Effects of temperature on time-domain dielectric diagnostics of transformers

Abstract

Time-domain dielectric testing techniques, namely the Return Voltage Measurement (RVM) and Polarisation and Depolarisation Current (PDC) measurement are being used by the power utilities for assessment of the condition of transformers oil-paper insulation. However, it has been found that the results of these tests are highly influenced by operating temperature. It requires adequate experience and extreme care to interpret the RVM and PDC results in the presence of temperature variations and thermal instability. This paper reports a detailed study on the effects of temperature on RVM and PDC measurements on a transformer under controled laboratory conditions.

Keywords:

• Transformer condition monitoring
• insulation diagnostics
• return voltage
• polarisation/depolarisation current
• oil-paper insulation

Additional information

Notes on contributors

T K Saha

Tapan K Saha

Tapan K Saha was born in Bangladesh and imigrated to Australia in 1989. Dr. Saha is an associate professor in the school of Information Technology and Electrical Engineering, University of Queensland, Australia. Before joining the University of Queensland in 1996, he taught at the Bangladesh University of Engineering and Technology, Dhaka, Bangladesh for three and half years and at James Cook University, Townsville, Australia for two and half years. He is a senior member of IEEE and Fellow of the Institution of Engineers, Australia. His research interests include power systems, power quality and condition monitoring of electrical plants.

P Purkait

Prithwiraj Purkait

Prithwiraj Purkait was born in Kolkata, India in 1973. He obtained his BEE, MEE and PhD degrees from Jadavpur University, Kolkata, India in 1996, 1999 and 2002 respectively. He served as a post-doctoral research fellow in the University of Queensland, Australia during 2002-2003. Presently he holds the post of assistant professor in the department of Electronics and Instrumentation Engineering in Haldia Institute of Technology, Haldia, India. His current research includes transformer insulation condition assessment techniques and advanced signal processing applications in high voltage engineering.