含风光出力随机性的独立微电网二次频率控制

SECONDARY FREQUENCY CONTROL OF ISLANDED MICROGRID CONSIDERING WIND AND SOLAR STOCHASTICS

针对风、光发电随机性的问题,提出一种考虑新能源减载参与二次调频的模型预测控制方法。建立包含随机功率扰动的扩展状态矩阵,采用卡尔曼滤波估算随机未知扰动;依据风、光最大可用功率,建立实时变约束,避免机组功率越限;设置合理的权重系数,优先风、光发电出力参与二次调频;通过求解变约束二次规划问题,获得各个机组的优化调频功率。最后,建立含多个光伏、风电的微电网模型,在不同场景下与常规二次调频方法进行对比仿真。仿真结果表明,所提方法能提高系统频率恢复速度,减小系统频率波动,尤其在风、光发电剧烈波动场景下。

This paper proposed a model predictive control(MPC)secondary frequency control method considering wind and solar power generation stochastics.The extended state-space matrix including unknown stochastic power disturbance is established,and a Kalman filter is used to observe the unknown disturbance.The maximum available power of wind and solar DGs is estimated for establishing real-time variable constraints that prevent DGs output power from exceeding the limits.Through setting proper weight coefficients,wind and photovoltaic DGs are given priority to participate in secondary frequency control.The distributed restorative power of each DG is obtained by solving the quadratic programming(QP)optimal problem with variable constraints.Finally,a microgrid simulation model including multiple PV and wind DGs is built and performed in various scenarios compared to the traditional secondary frequency control method.The simulation results validated that the proposed method can enhance the frequency recovery speed and reduce the frequency deviation,especially in severe photovoltaic and wind fluctuations scenarios.