Changes in phase resolved partial discharge patterns in a cavity embedded in paper insulation due to AC voltages andhigh voltage impulses
2012 (English)In: proceedings 10th NORDAC 2012, 2012, 93-103 p.Conference paper (Refereed)
Electrical insulation materials such as pressboards, oils and paper are important components inelectrical power equipment. The breakdown of insulation materials will cause severe failure of the equipment. Therefore, it is important to have condition monitoring methods in insulation materials of power equipment. A phase resolved partial discharge (PRPD) measurement is one of them.
In this work, the effect of high voltage impulses on PRPD patterns was investigated in test samples consisted of a cavity deliberately introduced between oil-impregnated paper used in power transformer bushings. In the first study, the test sample was highly stressed by 50 high voltage impulses. In the second study, the test sample was aged at elevated AC voltage during almost 5 hours, but with four high voltage impulses injected at selected times during the experiment. In the third study the test sample was aged by a PD activity at elevated AC voltage up to about 18 hours. The PRPD patterns were periodically recorded by an Insulation Condition Monitoring (ICM) system. In order to investigate how different electrical stresses affect the dielectric properties of the paper insulation, the fourth study about the dielectric spectroscopy (DS) measurements were performed. The results show that high voltage impulses can have a large impact on the behavior of PRPD patterns if the test sample is aged by partial discharges, but a smaller effect when the test sample is unaged.
Place, publisher, year, edition, pages
2012. 93-103 p.
Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-105038OAI: oai:DiVA.org:kth-105038DiVA: diva2:568006
proceedings 10th NORDAC 2012, Espoom Fubdabdm 10-11 Septenber 2012
QC 201211152012-11-152012-11-152014-03-03Bibliographically approved