Buck型动态电容器无功和负序电流的综合补偿

Comprehensive Compensation of Reactive Power and Negative Sequence Current for Buck-type Dynamic Capacitor

不平衡感性负载产生的无功和负序电流不仅会增加线路损耗,而且会引起电网中以负序分量启动的继电保护装置误动作,进而威胁电力系统的安全运行,因此补偿无功和负序电流尤为重要。针对三相三线负载不平衡系统,首先研究了Buck型动态电容器(D-CAP)进行功率因数校正和不平衡抑制之间的关系。然后分析了D-CAP补偿无功和负序电流的原理并确定了其补偿负序电流的能力。最后针对D-CAP提出了补偿无功和负序电流的优化方法和控制策略,在负载负序电流超过其补偿范围时,该优化方法和控制策略可以实现负序电流的最优补偿。仿真结果验证了理论分析的正确性和控制策略的有效性。

Reactive power and negative sequence current generated by unbalanced inductive load will not only increase line losses,but also cause the wrong action of relay protection devices starting with negative sequence components in power grid,which threatens the safe operation of power systems.So,it is particularly important to compensate reactive power and negative sequence current.In this paper,the comprehensive compensation of reactive power and negative sequence current for Buck-type dynamic capacitor(D-CAP)is studied.Firstly,the relationship between power factor correction and unbalance suppression in three-phase three-wire system is studied.Then the principle of D-CAP compensating reactive power and negative sequence current is analyzed and its ability to compensate negative sequence current is determined.Finally,the optimization method and control strategy for compensating reactive power and negative sequence current are proposed for D-CAP.When negative sequence current of load exceeds its compensation range,the optimization method and control strategy can realize the optimal compensation of negative sequence current.The simulation results verify the correctness of the theoretical analysis and the effectiveness of the control strategy.