The Calculation of Unbalanced Voltage on the tertiary bus of a single phase auto transformer in case of Parallel Operation with Different Manufacturer

제작소가 상이한 단상 주변압기 병행 운전시 불평형전압의 검토

This paper described the unbalanced voltage on the tertiary bus of a single Phase auto transformer in the case of parallel operation with different manufacturer at each Phase. The unbalanced capacitances between primary to secondary winding, secondary to tertiary winding and primary to tertiary winding makes unbalanced bus voltage in the tertiary bus side. The unbalanced voltage let the surge arrester to operate in the power frequency range, and it causes the arrester to burn out. The failure of the arrester at one phase makes line to ground fault, which lead to the surge arrester failure of the other two phase on the tertiary bus.