Analysis of high neutral current in three-phase four-wire multi-grounded distribution feeders

This paper presents a study of investigation and analysis of factors contributing to high neutral line current in a three-phase four-wire multi-grounded distribution system. In the study, the electromagnetic transient program, EMPT/ATP, is used to simulate different scenarios that lead to high neutral line current. Studies show that, in addition to typical imbalance caused by load characteristics, dominant factors contributing to high neutral current include asymmetrical connected types of transformers, failures of distribution feeder capacitor banks, and power theft.