Casing type CT and there is no bare soft copper wire connected to the copper row, casing type CT string center busbar is the manufacturer to bring both ends have a shielding ring do not need to be in the lead to the copper row, you should say is a string of current transformers, string center transformer wall has a metal mesh or graphite layer, in the metal mesh or graphite layer on a bare copper wire needs to be connected to the primary busbar, so that the busbar on the potential of the current transformer is equal to prevent corona phenomenon on the point of entry, to prevent eccentricity of the transformer, the wire is used to prevent corona phenomenon. Prevent the mother row eccentricity of the transformer into the point of corona phenomenon.