| With the fast development of subway in cities recently, the growing problems ofharmonic power and wattless power happened in power supply system of metro influence thepublic power quality deeply. Harmonic power is caused by direct current supply (DC),different kinds of converter plant and nonlinear lighting equipment in metro. Considering theparticularity of this power quality, I will analyse the sqare and content of harmonic power atboth sides of alternationg current (AC) and diret current (DC) on the basis of24pules rectifierelectric locomotive simulation model. Meanwhile, the necessity of static var compensator(SVC) will be pointed out through the power factor calculation under3cases, the peak hoursin daytime, leisure hours in night and traction load changes, based on relevant data from theLine1in Guangzhou metro.For improving the power supply circumstance, a new method for static var compensator(SVC) in35KV system, which is the first attempt in the area of satic var compensator (SVC)in metro power supply system, with the utilization of active power filter installed on the sideof0.4KV working in with reactor is proposed in this paper, will not only save costs, but alsomeet the requirement of power factor in metro power supply system. In this paper, the brifinstraction about the principle of APF working, which is the core of this new method,including working mode of the main circuit, control strategy and so on, is based on the thebasic structure of this new method and the analysis of relevant filtering theory throughconstructing mathematical model. Then, the choice of suitable control strategy of APF for0.4KV side, is made by the compare of two core techniques of APF, harmonic detectiontechnique and current tracking control technology. And at the last of this paper, the result ofthis new method will be put forward, with the utilization of Matlab/Sumlink simulationsoftware to identify the previous theoretical deduction emulational. |
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