基于串并联型潮流控制器的互联双极直流电网不平衡功率控制

Unbalanced Power Control of Interconnected Bipolar DC Power Grid Based on Series-Parallel Power Flow Controller

互联双极直流电网的不平衡潮流将增大网络的损耗甚至影响系统的正常运行。文中提出一种基于串并联型潮流控制器(SP-PFC)的互联双极直流电网不平衡功率抑制策略。首先,介绍了SP-PFC的拓扑及工作模式,然后推导了恒功率控制下SP-PFC的输出电压和线路电流表达式。由于SP-PFC的输出电压和电流呈非线性关系,在额定工作点处将SP-PFC进行线性化,并对比了线性和非线性模型的区别。在此基础上,分析了不平衡负荷及受端电压对SP-PFC输出电压和线路电流的影响。建立了含SP-PFC的双极直流电网小信号模型,分析了含SP-PFC的双极直流电网的稳定性。在MATLAB/Simulink中搭建了含SP-PFC的双极直流电网仿真模型,对SP-PFC抑制不平衡功率的有效性进行了验证。

The unbalanced power flow of the interconnected bipolar DC power grid increases the loss of the network and even affects the normal operation of the system.In this paper,a suppression strategy of unbalanced power based on the series-parallel power flow controller(SP-PFC)is proposed for the interconnected bipolar DC power grid.First,the topology and the operation mode of SP-PFC are described,and then the expressions of output voltage and line current of SP-PFC with the constant power control are deduced.Since the nonlinear relationship between the output voltage and current of SP-PFC,the SP-PFC is linearized at the rated operating point,and the difference between linear and nonlinear models is compared.On this basis,the effects of unbalanced load and receiving-end voltage on the output voltage and the line current of SP-PFC are analyzed.The small-signal model of bipolar DC power grid with SP-PFC is established,and the stability of bipolar DC power grid with SP-PFC is analyzed.The simulation model of the bipolar DC power grid with SP-PFC is built in MATLAB/Simulink to verify the effectiveness of SPPFC in suppressing unbalanced power.