Bi‐level optimised emergency load/generator shedding strategy for AC/DC hybrid system following DC blocking

This study presents a bi‐level optimised emergency control strategy, including load and generators shedding following DC blocking. Due to different constraints for networks with different voltages, a bi‐level optimised model spanning from the high voltages networks to the lower voltages is put forward. For the higher voltage level network, the overload area is identified and the seriousness of the overload is classified after DC blocking with the help of wide‐area measurement systems. Then, the objective function is built with the minimum total amount of load shedding and generator tripping to be solved by improved particle swarm optimisation (IPSO), considering the constraints of frequency and voltage stability, respectively. For the low voltage level networks, the least cost as the objective function with the constraints of load shedding and generator tripping strategy based on the analytic hierarchy process‐fuzzy comprehensive evaluation method. The modified 10‐machine 39‐bus system with HVDC lines is used as the test system. The simulation results demonstrated that the proposed strategy can give good control performance with consideration of different optimisation constraints following the DC line blocking.