| 摘要 |
<P>PROBLEM TO BE SOLVED: To attain a high operating voltage while restraining diameter enlargement of a polymer bushing insulator. Ž<P>SOLUTION: The polymer bushing insulator 1 is provided with: a conductor drawing rod 2 disposed in the center thereof; a hard insulator 3 attached to an outer periphery of the conductor drawing rod; and a polymer covering body 4 attached to the outer periphery of the insulator and formed with many pleat portions separated in the longitudinal direction on the outer periphery. The lower end of the conductor drawing rod is penetrated from the lower end of the insulator. At the portion in the vicinity of the lower end of the insulator and corresponding to the lower end of the polymer covering body, there is provided a large-diameter portion 33 having a tapered portion 33a formed so that the diameter thereof expands smoothly from high voltage side toward low voltage side. At an interface between the large-diameter portion and the polymer covering body, there is provided a field relieving layer 5 composed of a zinc oxide layer or a high-dielectric constant layer. At the large-diameter portion of the insulator, a cylindrical shielding metal fitting 6 is embedded in a concentric manner to the conductor drawing rod, and the field relieving layer comes into electrical contact with the shielding metal fitting. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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