大型光伏电站抑制低频振荡的有功阻尼控制策略

Active Damping Control Strategy in the Large-Scale Photovoltaic Plants Restraining Low-Frequency Oscillations

日益增大的光伏并网容量和光伏发电比重可能会对电力系统的低频振荡特性产生不良影响,大型光伏电站应该具备抑制低频振荡的能力。论文以大型光伏电站并入单机无穷大系统为研究对象,提出采用广域输电线路有功微分信号调节大型光伏电站最大有功输出的自适应阻尼控制策略,该控制策略能够尽可能多地输出有功并且确保光伏电站低频振荡抑制模式与最大功率跟踪模式之间的平滑切换。同时,考虑到相关标准对无功调压能力的要求,大型光伏电站无功控制沿用现有光伏系统无功调压的控制方法,进而形成大型光伏电站的功率控制策略。理论分析和仿真结果验证大型光伏电站有功阻尼控制策略能够显著提高系统抑制低频振荡的能力,保障系统安全稳定运行。

With the growing of photovoltaic capacity and permeability, which is likely to be a harmful effect on the low-frequency oscillations of the power system, large-scale photovoltaic plants should have the ability to restrain low-frequency oscillations. With the research object of single-machine infinite bus system including large-scale photovoltaic plants, this paper proposed the adaptive damping control strategy using the differential signal of the active power on the wide-area transmission lines to regulate the most active output in the large-scale photovoltaic plants. The strategy can offer active power as much as possible, and ensure smooth switching between low-frequency oscillation suppression mode and maximum power tracking mode. Considering the reactive power-voltage regulating ability in the related standards, the large-scale photovoltaic plants adopt the existing control strategy of power-voltage regulation. Theoretical analysis and simulation results show that： the large-scale photovoltaic plants which adopt the active damping control strategy can significantly improve the system＇s ability in restraining low-frequency oscillations and guarantee the security and stability of the power system.