Courtesy of NationalSwitchgear.com
Page 1: ...GEK 1291H INSTRUCTIONS OFFSET MHO DISTANCE RELAY TYPE CEB52A GENERAL ELECTRIC Courtesy of NationalSwitchgear com ...
Page 2: ...TESTS VISUAL INSPECTION MECHANICAL INSPECTION ELECTRICAL CHECKS OM UNITS ELECTRICAL TESTS TARGET SEAL IN UNIT INSTALLATION PROCEDURE LOCATION MOUNTING CONNECTIONS VISUAL INSPECTION MECHANICAL INSPECTION PORTABLE TEST EQUIPMENT OFFSET CHECK ELECTRICAL TESTS ON THE OM UNITS INSPECTION MHO UNITS PERIODIC CHECKS AND ROUTINE MAINTENANCE CONTACT CLEANING SERVICING CONTROL SPRING ADJUSTMENTS OHMIC REACH ...
Page 3: ...cs for this relay with the strong spring setting with and without offset When the relay is employed with bus potentials or if it is used in straight distance schemes a weaker spring setting may be employed The section under SERVICING describes how the spring setting can be changed Figs 7 and 8 give the operating characteristics for the weaker spring setting with and without offset The CEB52A will ...
Page 4: ...R X diagram it is easiest to arrive at the proper tap setting by means of a graphical solution as outlined below 1 Draw the R X diagram as in Fig 2 Draw line 0A at the impedance angle of the line and measure off the length to be protected In this case it is 6 0 ohms Through the point S representing the offset which in this case is R 0 X 0 5 draw the line BC at the angle of maximum torque for which...
Page 5: ... ohmic reach of the OM units can be adjusted in one percent steps over a 10 1 range for any of the basic minimum reach settings listed in Table II by means of autotrans former tap leads on the tap blocks at the right side of the relay The OM units may be offset Selection of either zero or 0 5 ohms offset is made by means of links on terminal boards located on the rear of the relay Fig 13 and by ad...
Page 6: ...sides by E and transpose equation reduces to The 1 cos 0 0 K Z or Y cos 0 0 K Thus the unit will pick up at a constant component of admittance at a fixed angle depending on the angle of maximum torque Hence the name mho unit When offset is used the transactors 01 02 and 03 are energized with line currents and introduce a voltage proportional to the current added to the line to line voltage receive...
Page 7: ...l operate may be somewhat lower than the calculated value This pullback or reduction in reach is shown in Figs 5 and 6 for the Strong Spring Setting The unit reach in percent of setting is plotted against the three phase fault current for three ohmic reach tap settings Note that the fault current scale changes with the basic minimum reach setting The 0M unit will operate for all points to the righ...
Page 8: ...tact with the unit connected for zero offset These curves also apply for faults in the forward direction if the unit is connected for 0 5 ohm offset The curves in Fig 10 show opening times of the normally closed contact with the unit connected for 0 5 ohm offset for faults in the direction of the offset reverse It will be noted that for equivalent conditions that is for the same operating current ...
Page 9: ...basic reach tap setting The burden on the two lower basic reach tap settings will be lower The above data includes the burden of the transactor used to offset the mho characteristic If the offset tap is in zero the burden will be slightly less POTENTIAL CIRCUITS The maximum potential burden imposed on each potential transformer at 120 volts is listed in Table V TABLE V Rated Frequency VA Watts Cir...
Page 10: ...umbscrews holds the connecting plugs in place The target reset mechanism is a part of the cover assembly The relay case is suitable for either semiflush mounting on all panels up to two inches thick and appropriate hardware is available However panel thickness must be indicated on the relay order to insure that proper hardware will be included A separate testing plug can be inserted in place on th...
Page 11: ...led in its upright position the contacts of all three units must be open The moving contacts of the units should rest against the backstop The armature and contacts of the seal in unit should move freely when operated by hand There should be at least 1 32 inch wipe on the seal in contacts Check the location of the contact brushes on the cradle and case blocks against the internal connec tion diagr...
Page 12: ...r so that the phase angle meter reads the value in Table IX for the unit to be checked at 120 volts and five amperes Disconnect the No 1 re straint tap leads from the tap block and set the mho units for maximum basic minimum reach and offset out With the voltage across relay studs set at 120V increase the current until the clutch just slips This should occur between the values given below TABLE VU...
