Physical Science, Measurement and Instrumentation, Management and Education, IEE Proceedings A

An extensive review is given of the published work on the conduction and dielectric properties of ZnO. This work ranges from microscopic studies to high-voltage tests for practical application. The many available equivalent-circuit representations are also described. The DC and AC characteristics of ZnO are known to intersect. The authors present test data which show this crossover effect, and provide high-voltage characteristics above the knee of conduction in the frequency range 20-200 Hz. An equivalent-circuit representation is given, based on these data, which takes account of the crossover effect, the importance of which may not only lie in a hysteresis effect at power frequency, but also in the response of ZnO arresters to fast voltage transients.