NZ264972A - Shield for electrical power line insulator and emergent lines - Google Patents

Description

PATENTS FORM NO. 5 Fee No. 4: $260.00 PATENTS ACT 1953 COMPLETE SPECIFICATION After Provisional Nq; 264972 Dated: 22 November 1994 APPARATUS FOR SHIELDING ELECTRICAL INSULATORS; ADJACENT TRANSMISSION LINES I/WE Dulmison (NZ) Limited, 107-111 Harris Road, East Tamaki, Auckland, New Zealand hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: 264972 Apparatus for Shielding Electrical Insulators.; Adjacent Transmission Lines Technical. Field This invention relates to electrical transmission apparatus. background art It is well known in the electrical distribution industry that the interference of birds and animals with sub-transmission installations is a continuous problem. Birds tend to seek the highest position in which to perch and in so doing larger birds in particular can entangle themselves or make cross contact with adjacent overhead lines. This invariably leads to electrocution of the birds and is also likely to short out a transmission system. In some instances this results in major inconvenience and long delays before transmission can be re-established. Climbing animals such as possums can also cause similar problems.

In addition to the above, overhead lines need to be routinely serviced for various reasons as a result of local conditions as they can be badly effected by sand, seaspray, dust and the like. As maintenance is generally carried out whilst the lines are live, the safety of maintenance workers is also a consideration. Protection of insulators and against paint spill or other contaminants during maintenance is also a consideration.

It is a general object of the present invention to provide a shielding apparatus for insulators and adjacent conductors in many situations.

A farther object of the invention is to prevent inadvertent short circuiting of transmission systems. ' /' fx ' 2 264 9 Further objects and advantages of the present invention will become apparent from the ensuing description which is given by way of example. disclosure of invention According to the present invention there is provided apparatus for shielding electrical insulators of a overhead power line comprising a plastics moulded cap of a substantially cylindrical configuration having side walls, a closed end and an open end and openings in opposite portions of said side walls to enable the cap to be fitted to an insulator adjacent an overhead power line.

The apparatus can include at least one insulating line shield fitted to an adjacent transmission line.

The line shield can be substantially cylindrical elougate sleeve having a longitudinal slit.

The line shield can be oversized in relation to the line to which it is designed to be fitted so that an overlap of edges of the slit occurs or can be achieved when it is fitted to a transmission line.

The cap walls can be contoured to be complimentary to an insulator to which it is designed to be fitted.

The line shields can fully or partially enclose a transmission line to which they are fitted.

The line shields can be provided with a series of projections to discourage birds and animals from walking on same. 3 The present invention also provides a method of shielding electrical insulators of an overhead power line comprising the step of fitting an insulator cap as aforesaid.

The method may include the further step of fitting one or more line shields adjacent the insulator caps.

The method may include the further step of introducing a sprayable insulation material between the insulator and inner walls of the cap.

Brief description of Drawings Aspects of the present invention will now be described with reference to the accompanying drawings in which: Figure 1: is a diagrammatic perspective view of a typical transmission line as is known in the art, and Figure 2: is a diagrammatic perspective view of an insulator and transmission line having fitted thereto a shielding apparatus in accordance with the present invention, and Figure 3: is a cross-section taken at 111:111 of Figure 2, and Figure 4: is a cross-section taken at IV:IV of Figure 2, and Figure 5: is an end view of the apparatus in accordance with one Figure 6: is a diagrammatic cross-sectional view of an insulator cap for a string of dish insulators. possible embodiment of the present invention, and 264972 Best Motors for Carrying opt the Invention With respect to the drawings, a typical overhead installation is illustrated by Figure 1.

Purely by way of example the installation illustrated comprises a support 5 column 1, a three arm supporting structure 2 with the ends of each of the arma of the structure mounting insulators 3. Fasteners (not shown) are used to secure transmission lines 4 to the insulators. If for example a large bird 5 entangles itself in the overhead lines this will likely short out the installation and apart from electrocution of the bird, switches 10 associated with the transmission system will trip. The owners or maintainers of the line then have the problem of tracing and reinstating the tripped switch in order to reinstate power to the line.

In addition, overhead lines need to be regularly serviced particularly where the lines are subject to adverse conditions and become 15 contaminated by salt, sand, dust or other materials.

