The Fault signal extraction research in the electric power metering system

摘要

On the basis of the resistance model of high voltage electric power metering system, we make a study on the saturation of the measuring CT when the load is heavy. Through experiments on measuring current transformers, we chose high-quality power frequency magnetic core of the least saturation. On the secondary side of the measuring CT, circuit debugging was carried on and through experiments, optimal circuit parameters were determined to optimize the detection circuit which reduced the resistance of the secondary side of the measuring CT to the utmost to decrease the magnetic flux in the magnetic core to weaken saturation. Through FIR filter we extract detection signal from the fault signal to diagnose the fault. The practical test show the extracted detection signal can accurately judge the fault.