The Analysis of Influence of HVDC Commutation Failure on Distance Protection

Distance protection is a common line protection. The protection range and sensitivity of protection are less affected by the operation mode of the system. At the same time, distance I protection has the advantages of stable protection range and identifying the direction of short-circuit points. However, by side close to the converter station in HVDC transmission distance protection, likely because of commutation failure in DC measurement impedance add-ons with DC fault current equivalent change and change, the different fault cases caused by the additional impedance value, may is inductive or capacitive, leading to refuse or delay action distance protection. This paper builds a DC transmission model based on PSCAD /EMTDC as a simulation tool, and the simulation verification shows that when the metal-grounded transmission line in the near area of dc inverter occurs, the phase-changing failure on the inverter may cause the distance protection rejection.