Stochastic harmonic load flow analysis and distortion mitigation of mass rapid transit systems

This paper investigates the stochastic harmonic distortion of a mass rapid transit (MRT) system by considering the dynamic load behavior of train sets. The mathematical model of 12-pulse uncontrolled rectifiers without interphase transformers has been used in the harmonic load flow analysis to solve the power demand and harmonic current injection for each time snapshot. The stochastic voltage harmonic distortion of each bus is solved according to the speed profiles of all train sets along the main line. Both the passive filters and hybrid filters are designed to reduce the harmonic distortion. The nonlinear programming is used to solve the optimal sizes and locations of harmonic filters so that the harmonic distortion can be alleviated within the specified tolerance.