Using the UHF technique to investigate PD produced by defects in solid insulation

Author

Sellars, A.G. ; Farish, O. ; Hampton, B.F. ; Pritchard, L.S.

Author_Institution

Centre for Electr. Power Eng., Strathclyde Univ., Glasgow, UK

Volume

2

Issue

3

fYear

1995

fDate

6/1/1995 12:00:00 AM

Firstpage

448

Lastpage

459

Abstract

The partial discharges produced by internal defects in solid insulation have been investigated using the ultra high frequency (UHF) technique. The work has shown that the discharges produced by a virgin cavity generate a UHF signal that may be detected using this UHF technique. The discharges are observed as a series of UHF pulses that occur less frequently as time progresses. The reduction in the number of UHF pulses has been attributed to a progressive change from the streamer discharge mechanism, that is observed with a virgin cavity, to the Townsend mechanism, which occurs when the cavity has been exposed to prolonged discharge activity. It also has been shown that the discharges associated with tree formation generate a detectable UHF signal. The paper describes a method of distinguishing between the streamer discharges and the discharges that cause treeing

Keywords

Townsend discharge; UHF measurement; gas insulated substations; insulation testing; partial discharges; trees (electrical); GIS test chamber; Townsend mechanism; UHF pulses; UHF technique; internal defects; partial discharges; solid insulation; streamer discharge mechanism; tree formation; treeing; virgin cavity; Capacitance; Electric breakdown; Electrodes; Geographic Information Systems; Partial discharges; Signal detection; Signal generators; Solids; Surface discharges; Trees - insulation;

fLanguage

English

Journal_Title

Dielectrics and Electrical Insulation, IEEE Transactions on

Publisher

ieee

ISSN

1070-9878

Type

jour

DOI

10.1109/94.395417

Filename

395417