Multi-load model for reliability assessment of HVDC converter

Because of ignoring common cause failures and load diversity, the conventional reliability assessment models for HVDC transmission systems are over-optimistic. Load-property interference analysis method is introduced to provide a valuable understanding of failure modes and mechanism of HVDC converter. Operating loads of HVDC converters are classified according to endurance performances of thyristor element and a multi-load model taking different loading conditions into account is established. Comparative calculations are performed on a 12-impulse HVDC converter to illustrate the effectiveness of the proposed model. Importance and sensitivity of different loads in influencing converter failure probability are also evaluated by critical importance index. Results show that the proposed model is more precise and reliable.