Page 13: ...es used in the previous check i e 315 degrees and 255 degrees are 30 degrees away from the angle of maximum torque An examination of the OM unit impedance characteristic in Fig 4 shows that the ohmic reach of the unit should be the same at both 315 degrees and 255 degrees and should be 0 866 times the reach at the angle of maximum torque TABLE X Phase Angle Meter Reading Basic Minimum Ohmic V Pick...
Page 14: ... result from instrument inaccuracies and to permit testing the mho units from a single phase AC test source the test circuit shown in schematic form in Fig 14 is recommended In this first R jK is the source impedance SF is the fault switch and R jX _ is the impedance of the line section for which the relay is being tested The autotransformerTA which is across the fault switch and line impedance is...
Page 15: ...e of the test reactor may be very accurately determined from its calibration curve it is desirable to check mho unit pickup with the fault reactor alone due account being taken of the angular difference between the line reactance X _ and mho unit angle of maximum reach The line reactance XL selected should be the test reactor tap nearest above twice the mho unit phase to neutral reach with account...
Page 16: ... unit reach at the 60 degree and 30 degree position The mho unit ohmic reach at the zero degree position may be checked by using the calibrated test resistor alone as the line impedance The calibrated test resistor is sup plied with a data sheet which gives the exact impedance and angle for each of the combinations available The test box autotransformer percent tap for pickup at a particular angle...
Page 17: ...e units will not operate PERIODIC CHECKS AND ROUTINE MAINTENANCE In view of the vital role of protective relays in the operation of a power system it is important that a periodic test program be followed It is recognized that the interval between periodic checks will vary depending upon environment type of relay and the user s experience with periodic testing Until the user has accumulated enough ...
Page 18: ...ccessible from the front of the relay Connect the relay as shown in Fig 13 leave the restraint taps at 100 percent and be sure that the basic minimum reach taps are in the position shown in Table XIV With current at five amperes and voltage at 120 volts set the phase shifter so that the phase angle meter reads the angle shown in the table for the unit to be checked Now reduce the voltage V g to th...
Page 19: ...5 5 75 2 35 3 20 285 1 0 3 0 4 0 Out 2 0 2 12 2 88 1 17 1 50 285 2 0 6 0 Out 4 0 4 0 1 06 1 44 0 60 0 80 TABLE XIV Basic Minimum Reach Taps Set Pickup Current Phase Angle Meter Reads Adjustment i VAB Offset Tap nit Used Volts Amps Bottom Top Middle 285 0 5 1 5 1 0 Out R13 R11 R 12 30 14 8 15 2 285 1 0 3 0 2 0 60 Out R13 R11 R 12 14 8 15 2 11 1 11 4 285 2 0 6 0 4 0 Out 90 R11 R 13 R 12 TABLE XV Pha...
Page 20: ...STRAINT TAPS R 13 MHO UNIT J 3 1 R 23 FIG 1A 8036592 Front View 4 1 2 OFFSET TAP BLOCK 4 1 2 TAP BLOCK BASIC MIN REACH 4 2 3 OFFSET TAP BLOCK J 2 3 BASIC MIN REACH 4 3 1 OFFSET TAP BLOCK 4 3 1 BASIC MIN REACH FIG IB 8036593 Back View FIG 1 Offset MHO Distance Relay CEB52A 20 Courtesy of NationalSwitchgear com ...
Page 21: ...GEK 1291 X 8 0 B A 7 0 6 0l _2L lu 5 0 4 0 3 0 i t 2 0 80 2 R 1 0 2 5 0 6 0 3 0 c FIG 2 0127A9443 0 Graphical Construction of Offset MHO Diagram 21 Courtesy of NationalSwitchgear com ...
Page 22: ... 15 5 3 10 Y rrY Y Y Y rY NO I CM POL POL E B FRONT R M B RESTR f u R 21 Bl El t B2 B3 E2ff E3 NT I 3 3 BACK NT 2 u B POL OUT TR Pri IN ii T2 2 I FIG 3 0246A3363 0 Schematic Connections of the MHO Unit 22 Courtesy of NationalSwitchgear com ...
