A new interpretation of commutation failure risk in multi-infeed HVDC systems

A new interpretation of commutation failure risk, considering the circuit topology when commutation, is presented in this paper. The basic idea is to compare the difference of commutation angle of the relevant inverter after a new HVDC system is constructed. The equivalent circuit is indicated to deduce and derive the commutation angle. Then analysis on the impact factor of commutation angle is carried out. As a result, the equivalent commutation impedance of the relevant inverter is proved to increase, and so is the commutation angle. Hence the risks of commutation failure are enlarged. Validated by case studies in PSCAD/EMTDC, the presented interpretation is confirmed.