Determination of Worst-Case Capacitor-Switching Overvoltage of MRT System Using Genetic Algorithms

This paper analyzes the worst-case DC transient voltages of mass rapid transit (MRT) systems due to utility-capacitor switching on AC supply systems. The various factors affecting this phenomenon are analyzed in detail using extensive EMTP (Electromagnetic Transients Program) simulations. These factors include the size and location of utility capacitor, point-on-wave switching angles on the three phases, and DC link parameters. In this paper, genetic algorithms (GAs) are applied to determine the worst-case DC overvoltage caused by nonsimultaneous energization of utility capacitor. The effectiveness of the proposed GA approach is verified by comparing results with traditional statistical approaches.