Electricity: conductors and insulators – Electric shock hazard protective devices – Shock protection – grounding devices
Patent
1997-05-22
1998-11-10
Ledynh, Bot L.
Electricity: conductors and insulators
Electric shock hazard protective devices
Shock protection, grounding devices
174138F, 52101, 47 23, H01B 1700
Patent
active
058346864
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an insulating article for protecting electrical equipment and to such equipment having the article mounted thereon.
2. Description of Related Art
Electrical equipment, such as power transmission lines, insulators, surge arresters, switchgear and transformers, operating at voltages in excess of 1 kV and particularly in excess of 10 kV (such voltages hereinafter being referred to as `high voltage`), often have parts thereof or parts associated therewith that are not insulated from the surrounding air. Thus, an exposed portion of such equipment can be at high voltage and be longitudinally separated from another portion at low voltage, for example at earth potential. The exposed high voltage portion may be physically supported by an insulator, for example when an overhead power line is mounted on an insulator that spaces it from a supporting tower that is itself at earth potential, or for example when a high voltage cable is terminated at a bushing or switchgear whose metal housing is at earth potential. In such instances outdoors, animals, birds and reptiles for example, and particularly the larger wildlife such as squirrels and birds with large wingspans, may be big enough to form a direct bridge, ie. an electrical short circuit, between the high voltage equipment and earth potential, with serious, usually fatal, consequences for themselves and often with serious consequences for the electrical equipment and the supply of electrical power--usually at least a fuse is interrupted or a circuit breaker triggered such that the power supply is interrupted.
One solution to this problem is to insulate the exposed parts of the high voltage equipment, at least in regions where a short circuit to earth is more likely to occur, for example unintentionally by wildlife, and products such as RAYSULATE insulation tapes and pre-shaped components are available from Raychem for this purpose. A further solution is to mount uninsulated components sufficiently far apart from each other. In some instances, however, these solutions may be impracticable and/or expensive.
Another solution is to mount an insulating guard on the apparatus so as physically to increase the distance between the two portions at such significantly different, ie. harmful, electrical potentials such that it is impossible, or at least more unlikely, that the wildlife will be able to form a direct bridge therebetween. A typical insulator for outdoor use, for example, may be made of porcelain or polymeric material and is usually provided with a plurality of rain sheds or skirts, that extend circumferentially around a central cylindrical core of the insulator and that are spaced apart along its length. A protective guard in respect of avoiding short-circuiting such an insulator by wildlife is known, the guard comprising two semi-circular discs that are brought together from each side of the insulator between two adjacent sheds. The semi-circular discs partially overlap and are interlocked, for example by means of projections on a face of one disc that engage apertures in the other disc. The diameter of the guard is typically about three times that of the sheds, and when in place provides an effective obstacle to wildlife extending themselves along the length of the shedded insulator from earth to high voltage. However, a guard of this configuration is not very convenient to position on the insulator, which may be difficult to access, as by being mounted on top of a pole of about 4 m height for example. It is necessary to support the two halves separately, bring them together in overlapping relationship, and then to operate the interlocking mechanism. This usually cannot be done from a distance, from ground level for example, and the power supply to the electrical equipment, to the power line supported on the insulator for example, may have to be interrupted in order properly to fit the guard.
SUMMARY OF THE INVENTION
It is one object of the present invention to provide an article
REFERENCES:
patent: 1766636 (1930-06-01), Holzel
patent: 2099540 (1937-11-01), Smith
patent: 2234391 (1941-03-01), Taylor
patent: 2617378 (1952-11-01), Osol
patent: 2999479 (1961-09-01), Carder
patent: 3005436 (1961-10-01), Caldwell
patent: 3016034 (1962-01-01), Raistakka
patent: 3056376 (1962-10-01), Bender
patent: 4053707 (1977-10-01), Ely et al.
patent: 4201883 (1980-05-01), Sheperd
patent: 4243628 (1981-01-01), Herold
patent: 4467387 (1984-08-01), Bergh et al.
patent: 4637164 (1987-01-01), Brown
patent: 4731507 (1988-03-01), Torimto et al.
patent: 5023406 (1991-06-01), Thornley
patent: 5293721 (1994-03-01), Richard et al.
patent: 5293835 (1994-03-01), Shagoury
patent: 5347769 (1994-09-01), Dinsmore
patent: 5446242 (1995-08-01), Barrett
Derwent Abstract WPI Acc. No. 93-026781 (1993) and JAPIO abstract No. 04021243 (abstracts of Chubu Elec. & Furukawa Elec., JP 05-012943 (1993).
Patent Abstract of Japan, vol. 13, No. 109 (E-727), 19 Mar. 1989 (abstract of JP 63-281323.
IEEE Standard No. 1264-1993, "IEEE Guide for Animal deterrents for Electric Power Supply Substations", Jan. 3, 1996.
Barrett Donald Christopher
Cook Michael Robert
Spalding Matthew
Burkard Herbert G.
Chao Yaun
Ledynh Bot L.
Patel Dhiru R.
Raychem Limited
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