capacitor and apfc system service manual
Contents
1. Connect the earth conductor to the panel terminal provided on either side of the panel Use the key provided to open the door of the panel make sure that electrical connection of all equipments are intact This is particularly important since vibration in transportation sometimes may have resulted inloose connections Using a star screw driver open the rear door of the free standing panel Make two number suitable cut outs for 3 5 core power cable and 2 core 2 Sq mm cooper multi stand C T control cable in the gland plate provided Using suitable size of cable gland connect the cables Ensure that the cable gland is fixed properly without any gaps in the gland plate for proper sealing of the opening to prevent any entry of vermins The cable rated for current capacity equivalent to main incommer of panel should be used Use suitable size lugs for connecting the power cables Connect the cable to the terminals provided for the power supply Make sure that the correct phase identification is maintained while connection to the incoming terminals to the panel with respect to phases of supply line As any mistake will lead to the malfunctioning of relay Connect the R phase C T cable to the terminals provided Refer Fig Number 1 for power connection and C T location The relay is pre set for a secondary current output of 5A In case the C T secondary is 1 Amps then change the dip switch provided behind mie HEER on the front fa2. Or If the CT connection is not done to the terminals Xc9 amp C10 Indicates H for 1sec and then system power factor for 5sec Indicates CL 04 or CL 06 This indicates the of steps which have been selected for the operation CL 04 for 4 steps relay CL 06 for 6 step relay Adjustment of pre set target power factor with the range 0 70 lag 1 0 90 lead by using amp buttons Adjustment of the step switching time 5 12000 seconds possible by using amp buttons For automatic function amp indication of present power factor Leave the rotary switch position for automatic operations in position No 3 Here it is possible to switch on the steps of system manually by using amp buttons Do not alter the setting as any fault in the steps will be sensed by relay and will be disconnected from the operation in case of capacitor contactor HRC fuse failure of particular step Available in 6 step relay No Setting required L amp T SWITCHGEAR E S P SERVICE MANUAL 82 gt L amp T SWITCHGEAR ESP SERVICE MANUAL 9 TROUBLE SHOOTING Power Factor Relay T Relay is not functioning R Check the CT and Voltage connection are done as per above given instructions Check the voltage across terminal A L2 amp L3 of relay it should be 415 440 volts T Contactor is not operating R Check the contractor coils and fuse connected to the terminal A of the relay Also ch
3. Textile industries 4 Hotel industries 5 Oxygen plants 6 Food processing plants 7 Hospitals 8 Shopping complex 9 Granite processing units 10 Commercial buildings 11 Pharmaceutical industries etc Following industries are presently installed with MD XL Capacitor Steel rolling mills Cement plants Sugar plants Govt research institutes Plastic moulding units Defence units Airports B PC L Software industries O N GC Plants 1 0 C L Department of Telecommunication 13 Automobile Industry etc ONO 8 PON Q N gt O Apart from above Capacitors MPP S are generally used in various industries having pure steady inductive loads Do not use in the industries having harmonic generating loads such as welding drives ups rectifiers furnace etc Note The industries like cement sugar software industries and steel plants need data of harmonics for designing suitable compensation components The recommendation for heavy industries should be given in consultation with L amp T MEHER Engineers as the harmonic generating loads are found to be increasing in all the industries 66 Pm 2 TESTING OF CAPACITORS AT SITE Measurement of Voltage Check the voltage using tongtester at capacitor terminals Ensure that the tong tester multimeter used is of True RMS type Please note that the current output ot 440 volt capacitor connected to a system of 415 volt wi
4. 197 uf between R amp Y phase 2 196 uf between B amp Y phase 3 200 uf between R amp B phase KVAr 2 3x Ca Cb Co x v2 x 2TUf 10 KVAr 2 3x 197 196 200 x 440 x 440 x 2 x 3 14 x 50 1000000000 24 04 Consider you have measured a capacitor rated for 415 volts where in measured capacitance value is as follows 4 197 uf between R amp Y phase Ca 5 196 uf between B amp Y phase Cb 6 200 uf between R amp Y phase Cc KVAr 2 3x 197 196 200 x 415 x 415 x 2 x 3 14 x 50 1000000000 21 39 Please note while calculating kVAr of capacitor using above formula the voltage rating should be taken from the name plate of capacitor The tolerance of capacitance of a capacitor is 5 to 10 of capacitor as specified in the Indian Standard IS 13340 1993 71 gt ESP SERVICE MANUAL 4 GUIDE LINE FOR INSTALLATION OF CAPACITOR Service condition L amp T SWITCHGEAR 1 Installation area should be dry free from excessive dust or chemical fumes and vibration Refer Annexure D point Number D 4 1 of I S 13340 1993 2 Ensure that the installation area enclosure have provision of cross ventilation Refer Annexure D point Number D 3 1 of I S 13340 1993 Termination and Mounting 1 Use suitable size lugs for connecting the cable to the terminals of capacitor N Ensure that there is no loose connection As loose connection may lead to failure of capacitor insula