Page 23: ...GEK 1291 FIG 4 0127A9528 Steady State Impedance Characteristic of the OM Unit 23 Courtesy of NationalSwitchgear com ...
Page 24: ...T CM RESTRAINT TAP SETTING 3NTHREE PHASE FAULT CURRENT STRONG SPRING SETTING 3 4 4 ft l 3 4C T 100 T 50 7 25 4 4 1 30 t 20 i t N 44 S 5 t 4 4 f SASIC VMIWIAJU flBACH 7 3 OHMS 9 10 5 2 OHMS 18 21 1 OHM 5 6 3 4 S2 7J5 6 4 1 3 1 5 9 2 3 is 30 FAULT CURRENT W AMPERES FIG 5 0203A8545 1 Steady State and Dynamic Accuracy of the OM Unit in the CEB52A Relay Strong Spring Setting 24 Courtesy of NationalSwit...
Page 25: ... 10 0 fc 50 n 5t o 100 7 3 0HMS BASIC 10 5 2 OHMS MIMIMJrf 21 1 OHM REACH 5 6 2 3 4 7 5 9 6 3 4 5 1 6 12 18 3 6 15 9 FIG 6 0203A8546 1 Steady State Accuracy of the OM Unit in the CEB52A Relay Strong Spring Setting 25 Courtesy of NationalSwitchgear com ...
Page 26: ...Y STATE CHARACTERISTIC DYNAMIC CHARACTERISTIC T 0M RESTRAINT TAP SETTING 30 THREE PHASE FAULT CURRENT t d DC 60 WEAK SPRING SETTING 4 1 U I F V 4 5Q E 3 40 T 100 T 50 T 29 5 30 rf 20 4 4 r V 5 V 10 4 I 4 4 0 1 2 3 4 5 0HMS BASIC 2 OHMS MINIMUM 1 OHM REACH 6 7 3 1 5 3 4 5 6 7 5 9 10 5 6 9 12 15 18 3 21 30 FAULT CURRENT IN AMPERES FIG 7 0203A8547 0 Steady State and Dynamic Accuracy of the OM Unit in...
Page 27: ...T TAP SETTING 300 PHASE FAULT CUfiROfT WEAK SPRING SETTING M it i 60 50 Z 40 u o I 30 T 100 T 501 T 25 cc 5 UJ 20 ct t 0 30 FAULT CURRENT IN AMPERES S 5 s V t s GO u i L Q i EU 5 M R 2 3 5 6 3 OHMS 2 OHMS 4 BASIC INIMUM REACH L5 7 5 9 10 6 3 4 5 6 21 1 OHM 12 15 18 3 6 9 8 0203A8548 1 Steady State Accuracy of the OM Unit in the CEB52A Relay Weak Spring Setting FIG 27 Courtesy of NationalSwitchgear...
Page 28: ...FIG 9 0203A8549 0 Operating Time Curves for the OM Unit with the Zero Offset Showing Time to Close Normally Open Contact 28 Courtesy of NationalSwitchgear com ...
Page 29: ...FIG 10 0203A8550 1 Operating Time Curves for the OM Unit with 0 5 Ohm Offset Showing Time to Open the Normally Closed Contact 29 Courtesy of NationalSwitchgear com ...
Page 30: ... 02 01 T NT 1 NT 2 I NT I 3 NT 3 2 fT r 4 T SI 01 2 101 2 CI2 4 T 5I CM 01 2 031 02 3 FOLAR POLAR POLAR It nR22 j Li j02 3 C I3 j 5 3U T95J5 15 95 0 I 35 riT NO I NO I n IZZF REST 3 RI2 REST 01 2 1 H R2sJ IP Rll n REST RI3 02 3 03 1 J01 2 AJ LAJ0 A 01 2 02 3 0K2 0 03 1 d Be B B O1 K OUT OUT OUT 4OFFSET 0 TR CT IN TR O 02 OFFSET OFFSET TR C 01 03 Y Y Y v Y V y V V 0 o o 9 C 7 3 6 6 o o 2 10 6 8 SHO...
