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Paper accepted for presentation at 2003 IEEE Bologna Power Tech Conference, June 23th-26th, Bologna, Italy

Stochastic Harmonic Load Flow Analysis and Distortion Mitigation of Mass Rapid Transit Systems
H. J. Chuang, Member, IEEE, C. S. Chen, Member, IEEE, C. H. Lin, Member, IEEE, and H. M. Shiau
train sets, the traction substations along the main line is used to step down the voltage level (22 kV/589 V) and 12-pulse rectifiers are applied to generate 750Vdc for train operation as shown in Fig. 2 [2].

Abstract-- This paper is to investigate the stochastic harmonic distortion of an 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. Index Terms-- Mass Rapid Transit (MRT), AC/DC Load Flow, Stochastic Harmonic Load Flow, 12 Pulse Uncontrolled Rectifier, Interphase Transformer

I. INTRODUCTION

Fig. 1. Control block diagram of VVVF inverters.

effective public transportation in the metropolitan areas because of the high efficiency and environmental friendliness. To ensure the efficiency and safety of MRT systems with very short headway, the automatic train operation (ATO) is applied to control the voltage and frequency of power source to the induction traction motors so that the proper torque and acceleration can be obtained. By this manner, the rain sets can be operated according to the predefined speed... [continues]

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