5. No replacement shall be considered in such cases where in the time is set below 60sec The chattering of contactor can also lead to failure of capacitor Refer point number 3 This chattering may happen due to low voltage or loose connection to contactor coils etc If the capacitors are operated in manual mode using push button check whether the on delay timer is provided in the individual steps Verify whether the time set of 60sec or not No replacement should be considered in such cases where in the timer is set below 60sec or it is not provided Check whether capacitor duty contactor is provided or if the inrush limiting inductor coils are used This becomes important in case the capacitors are switched ON with the other capacitor connected in the same bus Parallel switching of capacitor is generally found in capacitor panels having APFC and push buttons for switching on amp off Check whether the harmonic is present For this take a fresh capacitor charge the capacitor and then calculate whether the current drawn by capacitor is within the limit If the current is more then it may be due to over voltage If not then it is clear that the capacitor is drawing high current due to presence of harmonics The harmonics in the plant can be easily found If the plant has loads using power electronic components such as ups drives and furnace Loads such as are welding cfl tubes and electronic controlled machines also genera
6. available please take initial power factor as 0 75 lag Please note that the max demand given in electrical bill is in KVA not in kW Power factor kWH kVAH these data are generally provided in electricity bills Initial Power factor Before installation of capacitor Recorded demand 516kVA Highest recorded demand Req power factor 0 95lag To be decided by customer kW kVAx Power Factor 516 x 0 75 387 Required capacitor kW x Multiplying Factor 0 75 x 516 x Multiplying Factor 387 x 0 553 215kVAr 63 gt Multiplying factor for calculating kVAr Table 1 CALCULATION OF KVAr REQUIRED Target PF 0 6 0 9 0 91 0 92 0 93 0 94 0 95 0 96 0 97 0 98 0 99 1 0 6 0 849 0 878 0 907 0 938 0 970 1 005 1 042 1 083 1 130 1 191 1 333 0 61 0 815 0 843 0 873 0 904 0 936 0 970 1 007 1 048 1 096 1 157 1 299 0 62 0 781 0 810 0 839 0 870 0 903 0 937 0 974 1 015 1 062 1 123 1 265 0 63 0 748 0 777 0 807 0 837 0 870 0 904 0 941 0 982 1 030 1 090 1 233 0 64 0 716 0 745 0 775 0 805 0 838 0 872 0 909 0 950 0 998 1 058 1 201 0 65 0 685 0 714 0 743 0 774 0 806 0 840 0 877 0 919 0 966 1 027 1 169 0 66 0 654 0 683 0 712 0 743 0 775 0 810 0 847 0 888 0 935 0 996 1 138 0 67 0 624 0 652 0 682 0 713 0 745 0 779 0 816 0 857 0 905 0 966 1 108 0 68 0 594 0 623 0 652 0 683 0 715 0 750 0 787 0 828 0 875 0 936 1 078 0 69 0 565 0 593 0 623 0 654 0 686 0 720 0 757 0 798 0 846 0 907
7. manufactured within capacitance tolerance of 5 10 as per Clause No 15 3 of IS 13340 1993 68 E S P SERVICE MANUAL Pm Table 2 3 Record of current voltage and capacitance SL TYPE RATED RATED RATED INSTALLED MEASURED MEASURED NO OF kVAr VOLT CURRENT DATE VOL AND CURRENT CAPACITANCE VALUES es ee L amp T SWITCHGEAR 69 gt L amp T SWITCHGEAR 3 FORMULAE Formula 1 ESP SERVICE MANUAL The kVAr of capacitor will not be same if voltage applied to the capacitor and frequency changes The example given below shows how to calculate capacitor current from the measured value at site Example 1 Name plate details 15kVAr 3 phases 440v 50Hz capacitor Measured voltage 425v Measured frequency 48 5Hz KVAr fM fR x VM VR x kVAr KVAr 48 5 50 x 425 440 x 15 13 57kVAr fM fR VM Measured Voltage Measured frequency Rated frequency VR Measured Voltage 2 Name plate details 15kVAr 3 phases 415v 50Hz capacitor Measured voltage 425v Measured frequency 48 5Hz KVAr fM fR x VM VR x kVAr KVAr 48 5 50 x 425 415 x 15 15 26kVAr Formula 2 Formula for calculating rated current of capacitor with rated supply voltage and frequency kVAr x 10 3 XV Example 3 15kVAr 3 phase 440v 50Hz capacitor Il kVAr x 10 3X V I 15 x 1000 1 732 x
