Bushing insulators are used between the transformer rectifier and the discharge electrode suspension of an ESP for leading high voltage into the electric filed, functioning as insulating and supporting of the bus rod. By its own structure it is divided into two types: pure ceramic insulator and combined insulator.
A combined insulator consists of the ceramic body and metal fittings which are cemented together with binder that can withstand high temperature. The cementing faces on a ceramic insulator body are knurling or sanding treated, and a high temperature withstanding elastic layer is interposed between the ceramic body end and metal fittings, and a buffer is also applied between them to prevent from loosening.
Its operating voltage ranges from 72kV to 120kV.