1MAC309294-MB F Section 4Protection functionsRER620 83Technical ManualSection 4 Protection functions4.1 Current protection4.1.1 Single-phase non-directional overcurrent protection 51P/50P4.1.1.1 Identification4.1.1.2 Function blockFigure 34: Function block4.1.1.3 FunctionalityThe three-phase overcurrent protection 51P/50P is used as one-phase, two-phase orthree-phase non-directional overcurrent and short-circuit protection for feeders.The function picks up when the current exceeds the set limit. The trip time characteristicsfor low stage 51P and high stage 50P-1/2 can be selected to be either definite time (DT) orinverse definite minimum time (IDMT).The instantaneous stage 50P-3 always trips withthe DT characteristic.In the DT mode, the function trips after a predefined trip time and resets when the faultcurrent disappears. The IDMT mode provides current-dependent timer characteristics.The function contains a blocking functionality. It is possible to block function outputs,timers or the function itself, if desired.4.1.1.4 Operation principleThe function can be enabled and disabled with the Operation setting. The correspondingparameter values are “Enable” and “Disable.”Function description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberSingle-phase non-directional overcurrentprotection - Low stageSPHLPTOC 3I> 51PSingle-phase non-directional overcurrentprotection - High stageSPHHPTOC 3I>> 50P-1/50P-2Single-phase non-directional overcurrentprotection - Instantaneous stageSPHIPTOC 3I>>> 50P-3I_AI_BI_CBLOCKENA_MULT51P-1/2 TRIPTRIP_ATRIP_BTRIP_CPICKUPPICKUP_APICKUP_BPICKUP_CI_AI_BI_CBLOCKENA_MULT50P-1 TRIPTRIP_ATRIP_BTRIP_CPICKUPPICKUP_APICKUP_BPICKUP_CI_AI_BI_CBLOCKENA_MULT50P-2 TRIPTRIP_ATRIP_BTRIP_CPICKUPPICKUP_APICKUP_BPICKUP_C