With respect to Figure 2 of the drawings, the present invention provides a shielding apparatus generally indicated by arrow 6 for shielding insulators 3 and transmission lines 4 to lessen the likelihood of inadvertent or accidental shorting out of an overhead system.

The apparatus can may comprise a cap 7 and (optionally) one or more line shields 8. The cap 7 and line shields 8 can be moulded or fabricated in an electrical insulation material and the cap 7 and line shield(s) 8 are fitted to an insulator and adjacent overhead line(s).

The cap 7 can be contoured to suit its application to different^Bdsr of *20 FEB 7' ;/,* insulators. / 2 64972 The line shields 8 can partially or fully enclose any overhead line to which they are fitted.

The line shields 8 are substantially cylindrical and be provided with an elongate open or openable portion generally indicated by arrow 9.

The apparatus can be moulded in one piece or in a series of interlocking pieces.

The shields 8 can include a series of projections (not shown) to discourage birds or animals from walking on same and may be clipped or otherwise fastened relative to the insulator, insulator supports and/or an overhead line.

With respect to figure 3 of the drawings the line shield 8 cam be configured so that the overhead line 4 is completely surrounded, and clips (not shown) may be used to further secure the shields to the line. The line shields should be made of material which is sufficiently resilient for the openable portion 9 to be parted whilst the shield is fitted a line and so that its shape returns ensuring full enclosure of the line is achieved.

For figure 4 of the drawings the cap 7 is provided with contoured sides complimentary to the shape of an insulator to which it is fitted, a closed end 11 and an open end 12.

The cap 3 and shields 8 can be configured to suit a single or multiple insulators and associated lines.

In figure 5 of the drawings a shield 8 is shown in cross-section and the cap 7 in side elevation. Slots 13 in the wall 10 of cap 3 allow for its fitment adjacent a transmission line. 6 26 4 97 2 In figure 6 of the drawings a cap 7 is configured to fit over a string of synthetic dish insulators. The sidewalls of the cap are configured to follow the contour of the string as indicated. A combination of the cap 7 and line shields as previously described can be fitted at the base of the installation.

The apparatus of the present invention is such that it would be easily installed from a helicopter.

In some instances a service person may find that an insulator is physically damaged, for example it may be cracked. In such an instance a sprayable insulation material such as a sprayable and settable filler can be 10 introduced between the insulator and the inner walls of the insulator cap.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof, as defined in the appended claims. >/' 4 FEB 1936 ^ \ 7

Claims (7)

1. WHAT TO CkAIM IS; L Apparatus for shielding electrical insulators of a overhead power line comprising a plastics moulded cap of a substantially cylindrical configuration having side walls, a closed end and an open end and openings in opposite portions of said side walls to enable the cap to be fitted to an insulator adjacent an overhead power line.
2. 2. Apparatus as claimed in claim 1 including at least one insulating line shield fitted to an adjacent transmission line.
3. 3. Apparatus as claimed in claim 1 or claim 2 wherein the line shield is a substantially cylindrical elongate sleeve having a longitudinal slit.
4. 4. Apparatus as claimed in claim 3 wherein the line shield is oversized in relation to the line to which it is designed to be fitted so that an overlap of edges of the rl V occurs or can be achieved when it is fitted to a transmission line.
5. 5. Apparatus as claimed in any one of claims 1 to 4 wherein the cap walls are contoured to be complimentary to an insulator to which it is designed to be
6. 6. Apparatus as claimed in claims 3 to 5 wherein the line shields fully or partially enclose a transmission line to which they are fitted.
7. 7. Apparatus as claimed in any one of claims 2 to 6 wherein the line shield is provided with a series of projections to discourage birds and animals from walking on same. fitted. 8 26497 2 1L A method of shielding electrical insulators of an overhead power line comprising the steps of fitting an insulator cap as claimed in any one of claims 1 to 7. A method of shielding electrical insulators of an overhead power line including the further step of fitting one or more line shields as claimed in any one of claims 2 to 7 adjacent insulator caps. A method of shielding electrical insulators of an overhead power fine as claimed in claim 8 or claim 9 including the further step of introducing a sprayable insulation material between the insulator and inner walls of the cap. Apparatus substantially as herein described with reference to figures 2 to 6 of the accompanying drawings. A method of shielding electrical insulators of an overhead power line substantially as herein described with reference to figures 2 to 6 of the accompanying drawings. Dulmison (NZ) Limited 9