The temperature dependence of the dielectric strength of transformer oil and pressboard insulation at HVDC polarity reversal stress

C. Krause1, R. Woschitz2
1Weidmann Transformerboard Systems AG, Rapperswil, Switzerland
2Technical University of Graz, Graz, Austria

Tóm tắt

This work reports on measurements investigating the dielectric strength of insulating oil and Transformerboard, from very low (-20/spl deg/C) to increased temperature (+60/spl deg/C). Different insulation structure models-board puncture and creepage-were stressed with 1 hour DC step-by-step voltage increase of reversed polarity each step, until breakdown. The impact of adhesives and their orientation relative to the electric field was investigated. As a reference, the AC strength and the moisture content of the oil was measured. With the results from this study, important knowledge of the DC behavior of oil/cellulose insulation is gained. The findings constitute a profound basis for improved HVDC power transformer insulation technology.

Từ khóa

#Oil insulation #Temperature dependence #Dielectric breakdown #Dielectrics and electrical insulation #Power transformer insulation #HVDC transmission #Stress #Petroleum #Breakdown voltage #Dielectric measurements

Tài liệu tham khảo

10.1109/57.744585 moser, 1987, Transformerboard II, 53 1976, Voltage Tests on Transformers and Smoothing Reactors for Transmission, Electra, 19