Evaluation of Commutation failure Risk for HVDC Caused by Harmonic Voltage

The commutation failure is one of the most common faults in high voltage direct current transmission (HVDC) systems. The research on the HVDC commutation failure has made some achievements at home and abroad. However, the influence of harmonic on the commutation failure of HVDC has not been studied thoroughly. Based on the commutation process of HVDC and the commutation voltage-time area analysis, a harmonic influence factor is derived, and the influence of harmonics on the commutation process in HVDC is quantitatively analyzed. The evaluation index of the risk of commutation failure due to harmonics, which is defined as the harmonic influence superposition Esup, is proposed, and a method using Esup to evaluate the risk of commutation failure caused by harmonic voltage is given consequently. Finally, based on the PSCAD/EMTDC electromagnetic transient simulation platform, the proposed evaluation indicators are simulated and verified.