Intelligent distribution network based on energy storage and flexible multi-state switch will cause significant voltage deviation when the planned and unplanned feeder off-grid occurs. In order to improve the stability of the system
a planned feeder off-grid switching sequence is designed
which can reduce the exchange power between the AC power grid and the system to zero in advance. For unplanned feeder off-grid
power feed-forward control is introduced in the constant voltage control of the battery
which can quickly release the battery energy at the moment of feeder off-grid. To address the phase mutation problem for the fault load after the feeder off-grid
an improved V/f control strategy with the off-grid phase- locking function is proposed. The simulation results under different working conditions show that the intelligent distribution network function control strategies based on energy storage and flexible multi-state switches can achieve smooth switching when the planned feeder off-grid occurs
reduce bus voltage fluctuations when the unplanned feeder off-grid occurs
and quickly realize phase locking and tracking after off-grid switching
Cheng Yao,Changxin Zhou,Jiancheng Yu,Ke Xu,Peng Li,Guanyu Song.A Sequential Optimization Method for Soft Open Point Integrated with Energy Storage in Active Distribution Networks[J].Energy Procedia,2018.