基于失稳机理分析的暂态电压稳定性量化指标

Quantitative index of transient voltage stability based on instability mechanism analysis

在暂态过程中,当负荷母线电压值进入由系统特性和负荷特性决定的不稳定区时,会发生电压失稳。在单机单负荷系统模型中,证明同一系统静态P-V曲线和V-Q曲线的临界点具有一致性,基于动态跟踪系统特性变化的技术路线提出暂态潮流断面P-V曲线分析法,并给出暂态电压稳定性量化指标的计算方法和相应的稳定性判据。在多机系统中,虽然通常需要将所提方法与临界电压或戴维南等值电路的动态跟踪计算相结合才能应用,但也存在无需系统等值而直接应用基于单机模型的计算公式的场景。通过算例对暂态电压失稳机理、常规工程经验指标的局限性、所提指标和稳定性判据的有效性进行验证。

In the transient process,the voltage instability will occur when the load bus voltage value enters the unstable region determined by the system characteristics and load characteristics.In the single-machine and single-load system model,it is proved that the critical points of static P-V curve and V-Q curve of the same system are consistent,a P-V curve analysis method of power flow section during transient state is proposed based on the technical route of dynamic tracking system characteristic variation,and a calculation method of quantitative index of transient voltage stability and corresponding stability criterion are given.In the multi-machine system,although it is usually needed to combine the proposed method with the dynamic tracking calculation of critical voltage or Thevenin equivalent circuit for application,however,there still exist the scenarios where the calculation formula based on the single-machine model can be directly applied with no need of system equivalence.The mechanism of transient voltage instability,the limitation of conventional index based on engineering experience,and the effectiveness of the proposed index and stability criterion are verified by examples.