基于支路能量时空特征的电力系统暂态稳定性分析

摘要

Two performance indexes, that is, distribution entropy and approximation entropy of power system branch potential energy, are proposed for transient stability assessment.The general dynamic model of power systems and branch potential energy is firstly introduced.Distribution entropy is used to describe the spatial feature of branch potential energy and approximate entropy is used to describe the temporal feature of branch potential energy.After that, the methods for transient stability based on the proposed two performance indexes are presented in detail.Case study on the transmission system of Sichuan province demonstrates that, a higher energy injection caused by a fault and smaller energy distribution entropy will result in a more unstable system.Numerical results also show that smaller energy approximate entropy indicates that potential energy will accumulate faster in the critical subset of transmission lines, thus the system will be more unstable.%提出支路能量分布熵和支路能量近似熵指标,分别从扰动能量在电网中的空间分布聚集程度和从扰动能量随时间推移的振荡态势来分析故障后电力系统的暂态稳定性.首先简述系统动态模型和基于结构保留模型的支路势能分析方法,引入复杂系统熵理论构造支路能量分布熵指标;同时引入近似熵与多尺度熵理论构造支路能量近似熵指标,进一步给出基于两类熵指标的暂态稳定分析方法.四川电网算例研究验证了:线路故障注入电网的扰动能量越大,支路能量分布熵越小,则关键支路割集所聚集的能量越大,系统越容易失稳;支路能量近似熵越小,则聚集在支路上的能量随时间推移越发增加,系统越容易失稳.