Experimental Research on the Degradation of MOV Used in Multiplate Paralleling

Abstract

The structure of multiplate paralleling of MOV (metal oxygen varistor) are widely used in practical, which can not only decrease the residual voltage, but distribute current and prolong MOV’s lifetime. But the characteristic of the group of MOV would be largely effected without preparation by screening strictly. We forced our research on three pieces of MOV used in paralleling whose U1mA were different to each others. By analysising the variation of U _1mA, I _leakage and nonlinearity coefficient (α), the conclusions are obtained as following. Firstly, the piece with the minimum U _1mA initial would be the most likely to be degradation, the group of paralleling pieces would be more easier to be degradation because of the piece with initial minimum U _1mA, degradation ratio was 1% varied in each stock, about 2.7 times than other pieces, and the other pieces in paralleling would be also degradation comparatively. Secondly, analysising the variation trend of nonlinearity coefficient (α), the degradation finally leaded MOV to be short circuit.