GB2343301A

GB2343301A - Insulator suspension clamp with arc protection device

Info

Publication number: GB2343301A
Application number: GB9823475A
Authority: GB
Inventors: Iain Malcolm Strachan
Original assignee: CCL Systems Ltd
Current assignee: CCL Systems Ltd
Priority date: 1998-10-28
Filing date: 1998-10-28
Publication date: 2000-05-03
Also published as: GB9823475D0

Abstract

A suspension clamp assembly for an electrical power distribution system has a means for associating an electrical conductor 4 with a pylon insulator 6 and an arc protection device 17 attached to the associating means and in electrical contact with the conductor. Preferably the associating means comprises a yoke 9 and saddle 14 with a piercing member 15 for piercing the conductor's insulation.

Description

INSULATOR SUSPENSION CLAMP ASSEMBLY The invention relates to an insulator suspension clamp assembly. In particular, the invention relates to such an assembly for use with an arc protection device in an overhead electricity distribution system.

In many circumstances it is required to provide a connection to overhead power lines. Prime considerations for making such connections are naturally that the connection should be made in a safe and reliable manner.

To improve the safety and reliability of overhead lines, insulated lines are in use and this invention is primarily directed towards forming a connection to such insulated lines.

Arc protection devices (also known as spark protection devices and referred to hereinafter a APDs) need to be provided at any location where an over voltage causing damage to the lines is possible or likely.

APDs are commonly fitted to overhead lines adjacent to support structures.

In order to provide a connection to an insulated overhead line, it is necessary to pierce or remove the insulation surrounding the conductor. In the piercing type of connector, such piercing is typically carried out by providing a two-piece clamping arrangement to fit around the overhead line, the two pieces being joined together by a bolt or the like which, as it is tightened brings opposing jaws of the clamping arrangement together.

As the jaws close, teeth on the jaws pierce the insulating layer and establish a connection.

Figure 1 shows a typical prior art arrangement of arc protection devices. In that arrangement, various APD's 1 are connected to a pole structure 8 which, in conventional manner, supports and separates the three phases. In general, the APDs 1 are connected to the conductor 4 of a particular phase on either side of a pole top insulator 6 by means of an insulation piercing arrangement comprising a two-part connector 2,3, a trace wire 7 joining the APDs of the respective phase together and a binding wire (not shown) for neatly binding the trace wire 7 to the insulated conductor 4.

As mentioned above, APD's 1 are provided in pairs, one pair for each phase, with one APD of each pair positioned to one side of the insulator 6 for its phase, and the other APD in each pair being situated on the other side of the insulator for its respective phase. The conductors 4 are kept apart at the pole top by providing a cross-member 5 from which the pole top insulators extend. The trace wire 7 is typically an aluminium conductor wire. The arc protection devices 1 comprise spark protection horns which project obliquely downward from the conductor 4 to be protected. An electric spark generated by a lightning induced surge will discharge, for example, from the tip of the horn to the cross arm 5, or between the areas of the tip of one horn to the tip of the other horn. In this way, the integrity of the conductors 4 representing each electrical power phase may be protected.

A conventional system as described above, has a number of disadvantages.

Firstly, there are a large number of components required and correct setting up depends upon positioning the individual arc protection devices correctly in relation to both the phase conductor and the cross arm.

If the sparking gap is arranged to be too great then a lightning surge could, rather than following the preferred path to the cross-arm cause a shorting between phases. with a view to providing an improved system, there is provided an insulator suspension clamp assembly in accordance with claim 1 of the present application.

Preferred features of the assembly are disclosed in the dependent claims 2 to 11.

A preferred embodiment of the present invention will now be described by way of example only with reference to the accompanying Figures, in which: Figure 2 shows a pole top insulator having a yoke for a suspension clamp; Figure 3 shows the suspension clamp assembly complete with arc protection device and insulated air line in perspective view ; Figure 4 shows the assembly of Figure 2 in plan view; and Figure 5 shows the assembly of Figures 3 and 4 in side elevation.

Referring now to Figures 2 to 5, there is shown an insulator suspension clamp assembly.

Referring initially to Figure 2, there is shown a bottom part 10 of the clamp assembly which fits on top of a pole top insulator 6 (of similar type to that shown in Figure 1). The bottom part 10 of the clamp assembly comprises a yoke having first and second upstanding members 9A, 9C opposing each other and a base member 9B.

