随着新能源在电网中占比逐步增加,配备大容量分布式储能的光伏微网支撑火电厂黑启动成为可能.针对黑启动期间微网有功频繁波动,分布式储能荷电状态(SOC)越限导致黑启动失败的问题,提出一种考虑分布式储能SOC均衡的光储微网黑启动协调控制策略.该策略根据分布式储能单元SOC,将光伏系统负荷跟踪控制与最大功率跟踪控制相结合,使光伏出力有效跟踪微网负荷以避免SOC越限.在光伏出力与黑启动负荷不平衡时,分布式储能系统用于平滑系统有功功率差.对储能单元下垂控制进行改进,确保基于储能SOC的有功分配,实现各储能单元SOC均衡.通过基于一致性协议的储能二次控制,实现黑启动过程中系统有功波动下的频率稳定.仿真结果证明了光储微网黑启动可行性与所提控制策略的有效性.

With the increasing proportion of new energy in the power grid, photovoltaic microgrids equipped with large-capacity distributed energy storage have the potential to support the black start of thermal power plants. To address this issue of frequent fluctuation in the active power of the microgrid during the black-start period, and the risk of exceeding the state of charge (SOC) limits of the distributed energy storage, which could lead to the failure of the black-start, a coordinated control strategy for the optical storage microgrid black-start is proposed considering the SOC balance of the distributed energy storage. Based on the SOC of the distributed energy storage unit, the proposed strategy combines the load tracking control of the photovoltaic system and the maximum power tracking (MPPT) control, which ensures that the photovoltaic output effectively tracks the microgrid load to prevent the SOC from exceeding its limit. When the photovoltaic output becomes unbalanced with the black-start load, the distributed energy storage system is used to smooth the active power difference of the system. Furtherfore, the droop control for the traditional energy storage units is improved to ensure the active power distribution based on the energy storage SOC, enabling the SOC balance among energy storage units. Through secondary control of the energy storage units based on distributed consensus protocol, the strategy ensures frequency stability in the active power fluctuation during the black start process. The simulation results verify the feasibility of black start and the effectiveness of the proposed control strategy.