Candidate: Anurag Anand Devadiga
Title: Analysis of Transformer Insulation Under High-frequency Transients
Date: February 16, 2021
Time: 2:00 PM
Place: REMOTE ATTENDANCE
Supervisor(s): Jayaram, Sheshakamal
Abstract:
In recent years, the advent of renewable energy resources (RERs) has introduced new high-frequency stresses on the paper-oil insulation of transformers connected to RER networks. These stresses are developed due to the operation of power electronics and circuit breakers during the integration of renewable power, like wind power to the main electric grid. Under such stresses, various parameters like rise time, switching frequency, voltage magnitude, and duty cycle of the transient voltages influence their distribution along the transformer winding. The transient voltage stresses the turn-to-turn paper-oil insulation, and leads to degradation of the winding insulation reducing the transformer life. The current research focuses on understanding the transformer response, and analyse the paper-oil insulation dynamics under such high-frequency transients. The transformer frequency response and its high-frequency transient response will help to investigate the voltage amplification in the transformer winding under repetitive transient voltages. Having the knowledge of these voltage amplifications along the winding helps in investigating the paper-oil insulation dynamics under controlled test conditions. The paper-oil insulation dynamics study under high-frequency transients will involve a detailed understanding of the insulation ageing by using dielectric frequency response, partial discharge analysis, hydrogen gas analysis, and breakdown strength measurements under controlled environmental factors like temperature and humidity. The research will help in developing techniques to evaluate the ageing level of transformer paper-oil insulation by different parameters of repetitive fast transients.