同步发电机阻尼绕组和磁路饱和对低频振荡阻尼的影响

采用特征值分析法研究同步发电机阻尼绕组以及磁路饱和对低频振荡阻尼的影响。建立了同步发电机三阶以及考虑阻尼绕组的六阶小扰动线性化模型,并在模型中考虑了磁路饱和效应。为详细分析同步发电机阻尼绕组和磁路饱和对低频振荡阻尼的影响,采用了简化的单机无穷大系统。计算表明,在分析低频振荡问题时:同步发电机三阶模型不宜用于分析进相或轻载运行的机组,这一结论和是否安装电力系统稳定器(PSS)以及是否忽略磁路饱和无关;忽略磁路饱和的同步发电机三阶模型在额定工况附近具有比较高的准确性;磁路饱和对六阶模型的影响较小,但是对于含PSS的进相运行机组,不宜忽略磁路饱和;为得到准确的结论,建议在同步发电机模型中考虑阻尼绕组和磁路饱和的影响。

Effect of synchronous machine damper windings and magnetic saturation on low-frequency oscillation damping

Effect of damper windings and magnetic saturation of synchronous machine on LFO(Low-Frequency Oscillation) damping are studied with eigen analysis method.Both the 3rd-order linearized model of the synchronous machine and the 6th-order linearized model including damper windings are established with consideration of the effect of magnetic saturation,which are used in the analysis of LFO damping for single-machine infinite bus system.The computation and analysis indicate that:the 3rd-order model is not appropriate to LFO analysis when the synchronous machine is phase-leading running or under light load,independent of PSS(Power System Stabilizer)and magnetic saturation.However,it will provide precise results when the synchronous machine is running in normal condition.The effect of magnetic saturation is not significant when the 6th-order model is used for a synchronous machine except the machine is phase-leading running with PSS.Effect of damper windings and magnetic saturation should not be neglected in LFO analysis.