估计支路型事故后系统电压稳定边界的灵敏度算法

Sensitivity Method of Voltage Stability Margin Evaluation for Branch Outage Contingencies

提出一种改进的灵敏度算法估计支路型故障后系统的电压稳定边界。该方法首先在事故前的鞍结分岔点引入置换定理将预想故障支路对系统的作用转换为2个独立功率源对系统的作用,而后通过置换后的系统方便地求出负荷参数对支路传输功率的灵敏度,来估计事故后系统的电压稳定边界。所提方法在很大程度上消除了在简单灵敏度法中因负荷参数和支路导纳之间强非线性引起的估计误差。通过New-England 39节点系统、某实际639节点系统和IEEE 118节点系统算例表明,此算法与现有的简单灵敏度法相比,无需增加计算量就可给出更精确的估计结果。

An improved sensitivity method to evaluate the load power margins with respect to saddle node bifurcation under branch outage is proposed. The proposed method first replaces the function of potential outage branch to the system by functions of two independent power sources through introducing the substitution theorem at the saddle node bifurcation point of base case. Then based on the new system, the proposed method can easily give out the branch transmission power sensitivity of loading margin and evaluate the load power margin, removing the evaluation error in the simple sensitivity method induced by the highly nonlinear between load margin and branch admittance. The proposed approach is illustrated with New-England 39 system, a real 639 system and IEEEll8 system. The results show that the improved sensitivity method can provide more accurate estimates than the simple sensitivity method, without adding computation burden.