Scaling Law Applicability to Oil-insulated Parallel-plate Capacitors

This paper presents the derivation of the three dimensional scaling law for liquid insulators. The case of the parallel plate capacitor geometry was investigated, and it was assumed that the "breakdown voltage" random variable follows Weibull distribution. The deduced scaling law was experimentally verified for fresh and used mineral transformer oil. Good agreement of the obtained results with theoretical expectations confirms validity and applicability of the three dimensional scaling law in the investigated case. Results obtained in this paper indicate that application of the scaling law is more convenient in the case of oil insulators compared to other insulator types, due to mutual independence of discharge processes.