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Abstract—A new fault phase selection method for transmission lines is proposed in this article. First, fault phase selection factors are constructed based on the relationship between the fault current of each phase and the fault current difference of the other two phases at a relay point. By analyzing different characteristics of fault phase selection factors in the case of different fault types, fault phase selection criteria are proposed. Simulation results show that fast and accurate selection of the fault phase can be achieved within a period cycle after fault occurs. Also, it is verified that the method bears a high sensitivity to all types of faults and is immune to the impact of fault resistance, fault inception angle, fault location, load current, and high-voltage DC lines, which makes it relatively reliable. Even when a developing fault occurs, good selectivity is secure with this method. Furthermore, the method provides sufficient sensitivity for phase selection on the weak-infeed side and parallel lines. [ABSTRACT FROM PUBLISHER]

A new distance-relaying algorithm for single-phase-to-ground faults on series-compensated parallel transmission lines is proposed in this article. Fault impedance can be calculated using this algorithm without any parameters requirement of mutual coupling and series capacitor device (series capacitor/metal oxide arrestor/discharging gap). The series capacitor device is simplified as linearized impedance during faults. The parameters of mutual coupling and a series capacitor device can be used as variables in the fault loop equations. Real-time digital simulator tests show that the proposed distance-relaying algorithm can obtain more accurate results than traditional distance-relaying algorithms for series-compensated parallel transmission lines. [ABSTRACT FROM AUTHOR]