RIGOROUS EVALUATION OF THE VOLTAGE UNBALANCE DUE TO HIGH-SPEED RAILWAY DEMANDS

A rigorous way of evaluating the voltage unbalance due to single-phase high-speed railway (HSR) demands on a three-phase power system is int roduced in this paper, A three-phase power-flow program with simplifie d models of electric railway substations is adopted for rigorous studi es. Various transformer connection schemes, including single-phase, V, Scott, and Le Blanc connections, are considered. The results are comp ared with those obtained by simple formulas that currently are commonl y used to approximate the voltage unbalances, The comparison results i ndicate significant differences between these two approaches and empha size that related improvement projects should be evaluated and impleme nted by the rigorous approach, not the simple formulas.