Magnetizing inrush current control function Built-in digital protection relay equipment

摘要

PROBLEM TO BE SOLVED: To provide a digital protective relay incorporating an excitation rush current control function which can suppress the excitation rush current of a transformer effectively even in case of a fault of a transmission line or the attenuation of residual flux.;SOLUTION: The digital protective relay 1 comprises a phase control determination processing section 32 for storing the voltage phase during stoppage, calculating a closing time when the bus voltage or the line voltage has the voltage phase during stoppage for a first time upon elapsing the total time of the relay determination time or a processing time and the set closing time after a current time, calculating a residual time by subtracting the current time from the calculated closing time and then calculating a waiting time at the current time by subtracting the set closing time from the calculated residual time, and a phase control SQ processing section 42 delivering an output signal so that the closing signal of a circuit breaker 90 is outputted upon elapsing the waiting time calculated at the phase control determination processing section 32 after a time when the closing designation signal of the circuit breaker 90 was inputted.;COPYRIGHT: (C)2008,JPO&INPIT