Static electrification in large power transformers

Static electrification due to dielectric liquid flow has been found to be the cause of many field failures in the large forced-oil-cooled power transformers and in compact HVDC substations. The accumulation of static charge in the oil and isolated solid insulating surfaces causes the electric potent...

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Bibliographic Details
Main Author: Zhang, Jian
Other Authors: Cao, Long Jian
Format: Theses and Dissertations
Language:English
Published: 2009
Subjects:
Online Access:http://hdl.handle.net/10356/19729
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Institution: Nanyang Technological University
Language: English
Description
Summary:Static electrification due to dielectric liquid flow has been found to be the cause of many field failures in the large forced-oil-cooled power transformers and in compact HVDC substations. The accumulation of static charge in the oil and isolated solid insulating surfaces causes the electric potential to rise in the same fashion as a Van de Graff generator. The potential builds up until either the rate of charge accumulation equals to the rate of charge leakage, or spark discharges occur. Though the problems of flow electrification were well recognized in petroleum industry, the charging mechanism and effect on transformer insulation and operation are still under active investigation.