Search for new diagnostics for metal oxide surge arrester

A new diagnostic technique called “return voltage measurement” is investigated to assess its effectiveness for monitoring degradation in metal oxide blocks. The return voltage measurement was conducted on a number of distribution class zinc-oxide arresters. The findings from these measurements are described in this paper. The first part describes some results on the reproducibility of return voltage measurements and also the polarity effects on measurements. The second part presents the results of monitoring the arresters while being subjected to elevated temperatures using the return voltage measurement