Abstract：The unbalanced grid voltage has a serious influence on the output performance and safe operation of the static synchronous compensator(STATCOM), DC side capacitor produces double frequency voltage fluctuation, AC side output current contains negative sequence and third-order harmonic, and converter may be overcurrent caused by negative sequence current and third-order harmonic current. To solve this problem, the influence of unbalanced voltage to STATCOM is analysed on the basis of switch function method, a new dual-loop control strategy is proposed to suppress the influence and an improved switching function modulation is proposed to suppress the third-order harmonic current in order to make STATCOM safe in this paper. The STATCOM is operated as a current source controlled by the voltage at the point of common coupling(PCC) to suppress the unbalanced system voltage. The compensation effect is related to control parameters closely, and reasonable selection of PCC voltage phase angle can guarantee the minimum compensation capacity under the condition of optimal compensation performance of the STATCOM. Simulation and experimental results verify the correctness and validity of the present control strategy and theoretic analysis.
易桂平, 胡仁杰, 蒋玮, 黄慧春. 电网电压不平衡对STATCOM的影响及抑制[J]. 电工技术学报, 2014, 29(6): 238-247.
Yi Guiping , Hu Renjie , Jiang Wei , Huang Huichun. Influence of Grid Voltage Unbalance on STATCOM and the Countermeasure. Transactions of China Electrotechnical Society, 2014, 29(6): 238-247.
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