8. power factor it is required to connect a fixed capacitor or capacitor bank at the LT side of the transformer For approximate kVAr of capacitors required Refer Table No 1 1 2 If the installation is having various small loads with the mixture of large loads then the APFC should be recommended Note that APFC should have minimum step rating of 10 as smaller step 3 If loads are small then the capacitor should be connected parallel to load The connection should be such that whenever the loads are switched on the capacitor also switches on along with the load Refer Fig No 2 4 Note that APFC panel can maintain the power factor on L T side of transformer and it is necessary to provide fix compensation for Power transformer Refer Fig No 1 5 In case there is no transformer in the installation then the C T for sensing power factor should be provided at the incoming of main switch of the plant Refer Fig No 3 CT Supply Mete f QV bd Load Bus c SDF d Ci Capacitor stops Fi pA F1 Control fuses F2 Capacitor stop fuses es Kim Contactors CR mm SDF Switch disconnector fuse CR Power factor controller Ken T CT Current transformer e Fig No 3 L amp T SWITCHGEAR 65 L amp T SWITCHGEAR ESP SERVICE MANUAL Selection of Capacitor Following industries are presently installed with MPP H Capacitor 1 Floor mills 2 Rice mills 3
9. 1 049 0 7 0 536 0 565 0 594 0 625 0 657 0 692 0 729 0 770 0 817 0 878 1 020 0 71 0 508 0 536 0 566 0 597 0 629 0 663 0 700 0 741 0 789 0 849 0 992 0 72 0 480 0 508 0 538 0 569 0 601 0 635 0 672 0 713 0 761 0 821 0 964 0 73 0 452 0 481 0 510 0 541 0 573 0 608 0 645 0 686 0 733 0 794 0 936 0 74 0 425 0 453 0 483 0 514 0 546 0 580 0 617 0 658 0 706 0 766 0 909 0 75 0 398 0 426 0 456 0 487 0 519 0 553 0 590 0 631 0 679 0 739 0 882 0 76 0 371 0 400 0 429 0 460 0 492 0 526 0 563 0 605 0 652 0 713 0 855 0 77 0 344 0 373 0 403 0 433 0 466 0 500 0 537 0 578 0 626 0 686 0 829 0 78 0 318 0 347 0 376 0 407 0 439 0 474 0 511 0 552 0 599 0 660 0 802 0 79 0 292 0 320 0 350 0 381 0 413 0 447 0 484 0 525 0 573 0 634 0 776 0 8 0 266 0 294 0 324 0 355 0 387 0 421 0 458 0 499 0 547 0 608 0 750 0 81 0 240 0 268 0 298 0 329 0 361 0 395 0 432 0 473 0 521 0 581 0 724 0 82 0 214 0 242 0 272 0 303 0 335 0 369 0 406 0 447 0 495 0 556 0 698 0 83 0 188 0 216 0 246 0 277 0 309 0 343 0 380 0 421 0 469 0 530 0 672 0 84 0 162 0 190 0 220 0 251 0 283 0 317 0 354 0 395 0 443 0 503 0 646 0 85 0 135 0 164 0 194 0 225 0 257 0 291 0 328 0 369 0 417 0 477 0 620 0 86 0 109 0 138 0 167 0 198 0 230 0 265 0 302 0 343 0 390 0 451 0 593 0 87 0 082 0 111 0 141 0 172 0 204 0 238 0 275 0 316 0 364 0 424 0 567 0 88 0 055 0 084 0 114 0 145 0 177 0 211 0 248 0 289 0 337 0 397 0 540 0 89 0 028 0 057 0 086 0 117 0 149 0 184 0 221 0 262 0 309 0 370 0 512 0 9 0 029 0 058 0 089 0 121 0 156 0 193 0 234 0 281 0 3
10. 42 0 484 0 91 0 030 0 060 0 093 0 127 0 164 0 205 0 253 0 313 0 456 0 92 0 031 0 063 0 097 0 134 0 175 0 223 0 284 0 426 0 93 0 032 0 067 0 104 0 145 0 192 0 253 0 395 0 94 0 034 0 071 0 112 0 160 0 220 0 363 0 95 0 037 0 078 0 126 0 186 0 329 Table 1 1 KVAr REQUIRED FOR TRANSFORMER COMPENSATION KVA rating of the transformer KVA required for compensation Upto and including 315 kVA 5 of KVA ration 315kVA 1000 kVA 6 of kVA ration Above 1000 kVA 8 of kVA ration L amp T SWITCHGEAR ee es E S P SERVICE MANUAL 64 ESP SERVICE MANUAL Thumb Rule if HP is known The compensation for motor should be calculated taking the details from the rating plate of motor Or the capacitor should be rated for 1 3 of HP Refer Fig No 2 for the connection of capacitor Individual Compensation 1 Ensure the capacitor is protected using Supply Bus fuse MCB Transformer 2 The capacitor is switched ON along with starter Circuit Breaker 3 In case of star delta starter the capacitor should switch ON on delta mode Fig No 2 Where to connect capacitor 1 Fix compensation should be provided to take care of power transformer Power and distribution transformers which works on the principle of electro magnetic induction consume reactive power for their own needs even when its secondary is not connected to any load The power factor will be very low under such situation To improve the
11. 440 l 19 68AMPs 4 15kVAr 3 phases 415v 50Hz capacitor I kVAr x 107 V3 X V I 15x 1000 1 732 x 415 20 87 Amps Formula 2 1 The current of capacitor will not be same if voltage applied to the capacitor and frequency changes The example given below shows how to calculate capacitor current from the measured value at site heak C at Vis Xin Example Consider a capacitor of 15 kVAr 440V 50 Hz 19 68 Amps Three phase Capacitor IM 19 68 425 x 48 5 440 x 50 18 43 Amps Note Please ensure that the measurement is done using true RMS clamp meter 70 L amp T SWITCHGEAR ESP SERVICE MANUAL Formula 3 The capacitance value of a capacitor can be calculated using following formulae for delta connected 3 ph capacitor Please not that the value given below is between two terminals with third terminal open circuit C kVAx 10 4x II x f x v 3 phase capacitor Example 5 15kVAr 3 phases 415v 50Hz capacitor C 15 x 1000000000 4 x 3 142 x 50 x 415 x 415 138 62 uf micro farad 6 15kVAr 3 phases 440v 50Hz capacitor C 15 x 1000000000 4 x 3 142 x 50 x 415 x 415 138 62 uf micro farad Formula 4 KVAr calculation from the measured capacitance value of a capacitor KVAr 2 3 Ca Cb Cc x V27Uf 10 for three phase capacitor Consider you have measured a capacitor rated for 440 volts where in measured capacitance value is as follows 1
