3.2 Back-up protection functions GUID-A8D0852F-807F-4442-8730-E44808E194F0 v13IEC 61850 orfunction nameANSI Function description Line DistanceREL650 (A11) REL650 (A12)Current protectionPHPIOC 50 Instantaneous phase overcurrent protection 1 1OC4PTOC 51_671) Directional phase overcurrent protection, four steps 1 1EFPIOC 50N Instantaneous residual overcurrent protection 1 1EF4PTOC 51N67N2)Directional residual overcurrent protection, four steps 1 1NS4PTOC 46I2 Four step directional negative phase sequenceovercurrent protection1 1SDEPSDE 67N Sensitive directional residual overcurrent and powerprotection1LCPTTR 26 Thermal overload protection, one time constant,Celsius1 1LFPTTR 26 Thermal overload protection, one time constant,Fahrenheit1 1CCRBRF 50BF Breaker failure protection 1 1CCPDSC 52PD Pole discordance protection 1 1VRPVOC 51V Voltage restrained overcurrent protection 1Voltage protectionUV2PTUV 27 Two step undervoltage protection 1 1OV2PTOV 59 Two step overvoltage protection 1 1ROV2PTOV 59N Two step residual overvoltage protection 1 1Frequency protectionSAPTUF 81 Underfrequency protection 1 1SAPTOF 81 Overfrequency protection 1 1SAPFRC 81 Rate-of-change of frequency protection 1 11) 67 requires voltage2) 67N requires voltageSection 3 1MRK 506 383-UEN AAvailable functions24 Line distance protection REL650 2.2 IECCommissioning manual
