Digital fault location for parallel double-circuit multi-terminal transmission lines

Two new methods are proposed for fault point location in parallel double-ci rcuit multi-terminal transmission lines by using voltages and currents info rmation from CCVT's and CT's at all terminal. These algorithms take advanta ge of the fact that the sum of currents flowing into a fault section equals the sum of the currents at all terminals. Algorithm-1 employs an impedance calculation and Algorithm-2 employs the current diversion ratio method, Co mputer simulations are carried out and applications of the proposed methods are discussed. Both algorithms can be applied to all types of fault such a s phase-to-ground and phase-to-phase faults, As one equation can be used fo r all types of fault, classification of fault types and selection of faulte d phase are not required. Phase components of the line impedance are used d irectly, so compensation of unbalanced line impedance is not required.