12. L amp T SWITCHGEAR SAFE amp SURE CAPACITOR AND APFC SYSTEM SERVICE MANUAL INSTALLATION amp TROUBLE SHOOTING Ex LARSEN amp TOUBRO LIMITED ESP SERVICE MANUAL Pm 1 POWER FACTOR IS NOT IMPROVING L amp T SWITCHGEAR 1 Please check if required kVAr of capacitors are installed 2 Check the type of capacitor installed is suitable for application or the capacitors are derated 3 Check if the capacitors are permanently ON The Capacitor are not switched off when the load is not working under such condition the average power factor is found to be lower side 4 Check whether all the capacitors are operated in APFC depending upon the load operation 5 Check whether the APFC installed in the installation is working or not Check the CT connection is taken from the main incomer side of transformer after the fix compensation of transformer Refer Fig No 1 6 Check if the load demand in the system is increased 7 Check if power transformer compensation is provided TR Supply ACB Bus Transformer Compensation Cum Capacitor stops Flm Control fuses F2 Capacitor stop fuses Kim Contactors SDF Switch disconnector fuse CR Power factor controller CT Current transformer TR Power transformer APFC Panel Fig No 1 Calculation of required capacitor The capacitor required should be calculated taking the data from electrical bill copies of last 4 6 months if bill is not
13. UAL gt 5 TROUBLE SHOOTING for Capacitor S om Capacitor terminal over heating Over heating of unit Capacitor drawing less current Power factor is not improved Fuse blowing but the capacitor is healthy Leakage of capacitor L amp T SWITCHGEAR Proper size of lug is not used Loose connection Rating of cable is not adequate Lugs having bad crimping Capacitor drawing over current 1 Poor ventilation 2 Drawing excessive current 3 Over voltage 1 Low voltage 2 Failure of capacitor elements 3 Improper rating of short circuit device Presence of harmonic causing Capacitor installed is not operated as required Capacitor is permanently switched on Transformer fix compensation is not proved Capacitor installed is less than the actual requirement 1 Fuse rating improper Harmonic over loading Fuse rating improper Harmonic over loading Over voltage Switching timer not provided On delay timer High ambient temperature Check the size of lug used and replace with suitable size 2 Tighten the loose connection 3 Check the cable current carrying capacity and if req change 4 Rectify the crimping 5 Check the voltage and reduce it if possible Check for any harmonic in the supply voltage Ensure cross ventilation for the installation area inside the panel Check for any harmonic prese
14. ad capacitive power factor which is wrong power factor To correct the indication of power factor interchange the wires Xc9 amp Xc10 connected to terminals Terminal provided for C T connection Relay indicating 0 98 lag power factor The relay is pre set at factor for fISBSIzl lag power factor If it is required to be changed well qualified electrical person should do it Please note the relay will taken min 90 seconds to start the automatic operation for every time whenever the panel supply is switched ON after an interruption For programming remove MEHER from front facia of the relay amp follow the instruction given below llllooo Button Rotary Switch Button Dip Switches Relay has two small push button O amp O for OFF reducing the value amp for ON increasing the value push button are provided behind MEHER the small button can be operated by finger One rotary switch is also provided between the two buttons for the selection of function to be set To be operated using small screw driver line tester 81 By selecting the positions following parameters can be set given in the table below Position Parameter indication on the front Parameter to be programmed selection fascia of relay A Indicates OFF No settings required Indicates MHEEA which is pre set target power factor for improvement Indicates 60 This should not be altered Indicates the present system power factor
