关键词: 光储系统, 并网, 光伏发电, 控制模式, 电压-功率灵敏度, 静态电压稳定

Abstract: [Objectives] The static voltage problem caused by day and night power flow reversal and random variation of power output under large-scale photovoltaic-energy storage integration affects the safe and stable operation of the system. It is urgent to study the static voltage characteristics of the power grid after photovoltaic-energy storage access. [Methods] Based on the equivalent model of the system under the access of photovoltaic-energy storage, the analytical expression of the voltage amplitude of the grid-connected point of the photovoltaic-energy storage station is derived and established. Based on this, the sensitivity analysis method is used to obtain the voltage-power characteristics of the grid-connected point of the photovoltaic-energy storage station under constant power factor control, constant reactive power control and constant AC voltage control, and the static voltage stability of the grid-connected point under different control parameters is analyzed. [Results] It is found that under constant power factor control or constant reactive power control, reducing the power factor of the photovoltaic-energy storage station or increasing the reactive power command value will increase the risk of static voltage over-limit at the grid-connected point. Under the constant AC voltage control, the static voltage stability of the grid-connected point of the photovoltaic-energy storage station is the best. [Conclusions] The analysis results of this paper can provide technical reference for the operational optimization of high proportion photovoltaic-storage access system, and have important theoretical significance and engineering application value.

Key words: photovoltaic-energy storage system, connection to grid, photovoltaic power generation, control mode, voltage-power sensitivity, static voltage stability