基于能量函数的电网低频振荡及扰动源定位研究

由于电力系统稳定器在实际电网中的广泛配置,常规的离线小干扰计算分析已经难以得到负阻尼或弱阻尼的低频振荡模式.然而,实际系统中仍然频繁出现低频振荡现象,根据对大量事故的分析,发现多重扰动的发生以及周期性扰动源的存在都可能引发低频振荡.构造了基于联络线的能量函数,并将能量分解为振荡分量和准稳态分量,从而对多重扰动引起的系统低频振荡进行分析,以提供可供调度人员参考的动态安全信息;并将传统的支路势能分解为周期分量和非周期分量,利用非周期分量在网络中传播耗散的方向来实现周期性强迫扰动源的快速、准确定位.实际电网仿真算例验证了所提方法的有效性和可行性.

Research on Low Frequency Oscillation in Power Grid and Location of Disturbance Source Based on Energy Function

In conventional off-line small signal stability analysis,the low-frequency oscillation modes with negative or weak damping hardly ever appear in conventional small signal stability analysis due to the wide configuration of power system stabilizer(PSS),however,in actual power grids low-frequency oscillation phenomena frequently appear.Based on the analysis on a lot of failures,it was found that low-frequency oscillation could be induced by both occurrence of multiple disturbances and existence of periodic disturbance sources.To offer dynamic security information for dispatchers,an energy function based on tie-line was constructed and the energy was decomposed into oscillating component and quasi-steady component to analyze low-frequency oscillation induced by multiple disturbances in power grid;the traditional branch potential energy was decomposed into periodic and aperiodic components,then using the direction along which the aperiodic component propagated and dissipated the periodic forced disturbance source could be located rapidly and accurately.The effectiveness and feasibility of the proposed method were verified by simulation results of an actual large-scale interconnected power grid.