Theoretical Studies of the Cumulative Effects Related to the Application of Strong Electric Fields on the Lifetime of Solid Insulation Structures

• Published in: IEEE transactions on plasma science Vol. 49; no. 3; pp. 1201 - 1206
• Main Authors: Su, Jian-Cang, Zhao, Liang, Qiu, Xu-Dong, Li, Rui, Cheng, Jie
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Cumulative breakdown; Dielectric barrier discharge; Dielectric breakdown; Dielectrics; Electric breakdown; Electric fields; Electric potential; Insulation; insulation structures; lifetime; Partial discharges; Reliability; Solids; Statistical analysis; Voltage; Weibull distribution
• ISSN: 0093-3813; 1939-9375
• DOI: 10.1109/TPS.2021.3055813

The cumulative breakdown process of solid dielectrics results in partial discharge and degradation. As the pulse number or the time increases, the total insulation performance of a solid insulation structure decreases and the breakdown probability increases until the final breakdown occurs. A formula to describe the breakdown probability (<inline-formula> <tex-math notation="LaTeX">P </tex-math></inline-formula>) in the cumulative breakdown process is presented and a lifetime formula is defined as 1/<inline-formula> <tex-math notation="LaTeX">P </tex-math></inline-formula>. By assuming that the breakdown voltage (<inline-formula> <tex-math notation="LaTeX">V_{\mathrm {BD}} </tex-math></inline-formula>) conforms to the Weibull statistical distribution, a lifetime formula is derived with <inline-formula> <tex-math notation="LaTeX">V_{\mathrm {BD}} </tex-math></inline-formula> and its relative variance (<inline-formula> <tex-math notation="LaTeX">\delta </tex-math></inline-formula>) as the key parameters. It is found that the longest lifetime and the operation voltage conform to a power relation with 1/<inline-formula> <tex-math notation="LaTeX">\delta </tex-math></inline-formula> as the power exponent. In practice, <inline-formula> <tex-math notation="LaTeX">\delta </tex-math></inline-formula> should be as small as possible if a long lifetime is expected.