【摘要】 多端柔性直流输电系统的现有下垂控制方法可以将直流网络的不平衡功率在各换流站间进行合理分配,但忽略了各换流站交流侧系统的承受能力,无法根据交流侧系统的暂态响应情况来灵活调节各换流站所分配的不平衡功率量。因此,该文提出一种考虑交流电网调节能力的多端柔性直流网络改进下垂控制方法,该方法根据扰动后交流侧电网的频率偏移情况来自动调节下垂控制的斜率系数,在不改变控制器结构的前提下,可使直流侧的不平衡功率在各交流电网中得到更为灵活合理的分配。在实时数字仿真器(real-time digital simulator,RTDS)平台搭建了仿真模型,通过与固定斜率下垂控制方法和考虑功率裕度的自适应下垂控制方法进行对比,验证了该改进控制方法的有效性和优越性。更多还原

【Abstract】 The existing droop control methods for the voltage source converter based multi-terminal high voltage direct current( VSC-M TDC) system can reasonably distribute the unbalanced power of DC network among the converter stations,but neglect the bearing capacity of AC system in converter system,and cannot flexibly adjust the power output variation of converter stations according to the transient responses of the AC systems. Therefore,this paper proposes an improved droop control method for VSC-M TDC system considering the adjusting ability of AC grid. The improved method can adaptively modify the slope coefficient of droop control based on the frequency deviation of the AC grid,which can distribute the unbalance power in the DC grid more flexible and reasonable without changing the controller structure. Compared to the droop control method with fixed slope coefficient and the adaptive droop control method with considering power margin,the proposed improved control method is proved to be more effective and superior on the RTDS( real-time digital simulator)platform.更多还原