y Ua Unc Vea e 9 In four wire systems l 1
104. proper operation 45 Frequency measurement The signal for measurement of 10 second frequency values is taken from the L1 voltage chan nel It is the same signal which is used for synchronization of the PLL The L1 signal is sent to the 2 order band pass filter which passband has been set to 40 70 Hz This filter is to reduce the level of harmonic components Then a square signal is formed from such filtered waveform The signal periods number and their duration is counted during the 10 second measuring cycle 10 second time intervals are determined by the real time clock every full multiple of 10 second time The frequency is calculated as a ratio of counted periods to their duration 46 Harmonic components measuring method The harmonics are measured according to the recommendations given in the IEC 61000 4 7 standard The standard specifies the measuring method for individual harmonic components The whole process comprises a few stages e synchronous sampling 10 12 periods e Fast Fourier Transform FFT e grouping Fast Fourier Transform is performed on the 10 12 period measuring window about 200 ms As a result of FFT we receive a set of spectral lines from the 0 Hz frequency DC to the 40 harmonics about 2 0 kHz for 50Hz or 2 4 kHz for 60 Hz The distance between successive spectral lines depends directly on the determined length of measuring window and is about 5 Hz As the PQM 700 analyzer collects 2048 samples per me
105. se quence symmetrical components negative posi tive zero current lo h la io i2 Flicker factor Pst and Pr Active power consumed and supplied P P Reactive power consumed and supplied Q1 Q1 Qe QB Apparent power S Distortion power D Apparent distortion power SN Power factor PF Displacement power factor cosq DPF Tanq factor Active energy consumed and supplied Ep Ep Reactive energy consumed and supplied Ea Ea Apparent energy Es Total harmonic distortion for Voltage THD F Total harmonic distortion for current THD F Voltage harmonic amplitudes Un Unao Current harmonic amplitudes ln 1Inao 7 8 Power supply and heater Power supply Input voltage range 90 460 V AC 127 460 V DC Overvoltage category CAT IV 300 V Power Consumption max 30 VA Battery Li lon 4 5 Ah Operating time on battery gt 6h Battery charging time fully discharged battery 8h Current consumption from battery in analyzer off mode mains power failure does not apply to anti theft mode Heater lt 1mA Heater temperature threshold activation 5 C Heater power supply from internal AC DC ada pter Heater power max 10 W 7 Technical specifications 7 9 Supported networks Types of supported networks directly and indirectly 1 phase 1 phase with
106. t this phenomenon causes a deteriorated well being annoyance sometimes headache etc The luminous intensity fluctuations must have a specified frequency they may not be to slow as then human iris can adapt to changed lighting and they may not be too fast because the filament inertia 42 PQM 700 Operating manual offsets these fluctuations almost totally The tests have proved that maximum arduousness occurs at the frequency of about 9 changes per second The most sensitive light sources are traditional incandescent bulbs with tungsten fila ment Halogen bulbs which filaments have much higher temperature have also much higher inertia which reduces the perceived brightness changes Fluorescent lamps have the best flicker re sistance as due to their some specific properties they stabilize the current flowing through the lamp during the voltage changes and thus reduce the fluctuations Flicker is measured in so called perceptibility units and there are two types of flicker short term Ps which is determined once every 10 minutes and long term Pi which is calculated on the basis of 12 consecutive Ps values i e every 2 hours Long measurement time results directly from slow changing character of this phenomenon in order to collect a reliable data sample the meas urement must be long Ps equal to 1 is considered a value on the border of annoyance certainly sensitivity to flicker is different in different people this threshold has
107. ters waveforms recording event detection and event thresholds A few selected configurations are given in Tab 3 The last column presents approximate recording times for 2 GB memory card The typical configurations shown in Tab 3 assumes that ly current measurement is enabled 16 PQM 700 Operating manual Tab 3 Approximate recording times for a few typical configurations System Approximate Waveforms recording current rne after averag time with 2GB measure ing period allocated ment on space according to EN D e 50160 1000 events 1000 events according to the Voltages and 270 days currents profile according to the Power and har 23 days monics profile Configuration Averaging type Event wave mode profile time 60 years according to the Power and har monics profile 22 5 d 1000 events 1000 events ay all possible pa rameters all possible pa rameters all possible pa 64 days rameters 4 years 25 days 1000 events 1000 events 22 days day day all possible pa rameters 2 6 Measuring arrangements The analyzer may be connected directly and indirectly to the following types of networks e 1 phase Fig 5 2 phase split phase with split winding of the transformer Fig 6 3 phase wye with a neutral conductor Fig 7 3 phase wye without neutral conductor Fig 8 3 phase delta Fig 9 In three wire systems curre
