基于AQ节点的电力系统静态电压稳定裕度计算方法

为解决电力系统静态电压稳定极限点附近雅克比矩阵奇异、牛拉法潮流不收敛的问题,提出了一种基于AQ节点的静态电压稳定裕度计算方法。首先在两节点系统中推导了AQ节点的特性,该节点电压相角和无功为已知量,省略了其有功潮流方程,将AQ节点和平衡节点的相角差作为衡量负荷变化的依据。然后研究了含AQ节点系统的潮流计算方法,并应用于静态电压稳定性分析,将雅克比矩阵J映射为AQ节点法中的修正雅克比矩阵JAQ,引起矩阵奇异点在静态电压稳定临界点处的"偏移",完全消除了雅克比矩阵在系统静态电压稳定临界点处的奇异性。该方法具有比传统连续潮流法更好的收敛性,计算方法更简、速度更快,能高效、准确计算电网静态电压稳定裕度。太原市220kV实际电网和IEEE118节点标准算例的仿真结果证明了所提方法的有效性和实用性。

A Method for Calculating Static Voltage Stability Margin of Power System Based on AQ Bus

It is known that Jacobian matrix will become singular,resulting in convergence failure of Newton-Raphson power flow near voltage stability critical point.To solve this problem,a static voltage stability margin calculation method based on AQ bus is proposed in this paper.Firstly,the characteristics of AQ bus are analyzed in a two-bus system, where the bus angle and the reactive power of AQ bus are specified,so the active power flow equation can be left out. The voltage angle difference between AQ bus and swing bus is used to measure the AQ bus load.Then,the power flow calculation method of the power system containing an AQ bus is studied and applied to static voltage stability analysis.In this case,Jacobian matrix J is mapped to JAQ in the AQ bus method,resulting in-shift of the matrix singular point around voltage stability critical point.So,singularity is completely eliminated in this scheme.This approach is simpler and faster than traditional continuation power flow (CPF)method with better convergence.The proposed strategy can be employed to calculate power system static voltage stability effectively and accurately.Simulation results of an actual 220kV power grid in Taiyuan and IEEE 18-bus standard test system verify effectiveness and practicability of the proposed method.