Black-start Control Strategy of the Wind-storage Combined Power System under Isolated Island Condition

Energy storage system (ESS) plays an important role in the black-start (BS) process of new energy caused by its rapid response ability. In the process of BS, the new energy operates in island mode, and the stability of the system is greatly affected because it loses the support of the voltage and frequency of the large grid. Considering under isolated island operation, the failure of BS due to voltage and frequency fluctuation caused by power and load variation of wind-storage system, a BS coordination control strategy of wind-storage combined power system under isolated island condition is proposed in this paper. Firstly, the BS topology of wind-storage system is constructed, the general process of BS is analyzed. Secondly the BS control strategy of the wind-storage system is proposed based on power changes. The ESS switches charge/discharge mode according to the power and load changes to absorb or supplement the excess output power and power vacancy in time, maintaining the power balance of island system to keep the voltage and frequency stable, and guarantees the progress of BS is smooth. Finally, a simulation model is built based on PSCAD/EMTDC to verify the effectiveness of the proposed strategy.