关键词: 光储系统, 孤岛微网黑启动, 负荷跟踪, 分布式储能, SOC均衡

Abstract: With the increasing proportion of new energy in the power grid, it is possible for photovoltaic microgrid equipped with large-capacity distributed energy storage to support the black start of thermal power plants. Aiming at the problem that the active power of the microgrid fluctuates frequently during the black-start period, and the distributed energy storage SOC exceeds the limit, which leads to the failure of the black-start, a coordinated control strategy for the optical storage microgrid black-start considering the SOC balance of the distributed energy storage is proposed. According to the SOC of the distributed energy storage unit, the strategy combines the load tracking control of the photovoltaic system with the maximum power tracking control, so that the photovoltaic output can effectively track the microgrid load to avoid the SOC limit. When the photovoltaic output is unbalanced with the black-start load, the distributed energy storage system is used to smooth the active power difference of the system. The droop control of the traditional energy storage unit is improved to ensure the active power distribution based on the energy storage SOC and realize the SOC balance between each energy storage unit. Through the secondary control of energy storage based on distributed consensus protocol, the frequency stability under the active power fluctuation during the black start process is realized. The simulation results show the feasibility of black start and the effectiveness of the proposed control strategy.

Key words: optical storage system , black start of island microgrid , load tracking , distributed energy storage , SOC equilibrium