光伏电站接入对多机电力系统低频振荡的影响分析

Influences of Grid-connected Photovoltaic Power Plants on Low Frequency Oscillation of Multi-machine Power Systems

为了研究光伏电站接入对多机电力系统低频振荡的影响,综合考虑并网光伏电站的动态模型,详细推导并建立了含光伏电站的多机系统状态方程及其线性化模型。在此基础上,选取两区四机系统作为分析案例,采用模式分析法,针对光伏电站接入后系统转动惯量改变和转动惯量保持不变两种典型分析场景,研究不同接入点及不同渗透率情况下光伏并网对于电力系统低频振荡的影响,并通过时域仿真法验证了模式分析的正确性。仿真结果表明:光伏电站不会产生新的低频振荡模式。在转动惯量改变和保持不变的两种场景下,光伏电站的接入对于系统低频振荡的影响存在显著差异,取决于其接入位置与接入容量。最后,通过特征值灵敏度分析,验证了光伏电站不同接入位置、接入容量对于区间低频振荡模式的影响。

In order to investigate the influences of grid-connected photovoltaie （PV） power plants on the low frequency oscillation of multi-machine power systems, detailed derivations are made and the state equation and the linearized model of the multi-machine power system containing PV power plants are set up based on the dynamic model of grid-connected PV power plant. On this basis, the influences of different locations and penetrations of PV on low frequency oscillation of a two-area four generator system are analyzed systematically by using the modal analysis method, when the system rotational inertia is changed or unchanged. The influences are then validated by time domain simulations. The simulation results show that the PV power plant will not generate additional low frequency oscillation modes. There exist significant differences in influences of PV integration on low frequency oscillation when the system rotational inertia is changed or unchanged. The influences of PV integration depend on the location and penetration of PV power plant. Finally, the influences of PV location and penetration on inter area low frequency osciilation mode are further validated by eigenvalue sensitivity analysis.