Clarke circuit analysis for space-vector ellipse characterization of phase-to-ground faults in three-phase radial systems

This work deals with the technique for fault detection and classification in three-phase power systems based on the elliptical trajectory of the voltage space vector on the complex plane. A new approach is presented leading to the derivation of equivalent circuits directly in the Clarke domain where the space vector is defined. A specific methodology is introduced to manage the asymmetrical behavior of single-phase and double-phase faults. In particular, an in-depth analysis is presented for the single-phase-to-ground fault. The proposed equivalent circuits allow straightforward derivation and interpretation of the voltage ellipse for fault characterization. The analytical results are validated through the simulation of a three-phase radial system.