Statistical study on short-term dielectric breakdown of poly(vinyl chloride)

Abstract

This paper reports the breakdown voltage of plasticized poly(vinyl chloride) under AC and DC electric fields. The effect of ramp rate on breakdown voltage was investigated. A statistical analysis of breakdown data was carried out by using the two‐parameter Weibull distribution. The best linear fit was determined by an estimation based on the method of maximum likelihood. The 90% confidence intervals of Weibull plots were calculated, and the model was validated by the χ2 test. The study showed that the shape parameter varied with ramp rate. This result could be explained by the evolution of defect number and size. Breakdown voltage increased with ramp speed. This phenomenon was attributed to the time necessary for the accumulation of defects and charges to form a breakdown path. Breakdown voltage was higher under a DC field. This increase was due to the difference in dissipated energy under the two types of field and to the fatigue produced by AC stress. The DC breakdown voltage was greater under negative polarity. This finding was ascribed to the ratio difference of space charge accumulated under the two polarities. J. VINYL ADDIT. TECHNOL., 19:177‐182, 2013. © 2013 Society of Plastics Engineers

Breakdown Behaviour of Polyesterimide Enamelled Wire Subjected to Thermal Aging

“…Gockenbach and Schiller [22] found that the highest breakdown voltage of XLPE was measured at DC voltage with negative polarity and the lowest at AC voltage. In previous works, we pointed out that breakdown voltage of polyesterimide, polyamide imide and polyvinyl chloride depends on the shape of applied electrical field [23,24]. Iddrissu et al [25] reported that under DC stress, the initiation and growth of electrical trees are dependent on the polarity.…”

“…This phenomenon is allotted to the different amounts of the space charge accumulated under the two polarities. It was indicated effect of the form of applied voltage on dielectric breakdown [22][23][24][25]. Gockenbach and Schiller [22] found that the highest breakdown voltage of XLPE was measured at DC voltage with negative polarity and the lowest at AC voltage.…”