基于阻抗动态步进的PVZ曲线快速求解

FAST COMPUTATION OF PVZ CURVES WITH IMPEDANCE DYNAMIC STEP

提出了一种基于阻抗动态步进的PVZ曲线快速求解方法。该方法以负荷节点的阻抗为步进变量,利用改进的节点附加注入法并通过对负荷阻抗摄动的方式快速求取某一状态点下的戴维南等值参数,进而由此获得下一曲线点的负荷阻抗。该方法提供的算法全过程只需要在主循环之前进行一次性的矩阵消去运算,其计算量较小,速度较快;同时,该方法求得的负荷阻抗步进量具有动态变化特性,并且求得的曲线点还可能具有分布于曲线临界点两侧的特性。这些特性允许算法可以根据需要求得尽可能多的曲线点,从而有助于提高曲线及其临界点的逼近精度。最后,通过算例验证了所提方法在计算效率和逼近精度方面的良好品性,它为在线 实时评估电力系统的静态电压稳定性提供了有效的分析工具。

This paper proposes a fast method of computing PVZ curves using load impedance as dynamic step. By the adapted node additional injection method and the perturbation method, the paper first quickly calculates the Thevenin's equivalent parameters of some one state, and then obtains the load impedance of next state with them. The whole procedure of the algorithm needs only one matrix expunction computation before the main loop, so the computation load is smaller and the efficiency is higher. Moreover, the load impedance step is dynamic, and the points computed by the method are possibly distributed over two sides of the critical points on PVZ curves. These characteristics above can allow the algorithm compute points as many as possible or as expected, which supplies guarantees for raising approximation accuracy of the curves and their critical points. In the end, examples show that the method is of high efficiency and precision, and can supply an effective analysis tool for real time on-line assessment of voltage static stability in power systems.