The Impact of HVDC Commutation Failure on the Distance Protection

Analysis of the equivalent fault characteristics of DC system and its impact on distance protection based on power‐frequency variation

“…Equation (20) can be converted to (21), where the effect of load is omitted In (21), Z′ zd is the equivalent impedance of setting impedance in which the effects of k rel and Δ Z are considered. In traditional AC system, Δ Z is equal to the impedance of AC system Z S , which is inductive [8]. According to the preceding analysis, Δ Z is capacitive in HVDC system under certain conditions, which may influence the size of the protection zone.…”