108. the cause of harmonic components in voltage What is the cause of harmonic components in current Seemingly these two questions are almost identical but separation of current and voltage is extremely important to understand the essence of this issue The answer to the first question is as follows harmonics in voltage are a result on a non zero impedance of the distribution system between the generator assuming that it generates a pure sinusoid and the receiver Harmonics in current on the other hand are a result of non linear impedance of the receiver Of course it must be noted that a linear receiver to which distorted voltage is supplied will also have identically distorted current waveform For years in the literature the following statement has been used receiver generates harmon ics It should be remembered that in such case the receiver is not a physical source of energy as suggested by the word generates The only source of energy is the distribution system If the receiver is a passive device the energy sent from the receiver to the distribution system comes from the same distribution system What we have here is a disadvantageous and useless bidirec tional energy flow As discussed earlier in the section on power factor such phenomenon leads to unnecessary energy losses and the current generated in the receiver causes an additional load on the distribution system Let us consider the following example A typical non lin
109. ting clamp placement around the con ductor the return end is placed inside the coil at its entire length The current flowing through the measured con ductor causes centric magnetic field lines which due to the self induction phenomenon induce the electromotive force at the end of the coil This voltage however is pro portional to the rate of current change in the conductor and not to the current itself In comparison with current transformers the Rogowski coil has a few indisputable advantages As it does not have a core the core saturation effect is elimi nated thus being a perfect instrument to measure large currents Such coil has also an excellent linearity and a wide pass band much wider than a current transformer Fig 17 Rogowski coil and its weight is much smaller However until recently the wider expansion of flex ible clamps in the current measurement area was diffi cult There are some factors which hinder practical implementation of a measurement system with a Rogowski coil One of them is a very low voltage level which is induced on the clamps it depends on geometrical dimensions of the coil For example the output voltage for the 50 Hz frequency of the F series flexible probes to be used with PQM 700 is about 45 HV A Such low voltages require the use of precise and low noise amplifiers which of course increase the costs Because the output voltage is proportional to the current derivative it is necessary to us
110. to L1 The term of positive sequence component will be discussed in more detail in the section devoted to unbalance The value of reactive power of the fundamental component is the main value which allows es timating the size of capacitor to improve the displacement power factor DPF that is the displace ment of the voltage fundamental components in relation to the current fundamental component i e compensator of the reactive power of the fundamental component 6 4 3 Reactive power and three wire systems Correct reactive power measurement is impossible in unbalanced receivers connected accord ing to the three wire system delta and wye systems without the N conductor Such statement may come as a surprise for many people The receiver can be treated as a black box with only 3 terminals available We cannot deter mine its internal structure In order to calculate the reactive power we need to know the phase shift angle between the voltage and the current at each leg of such receiver Unfortunately we do not know this angle In the delta type receiver we know the voltages on individual impedances but we do not know the current in such systems the phase to phase voltages and line currents are meas ured Each line current is a sum of two phase currents In the wye without N type receivers we know the currents flowing through impedance but we do not know the voltages each phase to phase voltage is a sum of two phase to neutral volta
