电力系统仿真计算中变电站等值模式研究

Substation Equivalent Model in Power System Simulation Calculation

电网调度运行机构通过仿真计算掌握实际电网运行特性,给出相应控制策略,建模精度(变电站等值模式)成为制约仿真结果的关键因素。从实际电网出发,构建了两种变电站等值模式,模式一包含了较低电压等级的主变及接在低电压等级侧的电源,模式二在模式一基础上对变电站接于低电压等级的电源和负荷进行了整合。基于两种等值模式,针对实际电网从静态安全分析、暂态稳定分析、短路电流分析、小扰动动态稳定、电压稳定等多个角度进行了理论分析,并利用PSASP软件进行了仿真比对。结果表明两种模式下静态安全分析结果基本一致,当低电压等级中小机组电源较多时,其他类型仿真结果相差较大。最后,给出了不同电源结构、不同仿真要求下的变电站等值建议。

Power grid dispatching and controlling center usually masters the operating characteristics of the actual power system through simulation calculation and acquires the corresponding control strategies;therefore,the modeling accuracy（i.e.substation equivalent model）,is the key factor to restrict the simulation results.This paper formulates two substation equivalent models of the actual power grid,one of which contains the low-voltage transformers and generating units connected to the low-voltage grid and the other of which integrates the low-voltage transformers and the corresponding generating units.Based on the given models and the actual grid,the related analysis of static security,transient stability,short circuit,dynamic stability,small-signal stability and voltage stability are illustrated from the theoretical and actual calculation by PSASP.Simulation results show that static security results under the two equivalent models are basically unanimous,while other results are different especially for the low-voltage grid containing more small and medium-sized units.Finally,the equivalent substation model is suggested according to the different requirements and different grid.