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.

Systematization of the Simulation Process of Transformer Inrush Current Using EMTP

“…Meanwhile, the absolute value of residual flux can be quite different from one transformer to another. Its true nature has not been experimentally clarified because the flux values in the transformer core cannot be measured directly and field tests cannot be easily conducted [25][26][27]. However, [28,29] conducted the field test of inrush current.…”