GB1014624A - Improvements in or relating to electrical insulators - Google Patents

Abstract

1,014,624. Insulators. CENTRAL ELECTRICITY GENERATING BOARD. Nov. 12, 1964 [Dec. 12, 1963], No. 49210/63. Heading H2C. An insulator for supporting a conductor carrying A.C. has a length of electrically insulating material incorporating one or more elements of ferroelectric material located in the A.C. field so that the insulator is heated by ferro-electric hysteresis, appropriate choice of the Curie temperature allowing the degree of heating to be controlled. In a preferred embodiment (Fig. 2) ferro-electric hollow cylinders 29 are sandwiched between insulators 30 and are arranged around an insulating core 22 which is screwed at each end into metal pieces 23 and 24. Metal inserts 32 electrically connect the hollow cylinders 29 which are held under pressure by a metal cylindrical bellows 33 so that a conductive path exists between a conductor and support. The ferro-electric material can have a Curie temperature between - 5‹ C. and 350‹ C. by alloying titanates, stannates, tantalates, niobates, zirconates and vanadates of elements such as barium, calcium, strontium, silver and lead. In a further embodiment (Fig. 1, not shown) a ferro-electric core is contained within an insulator body and is connected between cast iron or aluminium end caps of the insulator. Alternatively a ceramic ferro-electric material may be fired on a porcelain insulator. The insulator sheds 31 can be made of polyethylene or of the insulating material of the core 22 and insulator body which may be resin-bonded glass fibre or resin-impregnated wood.