光伏电站参与大电网一次调频的控制增益研究

随着光伏发电等新能源的大规模快速发展,电力系统对其参与一次调频提出了相关要求。调频控制增益(调差系数的倒数)是一次调频控制的关键参数,目前其主要参照常规电源机组设置值和部分仿真计算结果制定,欠缺理论分析,国内外不同机构或标准提出的参数推荐值差异较大,不合适的参数可能导致频率调节不稳定。文中首先介绍了国内外有关光伏发电参与一次调频的技术要求,然后建立了光伏电站接入系统的一次调频控制分析模型,鉴于该模型含有死区和饱和等非线性环节,采用基于描述函数的非线性奈奎斯特稳定性判据分析了光伏电站接入系统前后调频控制增益的稳定范围。单机系统和两机系统算例仿真结果验证了所述分析方法和结果的正确性,该分析方法容易推广应用于风电等其它系统,分析结果可对相关标准和现场调频装置参数整定提供借鉴。

Research on Control Gain for Photovoltaic Power Plants Participating in Primary Frequency Regulation of Large Power Grid

With rapid and large-scale development of renewable energy sources such as photovoltaic(PV) power generation, relevant requirements of power systems are put forward for its participation in primary frequency regulation. Control gain(reciprocal of droop rate) is the key parameter of primary frequency regulation, at present mainly formulated in reference to the setting values of conventional power units and some simulation results, lacking theoretical analysis. The recommended values of the parameters proposed by different institutions or standards in China and abroad are quite different, and inappropriate parameters may lead to instability of frequency regulation. This paper firstly presents the technical requirements of PV power generation participating in primary frequency regulation in China and abroad, and then establishes an analysis model of primary frequency regulation control for the system with PV power plant. Considering that the model contains dead zone and saturation nonlinear links, the stability criterion of nonlinear Nyquist stability based on describing function method is used to analyze the stability of frequency control gain before and after PV power plant integration to power system. The simulation results of single-and two-machine systems verify correctness of the analysis method and results. The analysis method can be easily applied to othersystems such as wind power generation. The analysis results can provide reference for relevant standards and parameter setting of primary frequency regulation devices.