Research Of Negative-Sequence Current Differential Protection Algorithm

It is necessary to install right protectors for power transformer as it plays animportant role in power system. On the basis of negative-sequence current, whichindicates the characteristics of asymmetric faults, the negative-sequence currentdifferential protection algorithm is proposed. It can distinguish turn-to-turn faults with ahigh sensitivity. The additional criterion and positive-sequence current restrainingtechnique are used to heighten resistance to CT saturation and avoid maloperation. Itdiscusses problems met in usage, such as magnetizing inrush, developed fault andoscillation, which testify the algorithm's feasibility.