Using the 6100A Electrical Power Standard to calibrate energy meters
Contents
1. Channel 1 only Sum of Channel 1 2 and 30 Channel 1 to 2 independent Channel 1 to 3 independent Channel 1 to 4 independent O Channel 1 to 5 independent O Mean of all MUT channels e Fig 12 Channel Configuration and Meter Constants screen The basic setup is now complete The user can now enter the required combinations for L1 L2 and L3 if using a two three or four phase system via the 6100A s output menu Now the meter testing is ready to begin To start the test the user simply presses the 6100A s green OPER button unless in Gated mode whereupon the 6100A s OPER button must first be pressed before the 6100A can identify the appropriate gate signal to begin the test A typical output menu screen when running a full test can be seen in figure 13 At this point it is worth noting that the 6100A can only be used with devices that have a provision for independent auxiliary power for their internal circuits The task of the 6100A is to accurately maintain its voltage output at the shape and level demanded by the user for a wide range of loads The 6100A cannot maintain its precision output if loaded by the short term cycle by cycle vanations in current demanded by the meter under test s power supply units Typical 6100A energy applications Energy meter testing typically falls into one of three categories In service testing calibration e Man2. Using the 6100A Electrical Power Standard to calibrate energy meters Over the last few years the significance of accurate electrical energy calibration has become increasingly important With deregulation increased competition and more cross network power supply transactions the need to make more measurements more frequently and at a higher degree of accuracy has never been more important As a consequence both suppliers and consumers of electrical energy now need to know that what they have distributed or received is exactly what was expected As a result energy meter calibrations have in most countries now become compulsory However energy meter calibration has until recently been a task of bringing together a complex array of test instruments including voltage and current supplies energy reference meters and pulse comparators This in itself not only has a detrimental effect on the uncertainty of the whole energy meter calibration process but is also a costly one to introduce and maintain With this in mind Fluke recently introduced the 6100A Electrical Power Standard Energy option This application note sets out to explain how the 6100A can be used to accurately calibrate energy meters without the need for a multitude of test equipment thereby lowering both testing and maintenance costs while also optimizing the measurement uncertainties and accuracy The basic energy meter calibration a
3. the 6100A energy option does enable the user to perform the calibration without the necessity of using the energy reference meter and or the pulse comparator thereby effectively replacing the functionality of both instruments Replacing the reference meter with a 6100A The energy reference meter serves two main purposes PULSES OUT PROM UUT AND REFERENCE CURRENT SUPPLY BLOOA Fig 2 An energy meter calibration setup using a 6100A Electrical Power Standard TTL LED OR DISC COUNTER ENERGY PULSE OUTPUTS VOLTAGE SUPPLY Fluke Corporation Using the 6100A Electrical Power Standard to calibrate energy meters reliable source of traceability and secondly to measure the amount of energy actually delivered The 6100A s ability to measure or calculate time means that it already knows how much energy it has delivered with a high degree of accuracy The function of the reference meter therefore becomes redundant In this type of setup the comparator is still used but with the 6100A now generating the pulses instead of the reference meter To mimic the K value of the meter under test it is possible to program the 6100A to generate a specific number of pulses per unit of energy delivered This calibration setup is shown in figure 2 Replacing the comparator with a 6100A The 6100A s ability to receive count and compare pulses means that it can also perform all of the functions o
4. High 150 RO Level Low 1k2 Fig 8 Voltage dips and short interruptions In this mode no time constants or energy criteria are specified This is particularly useful for meter verification testing as it quickly establishes the condition of the energy meter Free running mode is also useful for carrying out creep tests or even simply to make adjustments to a meter Fig 9 Energy Counter Timer mode configuration screen 4 Fluke Corporation Using the 6100A Electrical Power Standard to calibrate energy meters Creep testing is when the voltage coils of the energy meter are energized with the rated voltage but with no current in any current coil The test is performed over a specific period of time and fundamen tally establishes how much the meter dial advances without any usage by the consumer This is easily done using the 6100A s basic setup user inter face screens described on page 6 of this application note Counted Timed mode When the 6100A is setup in Counted Timed mode the user must first enter or select data within three panels on the energy counter time mode screen before counting is initiated see figure 9 Firstly a warm up time can be specified This allows the user to run the meter for a user definable period of time so that the energy meter can reach a suitable operating temperature prior to testing Then the test period criteria must be selected This panel incor