15. cia of the relay Refer the printed information given on rear side of the relay Caution The site should be free from excessive dust chemical fumes amp vibrations as the fumes and vibrations will lead to damage of electrical contacts Ensure that all the electrical connection in the panel are tight as any loose connection will lead to increase in temperature and short circuit Ensure that APFC panel is installed with capacitors suitable for your electrical network As loads such as Arc furnace Welding Battery Charges UPS Power Electronics for motor controls AC DC Drivers and Telecommunication equipment generates harmonics which may lead to failure of normal capacitor 80 ESP SERVICE MANUAL Pm 8 OPERATING INSTRUCTIONS L amp T SWITCHGEAR Switch on the three phase power supply to the panel All the 3 phase indicating lamp will glow this indicates that the supply is available at the incoming terminals of the system Now switch on the main incommer of the APFC system When the main incommer of system is closed the relay start flashing the instantaneous power factor of the installation This power factor indicated by the relay is of the point from where the C T connection is taken The power factor indicated by the relay should be inductive and not capacitive For example it may indicate i0 75 which is 0 75 lag inductive power factor which is correct power factor or c0 75 which is 0 75 le
16. ctors separately Proper lugs are used for termination Proper size of cable is used Ph ph gap is 25mm and ph earth is 19mm The bus bar used for banking is 1 8 x rated bank current Forced cross ventilation should be provided in the installation area The plant has the facility to trip the filter banks under over voltage conditions Set for 1096 over voltage Filter banks are provided with suitable size of MCCB rating for protection Refer recommended switchgear Table 5 1 The MCCB is set for 1 3 x rated current of filter bank MCCB are recommended Filter is provided with suitable on delay timer to ensure that the capacitor is not switched on within 60sec After it is switched off Filter is installed in the area free from entry of dust chemical fumes and rain water APFC relay provided in the panel for switching filters is set for 60 second L amp T SWITCHGEAR 79 gt L amp T SWITCHGEAR E S P SERVICE MANUAL INSTALLATION GUIDELINES FOR APFC PANEL Shift the panel to the location where it is required to be installed a Position the panel on the foundation and lock the panel base frame with the foundation bolts for free standing panels by using spirit level and plumber block for achieving horizontal and vertical leveling b Position panel of the wall structure and fix with wall mounting brackets provided along with the panel Leveling should be done here also as explained above
17. d c Do the second check after six months and then once in every six months Inspect all wiring for wear and cuts and insulate replace as required Look for indications of over heating and insulation breakdowns Rectify the defect Inspect all contacts of power contactor and replace if necessary Clean the panel every month and remove any accumulated dust in the filter if provided use only compressed air for cleaning ak WN L amp T SWITCHGEAR 84
18. eck the fuse provided for individual contactor protection T Contactor are operating but it is not holding AL display R1 Check the location of CT and supply voltage phase identification given to the panel The voltage of the bus on which CT mounted with respect to relay A point of relay should be zero The voltage between A L2 amp L3 should be 415 440 volts Terminal Connection View of the Relay R2 Select position 4in relay for manual operation Switch ON the capacitor using button refer operating instruction The power factor should improved If not then it should come down If power factor is coming down then the voltage PHASE connection to the panel terminal is not correct Interchanging the wires connected to terminal A L2 and L3 of relay Note that after interchanging the relay may display leading power factor To correct this interchange the XC 9 amp XC 10 wires connected to the terminal blocks provided near the incomer of the panel This should be checked every time The Voltage terminal A L2 are Interchanged Again switch ON the capacitor see the change in the power factor The power factor should improve in one of the interchanged connection If power factor indication has no change after changing the A L2 amp L3 terminals then C T mounting location should be rechecked with reference to figure number 1 The C T should be always mounted on supply side of the plant where full load current of the plant s
