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Abstract

A DC step test and a number of DC life endurance tests have been performed at a temperature of 20C on 200 m thick samples of a commercial (AC grade) XLPE and its nanocomposite which is intended for DC use. It was found that the breakdown strength of the nano-composite on the DC step test was considerably larger than that of the unfilled XLPE. However, the endurance tests showed that the difference between the characteristic lifetime of the nano-composite and its unfilled base polymer reduced as the applied field was reduced and the lifetimes became essentially the same when the applied field was 130 kV/mm, which is the lowest for which we have data at present. The life line was analyzed as an inverse power law and gave median life exponents of n = 10.76 for the nano-composite and n = 13.58 for the XLPE. These values are consistent with estimates from step tests on the same materials that have been recently published, and imply that the nano-composite will perform worse than the AC grade XLPE as a DC insulator if the inverse power law continues to be obeyed down to service fields.

Publication Type:	Article
Additional Information:	© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
Publisher Keywords:	XLPE, nano-XLPE, DC aging parameter, inverse power law
Subjects:	T Technology > TJ Mechanical engineering and machinery
Departments:	School of Science & Technology > Engineering
SWORD Depositor:	Symplectic Administrator

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