TRANSMISSION SYNCHRONIZING SYSTEM FOR CURRENT DIFFERENTIAL RELAY

摘要

PROBLEM TO BE SOLVED: To synchronize the sampling time by providing means for inserting an idle bit into the fixed frame length of a transmission signal in order to sample the terminal current of a power system at a same time and a constant period and thus performing protective operation using the sampled current data. SOLUTION: A current differential relay 2 samples a current data according to the output signal from a sampling synchronization oscillator 107 and converts the sampled current data into a digital quantity. A transmitting means 102 converts it into a transmission signal being delivered to an idle bit inserting means 105 and an operating means 104 simultaneously. The idle bit inserting means 105 adjusts the transmission data length and delivers the adjusted data as a transmission signal. A sampling synchronization control means 108 computes the sampling synchronization error ΔT and delivers a sampling synchronization signal to the sampling synchronization oscillator 107 in order to control the oscillation frequency such that the sampling synchronization error ΔT goes to 0 thus synchronizing the sampling time.