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限流式统一潮流控制器(UPFC)可以有效避免串联变换器因系统短路电流冲击而损毁。针对限流式UPFC已有功率控制策略的不足,建立了含限流式UPFC的系统模型,提出了基于线路电流控制的功率控制策略。分析了限流式UPFC的启停过程,给出了完整的启停控制方案。启动阶段接入限流电阻以防止直流电容充电电流过大而导致过电压和过电流损坏。停机时通过并联变换器释放直流电容的一部分能量从而降低放电电阻的设计要求。PSCAD/EMTDC软件的建模与仿真结果证明了基于线路电流控制的限流式UPFC功率控制策略具有良好的动态和稳态性能,同时也验证了启停控制方案的合理性和有效性。
The current-limit unified power flow controller (UPFC) can effectively prevent the series converter from being damaged by the system short-circuit current impact. Aiming at the insufficiency of existing power control strategy of current-limited UPFC, a system model with current-limited UPFC is established and a power control strategy based on line current control is proposed. The start-stop process of the current-limited UPFC is analyzed, and a complete start-stop control scheme is given. During the start-up phase, the current limiting resistor is connected to prevent the DC capacitor charging current from being too large, resulting in over-voltage and over-current damage. Shutdown through the parallel converter to release part of the DC capacitor energy to reduce the design requirements of the discharge resistance. The modeling and simulation results of PSCAD / EMTDC software show that the current-limited UPFC power control strategy based on line current control has good dynamic and steady-state performance, and also verifies the rationality and effectiveness of the start-stop control scheme.