Study on the Optimization of Generator Tripping Control Strategy of Sending HVDC System with Multi-type Power

The steady state overvoltage problem may arise after HVDC blocking and generators tripping off, with various types of power supply. Different types of power supply tripping off has different influence on the overvoltage, and the control cost of different types of power supply is different. Therefore, further study is needed on the optimization of the generators tripping-off strategy, which takes into account the system security and control cost. This paper analyzes the calculation method and influence factors of the system steady voltage after the HVDC blocking and generators tripping-off. Then the optimization method and implementation steps of the control strategy was proposed, which takes into account the steady-state voltage rise of the key bus and the total control cost after the accident. Firstly, under the condition that the transient power angle, frequency and voltage of the system is stable, the total quantity of tripping-off generators after HVDC fault is determined. Secondly, the tripping-off sequence of all kinds of power sources is sequenced according to the influence of different types of power sources on the steady-state voltage rise after the accident. Finally, based on the constraint of the system steady-state voltage rise after the accident, the optimization objective is to minimize the total control cost, and the optimized control strategy is finally determined. The simulation results of the actual power grid verify the rationality and effectiveness of the proposed optimal control strategy, taking into account the safety and control cost of the system. The conclusion can provide theoretical and practical reference for the control strategy of the HVDC external transmission system with multi-type power supply.