Preliminary Results on the Surge Current Withstand Capability of Natural Ester Oil

Natural ester oils are an environmentally friendly substitute for mineral oils that are commonly used as dielectric insulating liquid and coolant in power transformers. In this study, the real relative permittivity and DC breakdown voltage of a natural ester oil are experimentally examined. An accelerated degradation test employing 15 current impulses is employed to investigate the change of the basic electrical characteristics of the oil under study with the aid of a 1 MV/ 7 kJ Marx generator. Experimental results on the surge current withstand capability of the natural ester oil are presented and discussed.