Accurate phase comparison scheme with synchronised measurements

Segregated phase comparison technique is a special form of current differential protection. It takes into account the difference of phase angle of currents entering at one terminal and current leaving out of other terminal of transmission line. Line charging current causes significant change in phase angle of two end currents of a transmission line. This paper presents novel phase comparison technique which compensate for line charging currents in presence of synchronised measurements using equivalent-π model of transmission line. A novel phase differential function is developed in phase coordinates. Global positioning system is used for synchronised measurements and fiber optic is considered for data communication. The scheme is implemented on one of the tie line of IEEE 14 bus system and simulations are carried out in ATP/EMTP. The results demonstrate the superiority of the proposed novel approach.