Comparative Study of Effectiveness in Unbalance Voltage Factor Reduction by Using Different Transformers for Railway Electrification System

Abstract

Nowadays, railway system becomes a part of life in the urban city. The most important equipment for railway electrification system is a transformer. In the past, single-phase transformer was widely used to supply the electrical energy to the train. However, single-phase transformer is the cause of voltage and current unbalances in the power system network that the railway electrification system is connected. In order to solve these issues, special transformers, i.e. Scott transformer and Le-Blanc transformer, have been proposed to be used in railway electrification systems. This paper focuses on developing the special transformer models using DIgSILENT PowerFactory software. The developed models have been verified with a simple train system and the effectiveness of reduction of voltage unbalance factors by using each type of transformers are compared. In addition, the developed special transformer models can be applied in a large-scale power system network for power quality analysis.