Investigations into the transformer inrush current problem

Abstract

A transformer being energised may draw a large transient current from the grid supply, resulting in a temporary voltage dip at the point of connection (POC) where customers are connected. The voltage dip is dependent upon the magnitude of the transformer inrush current. The peak current of the first cycle, under worst conditions, is considered important. This paper presents the results achieved following the energisation of a 10MVA 132/11kV transformer as well as the practical mitigation measures to minimise the impact of the transformer energisation. http://dx.doi.org/10.4314/njt.v37i4.27