111. tot where Qtor Qstot when Budeanu method was chosen Quot Qitot when IEEE 1459 method was chosen Total active energy con sumed and supplied 35 formula same as in split phase system 5 Calculation formulas Total Budeanu reactive energy consumed and supplied QB tot EQB tot formula same as in split phase system Total reactive energy of fundamental component consumed and supplied Eatstot Ea1 tot formula same as in split phase system Total apparent energy Estot SOTO i 1 where iis subsequent number of the 10 12 period measure ment window Se i represents the effective apparent power Se calcu lated in i th measuring window T i represents duration of i th measuring window in hours RMS value of zero volt age sequence 1 Uy 3 Uni Up Uc Uo mag Up where Uar UB Uc are vectors of fundamental compo nents of phase voltages Us Us Uc Operator mag indicates vector module RMS value of positive voltage sequence 1 U z Wa aUg a Hen U mag U1 where Uar UB Uc are vectors of fundamental compo nents of phase voltages Us Us Uc Operator mag indicates vector module l 1 v3 EE a gy Z a le 2 2 j 1 v3 2 149024 5 O a 1e 2 zi RMS value of negative voltage sequence 1 2 Ue Up a Up aU es Uz mag U where Uar Us Uc are vectors of fundamental compo nents of phase voltages Us
112. uarantee card calibration certificate 8 2 Optional accessories Additionally the following items that are not included in the scope of standard equipment can be purchased from the manufacturer or the distributors CT clamps C 4 1000 A AC WACEGCAOKR CT clamps C 5 1000 A AC DC WACEGC5OKR CT clamps C 6 for low currents in 10 A AC transformers WACEGC6OKR CT clamps C 7 100 A AC WACEGC7OKR flexible clamps F 1 for current up to 3 kA AC length 120 cm WACEGF10KR flexible clamps F 2 for current up to 3 kA AC length 80 cm WACEGF2OKR flexible clamps F 3 for current up to 3 kA AC length 45 cm WACEGF3OKR battery replaceable by SONEL after sale services WAAKU11 phase splitter AC 16 WAADAAC16 a set of magnetic voltage adapters 3 pcs black and 1 pc blue WAADAUMAGKPL a set of voltage adapters threaded 3 pcs black 1 pc blue and 1 pc yellow WAADAM4M6 a case for the analyzer and standard accessories WAWALXLA hard case for clamps WAWALL2 72 PQM 700 Operating manual 8 2 1 C 4 current clamp The C 4 clamp is used to measure the alternating current in medium and high power electrical installations The output sig nal is voltage proportional to the measured current The output signal is supplied by a 1 5 meter lead with a pin adapted for the Socket in the meter The arrow located on one of the jaws indicates the current flow direction It is assumed that the current is flowing in the pos
113. ve power Research in this area has shown that reactive power occurs also in circuits without any energy oscillation This statement may surprise many engineers In latest publications on power theory the only physical phenomenon mentioned which always accompanies appearance of reac tive power is phase shift between current and voltage The reactive power formula given above is correct only for one phase sinusoidal circuits The question thus arises how do we calculate the reactive power in non sinusoidal systems This ques tion opens a proverbial Pandora s box among electrical engineers It turns out that the reactive power definition in real systems and not only those idealized has been subject to controversy and now 2009 we do not have one generally accepted definition of reactive power in systems with non sinusoidal voltage and current waveforms not to mention even unbalanced three phase sys tems The IEEE Institute of Electrical and Electronics Engineers 1459 2000 standard from 2000 does not give a formula for total reactive power for non sinusoidal three phase systems as three basic types of power the standard mentions are active power apparent power and attention 44 PQM 700 Operating manual nonactive power designated as N Reactive power has been limited only to the fundamental com ponent and designated Qi This standard is the last document of this type issued by recognized organization which was to put the pow
