Staged Fault Tests with Single Phase Reclosing on the Winnipeg-Twin Cities 500kV Interconnection

Staged line-to-ground fault tests were performed on the longest section of single-phase switched line in the world, the 528 km Dorsey-Forbes 500 kV line. Fault location and line loading conditions were varied for the nine fault tests applied and measurements were made of the primary and secondary arc currents and the arc recovery voltage. Arc extinction occurred rapidly with no restrikes during all of the tests. Secondary arc extinction occurred less than 50 ms after the beginning of the open phase deadtime. The rennants of the direct current offset in the fault current had a significant effect in delaying the secondary arc extinction.