19. f the main incomer of the panel All the control fuses are intact MCB is switched on Emergency push button is released Panel are installed in the area free from entry of dust chemical fumes and rain water Note Above points should be confirmed by contractor handling the job and then only the panel should be commissioned in presence of L amp T Engineer Check List 4 The following verification are required to be done for APFC relay used for switching 1 The relay is micrpocessor based 2 The setting of power factor and other parameters are set digitally 3 The time set in the relay is 60sec This should be verified by operating the relay 4 Relay should switch off all the capacitor banks in case of interruption in the supply voltage 5 Relay should not have malfuntioning problem such as chattering of contacts etc L amp T SWITCHGEAR 78 E S P SERVICE MANUAL Check List 5 Verify the following in the installation before commissioning harmonic filter banks a 7 Capacitor banks without reactor should not be permitted on the secondary size of transformer circuit which is having filter banks connected Please remove capacitors without reactors from the same network as IEC 61642 Filter rated voltage is equal to the max voltage recorded in the installation Capacitor used with reactors are always of special voltage recorded in the installation Earthing should be done at capacitors and rea
20. g tong tester Ensure that the tong tester used is of true RMS type Please note that meter contains True RMS Clamp Meter sticker Make a x record of measurement data of individual CA phase and other parameter as given in the table no 2 3 Check wether the current measured is within the limit value with respect to supply voltage amp data given in the name plate of capacitor Refer formula no 2 and 2 1 for calculation Discharge of Capacitor L T power capacitors are provided with discharge resistor to discharge the capacitor which is limited to one min The resistor are provided as per clause No 7 1 of IS 13340 1993 Switch off the supply to the capacitor and wait for 1 minute and then short the terminals of capacitor to ensure that the capacitor is completely discharged This shorting of terminals ensures the safety while handling the capacitor Discharge of capacitor also becomes necessary for the safety of meter used for capacitance measurement Measurement of Capacitance After discharging capacitor measure capacitance between two terminals and repeat for other terminals RY YB and BR Check the value from the Table No 2 1 amp 2 2 Please refer to the corresponding table for rated voltage You can also calculate the kVAr from the formula No 4 for the capacitor which may be derated Ensure that you have selected the right range for the measurement of capacitance Note The capacitor is
21. hould be sensed by the current transformer The cable to panel should come after C T any where on load side Refer Figure number 1 83 E S P SERVICE MANUAL 10 TROUBLE SHOOTING for APFC Panel Relay not functioning Check the connection of CT Refer Fig No 1 Relay not energizing Check that the supply is available at the terminal A L2 amp L3 Relay indicating wrong power factor Check that the supply is as per requirement of capacitor rating Capacitor drawing low current Check that the supply is as per requirement of capacitor rating Capacitor drawing high current It may be due to harmonics report to L amp T Immediately Sleeves of bus bar melting Check for loose connection tighten all the bus bar and switchgear terminals Switchgear problem Report to L amp T office Stockist Abnormal heating of enclosure Report to Meher L amp T immediately with correct location of heating area and measured temperature if possible Check and clean and filter Check for the proper function of the fans if provided Abnormal heating of Check whether the current drawn by the capacitor terminals capacitor is in excess of its rated value Check for loose terminal connection and re solder tighten as applicable Humming sound Check for the dust collection in the moving part Of the contractors Maintenance 1 Check tightness of all bolted joints a Prior to energisation b Six months after load is connecte
22. lay timer to ensure that the capacitor is not switched on within 60sec After it is switched off Capacitor is provided with insulating cover to ensure the safety Capacitor is installed in the area free from entry of dust chemical fume and rain water APFC relay provided in the panel is set for 60 second On delay provided are also set for 60 second The filter banks are provided with MCCB for protection apart from above points The MCCB should be set for 1 3 x rated current of filter bank Note The above points should be communicated to all the stocklist and panel builders to ensure the safety and long life operation of capacitors L amp T SWITCHGEAR 77 ESP SERVICE MANUAL Check List 3 Following points is required to be verified before commissioning APFC panel pol re All the electrical connection is checked for loose connection in the panel The C T Is connected to the terminal provided near the incomer of the panel The C T is located before the cable connection of APFC panel towards source main breaker of installation The C T is mounted on R phase Neutral cable is connected to the panel Current carrying capacity of cable in the APFC panel is rated equal to incommer switch current rating Capacitor is checked for any loose connection Earthing bus is connected Megger test is conducted for the cable connected to the incomer of panel This should be done after switching of
