Traveling-wave differential protection on UHV transmission line with shunt reactor

The traditional traveling-wave differential protection cannot be applied to ultra/extra high voltage transmission line with shunt reactor, so this paper describes a novel differential current expression. Based on traveling-wave differential protection a new scheme with low proportional restraint characteristic is presented. This scheme can avoid transient unbalance differential currents under different operation conditions. It also has high sensitivity for internal high-resistance fault. Theoretical analysis and EMTP simulation show that the scheme operates sensitively and rapidly. The protection has no special demands for sampling rate and communication speed and can be realized by existing technique.