A fast and high-accurate commutation failure identification method for LCC-HVDC system

Commutation failure(CF)is one of the most common issues in line-commuted converter-based high voltage direct current systems(LCC-HVDC),leading to critical power system security and stability problems.Accurate and rapid identification of CF is crucial to prevent subsequent CF in HVDC systems.However,the existing CF identi-fication methods are lack of the required accuracy and speed.The relationship between bridge arm current,commutation voltage,and trigger pulse based on the commutation progress mechanism after the AC fault is analysed in this paper.A novel CF identification method is presented,which utilises the CF identification factor,enabling fast and high-accurate identification without relying on the value of the extinction angle.The pro-posed method offers a simpler and more efficient implementation in engineering practice.Finally,the effectiveness of the proposed method is verified in both the standard In-ternational Council on Large Electric systems HVDC model and the Hardware in Loop test using practical project parameters.The results demonstrate that the proposed method can accurately and fast identify CF.