基于改进动态阻抗法的电网静态电压稳定裕度快速评估

Rapid evaluation of power system static voltage stability margin based on improved dynamic impedance

戴维南等效参数准确辨识是实现电网静态稳定在线评估的关键。采用两个时刻潮流的辨识方法很难保证两时刻之间等效参数不变的假设条件。首先分析了现有等效参数辨识方法存在的问题,提出了一种基于动态等效阻抗的改进等效参数辨识方法,利用当前运行点和预估点在线快速计算等效参数。改进方法解决了负荷功率恒定和多节点负荷功率同时变化时原方法失效的问题。在此基础上,利用阻抗模指标对电网静态稳定裕度进行评估。最后,通过仿真验证了所提方法的有效性。

Accurate identification of Thevenin equivalent parameters is the key to realize the power system static stability on-line assessment. It is very difficult to guarantee the assumption that the equivalent parameters are constant between the two moments when the identification method of the two-time power flow is used. Firstly, the existing problems of equivalent parameter identification methods are analyzed, and an improved equivalent parameter identification method based on dynamic equivalent impedance is proposed. The equivalent parameters are calculated on-line quickly from the current operating points and the predicted points. The improved method solves the problem that the original methods are invalid when the load power is constant and the multi-node load power is changed at the same time. On this basis, the static stability margin is evaluated by using the impedance modulus index. Finally, the effectiveness of the proposed method is verified by simulation.