A Short-Circuit Current Study for the Power Supply System of Taiwan Railway

The western Taiwan railway transportation system consists mainly on a mountain route and ocean route. Taiwan Railway Administration (TRA) has conducted a series of experiments on the ocean route in recent years to identify the possible causes of unknown events that cause the trolley contact wires to melt down frequently. The conducted tests include the short-circuit fault test within the power supply zone of the Ho Long Substation (Zhu Nan to Tong Xiao) that had the highest probability for the melt down events. Those test results, based on the actual measured maximum short-circuit current, provide a valuable reference for TRA when comparing against the said events. The Le Blanc transformer is the main transformer of the Taiwan railway electrification system. The Le Blanc transformer mainly transforms the Taiwan Power Company (TPC) generated three-phase alternating power supply system (69kV, 60Hz) into two single-phase alternating power distribution systems (M phase and T phase) (26kV, 60Hz) needed for the trolley traction. As a unique winding connection transformer, the conventional software for fault analysis will not be able to simulate its internal current and phase difference between each phase current. Therefore, besides extracts of the short-circuit test results, this work presents an EMTP model based on the Taiwan Railway Substation equivalent circuit model with a Le Blanc transformer. The proposed circuit model can simulate the same short-circuit test to verify the actual fault current and accuracy of the equivalent circuit model.