5. designed specifically to give arbitrary time energy or count control of the 6100A Using the 6100A Electrical Power Standard to calibrate energy meters 5 6 Fluke Corporation Energy packet mode In energy packet mode also known as dose mode the power from the output terminals is timed to deliver the requested amount of energy to the meter under test This can be defined as either energy counts or time However unlike Counted Timed mode there is no warm up period This is advantageous to those wishing to eliminate initial dial advance on the meter under test Dial advance is when both the reference meter and meter under test advances more than the meas ured amount on the 6100A This is perfectly normal and represents settling and warm up times included in the test Furthermore please note that when using the 6100A s other modes the actual test duration and count to achieve the displayed result is perfectly accurate In energy packet mode dial advance does not become an issue as there is no warm up period As with other modes the mode s own configuration screen must be setup prior to testing See Figure 11 The 6100A s user interface and basic setup The 6100A s energy user inter face can be accessed via the waveform menu Note If accessed directly from power up then the Esc key on the key board must be pressed first Here a softkey labeled Energy Counting can be found Upon sel
6. d external world most users see it as a regulatory agencies all adhere means to verify calibrate or to the requirements of IEC design their energy meters for 61036 In other parts of the type approval In many countries world similar standards exist conforming to the necessary and consequently dictate the standards has become a legal way energy meters are both requirement manufactured and applied Fluke Keeping your world up and running Fluke Corporation PO Box 9090 Everett WA USA 98206 Fluke Europe B V PO Box 1186 5602 BD Eindhoven The Netherlands For more information call In the U S A 800 443 5853 or Fax 425 446 5116 In Europe M East Africa 31 40 2 675 200 or Fax 31 40 2 675 222 Canada 800 36 FLUKE or Fax 905 890 6866 From other countries 1 425 446 5500 or Fax 1 425 446 5116 Web access http www fluke com 2004 Fluke Corporation All rights reserved eS Trademarks are the property of their respective owners Printed in UK 02 2004 2130388 A ENG N Rev A DS272 The most accurate comprehensive and flexible source of electrical power signals Fluke Corporation Using the 6100A Electrical Power Standard to calibrate energy meters
7. ecting this key the user must then configure the 6100A according to his test setup This can be done by selecting the softkey Configure Meter Constants which in turn accesses the Channel Configuration and Meter Constants screen see figure 12 The first panel MUT Source determines which sockets on the front panel of the 6100A are being used as energy pulse inputs Test Period Derivation Energy Packet Mode Configuration puraten ZO Pulse Source Fig 11 Energy packet mode configuration screen A number of different configu rations can be setup in this panel from one to six single phase meters or even a single pulse three phase meter The Sum of Channel 1 2 and 3 check box Having identified the pulse source channel s the user must then select the reference source This will depend upon which circuit as shown in figures 2 3 and 4 the user has chosen to perform the tests If the 6100A s internal reference is being used as shown in figure 4 the check box Main Output must be selected Alternatively if either an external single phase or three phase meter are utilized as a reference then one of other five check boxes must be selected according to the test setup being used Two such examples are shown in figures 1 and 3 The Meter Constant Base drop down menu allows users to select any one of three meter base units depending upon the meter being tes
8. f the comparator effectively making it redundant as well The set up for this is shown in figure 3 CURRENT SUPPLY PULSES OUT TTL LED OR DISC COUNTER REFERENCE ENERGY PULSE INFUTS VOLTAGE SUPPLY Fig 3 The 6100A Electrical Power Standard eliminates the need for comparators in the calibration setup Replacing the reference meter and the comparator with a 6100A Having established that it can effectively replace both the comparator and the reference meter the 6100A can also combine both of these functions together and so replace all of the other instruments required thereby allowing it to perform the complete calibration process on its own This more consoli dated setup is shown in figure 4 CURRENT SUPPLY 6100A Complex waveshapes a unique 61004A attribute In the applications already described there is a growing requirement to verify or calibrate measurements under non sinusoidal conditions In fact various standards have been in place for a number of years which define testing techniques for energy meters and in some cases actually specify detailed waveshapes that are used for type testing design qualification against standards ENERGY FULSE OUTPUTS VOLTAGE SUPPLY Fig 4 Using a 61004A Electrical Power Standard to eliminate the comparator and reference meter as well as a supply for both voltage and current Fluke Corporation One such standard is IEC 61036 sta
9. ndards around the world vary considerably as does their implementation and legal status The waveshapes given in figures 5 6 7 and 8 are all examples specifically required by IEC 61036 and were all generated by a 6100A Electrical Power Standard The half wave rectified signal phase fired signal and burst fire signal can all be generated on either the voltage or current channels but under normal circumstances would usually be performed using the latter These wave shapes are easily replicated on the 6100A s voltage or current channels The 6100A s four testing modes When used to test calibrate or verify energy meters the 6100A can be used in any one of four testing modes These are e Free running mode e Counted Timed mode e Gated mode e Energy packet mode also known as Dose mode Each offer benefits specific to the type of test being performed Using the 6100A Electrical Power Standard to calibrate energy meters 3 Fig 7 Burst fire signal Free running mode In free running mode the 6100A will not begin counting meter pulses until the output OPER ate switch is turned on Once the output switch is enabled counting will continue indefinitely until the switch is once again turned off Energy Counted Timed Mode Configuration Derivation As Time Delay Seconds Lx Duration jo Seconds Gate Out Configuration Signal Type Active Level Internal pull up Enable Gate Out C Puke O
