Electrical treeing in a glassy epoxy resin – the filamentary tree and the PD tree

Hualong Zheng, Simon Rowland

    Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

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    Two types of electrical trees have been observed to grow in a glassy epoxy resin of needle-plane geometry under 50 Hz AC voltage. They differ in their constituent channel radii and the associated partial discharge activity. The so-called ‘filamentary tree’ has finer channels and much smaller discharge
    magnitudes than the ‘PD tree’. This work describes an electrical treeing process containing a clear transition from filamentary tree growth to PD tree growth with associated changes to partial discharge measurements. Apart from emphasizing the importance of recognizing tree channel thickness, it provides experimental evidence for an electro-mechanical treeing process in which filamentary channel propagation is followed by enlargement of the channel radius by partial discharges. Moreover, the PD characteristics during the transient stage are
    assessed. The magnitude of partial discharges during the transition stage was found to be polarity dependent.
    Original languageEnglish
    Title of host publicationIEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP),
    Publication statusPublished - 2018


    • electrical tree
    • partial discharge
    • filamentary tree


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