考虑直流输电的电力系统无功备用优化

Optimal reactive power reserve dispatch method considering DC transmission lines

目前无功备用研究较少涉及包含直流输电线路的电力系统。提出一种针对交直流混联系统的电力系统无功备用优化模型。基于交直流混联潮流方程,该模型首先利用发电机端电压及无功功率控制灵敏度定义直流输电系统的有效无功备用。以此为目标,在考虑各种系统约束的情况下建立考虑交直流混联的电力系统无功备用优化模型。针对无功备用优化模型耦合两个运行状态而难以准确求解的缺陷,提出一种解耦方法进行求解。对改进IEEE39节点系统的算例分析结果表明,所提无功备用定义可有效衡量系统的无功电压水平,而所提模型可以有效提高含直流输电线路电力系统的无功备用和电压稳定裕度,保障电力系统的安全稳定性。

The reactive power reserve of AC-DC transmission networks is not yet within the focus of current research. An optimal reactive power reserve dispatch method is established for the AC-DC transmission network. At first, deduced from the AC-DC power flow equations of AC-DC networks, an effective reactive power reserve definition is proposed for the AC-DC transmission network by the generator control sensitivities of both voltage and reactive power. Based on which, an optimal reactive power reserve dispatch model is proposed under several operational constraints. To solve the above optimal power flow problem with two operational statuses, a decoupling solution is proposed. The simulation results on IEEE 39 bus system manifest that, the proposed definition of reactive power reserve is able to represent the voltage level of AC-DC networks, and the proposed model is able to enhance the security of power system via the increments of the reactive power reserve and voltage stability margin.