Page 31: ...9 5 6 6 10 FIG 13 0203A8617 0 Rated Frequency Test Connections for Checking Correct MHO Unit Operation T RS lLOAD BOX SF LEAD A 115 VOLTS SYSTEM FREQ XL TA 1 Q 1 i LEAD 8 1 1 LEAD D LEAD C CONNECT LEAD TO RELAY STUDS AS FOLLOWS UNIT JUMPER RELAY STUDS LOCATION UNIT LEAD A LEAD B LEAD C LEAD D TOP 01 2 15 IT 6 8 10 5 7 19 7 6 8 10 MIDDLE 02 3 17 9 15 5 6 8 10 BOTTOM 03 1 19 9 FIG 14 0203A8616 0 MHO...
Page 32: ...l rJ I i a Vo IA ft O n c ws tf X r S u 3 O 1 0 2 Q BOTTOM TEST PLUG 9 4 4 t 2 8 o c I N CM rJ 10 3 8 o 8 o N O rJ I ie vT i o i 3 I w A e le n T is k k i ft o c j 11 0 0 019 CONNECTIONS TO PHASE ANGLE METER TO CHECK PHASE 2 CURRENT AND PHASE 2 3 VOLTAGE UJ o 12 020 o UJ E UJ TOP TEST PLUG UJ 3 91 UJ 1 n co 1 3 CM CM CM UJ I C D UJ x o ft 5 a cr cs CM CM CO CO I I I I I I UJ 4 O O UJ w UJ x I QC E...
Page 33: ...ION 10 20 NO TYPE 7 17 1 14 6 ELEN 21 Zl CEY51A 3 PHASE 1ST 70NF UHT1 REI AY _ CL ISI LIWttfaiBm so T SI T y si 19 16 16 13 PriA ETC7 L T SI 1X 3L rZL T 4 SI TARGET 4 SEAL IN UNIT TX oRED 21 22 CEY52A 3 PHASE 2N0 ZONE MHO RELAY 13 19 LAMP 0 1 2 PHASE 1 2 UNIT ETC T 4 SI TARGET 4 SEAL IN UNIT 21 Z3 CE652A 3 PHASE 3RD ZONE QFESET MHO RELAY 11 11 11 zz 2ix 0 1 2 PHASE 1 2 UNIT ETC rr 21 Z2 TsT TR 1 P...
Page 34: ...UDS A 10 OF 21 13 DEVICE CIRCUIT BREAKER 3 2 1 W LFGFND 1 It 6 DEVICE DEVICE INCL ELEM DESCRIPTION XL NO TYPE TS1 CEY51A 3 PHASE 1ST 70NF MHO RFI AY m ri T T maifegfa ETC7 oRED T A S I TARGET A SEAL IN UNIT 13 16 13 LAMP 21 72 3 PHASE 2ND ZONE MHO RELAY CEYS2A tf 1 2 PHASE 1 2 UNIT ETC T A S I TARGET A SEAL IN UNIT 11 11 11 21 73 CE852A 3 PHASE 3R0 ZONE OFFSET MHO RELAY J 21 23 21 Z2 T5T 21 Zl T5T...
Page 35: ...G MOVING CONTACTS UPPER CONTROL SPRING NORMALLY OPEN STATIONARY CONTACT NORMALLY CLOSED STATIONARY CONTACT FIG 19 8041447 Four Pole Induction Cylinder Unit Typifying Construction of the MHO Units in the CEB52 Relay 35 Courtesy of NationalSwitchgear com ...
Page 36: ...0 3 16MM 5 8 9 875 251MM r 9 937 7 781 198MM 1 75 44MM 075 I 171 MMJ 252MM L L i 0 3 5 0 PT342MM t doll 241MM T OPo 00 t 3 500 19 75 502MM 15 562 396MM CUTtlUT 19 875 504MM 88MM I I I 4 1 468 37MM I J 718 250 2 843 72MM 18MM 6MM 500 218 218 5 25 12MM TYPICAL 5MM 5MM 133MM 5 687 3 4 DRILL 20 HOLES 19MM 144MM PANEL PANEL DRILLING FDR SURFACE MOUNTING FRONT VIEW 111 PANEL DRILLING FOR SEMI FLUSH MOUN...
