Patent ID: 8319101

Claim:
A polymer bushing comprising: a rigid insulator extending along a longitudinal axis from an upper distal end to a lower end and surrounding a central conductor bar having a conductor insertion hole in the lower end and extending along the longitudinal axis, the rigid insulator having a receiving port for receiving a termination of a cable, the rigid insulator including integral small and large diameter portions, the large diameter portion including a tapered part with a diameter which increases from the small diameter portion toward the conductor insertion hole; a polymer covering around an outer circumference of the rigid insulator, the polymer covering having a plurality of shades which are formed separately and spaced along the longitudinal axis of the rigid insulator, at an outer circumference of the polymer bushing; an electric-field stress-control layer provided at an interface between the large diameter part and the polymer covering and composed of a zinc oxide layer or a high permittivity material having a relative permittivity of 10 or more; and a cylindrical shielding metal fitting concentrically embedded together with the conductor bar in the large diameter portion of the rigid insulator; and wherein the electric-field stress-control layer is in electrical contact with the cylindrical shielding metal fitting.