ZONE 1ZONE 2OpModeZ3Z3FwdZ3RevtZ3LoadEnchModZ3ZONE 3OpModeU<U<tU<UVSealIn³³U3PI3PBLKZBLOCKBLCKUVTRUVTRZ3STZ3OPERATETRZ2STZ2STARTTRZ1STZ1OpModeZ2Z2FwdZ2RevtZ2LoadEnchModZ2OpModeZ1Z1FwdZ1RevtZ1LoadEnchRLdArgLdSTUV11IEC11000295-3-en.vsd³1IEC11000295 V2 ENFigure 147: Block diagram of ZGVPDIS7.10.7.1 Operation principle of zone 1In general, the zone 1 must cover the generator winding, the cables or busbars and stepup transformer.Under impedance functionality is provided as selective protection for the phase-to-phase faults in zone 1. Hence the functionality of zone 1 includes only phase-to-phasemeasuring loops.Zone 1 functionality can be set to PP Loops or Off using the setting OpModeZ1.Figure 148 shows the functionality of zone 1.Section 7 1MRK502052-UEN BImpedance protection324Technical manual
