基于广域测量系统的电压稳定指标

A On-Line Voltage Stability Index Based on Wide Area Measurement System

综述和比较了多种基于广域测量的在线电压静态稳定指标,通过理论分析指出了这几种指标的理论缺陷和使用限制。利用同步测量的母线电压相量、线路潮流等电气量,根据线路潮流电压方程计算比较线路两侧电压水平,提出了一种新的电压稳定性指标Ivs,指示被监测线路或母线的电压稳定情况。通过系统等效的方法解耦多机系统的线路电压耦合性,可将该指标推广到多机系统。在单机单负荷系统和IEEE 14节点系统的仿真表明,Ivs可以准确快速地判断系统线路电压稳定情况,预测线路电压失稳点,且适用于所有种类的线路。与之前的电压静态稳定指标相比,Ivs具有无需判断线路电阻,物理概念清晰,适用范围广,线性度好等优点,有利于实现在线电压稳定监测和评估。

On-line steady state voltage stability indices based on wide area measurement system （WAMS） are summarized and compared. Based on theoretical analysis, the theoretical defects and usage limitations of these indices are pointed out. Utilizing synchronously measured electric quantities such as bus voltage phasors and line power flows and according to the comparison results of voltage levels, which are calculated by power flow and voltage equations of transmission line, at both terminals of transmission lines, a new voltage stability index I^s is proposed to indicate the voltage stability condition of monitored bus or transmission line. By means of system equivalence, the coupling of line voltage in multi-machine power system is decoupled, thus the proposed voltage stability index can be applied to multi-machine power system. Simulation results from single-machine single-load system and IEEE 14-bus system show that voltage stability condition of transmission line can be rapidly judged and the voltage instability point can be predicted by the proposed index Ivs, and the proposed index is suitable to all kinds of transmission lines. Comparison of the proposed voltage stability index with previous steady state voltage stability indices show that the proposed voltage stability index possesses following advantages： needing not judge the line resistance, clear physical conception, wide application range and satisfied linearity and so on. Utilizing the proposed index is favorable to implement of on-line monitoring and assessment of voltage stability.