The Network-model On-line Monitoring System of ZnO Surge Arresters in 500kV Substation

In this paper, some existing problems of the on-line monitoring of ZnO surge arresters are discussed. On the basis of the measuring method of resistive basic harmonic current, some improvements are introduced, including the unique device for signal acquisition, selection of reference signal, time sharing and self calibration technique. The on-line monitoring of 500 kV ZnO surge arresters shows that the performance of this instrument is perfect in the collection, processing of the signal and preventing electromagnetic disturbances. Furthermore, it can be used freely among the 3 modes of local test, remote test and automatic test to realize the goal of full automation