多回直流紧急功率支援与电压稳定控制

Strategy of Emergency Power Support and Voltage Stability Control with HVDCs

复杂交直流并联输电系统中,由线路故障导致的大规模功率转移可能引发系统波动,甚至导致系统崩溃。针对上述问题,提出当多回直流输电系统中的一回直流因故障停运时,可以在其他直流紧急功率支援的同时,通过电气距离较近的换流站的无功协调控制来提高系统的电压稳定性,并给出了相应的控制策略。在EMTDC/PSCAD仿真软件中搭建了三直一交混合输电系统模型并对其进行了仿真分析。仿真结果表明该控制策略对维持系统的频率稳定和电压稳定均有明显效果,对实际系统有一定的参考价值。

A line fault of a complex power grid with multiline DC and AC transmission in parallel can cause the mass shift of the active power, which may lead to the system fluctuation and grid disruption. A reasonable solution is given after the analysis of the relationship between the EDCPS and reactive power control. When a fault occurrs in one of the DC lines in parallel, the voltage stability is improved by the reactive power coordination control system of the nearly convertor station, as well as the emergency DC power support of other DC lines. A hybrid power system with one AC and three DC lines in parallel is created in PSCAD/EMT- DC. Simulation results show that this strategy can significantly improve the frequency and voltage stability, and it is available to the actual system.