Study of Oil/Pressboard Creeping Discharges under Divergent AC Voltage—Part 1: Fundamental Phenomena and Influencing Factors

authored by: Xin Zhou, Peter Werle, Ernst Gockenbach, Hui Bin Shi, Moritz Kuhnke
Abstract: This paper presents an experimental study of the fundamental phenomena of progressive creeping discharge as well as the influences of pressboard ageing and voltage amplitude under divergent AC voltages. A ramp-stress test is used to determine the partial discharge inception voltage (PDIV) and the flashover voltage of oil/pressboard interface versus pressboard ageing. Constant-stress tests are carried out to investigate the partial discharge (PD) behaviors, the pressboard surface temperature, and the oil-dissolved gases of progressive creeping discharges. It is found that the pressboard ageing affects only the interface PDIV. The progressive creeping discharges concentrate at the triple-junction and comprises probably oil corona discharges and surface discharges in pressboard dimples. If no pressboard damage is present, the progressive discharges exhibit in general a constant PD pattern but a diminishing intensity, and nevertheless can be sustained for the severely-aged pressboards under strong voltages. The underlying causes are correlated with the competing effects of pressboard ageing on interface moisture and the triple-junction field intensification. Gas analyses indicate the hydrogen is the principal faulty gas and the Duval's Triangle diagnoses the progressive creeping discharges as either low-energy or high-energy discharge fault. No pressboard overheating is observed during the discharges.
Organisation(s): High Voltage Engineering and Asset Management Section (Schering Institute)
Type: Article
Journal: IEEE Transactions on Dielectrics and Electrical Insulation
Volume: 28
Pages: 355 - 363
No. of pages: 9
ISSN: 1070-9878
Publication date: 15.04.2021
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Electrical and Electronic Engineering
Electronic version(s): https://doi.org/10.1109/tdei.2020.009196 (Access: Closed)