Sub-cycle ground fault location — Formulation and preliminary results

A new time-domain approach of locating transitory, sub-cycle faults is introduced with a detailed formula derivation of the fault distance calculation for a single line-to-ground fault in the circuit of a substation, utilizing only the discrete voltage and current samples obtained at the substation. The formula is obtained from an equivalent circuit of the faulted circuit with voltage injection and the superposition principle using the parameters of net fault voltage and current. In addition to the fault distance, the approach also derives an equation which can produce the source reactance of the substation bus by the same parameters. The steps for implementing the derived formula in a practical application are illustrated, and then a preliminary test result with the actual substation measured data is discussed.