动态电压振荡型失稳边界分析与算法研究

提出了全参数空间下的最近动态电压振荡型失稳边界的计算方法。在每次迭代中，采用逐步增长负荷的迭代方式找到振荡型失稳边界，求取失稳边界的超平面法向量。将该法向量作为新的负荷增长方式寻找下一步失稳边界，最终找到系统发生电压振荡型失稳的最近边界及其对应的最危险负荷增长方向。相对于摄动方法而言，该方法将各种因素对于电压稳定域的影响考虑在内，且不需要求取控制参数的海森矩阵，具有计算速度快、精度高的特点。选取系统有功负荷作为控制参数，研究了负荷的不同增长方式对系统振荡失稳边界的影响，并根据超平面的法向量求解出系统发生振荡型失稳的最近边界以及所对应的最危险的负荷增长方向。提出2类电压稳定指标，所提指标有助于综合评估系统动态电压稳定裕度。采用3节点和IEEE 14节点仿真系统对算法的有效性进行了验证。

Influence of Load Increase Pattern on the Oscillatory Instability Margin of Power Systems

An effective iterative algorithm for computing the closest dynamic oscillatory stability margin in full parameter space was proposed. In each iterative step, oscillatory stability margin was found through load increase in given direction and at bifurcation point the normal vector to the hyper surface of dynamic stability boundary was calculated. The calculated normal vector was adopted as the renewed load increase direction for the next iteration. Finally the closest dynamic oscillatory stability margin was found and the most dangerous load increase pattern was achieved. Compared to perturbation method, the influences of many factors on voltage stability margin are considered and Hessian matrix of control parameters is not necessarily calculated. The method has high calculation speed and accuracy. The active load power at load nodes was selected as control parameters and the influence of different load increase patterns on stability boundary was studied. The closest oscillation stability boundary and the most dangerous load increase pattern were obtained based on the iterative algorithm with the normal vector calculation. Two kinds of stability indices for stability margin measurement were proposed and compared. The proposed indices are valid in the estimation of dynamic voltage stability margin. Simulation results of the both 3-bus and IEEE 14-bus test system show that the proposed methods are effective with good convergence.