Sepam - HV/MV Protection and control units (ENG) - Trinet

Neutral voltage displacement protectionANSI code59Nfunction n° F39X for Vo neutral voltage displacement 1 ≤ X ≤ 2F41X for Vo’ neutral voltage displacementEquipmentc single-phase and three-phase voltage generatorsc voltmetersc chronometerc calculatorc documentationWiringc diagram B4 or B7c protective relays:F391/1, F391/2F392/1, F392/2F411/1, F411/2F412/1, F412/2Testc read the section entitled measurement and testingmethodc status parameter settingv select Fn network frequency (50 or 60 Hz)v set Unp network phase-to-phase voltagev select the number of connected VTs given thatmeasurement by the sum of Vo voltages can only beused with 3 VTsv set Uns VT secondary circuit phase-to-phasevoltagev select Vnso the VT secondary circuit value whichenables Vo to be measured(Uns/1.732 or Uns/3 or sum of 3 Vs)v check the microswitches on the 3U/Vo moduleMicroswitch setting determines the Vo measurementmethod, i.e.:- no Vo measurement- measurement by open delta star VT of secondaryvalue Uns/1.732 or Uns/3 (A1-A2 inputs)- measurement by the sum of the 3 voltages(A1-A6 connection)Procedurec protection parameter setting: N Vol Dispv set Uso to the desired valuev set T to the desired valuev disable the lowest protection set point and P Seq U/V XTesting by injection with sum of the 3 voltages (diagram B4)Cut off Sepam's 2000 auxiliary power supply to set the microswitches (SW1).Measurement of Voby sum of 3VTsSum of3 VTsTesting of set pointc status parameter settingv select number = 3Uv select Vnso = sum 3Vc protection parameter setting: N Vol Dispv set Vso to the desired valuev set T to 0.05 sv wire all the voltage inputsc testv gradually increase one of the voltages (leaving the other 2 voltages at zero) untilthe output relay picks upv read the voltage value on the voltmeter and on the pocket terminalThe value will be: u = Vsov stop injectionv press reset (1) on Sepam 2000 to erase the messages and reset the output relayTesting of time delay T (sum of VTs)c protection parameter setting: N Vol Dispv set T to the desired valuec testv prepare the injection with 1.2 times the value of Vso (see above)v set the chronometer to zerov start injection and the chronometer at the same timev Sepam's 2000 output relay stops the chronometerv read the value measured by the chronometerIt is possible to conduct the test with a single-phase voltage generator.Remember to short-circuit the 2 voltage inputs which are not being used viaterminal A2.Example: microswitches set for sum of VTsc status parameter settingv Unp = 20 kVv Uns = 100 Vv number = 3Uv Vnso = 3 Vc protection parameter settingv Uso = 11.5 kVv T = 0.5 sFor an injection of u > 57.7 V, in accordance with diagram B4, into one of the phasevoltage inputs (the others = 0), the protection will trip after a period T = 0.5 s.(1)remember to reactivate the protections at the end of testing.X = number of the protective relay.1/36Sepam 2000 - Testing