114. ways met for sinusoidal waveforms these elements maintain linearity However when the voltage is distorted the RLC load does not ensure absence of current distortion in relation to voltage any more and the load is no longer linear it is necessary to meet some additional conditions module and phase of load impedance changing with frequency 45 6 Power Quality a guide And then is really Ds a measure of such distortion Unfortunately also in this case the Bude anu s power theory fails It has been proven that the distortion power can be equal to zero in a situation when voltage is distorted in relation to current waveform and vice versa the distortion power can be non zero at total absence of distortion Practical aspect of this power theory which relates to improvement of power factor in systems with reactive power was to be the feature to take the most advantage of correct definitions of reac tive power The compensation attempts based on the Budeanu reactive power and related distortion power fell through These magnitudes did not allow even a correct calculation of correction capaci tance which gives the maximum power factor Sometimes such attempts ended even with addi tional deterioration of power factor How come then that the Budeanu s power theory has become so popular There may be several reasons Firstly engineers got accustomed to old definitions and the curricula in schools have not been changed for years This f
115. when the information about a limit value of the measured parameter is essential the user can take advantage of the option of measuring the minimum maximum and instantaneous values in the averaging period If a given parameter is measured in the 10 12 period time the minimum and maximum value is respectively the smallest and the largest 10 12 period value measured in a given averaging interval On the other hand the instantaneous value is the last 10 12 period value in this averaging interval In case of RMS current and voltage the method of searching for minimum and maximum values is more flexible and it is controlled by the Min Max calculation period parameter The user can take advantage of the following options half period 200 ms 1 s 3 s and 5 s If the half period option is selected the minimum and maximum values will be searched for with the highest sensitivity to the Uma As this time is increasing additional smoothing is being introduced for example with 5 seconds first a 5 second average value is calculated which is then used to search for the minimum and maximum values This gives less sensitivity to instantaneous changes of the measured value Note similarly to the averaging times shorter than 10 seconds the 200 ms 1 s 3 s and 5 s times are actually the multiples of the mains period 10 12 50 60 150 180 and 250 300 mains periods respectively Selecting the right averaging period is not easy To a large extent it depends
116. y of the requirements is presented in the table below Tab 2 Summary of selected parameters in terms of their compliance with the standards Aggregation of measure ments at different inter vals IEC 61000 4 30 Class S e Basic measurement time for parameters voltage current harmonics unbal ance is a 10 period interval for 50 Hz power supply system and 12 period in terval for 60 Hz system e Interval of 3 s 150 periods for the nominal frequency of 50 Hz and 180 peri ods for 60 Hz e Interval of 10 minutes Real time clock RTC uncertainty IEC 61000 4 30 Class S e Built in real time clock set via Sonel Analysis software no GPS radio syn chronization e Clock accuracy better than 0 3 seconds day Frequency Compliant with IEC 61000 4 30 Class S of the measurement method and uncer tainty Power supply voltage Compliant with IEC 61000 4 30 Class S of the measurement method and uncer tainty Voltage fluctuations flicker The measurement method and uncertainty meets the requirements of IEC 61000 4 15 standard Dips interruptions and swells of supply voltage Compliant with IEC 61000 4 30 Class S of the measurement method and uncer tainty Supply voltage unbal ance Compliant with IEC 61000 4 30 Class S of the measurement method and uncer tainty Voltage and current har monics 13 Measurement method and uncertainty is in accordance with IEC 61000 4 7 Class I
117. y of active power fundamental component Conditions p 60 Unus 5 Unom Iams 5 Inom Fundamental uncertainty equals 1 02 Sbn For the 0 200Hz frequency range the PQM 700 phase error is lt 1 After substituting to the equation Syn 100 1 999779 100 1 EED 3 04 cos 60 then the measurement uncertainty is y 1 0 3 04 3 20 Under the same conditions but with the phase shift p 10 we will ob tain 6 p and the measurement uncertainty is y 1 0 0 32 1 05 The above calculations do not take into account additional errors caused by used clamps and transducers 100 1 25022 0 32 cos 10 Te KT 5 wo tao al 9 60 80 p 50 70 60 9 407 50 40 220 9 20 30 0 5 10 15 20 25 30 Fig 24 Additional uncertainty from phase error depending on phase shift angle PQM 700 Operating manual 7 3 8 Flicker Flicker Pst 10 min Pit 2 h Resolution 0 01 Ranges and conditions 0 4 10 for Unus 2 80 Unom Basic uncertainty 10 within the values presented in tables of IEC 61000 4 15 standard 7 3 9 Unbalance Unbalance voltage and current Ranges and conditions Resolution Basic uncertainty Unbalance factor for positive negative and for 0 0 10 0 0 196 0 3 absolute uncertainty zero sequence 80 Unom S Unus lt 150 Unom 7 4 Event detection v

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