| 摘要 |
PROBLEM TO BE SOLVED: To provide a protective relay device which automatically protects a power system even if a bus grounding accident occurs when a bus contact breaker is ON and besides a grounding order breaker is not used.SOLUTION: The protective relay device 10 includes trip signal generators 40 and 50 which generate seventh trip signals TRfor breaking the bus contact breaker 4 when the phases of second to sixth zero-phase currents I-Iare all within the range of ±90° to the phase of a first zero-phase current Iin case that both of first and second zero-phase voltages V, Vexceed a zero-phase voltage setting V, generate eighth trip signals TRfor breaking a first power receiving breaker 4in case that only the first zero-phase voltage Vexceeds the zero-phase voltage setting Vafter the bus contact breaker 4 is broken, and generate ninth trip signals TRfor breaking a second power receiving breaker 4in case that only the second zero-phase voltage Vexceeds the zero-phase voltage setting V. |
