7.4.2 FunctionalityThe out-of-step protection OOSPPAM (78) function in the IED can be used for bothgenerator protection and as well for line protection applications.The main purpose of the OOSPPAM (78) function is to detect, evaluate, and take therequired action during pole slipping occurrences in the power system.The OOSPPAM (78) function detects pole slip conditions and trips the generator as fastas possible, after the first pole-slip if the center of oscillation is found to be in zone 1,which normally includes the generator and its step-up power transformer. If the center ofoscillation is found to be further out in the power system, in zone 2, more than one pole-slip is usually allowed before the generator-transformer unit is disconnected.Consideration can be taken to the breaker trip time by parameter setting. If there areseveral out-of-step relays in the power system, then the one which finds the center ofoscillation in its zone 1 should operate first.7.4.3 Function blockANSI10000106-1-en.vsdOOSPPAM (78)I3P*V3P*BLOCKBLKGENBLKMOTEXTZONE1TRIPTRIPZ1TRIPZ2RIGENMODEMOTMODERXANSI10000106 V2 ENFigure 75: OOSPPAM (78) function block7.4.4 SignalsTable 70:OOSPPAM (78) Input signalsName Type Default DescriptionI3P GROUPSIGNAL- Group connection for three-phase current inputU3P GROUPSIGNAL- Group connection for three-phase voltage inputBLOCK BOOLEAN 0 Block of functionBLKGEN BOOLEAN 0 Block operation in generating directionBLKMOT BOOLEAN 0 Block operation in motor directionEXTZ1 BOOLEAN 0 Extension of zone1 reach to zone2 settingsSection 7 1MRK 502 048-UUS AImpedance protection174Technical manual
