An integrated technique for fault location and section identification in distribution systems

• The paper presents a technique to locate faults on large and multi-branched distribution feeders.
• The method integrates apparent impedance and transient analyses.
• Unbalanced operation, intermediate loads and time-varying load profile are considered.
• The transient analysis uses time and frequency domain correlation of traveling waves.
• A real distribution feeder with 3472 buses is used to check the method's performance.

This paper proposes an integrated impedance and transient-based formulation for fault location in distribution systems. The technique uses an extended apparent impedance analysis in order to estimate the fault distance, taking into account the unbalanced operation, intermediate loads, laterals, and time-varying load profile of distribution systems. The fault distance information is used in calculating characteristic frequencies associated to each possible fault location. A transient analysis is proposed to evaluate the spectral content of the fault-generated traveling wave, thus identifying its most significant frequency components. Based on the time–frequency correlation it is possible to eliminate the multiple estimates obtained from the impedance-based method, thus resulting in a single fault location. Aiming to verify the application of the proposed methodology, simulations were carried out in the ATP/EMTP Software considering a real distribution feeder with 3472 buses.