高渗透率可再生能源微电网的风柴荷协调调频策略

微电网中包含的高渗透率风机、光伏及柴油机、负荷等元件使微电网调频困难。为充分利用风柴荷备用资源对微电网调频性能的改善作用,考虑微电网频率总体最优,提出了一种基于高渗透率可再生能源微电网的风柴荷协调调频策略。考虑风柴荷与微电网频率特性的相互作用,推导了含高渗透率风电的微电网频率特性,建立了风柴荷联合调频下微电网频率特性模型,对比分析了不同调频参数下的微电网频率特性。其中风机和柴油机始终优先参与调频,可控负荷仅在负荷突变量大于风柴备用容量时参与调频,同时可控负荷调频系数根据频率波动大小而改变,兼顾风柴调频备用与供电可靠性,使微电网既能充分利用风柴调频能力,又能减少可控负荷调频压力,保证了需求侧供电的可靠性。仿真结果表明,所提出的调频策略可有效改善高渗透率可再生能源微电网的频率稳定问题,并减轻可控负荷调频压力。

Coordinated Frequency Regulation Strategy of Wind, Diesel and Load for Microgrid with High-penetration Renewable Energy

Since a microgrid includes high-penetration wind turbines, photovoltaic generation units, diesel generators, load and other components, its frequency regulation is difficult. In order to make full use of standby resources(wind, diesel and load)on improving the performance of frequency regulation, considering the optimization of overall microgrid frequency, this paper proposes a coordinated frequency regulation strategy of wind, diesel and load for microgrid with high-penetration renewable energy. According to the interaction of frequency characteristics between wind, diesel, load and microgrid, the frequency characteristics of the microgrid with high-penetration wind power are deduced, and a frequency characteristic model of microgrid combined with coordinated frequency regulation of wind, diesel and load is developed. Then the frequency characteristics of the microgrid under different regulation parameters are compared and analyzed. The wind turbines and diesel generators always participate in the frequency regulation, and the controllable load is involved in the frequency regulation only when the sudden change of load is greater than the spare capacity of wind turbines and diesel generators. The frequency regulation coefficient of the controllable load changes according to the frequency fluctuation. Thus, the spare capacity of wind turbines and diesel generators for frequency regulation and the power supply reliability are both considered. The microgrid can not only make full use of the frequency regulation capability of wind turbines and diesel generators, but also reduce the frequency regulation pressure of the controlled load, to ensure the power supply reliability on the demand side. The simulation results show that the proposed frequency regulation strategy can effectively improve the frequency stability of microgrid with high-penetration renewable energy, and reduce the frequency regulation pressure of controlled loads.