On Protection of Transformer Coils

Abstract

Abnormal potential gradient which threatens the layer insulation of transformer co ls, can be removed by shunting each section of the coil with graded capacities.* The auther gives mathematical investigations about the mode of the gradation of the capacity and obtained C_s=δC(1/2y²+constant), where y=distance of the point, considered, from the end surface of the bobbin of coil, containing the electrical neutral point, δ=length of the wire of coil per unit length of bobbin, C= capacity of the wire of coil to ground, per unit length.
If we use the shunting capacity given above, no danger takes place in the transformer coil.