基于虚拟同步发电机的风电场并网控制研究

Control strategies of grid-connected wind farm based on virtual synchronous generator

随着风力发电容量占电网容量的比重不断加大,风电场对电网稳定性的影响也越来越大。同步发电机具有调节系统功率平衡,维持电网电压稳定的作用,并具有自同步特性,适于系统并联。通过在风电场交流侧配置储能电池,并对储能系统的逆变器采取基于同步发电机模型的控制策略,将风电场等效为虚拟同步发电机(Virtual Synchronous Generator-VSG),使风电场向电网输送的功率平滑,并对大电网体现同步发电机的特性。根据负荷的波动,调节自身输出功率,维持系统频率与电压稳定,有效提高了大规模风电场并网性能。建立了由风力发电机组、储能电池及汽轮发电机组组成的系统仿真模型,仿真结果验证了控制策略的可行性。

With the increase of grid-connected capacity of wind power generation, the influence of wind farm power fluctuation on the grid stability becomes more and more serious. In power system, synchronous generator can adjust system power and stabilize grid voltage and it has the feature of self-synchronization, fitting for system shunt connection. By adding a energy storage battery to wind farm AC side and adopting control strategy based on synchronous generator model to the converter of storge system, this paper makes the wind farm behave like a virtual Synchronous Generator （VSG） and makes the power sending to power grid from wind farm smooth and makes it embody the feature of the synchronous turbine. According to load fluctuation, it can adjust its output power, stabilize system frequency and voltage, and effectively enhance the grid-connected performance of large-scale wind farm. A detailed model consisting of wind turbine, energy storage and steam turbine unit is developed by using MATLAB/Simulink. The simulation results show the feasibility of the control strategy.