A Fast Calculation Method for the Local Commutation Failure Immunity Indices in Single- and Multi-infeed HVDC Systems

The Commutation Failure Immunity Index (CFII) is a good predictor which quantifies the susceptibility of an HVDC system to commutation failure. However, this index is based on many electromagnetic simulations and requires extensive computational time. In this paper, a faster calculation method for CFII is proposed and verified. This method significantly reduces the simulation effort and is applicable to single and multi-infeed HVDC system with different short circuit ratios (SCR). The paper gives a comparison of time savings and accuracy of the proposed approach for the study of commutation failure in HVDC systems.