10. porates three selection criteria 1 Derivation 2 Duration 3 Pulse source The selection made within the Derivation drop down menu determines the way the 6100A delivers the energy required This can be specified in either time pulse counts or as a measure of energy The duration entry is merely a length or period of time dependent upon the selection made within the Derivation drop down menu This will be specified as either a time in seconds minutes or hours a number of counts or Watt hours stated in either Watt hours kilo Watt hours or Mega Watt hours Input Gate Configuration Signal Type Pulse Level Having chosen the method in which energy is delivered a pulse source must then be chosen This will identify which channel or channels on the 6100A are used to input the counting pulses from the energy meter It is worth noting at this point that with six channels the 6100A is also capable of testing multi phase energy meters with multiple pulse outputs as well as those with a single pulse output Finally an Energy Gate In Out socket on the rear of the 6100A can be enabled and then configured according to the user s requirements Having enabled the Energy Gate Out function the operator can select the signal types as either a signal consisting of a level to the required duration or as a start and end pulse This can also be either active high o
11. pplication Calibration of instruments that measure energy is no different to any other calibration The instrument under test is supplied with a known quantity of the parameter being calibrated and the instrument is interro gated in order to ascertain the value of the parameter that it has measured This value is then compared with the quantity supplied and the measurement error is calculated Electricity meters almost without exception use a tech nique of generating pulses to indicate the amount of energy they have measured Each pulse represents a specific number of watt hours or VA hours VAR hours etc These pulses are transmitted from the meter in a number of different ways From the Fluke Digital Library www fluke com library Application Note 1 On older meters energy is recorded by counting the number of passes of a black mark on the surface of a spin ning metal disc 2 By a flashing LED 3 As a direct electrical output Typically TTL 4 Some of today s newer meters will even include highly advanced reporting mechanisms such as Ethernet or Bluetooth interfaces Because meters are used to measure a wide range of energy from watt hours to Gigawatt hours the pulses generated can represent different amounts of energy This amount of energy is specified by the meter manufacturer and is known as the meter constant sometimes referred to as k For example a specific meter may gene
12. r low Lastly the source impedance of the internal pull up resistor can be specified as either 150 Q or 1 kQ to match the meter or monitoring system s own source impedance This should be determined from the equipments own user manual prior to connecting to the 6100A Energy Gated Mode Configuration _ Active Signal Level High Low Ce Fig 10 Energy Gated mode configuration screen Fluke Corporation Gated mode In Gated mode the user has the opportunity to remotely activate the 6100A s output and counting cycle This is achieved by applying an active signal to the 6100A s Energy Gate In Out Connector on the rear panel This connector automatically becomes an input socket when the gated mode is selected However before testing can begin the parameters of the active signal being used must first be configured within the 6100A s Energy Gated Mode Configuration screen see figure 10 Here the signal type active signal level and internal pull up parameters must initially be set up Details on how to do this can be found in the 6100A user manual Having completed this process the 6100A now requires the user to enter the length of the test period in readiness to switch either the output or counting function on and off from an alternative piece of test equipment or system with active signal capability This could be a PC set up with the users own dedicated software program
13. rate 100 pulses for every kilowatt hour measured another may generate the same number of pulses per megawatt hour measured Whatever the criteria the calibration system must have the ability to have this number set within its system in order that it can calculate the correct quantity of energy from the pulse count Energy meter calibration methods Calibrations are typically performed by using a reference measurement technique A known amount of energy is simultaneously supplied to a reference meter and to the unit under test UUT A reading from the reference meter is then compared to a reading from the UUT and the error is calculated Three separate pieces of calibration equipment are typically required to complete this task 1 An energy supply a power supply 2 A reference energy meter 3 A device for counting pulses from both the reference meter and the UUT which then compares the two counts and generates an error indication The block diagram of the calibration set up is shown in figure 1 PULSE COMPARATOR PULSE COMPARATOR PULSES OUT FROM UUT AND REFERENCE TTL LED OR DISC COUNTER CURRENT SUPPLY REFERENCE METER Fig 1 A typical energy meter calibration setup In this setup the 6100A is used Firstly it is used to provide a simply as the energy supply current supply and voltage supply and without the use of any other functions available with the 6100A s energy option However
