Lumped parameter electromagnetic modelling approach for transient analysis in EHV transformers

摘要

This paper presents a novel lumped parameter high frequency circuit model of transformer using EMTP analysis of transients within the windings. The model which has been developed based on transformer geometry, configuration and design parameters, can adequately reproduce the frequency response characteristics of the original transformer. The response characteristics of the EMTP model presented in this work has been validated with the original transformer's laboratory test results. The behavioural responses of the windings were studied under 1.2/50 μs standard lightning impulse and fast-front switching surge. It has been observed that the developed model successfully reproduced the windings response under these transients and the results indicate that the voltage stresses developed on the winding insulation are marginally higher under fast-front switching surge as compared to standard lightning impulse.