An Initial Investigation for Locating Self-Clearing Faults in Distribution Systems

An approach of inverse time-domain transient analysis is devised as a possible method of locating self-clearing, sub-cycle incipient faults in distribution systems. Simplified modeling and formulation of a fault distance calculation from a substation for ground faults in circuits is made using only the discrete voltage and current samples obtained at the substation. The formula in principle seeks to find the value of a line inductance to the fault from the substation by analyzing the transient waveform of phase voltage and current. In particular, in the equivalent circuit of the faulted system, the method applies voltage injection and superposition principle, obtains net fault voltage and current, and calculates the line inductance to the fault as fault distance. The steps for implementing the formula from substation sampled data are detailed and illustrated, followed by validation test results with eleven actual transient faults.