23. ll be lesser than rated value Table no 2 1 amp 2 2 gives you the resultant kVAr output of the capacitor due to variation in supply voltage Refer formula no 1 3636 eco TRUE RMS CLAMPMETER TABLE 2 1 Three phase 440V Capacitor kVAr Line kVAr Line Measured capacitance across two 440V current at Current terminals with third terminal open 440V 415V at 415V Micro farad 440V 5 6 56 4 45 6 188 41 10 7 5 9 84 6 67 9 28 61 66 10 13 12 8 90 12 38 82 21 12 5 16 4 11 12 15 47 102 76 15 19 68 13 34 18 56 123 31 20 26 24 17 79 24 75 164 42 25 32 80 22 24 30 94 205 52 TABLE 2 2 Three phase 415V Capacitor kVAr Line kVAr Line Measured capacitance across two 415V current at Current at terminals with third terminal open 415V 440V 415V Micro farad 415V 5 6 95 5 62 7 38 46 21 7 5 10 43 8 43 11 06 69 31 10 13 91 11 24 14 75 92 41 12 5 17 39 14 05 18 44 115 51 15 20 87 16 86 22 13 138 62 20 27 82 22 48 29 50 184 82 25 34 78 28 10 36 88 231 03 Caution Please ensure customer is not comparing wrong technologies such as our MPP S Capacitors with other makes APP MD or heavy duty MPP Capacitor Please also ensure that the customer is comparing with similiar voltage rated capacitor L amp T SWITCHGEAR ESP SERVICE MANUAL 67 L amp T SWITCHGEAR ESP SERVICE MANUAL Measurement of Current The capacitor current can be measured usin
24. n cases that the type of capacitor were selected with out considering future expansion of machineries in the plant Some time these machines are found to be generating harmonic affecting the life of capacitor 13 No replacement should be considered if capacitor is failed due to harmonics and customer has used normal capacitors without consulting L amp T MEHER Engineers Check List 2 The following points should be verified before charging capacitor banks installed in parallel or in APFC panel m o o o o oo o o Capacitor voltage rating is equal to the max voltage recorded in the installation Capacitor is mounted vertically Earthing at two different point is done Proper lugs are used for termination Proper size of cable is used Ph ph gap is 25mm and ph earth is 19mm The bus bar used for banking is 1 8 x rated current of the bank Cross ventilation provision is provided in the installation area in the panel oo NODA PF wWN The plant has the facility to trip the capacitor under over voltage conditions 10 Capacitor is provided with suitable size of HRC fuse MCCB rating for protection Refer recommended switchgear given in Table No 5 1 Suitable inrush current devide is connected in series with contactor to limit the inrush current or capacitor duty contactor is used Refer sheet no 13 indicating capacitor connected with inductor coil Annexure d is 13340 1333 Capacitor is provided with suitable on de
25. nce in the network Maintain the voltage within limits Refer the specification of capacitor Voltage to be maintained Should be checked if the capacitor are installed and operated as per guide line given above In case of improper HRC fuse rating the capacitor element would have failed during over current condition Check the operation of capacitors Capacitor should be allowed to switch on only when it is required Transformer should be provided with fix compensation Check the rating of capacitor installed is sufficient or not Fuse rating should be properly selected refer Table No 5 1 Check for harmonic over loading and if required install detuned filter banks Fuse rating should be properly selected refer Table No 5 1 Check for harmonic over loading and if required install detuned filter banks Replace capacitor in case it has no other problems 74 ESP SERVICE MANUAL gt Replacement of Individual Cells L amp T SWITCHGEAR i PSD operated cell 1 Using suitable size of star screw driver open the capacitor and remove front sheet of capacitor Check the capacitor cells by using capacitance meter The photo indicates the PSD operated cell which can be replaced with new cell Check the total number of cell inside the capacitor Please check whether cells are of single phase or Three phase Desolder the wire of
26. te harmonics Note that neighbouring plant connected to the grid may also affect the capacitors by importing the harmonic Harmonic voltage easily travels through the grid from one installation to another the effect of such voltage leads to failure of capacitor Check other points given in installation guide line of capacitor In case the installation is having MD XL capacitors with connected loads generating harmonics then the capacitor may be drawing additional 30 current In such conditions the fuses may blow out cable will heat up and Temperature of capacitor will be also increased Ensure that the fuse rating should not be increased The switchgear and cable size should be suitably increased The capacitor will continue to work but the life of capacitor may not be longer This clearly indicates that the capacitor is over loaded and if required the reactor should be provided for controlling the over current E S P SERVICE MANUAL 76 E S P SERVICE MANUAL 11 Check the short circuit protection device are as per Table no 5 1 Please note that you may come across the customer using fuses almost double the current rating of capacitors This is generally found in the plants having harmonic problems and the installations having hired local electricians for maintenance 12 Check the date of installation of capacitor and type of additional load being connected after installation of capacitors As it is observed in certai