Associated with the first upstanding member 9A, there is a first fitting 13 and associated with the second upstanding member 9C, there is a second fitting 12. The two fittings 12,13 are adapted to carry a top part of the clamping assembly.

Referring now to Figure 3, there is shown an assembled suspension clamp comprising the bottom part 10 and a top part comprising a saddle member 14 which is arranged to cooperate with the bottom clamping part 10 by pivotally attaching it to the first and second upstanding members 9A, 9C of the yoke by means of nut and bolt arrangements 12,13.

The saddle 14 has, fitted to its underside, an arc protection device 17 (which fitting may be permanent, such as being attached to the saddle 14 by welding). Further, the saddle 14 includes a conductor carrying element which serves to associate the conductor 4 of the particular phase with the electricity pole/pylon 8 and, secondly, forms the electrical connection between the conductor 4 and the arc protection device 17. The conductor carrier 15 is an insulation piercing arrangement which has teeth formed internally for penetrating the outer insulation of the conductor 4 and connecting with the conductive material inside. The nut and bolt arrangements 16 are used to tighten the conductor carrier 15 onto the conductor and urge the insulation piercing teeth within the carrier 15 against the core material of the conductor.

The various advantages of the suspension clamp assembly and the utility of the assembly will now be discussed.

Firstly, the bottom part 10 of the assembly is arranged to cooperate with standard fittings for the insulator 6. For instance, the top part of insulator 6 may have an externally threaded end piece with which the bottom part 10 of the assembly cooperates, by virtue of providing a corresponding internal thread on that base part 10.

Fitting of the suspension clamp assembly is, in this case very straight forward and simply involves the removal of an existing suspension clamp from the top of the insulator 6 and replacing that suspension clamp with a clamp in accordance with the teachings of the present invention.

Because the arc protection device 17 can be provided as an integral part of the suspension clamp assembly, no extra external arc protection devices need to be provided.

This simplicity of approach means that the external insulating layer of the conductor 4 only needs to be pierced or removed in the area of the suspension clamp and therefore problems due to corrosion of the internal conductor by multiple piercing are minimised. Further, given the fact that the insulators 6 are effectively standard parts, the spark gap between arc protection device and, for instance, cross piece 5 of the pylon 8 is known from the outset and there is therefore no need to make further adjustments to the positioning of the arc protection device at the pole top as the required angle of the horns of the arc protection device 17 can be preset at the point of manufacture.

It will be appreciated that other variations to this suspension clamp assembly may be made, whilst still being within the scope of the invention. For instance, the base part of the assembly may be available with different fittings to suit different insulators 6.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment (s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS 1. A suspension clamp assembly for an electrical power distribution system, the assembly comprising: means for associating an electrical conductor with an insulator of an electricity pylon; and an arc protection device mechanically attached to said means for associating and arranged, in use, to be in electrical contact with said conductor.
2. An assembly according to claim 1, wherein said means for associating comprises a first part for cooperation with said insulator and a second part for attachment to said electrical conductor.
3. An assembly according to claims 1 or 2, wherein said means for associating comprises an insulation piercing member for piercing an outer insulating sleeve of the electrical conductor and making an electrical connection between said conductor and said arc protection device.
4. An assembly according to claim 2 or 3, wherein said first part comprises a yoke having a base part and a pair of opposed arms upwardly depending from said base part and adapted to carry said second part.
5. An assembly according to claim 2,3 or 4, wherein said first and second parts are pivotally connected.
6. An assembly according to any of claims 2 to 5, wherein said first part includes means for attaching said assembly to an existing connection point of said insulator.
7. An assembly according to any of the preceding claims, wherein said insulator is a pole (or pylon) top insulator.
8. An assembly according to claim 7, wherein said insulator is attached to a cross-piece of the pole or pylon.
9. An apparatus according to any of claims 2 to 8, wherein said second part comprises a guide member for guiding said electrical conductor along a predetermined path.
10. An assembly according to any of claims 2 to 9, wherein said arc protection device is permanently associated with the second part.
11. An assembly according to any of claims 2 to 9, wherein the arc protection device is permanently associated with the first part.
12. An assembly according to any of claims 2 to 9, wherein the arc protection device is removably attachable to said means for associating.
13. An assembly substantially as herein described with reference to Figures 2 to 5.