考虑换流站独立控制约束的交直流系统静态无功优化方法

交直流互联电网的三级电压控制结果应当满足换流站运行的独立控制方式,为此,提出一种考虑换流站独立控制约束的交直流系统静态无功优化方法.新模型以三级电压控制周期内直流功率及离散调压设备保持初始运行状态不变为基本假设,在常规交直流系统静态无功优化模型基础上,进一步考虑了直流系统就地无功平衡的死区控制约束以及直流配套电源的非固定边界可调范围约束;算法上,采用内点法进行求解.以中国东北某特高压直流换流站及其近区交流电网仿真验证所述方法的有效性.仿真结果表明,所提方法能够降低换流站离散调压设备的频繁动作风险,实现换流站暂稳态无功功率的协调控制.

Optimization Method for Static Reactive Power of AC/DC System Considering Independent Control Constraints of Converter Station

The results of three-tier voltage control for AC/DC interconnected power grid should satisfy the independent control mode of converter stations. Therefore, an optimization method for static reactive power of AC/DC systems considering independent control constraints of converter stations is proposed. The basic assumption of the new model is that the initial operation state of DC power and discrete voltage regulation devices remain unchanged during the period of three-tier voltage control. Based on the conventional static reactive power optimization model of AC/DC systems, the dead zone control constraints of local reactive power balancing of DC systems and the adjustable range constraints with non-fixed boundary of auxiliary power supply for DC systems are further considered. The problem is solved by the interior point method. An ultra-high voltage direct current (UHVDC) converter station with its nearby AC power grid in Northeast China is simulated to verify the effectiveness of the proposed method. The simulation results show that the proposed method can reduce the risk of frequent operation of discrete voltage regulation devices and realize the coordinated control of the transient and steady-state reactive power of converter stations.