EEAC与直接法的机理比较(三)定性判稳与定量分析

A CRITICAL COMPARISON OF VARIOUSMETHODSFOR TRANSIENT STABILITY ASSESSMENT Part Three Qualitative Criterion and Quantitative Analysis

讨论了长期困惑电力系统学术界的暂态稳定性理论和算法 ;归纳出 1 0个要素 ,即受扰程度函数、壁垒点、观察点、参考点、积分路径与被积函数、定性判据、轨迹稳定裕度、临界轨迹与参数极限值、迭代求解与初始轨迹、搜索策略与收敛判据。由 4篇短文组成的系列文章按照上述各要素 ,讨论了针对平衡点稳定性的李雅普诺夫法、将平衡点稳定性理论应用于有界稳定性的暂态能量函数(TEF)法以及针对有界稳定性的扩展等面积准则 (EEAC)这 3种稳定性理论在大扰动稳定性的分析中的应用。作为第 3篇 ,主要讨论参考点、积分路径和被积函数、稳定裕度、极限值搜索等要素的不同处理原则 ,证明不但对于任何多机系统 ,并且对于具有非线性负荷或非自治因素的单机系统 ,稳定分析都离不开包括故障清除后的实际受扰轨迹 ;指出稳定极限值和临界轨迹之间互相依存 ,只能通过迭代求解。以单机无穷大系统为例 ,从理论观点和可计算性观点出发 ,论证壁垒点和参考点都应该在实际轨迹上 ,而暂态能量的参考点则必须取故障前的稳定平衡点 ,而不能取故障后的稳定平衡点。

Ten essentials are abstracted for large- disturbance stability theory.In term s of each of the essentials,L yapunov direct methods,transient energy function TEF methods and extended equal- area criterion EEAC are critically compared in this four- part paper.The third- part reviews different opinions on the reference point,the integrating path and the integrated function,qualitative criterion,trajectory stability m argin,critical trajectory and stability lim its,iteration and the initial trail,searching strategy and convergence criterion.It is crucial for transient stability analysis of m ultimachine systems as well as nonautonomous one- m achine infinite- bus system s to use information of the whole disturbed trajectory including that during the post- fault period.With simple one- m achine infinite- bus systems as examples,it is also proved that not only the barrier point and the observation point but also the reference point for the function should be on the actual disturbed trajectory.