大型水电站高压厂用变压器差动保护的几个问题

Some Problems of Differential Protection for Station Transformer of Large Hydraulic Power Plant

大型水电站的发变组容量大、系统等值电抗小 ,高压厂用变压器 (以下简称厂高变 )容量特小而短路阻抗大 ,造成厂高变两侧短路电流相差悬殊 ,给差动保护的互感器选择和定值整定带来麻烦。

The capacity of generator transformer for large hydraulic power plant is bigger, the impedance of power system is smaller, while the capacity of HV station transformer is very small and its S/C impedance is very bigger. Thus the currents for S/C at both side of the station transformer are very different, the selection of TA and the setting of differential protection are difficult.The type selection of TA and calculation setting of the differential protection for HV station transformer are discussed.