Maintaining balanced three‐phase load voltage during single‐phase auto‐reclosing in medium voltage distribution lines

Abstract

Single-phase auto-reclosing (SPAR) is used for restoring power supply to clear temporary single-phase to ground fault in medium-voltage distribution systems. A zigzag winding grounding transformer connected at the remotest load bus rebuilds the three-phase voltage during the SPAR dead time. A distribution system having more than one branch needs one zigzag transformer at the remotest end of each branch. Build-up three-phase voltage during SPAR is not balanced. Operation of distributed generator connected to the system during SPAR needs the voltage to be balanced. Magnitude of the negative sequence voltage may be reduced by connecting capacitor in series with the neutrals of each zigzag transformer.