Transient stability enhancement for power grid with MMC-MTDC under N-k contingencies

Abstract

With the global climate change, the frequency of extreme weather is getting higher and higher, and the threat to the safe operation of the power system is gradually increasing, which is likely to cause large-scale power outages then result in N-k contingencies. Meanwhile, Modular Multi-level Converter (MMC) based Multi Terminal High Voltage Direct Current (MTDC) has been confirmed that can provide the possibility for the network interconnection between regional power systems and various renewable energy resources to boost supply reliability and economy. To enhance the transient stability of the power grid, a generation rescheduling scheme by optimal emergency control that considers the risk-based dynamic security constraint and reactive power constraints is proposed. The proposed strategy can avoid subsequent N-k-1 contingencies in the harsh environment by changing the generating capacity of the generator and the operation state of the MMC. The simulation results from studies on a 10-machine-39-bus power system have been demonstrated the effectiveness of the proposed control strategy.