14. sociated with them Now all of these organizations use the 6100A to test their energy meters prior to deploy ment to verify them before use into a new installation However these very Same companies and organizations are now also using the 6100A to verify existing meters in the field particularly in circumstances of dispute Fluke 6100A Electrical Power Standard ewe ww SOO 000 6 Cust tb Global Settings Menu L1 Y 110 000 V 0 000 Degrees Range 33 66Hz 0 500000 A 0 000 Degrees Frequency 600 He I Y 110 000 V 120 000 Degrees T 0 500000 A 0 000 Degrees Line Locking iig Y I L3 nooov 1200000 Doeane cre e el 0 500000 4 0 000 Degrees 1 AbsouteRMS x Pwr Budeanu 55 000 FCounted Timed Mode g Elapsed Test Time 0000 01 44 6 55 000 1 000 MUT Real Power Acc Energy Reference Acc Energy Error 0 000 Channel 1 360 00 Ww 8 8607 Wh Mean All 8 4975 Wh 4 274 Channel 2 360 00 Vv 8 6296 Wh Mean All 8 4975 Wh 1 554 Channel 3 360 00 Wy 8 6163 Wh Mean All 8 4975 Wh 1 398 Channel 4 360 00 Ww 8 6291 Wh Mean All 8 4975 Wh 1 548 Channel 5 360 00 Vv 7 6203 Wh Mean All 8 4975 Wh 10 323 Channel 6 360 00 W 8 6117 Wh Mean All 8 4975 Wh 1 548 Ready Degrees 4Wire Radians 2WireC Fig 13 The 6100A s Output Status screen With several different type In Europe meter manufacturers testing applications around the utility companies an
15. ted Wh Real power VAh Apparent power or VARh Reactive power Having selected this the meter constants must then be specified This must be done for both the meter under test the external energy reference meter if used and finally the reference pulse output of the 6100A For both the Meter Constant MUT and Meter Constant Reference panels this will be entered according to the output specifications of the meter under test and external energy reference meter if used Using the 6100A Electrical Power Standard to calibrate energy meters In the case of the Meter Constant Output panel a value can be set which specifies the effective meter constant of the Pulse Out connector Whenever an energy test is active this output is a pulse stream representing the total power and energy of the active V I outputs of all 6100A 6101A s in the system There are also internal user selectable pull up resistors for pulse inputs This is particularly useful for meters with open collector outputs A separate pull up resistor is associated with each meter constant For the meter under test and reference meter these can be selected as either 150 Q or 1 KO Similarly a user selectable internal pull up is provided for the main output s energy pulse output This can be selected or deselected using the Use Internal pull up check box Channel Configuration and Meter Constants MUT Source
16. type of application on power alone is outside the 6100A s or any of its config ured systems intended work load However that said it is also becoming common for such meter shops to employ a specials test rig This type of versatile test rig is designed to accommodate other such energy meters that for one reason or another cannot be tested in the larger arrays This may be due to physical size unique environ ment requirements or even for non compatibility reasons For such lower denomination test rigs the 6100A is ideal Power requirements are a lot lower and the number of input channels required to perform the tests is easily within even a single 6100A s capability 7 Manufacturing testing and Type testing approval Meter manufacturers are using 6100A s and 6100A systems for meter type testing and approval work within their own design centers and engineering development groups With a multitude of new and differing standards all with several derivations from country to country regularly being introduced around the world the 6100A is being recognized as the only single box solution that can replicate and test them all Furthermore it can do so with the highest accuracy and traceability For the energy meter manufacturers this whole new philosophy of type testing and approval was driven primarily by their customers utility companies and other similar operators and the regulatory agencies as
17. ufacturing testing e Type testing approval In service testing calibration In service testing calibration is where energy meters already in the field are brought in at regular intervals for verification and or calibration This regime varies from country to country however in most cases energy meters will be batch tested in a meter shop several meters at a time This is particularly prominent in some countries where state law dictates that consumer energy meters must be tested each year With this in mind these countries have meter testing shops in abundance Clearly to get through such numbers in one year requires batch testing on a large scale To overcome this several energy meters are wired into vast meter testing arrays with multiple sensors Smaller arrays can test ten meters simultane ously Fluke Corporation Meter Constant MUT Meter Constant Reference Using the 6100A Electrical Power Standard to calibrate energy meters oKf x Meter constantbase units Re E MUT Internal Pull up 150 20 1k2 e Ref Internal pull up 150 20 1 kR e Use Internal pull up In some countries this number can rise to one hundred and beyond There may be many advantages to testing meters in this way not least the high numbers that can be tested at one time However there are several disadvantages too The greatest one being the amount of power required to carry out such tests Plainly this
Download Pdf Manuals
Related Search