“9.1”内蒙古西部电网振荡的仿真研究

Simulation Study on West Inner Mongolia Power Grid Oscillations Occurred on September 1st, 2005

内蒙古西部电网于2005年9月1日发生了3次相对华北主网的振荡。笔者采用在电网不同地点施加周期性冲击负荷的方法计算电网的动态响应,分析线路的功率摇摆情况,将计算结果与华北电网同步相量测量单元的测量结果和现场故障录波结果进行比较,初步确定了振荡引发地点,并通过时域稳定计算和频域仿真计算分析出振荡发生的原因和性质,即:振荡发生前万家寨电厂机组对系统振荡模式的阻尼已经较弱,随着电厂有功出力的增加或无功出力的减少,该振荡模式的阻尼进一步降低,引发了万家寨电厂机组对系统的低频同步振荡,由此造成蒙西电网对华北主网的功率振荡。

On September 1st, 2005, three cases of low-frequency oscillations of units in West Inner Mongolia power system to those in North China power grid emerged. By exerting periodical load disturbances with oscillation frequency captured by PMUs to different buses, the power system dynamic responses were calculated and the power oscillations in transmission lines were analyzed. The calculation results were compared with both results measured by PMUs configured in North China power grid and on-site fault recorded data, thus the bus giving rise to oscillations was tentatively determined and the cause and quality of oscillation were analyzed by stability simulation in both time-domain and frequency-domain. The cause could be explained as followed： the damping of oscillation mode of units in Wanjiazhai power plant to the main power network was relatively insufficient before the oscillations occurred, along with the increment of power plant＇s active power output or the decrement of its reactive power output the damping of above-mentioned oscillation mode further declined, so that the low-frequency synchronous oscillation of units in Wanjiazhai power plant to other units in West Inner Mongolia power system was triggered and the oscillation of units in West Inner Mongolia power system to those in main network of North China power grid occurred.