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

Commissioning, settingNeutral current is measured:c by CSH sensor,c by a 1A or 5A current transformer associated with aCSH30.Residual current is measured by the internal vectorsum of the 3 phase currents.Check:c the connections,c the position of microswitch SW1:c the position of microswitch SW2 for the useof 1A or 5A CT or CSP sensor,c general parameters in the status menu.Set the Iso current:c Iso is set as an rms value, in amps or kiloamps.The 999 kA setting may be used to inhibit theprotection: all the outputs are set to zero.SensorsRestricted earth fault protection F641 is relatedto the currents connected to the following connectors:current sensor connectorI1, I2, I3 1A or 5A CT 2BCSP2L1, 2L2, 2L3Ineutral CSH 2AIo CT+CSH30 2ARestricted earth fault protection F651 is relatedto the currents connected to the following connectors:current sensor connectorI1’, I2’, I3’ 1A or 5A CT 3BCSP3L1, 3L2, 3L3Ineutral CSH 3AIo’ CT+CSH30 3ARestricted earth fault protection F651 is relatedto the currents connected to the following connectors:current sensor connectorI1”, I2”, I3” 1A or 5A CT 4BCSP4L1, 4L2, 4L3Ineutral CSH 4AIo” CT+CSH30 4AIn order to guarantee the accuracy and stability of the protection, the currenttransformers must be of the 5P20 type.The power rating should be chosen so that the wiring resistance is less than therated load of the current transformer, i.e.:VA CT> R wIn 2VA CT: current transformer rated loadR w: wiring resistanceIn: CT secondary rated currentIn those conditions, correct operation is ensured in most applications.To size class X CTs, the following rules must be followed:c restricted earth fault protection on the transformer secondary circuit:external fault stability is ensured if the phase CT saturation current is more than2.4 times the phase-to-earth fault current and 1.6 times the 3-phase fault current.Internal fault sensitivity is ensured if the neutral CT saturation current is more than2 times the phase-to-earth fault current.c restricted earth fault protection on the transformer primary circuit:external fault stability is ensured if the phase CT saturation current is more than2.4 times the protected transformer phase-to-earth fault current.Internal fault sensitivity is ensured if the neutral CT saturation current is more than2 times the protected transformer phase-to-earth fault current.c restricted earth fault protection for generators:external fault stability is ensured if the phase CT saturation current is more than 2times the generator rated current.Internal fault sensitivity is ensured if the neutral CT saturation current is more than2 times the generator phase-to-earth fault current.CharacteristicsIso set pointrangeresolutionaccuracy (1)0.05 In to 0.8 In for In u 20 A0.1 In to 0.8 In for In < 20A1 A or 1 digit±5% or 5% Indrop out/pick-up ratio (93 ±5)%minimum return varianceIo restraint-Ineutral/Iofixed value 1.05accuracy (1) ±2%characteristic timesoperation timememory timefault recognition timereset timeoutputs availaible for program logicmin. 0.4% In< 40 ms< 25 ms< 25 ms< 40 msinstantaneous F641/1, F651/1, F661/1remote reading, remote setting* (1)function code F64, F65, F66identification number 164h, 65h and 66hparameters Iso set point unit: 1 A(1)in reference conditions (IEC 60255-13).(1)the data formats are defined in the manuals that describe each communication protocol.Protection functions2/67