紧急直流功率支援时的无功功率配合研究

紧急直流功率支援能够提高单回直流双极闭锁后系统的稳定性,而换流站无功功率容量的不足往往会导致直流功率无法提升至指定功率值,大大减弱紧急直流功率支援的效果。为此,对直流换流器无功功率消耗进行分析,提出3种紧急直流功率支援期间的无功功率补偿方式,即:分段切除故障直流换流站内滤波器;加装静止无功补偿器;改进直流整流站附近的发电机励磁控制。仿真结果表明这3种措施均能在直流暂时过负荷期间弥补直流输送功率的缺额,提高系统的稳定性。分段切除故障直流换流站内的滤波器仅对故障直流换流站附近的其他直流线路功率有一定影响,且容易导致故障直流换流站过电压;静止无功补偿器及整流站附近发电机励磁控制均可减少紧急直流功率支援后的切机量,但发电机励磁控制效果更佳。

Study on Reactive Power Coordination during Emergency DC Power Support

Emergency DC power support can improve stability of power system when one DC link is blocked. Lacking of re active power will disable the supporting DC link from reaching its own set point and thus reducing the effect of emergency DC power support. In this paper, three methods are presented to provide reactive power, such as switching the filter of the blocked DC link step by step, installing SVC and improving additional excitation control of the generators that are near the rectifier station. The simulation result shows that the above three methods can increase the emergency DC power and en hance stability of power system. The reserved filters can only affect DC links which are near the blocked DC link and may cause the converter station of the blocked DC link voltage; SVC and excitation control can reduce the number of tripped generators, however excitation control shows better performance, the voltage of the generator also can be controlled within a reasonable range.