基于戴维南等值和支路传输功率极限的电压稳定评估方法

Evaluation Method for Voltage Stability Based on Thevenin Equivalent and Power Transfer Limit of Branch

提出了一种基于戴维南等值和支路传输功率极限的电压稳定评估方法。通过增大所要评估负荷节点的注入功率,并计算该状态下的系统潮流,求得该负荷节点对应的戴维南等值参数。利用所得到的戴维南等值参数构建包含该负荷节点的2节点系统,分析其节点功率平衡方程,得到其静态电压稳定的判别式。由判别式计算得到2节点系统的支路传输功率极限以及该节点的相对功率裕度,进一步建立整个系统的静态电压稳定指标,将其用于在线评估。此方法无需本地量测数据、计算快速方便、能够给出包含极限传输功率的评估指标,适用于电网调度中心,可实现对电网的在线电压稳定评估。运用该方法对IEEE14节点与118节点系统进行电压稳定评估,验证了此方法的合理性与正确性。

This paper proposes an evaluation method for voltage stability based on Thevenin equivalent and the power transfer limit of branch.The Thevenin equivalent parameters of the node under evaluation,based on which a 2-node system can be constructed,is acquired through increasing the injection power of the node and then calculating the system load flow of the new state.Then the static voltage stability discriminant of the system is obtained by analyzing its power equations.Utilizing the discriminant,the power transfer limit is calculated out.Next,the relative power margin of the node is obtained,and the static voltage stability index of the whole system which can be applied to on-line assessment is acquired ulteriorly.The method proposed here is independent of local measurement data,owning a fast calculation speed,and providing an assessment index.So it is applicable to the grid dispatching center,achieving the online voltage stability assessment of the system.Tests on IEEE 14-node and IEEE 118-node system verify the rationality and correctness of the proposed method.