MOA Resistive Current Detecting System Based On GPS Synchronization

It is useful for diagnosing the running state of the MOAs, discovering and removing a hidden danger to measure the variety of leakage resistive current in MOAs at regular intervals.This paper analyzed the method and disadvantage of the conventional MOA resistive current detection. And based on the analysis, it suggested MOA resistive current detection method based on GPS and wireless communication. That method took advantage of PPS pulses and wireless communication to accomplish the synchronous measurement of MOAs'voltage and leakage current. There was no need to make connections on the secondary side of PT in the measurement process, so it reduced the potential safety hazard. Apply phase difference algorithm based on Fourier series to calculate the phase difference between voltage and leakage current. Analyze the measurement error caused by the quantization bits, sample rate, sample time and system voltage variation through the simulation. The result of the analysis proved that the phase difference algorithm based on Fourier series can reduce the effect of measurement of resistive current fundamental wave caused by harmonic waves in the power system efficiently, and it has high precision.Propose the hardware design project of resistive current detecting system based on the theoretical analysis, and accomplish the circuit designing and software development. On account of the situation of cruel electromagnetism environment in the substations, introduce the method of anti-interference testing and the solution of certain problems in detail.The prototype devices are running in an 110kV substation. The on-the-spot data professed that the system can measure the resistive current in MOAs effectively and has preferable ability of anti-interference.