27. th each other then ON delay timer 60sec should be provided and in case of parallel operation once again point No 1 should be taken care Clause No 7 1 of IS 13340 1993 The capacitor mounted in the panel should have min gap of 25 30 mm between the capacitor and 50 mm around the capacitor to the panel enclosure In case of banking a min gap of 25mm between the phase to phase and 19mm between the phase to earth should be maintained Ensure that the banking bus bar is rated for 1 8 times rated current of bank The panel should have provision for cross ventilation the louver fan can be provided in the care Annexure d point No d 3 1 IS 13340 1993 For use of reactor and filter in the panel fan should be provided for cooling Short circuit protection device HRC fuse MCCB should not exceed 1 8 x rated current of capacitor In case of detuned filter banks MCCB is recommended for short circuit protection Maintenance Loo Ga NN EEUU 1 2 L amp T SWITCHGEAR Check the current of capacitor and cable connection Tighten the connections if termination is found loose Clean the area around the capacitor Make use of table no 2 3 for recording the data of measurements Check the capacitance of capacitor once in three month Disconnect capacitor drawing over 3096 current than rated Contact us on help line for further action Disconnect the capacitor having leakage problem and replace 73 ES P SERVICE MAN
28. the cell which has operated PSD Remove the cell from capacitor by loosening the bolt in the bottom of cell Replace the cell and resolder the wire Qo o 0 00 FW ND The cells can be ordered accordingly depend upon the requirements Please contact L amp T sales office or L amp T stockist a a a Internal view of the capacitor Inductor coil connected with capacitor 75 P 6 CHECK LIST L amp T SWITCHGEAR Check List 1 am a The following points should be verified before considering replacement 1 Supply voltage to capacitor should be checked for any over voltage This can be verified of voltage stabilizers are connected in the installation light fitting are regularly replaced this indicates the over voltage It is generally found that i c base APFC relays are big in size as compared to microprocessor relays These ic based relays are found to be malfunctioning The capacitors are switched OFF amp ON very fast without discharge of capacitor leading to high current drawn by capacitors Such operation leads to failure of capacitor Check the time set in APFC relays connected for the operation as various make of relays are preset for 15 20 sec This setting of time should be verified in presence of customer at panel with operation of relay The switching of capacitor from one step to another should have min time gap of 60 second This should be physically watched
29. tion break down of cable Use proper tools for connection tightening Ensure that the capacitor is mounted vertically The earthing of capacitor should be done before charging oa e w The applied voltage should not exceed more than 10 Refer technical specification of capacitor 7 The capacitor should be provided with the short circuit protection device as indicated in Table number 5 1 Do not connect higher rating protection device Annexure D point Number D 7 1 IS 13340 1993 Table 5 1 Recommended switchgear KVAr I C HRC Fuse Contactor Cable Amps 5 FNX FN32 12 Amps MNX12 12 Amps FNX FN32 25 Amps MNX25 25 Amps 25 Amps FNX FN32 32 Amps MNX32 32 Amps 32 Amps FNX FN32 32 Amps MNX32 32 Amps 32 Amps so memas asanes woo tes amps anes L7 Futamo 200mos wbx22s atbmps z0Amps 72 ESP SERVICE MANUAL Use of capacitor in APFC panel 1 The capacitor should be provided with suitable designed inrush current limiting inductor coils or special capacitor duty contactors Annexure d point no d 7 1 of IS 13340 1993 Once the capacitor is switched off it should not be switched on again within 60 seconds so that the capacitor is completely discharged The switching time in the relay provided in the APFC panel should be set for 60 seconds for individual steps to discharge Clause No 7 1 of IS 13340 1993 If the capacitor is switched manually or if you are switching capacitors connected in parallel wi
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