基于二次型迭代逼近法的电力系统电压鞍结分岔点识别

Identification of Voltage Saddle Node Bifurcation Point in Power System Based on Quadratic Form Approximation Method

为实现负荷增长过程中电力系统鞍结分岔点(SNB)的快速准确识别,提出一种直接计算电力系统电压崩溃点的二次型迭代逼近方法,基于系统中PQ节点输出的PV曲线为近似二次型的特点,在节点功率平衡方程中引入负荷增长参数,运用复合函数求导法则就功率方程进行两次求导,理论推导节点电压对负荷参数的一阶、二阶导数表达式,由此确定PV曲线二项式,依靠顶点坐标确定电力系统鞍结分岔点的初始位置,经多次迭代收敛逼近电压崩溃点。所提方法避免了连续潮流法的多次潮流计算,可显著降低计算量。以IEEE 14,IEEE 118节点系统进行仿真验证,证明了该方法的有效性,相较增补P’Q节点法及戴维南等值法,二次型迭代逼近法具有较高的计算效率和鲁棒性。

In order to intervale evaluate saddle node bifurcation points(SNB)in a power system during load growth quickly and accurately,a quadratic approximation method to directly calculate the power system voltage collapse point of was proposed.Based on the approximate quadratic PV-curve of output PQ nodes in the system,load parameters were introduced into the node power balance equation,by using the complex function derivative rules to differentiate power equation twice,the first and second derivatives of node voltage to load parameters were derived theoretically,and the expression of PV curve function was further determined,then vertex coordinates were used to determine the initial position of saddle junction bifurcation point in the power system and the voltage collapse point was approximated by multiple iterations of convergence.The proposed method avoids multiple power flow calculations using the continuous power flow method,significantly reducing computational complexity.Simulation results on IEEE 14 and IEEE 118 bus systems demonstrate the effectiveness of this method.Compared with the supplemented P’Q node method and Thevenin's equivalent method,the quadratic form iterative approximation method has higher computational efficiency and robustness.