Secured zone 3 protection during load enchrochment using synchrophasors

Load encroachment function fails to prevent zone 3 maloperation during high reactive loading condition. Such maloperations often causes in cascaded tripping which leads to wide area blackouts. In this work, a group of Phasor Measurement Units (PMUs) are selected to support the distance relay decision during load encroachment. An index D is computed using change in magnitude and phase angle of voltage collected from the selected PMU buses. The negative D depicts a load encroachment and supports the zone 3 decision when apparent impedance enters inside zone 3 characteristic. Performance of proposed method is tested with IEEE 39-bus simulated in EMTDC/PSCAD. Results show the accuracy of the proposed method.