基于灵敏度约束的电压鞍结分岔点快速算法

Fast Algorithm for Determining Voltage Saddle Node Bifurcation Point Based on Restriction of Sensitivity

提出一种基于灵敏度约束的电压鞍结分岔点快速算法。该算法根据PV曲线的特点,通过弱节点电压对负荷参数的2阶灵敏度约束负荷增长步长,大跨度逼近鞍结分岔点,并且利用发电机输出无功对负荷参数的2阶灵敏度考虑发电机无功极限,以此来判断无功/电压约束转换点。当PV曲线上运行点的斜率满足设定值时,通过局部曲线拟合技术精确求出鞍结分岔点值。所提方法可运用潮流计算得到的雅可比矩阵直接求取各阶灵敏度,预知下一预测点情况;负荷增长步长随PV曲线斜率的变大自动缩减;靠近临界点处的局部曲线拟合使计算更精确。对IEEE测试系统的数值计算表明,所提方法是有效、实用的。

A fast sensitivity based algorithm for the determination of voltage saddle node bifurcation （SNB） point was presented. According to the characteristics of PV curve, using second-order sensitivity guidance technique, the load increment step can be determined. During the processing for approaching the SNB point, reactive power limit of generator is considered, and it can be used to determine the reactive power/voltage type conversion. When the slope of the PV curve is satisfied for the required slope, the value of SNB point can be accurately calculated by local curve fitting. The advantages of the proposed algorithm is that the second-order sensitivity can be obtained by power flow Jacobin matrix and it is used to predict the next forecast point; load increments step can automatically be reduced with the slope of PV curve increased; the value of SNB point can more accurately be calculated as local curve fitting is close to the critical point. Case studies with IEEE systems indicate that the proposed method is effective and suitable.