Study on Control Strategy of Cascading Failure for Power System with Multi-send HVDC and Large-scale wind farm

There will be much deep coupling among the large-scale renewable generators, multi-HVDC, and AC system after the system disturbance, in the power system with high proportion renewable energy and multi-send HVDC. As a consequence of that, the risk of cascading failures is greatly increased. Further research on the control strategy of the cascading failure is therefore required. Firstly, time domain simulation is used to search cascading chains with high risk, which is based on action evaluation index of security control devices. So that the actual evolution process of cascading failures can be better expressed in fault chain model. Secondly, a new emergency control method based on searched cascading chains is proposed, to set up emergency control measures for those events that may evolve into cascading failures. This new control method could further strengthen and perfect the ability to block the fault chain of cascading failure of current emergency control system. In order get the lowest risk cost of the control strategy, the preventive control and emergency control is coordinated and optimized. Finally, simulation results and analysis based on real-sized power grid in Northwest China prove the rationality and effectiveness of the proposed control method and strategy.