基于惯量支撑和一次调频需求的VSG储能单元配置方法

Configuration Method for Energy Storage Unit of Virtual Synchronous Generator Based on Requirements of Inertia Support and Primary Frequency Regulation

分布式电源大量接入电网会引发电网惯量、阻尼缺失和系统稳定性下降问题,虚拟同步发电机(VSG)在分布式电源友好接入和提高电力系统稳定性等方面极具应用前景。作为虚拟惯量的物理基础,储能单元的配置直接影响着VSG的性能和成本。文中基于VSG的惯量支撑、一次调频两大基本功能,建立了响应电网频率波动的储能单元出力模型,提出了一种以元件参数和控制参数为基础的储能单元配置方法。然后,计及下垂系数、阻尼系数和惯性常数,研究了储能单元出力的暂态特性及其调节机制,并分析了储能单元功率、容量需求受控制参数影响的机理,明确了影响程度最大的控制参数。最后,借助仿真和实验证明了所提方法的正确性。

Large amount of distributed generators(DGs) connected to power grid will cause loss of grid inertia and damping as well as decrease of system stability. The virtual synchronous generator(VSG) has great application prospects in the friendly access of DGs and the improvement of power system stability. As the physical basis of virtual inertia, the configuration of energy storage unit could directly affect the performance and cost of the VSG. Based on the two basic functions of the VSG(i.e. inertia support and primary frequency regulation), this paper develops an output model of the energy storage unit in response to the grid frequency fluctuation. And a configuration method of energy storage unit based on component parameters and control parameters is proposed. Considering the droop coefficient, damping coefficient and inertia constant, the transient characteristics of the output for energy storage unit and its adjustment mechanism are studied. Furthermore, the mechanism of the control parameters affecting the power and capacity requirements of the energy storage unit is analyzed, and the most influential control parameters are identified. Finally, the correctness of the proposed method is verified by simulations and experiments.