Properties of Space Charge Distributions and Conduction Current in XLPE and LDPE under DC High Electric Field

Abstract

Space charge behavior and conduction current in polyethylene under dc stress were investigated. One of the reasons for the different breakdown property in crosslinked polyethylene (XLPE) from that in low-density polyethylene (LDPE) may be based on the existence of cross-linking by-products in XLPE. Furthermore, a thermal history in cross-linking process for XLPE may also cause of the difference. It is generally accepted that the existence of the cross-linking by-products increase the conduction current in XLPE under dc stress. It is also said that an anneal treatment in air atmosphere may affect to the electrical properties under dc stress. Therefore, we investigated the effect of the cross-linking by-products and the anneal treatment on space charge behavior and conduction current in polyethylene under dc stress. In our research, it is thought that the increasing dissipation power in XLPE is the cause of the breakdown in it under dc stress. Therefore, to calculate the dissipation power in the bulk of test sample, we measured the space charge distribution and the external circuit current simultaneously. Based on the results, we discussed the reason of the difference of the space charge properties in XLPE and LDPE focusing on the cross-linking by-products and the oxidation of the test samples. C⃝ 2016 Wiley Periodicals, Inc. Electr Eng Jpn, 198(3): 19-26, 2017; Published online in Wiley Online Library (wileyonlinelibrary.com).

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