WO2009049376A1

WO2009049376A1 - Power line supporting apparatus

Info

Publication number: WO2009049376A1
Application number: PCT/AU2008/001544
Authority: WO
Inventors: Gregory James Nunn
Original assignee: FARALLON CAPITAL Pty Ltd
Current assignee: FARALLON CAPITAL Pty Ltd
Priority date: 2007-10-19
Filing date: 2008-10-17
Publication date: 2009-04-23
Anticipated expiration: 2010-04-19

Abstract

Apparatus for supporting a power line above ground, the apparatus including at least one arm having a first end and a second end, the first end being connectable to a support so as to allow adjustment of a position of the arm relative to the support, the second end having a mounting for receiving the power line, and at least part of the arm being electrically insulating.

Description

POWER LINE SUPPORTING APPARATUS

Background of the Invention

The present invention relates to apparatus for supporting a power line in an electricity supply system, and in particular to apparatus for supporting a power line above ground utilising a support, such as a pole.

Description of the Prior Art

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Typically power lines are held above ground and are strung between cross arms mounted on supporting poles. It is usual to provide a horizontal timber, steel, or other metallic cross arm with spaced insulators being secured to the cross arm to allow the power lines to be suspended from or supported on the insulators.

Due to negative environmental considerations concerning the use of timber and its availability it would be desirable to provide an alternative to the present timber cross arms.

Steel or other metallic cross arms are conductive and therefore flashovers of insulators will occur during periods of over voltages such as lightning or switching, thus making them undesirable.

Present methods of supporting conductors are inflexible and require a high degree of field work and skill to drill and fix the cross arms and insulators in place. Present methods also require a large inventory of parts.

Alternatives to basic timber, steel or other metallic cross arms have been proposed in the patent literature and these include the use of insulating material as the cross arm. These generally involve the use of some form of fibre reinforced material employed to form the cross arm with a wide variation in designs from quite simple arrangements to arrangements which are quite complex and expensive.

US Patent No 4,682,747 to King et al describes a cross arm for supporting electric utility wires where the cross arm is made, from insulating material, having an inner structure formed of alternate layers of polyester resins and synthetic fabric.

US Patent No 5,605,017 to Fingerson et al finds a much simpler arrangement employing a hollow horizontal beam as a cross arm. This may be used as tangent cross arm or a dead-end and includes a hollow fibre reinforced beam with a bushing inserted into a transverse hole in the beam. The hollow beam is pultruded and includes end caps to seal the beam. US Patent No 6,834,469 to Fingerson et al, again employs a pultruded beam, but in this case with a simpler reinforcing member located in holes through the beam to prevent crushing of the beam by the bolts employed to secure other elements to the beam.

US Patent No 6,347,488 to Koye describes a cross arm for a utility pole where the cross arm includes an elongated, hollow bar member moulded from synthetic material such as a sheet moulding compound of polyester glass reinforced plastic. The bar member has a first end, a second end opposite the first end,"¹ a plurality of through holes for mounting the cross arm to utility poles with fasteners and for mounting electrical line support insulators.

International Application No WO2007/070966 to Preformed Line Products (Australia) Pty Ltd describes a fixed length integrated cross arm where the cross arm design has a complex shape including sheds, mounting brackets and other features all moulded into one fixed length integrated cross arm. Similar arrangements are described in WO 01/23691 and US Patent No. 4,682,747

US Patent No. 4,262,047 describes a generally horizontal log of fibre glass honeycomb material defining side by side upstanding adjacent cells substantially throughout the log. The log includes a hard outer covering enclosing the log on all sides. See also FR 1445447.

US Patent No. 3,013,584 to Reed et al. describes a proposal to utilise glass fibre reinforced plastics in other parts of utility pole lines apart from the cross arm where a hollow pole structure has an inner and outer ring joined by radially extending connectors. In addition, the inner tube may be filed with plastic foam. This is said to improve the rigidity in the flexural strength by the provision of a liner comprising a tubular sleeve made up of a plurality radially disposed circumferentially spaced apart strip of cellulosic fibres impregnated with a thermosetting resin.

US Patent No. 6,609,345 to Schauf et al. describes a structural member and method of manufacturing same with these structural members primarily for use in power poles. They may be used as part of the poles or as the cross arm. This patent describes an extruded cross arm cut from an extruded hollow body which may be filled with foam.

While the prior art referred to above provide an alternative to timber it would be desirable to provide a further alternative that provides greater flexibility in terms of the positioning of power lines relative to the power pole.

Summary of the Present Invention

In a first broad form the present invention seeks to provide apparatus for supporting a power line above ground, the apparatus including at least one arm having a first end and a second end, the first end being connectable to a support so as to allow adjustment of a position of the arm relative to the support, the second end having a mounting for receiving the power line, and at least part of the arm being electrically insulating.

Typically the apparatus includes a plurality of arms, each of the arms being for supporting a respective power line.

Typically the second end includes an electrically insulating material for electrically isolating the mounting from the first end.

Typically the first end includes a connector for connecting the arm to the support so as to allow adjustment of the position of the arm.

Typically the connector includes an aperture for receiving a spigot projecting from the support, thereby allowing the connector to be rotatably mounted to the spigot. Typically the apparatus includes a plurality of arms, each of the arms including a connector having an aperture, thereby allowing a number of arms to be rotatably mounted to the spigot.

Typically the connector includes a number of positioning elements for co-operating with corresponding positioning elements on at least one of the support and another arm, to enable the arm to be selectively positioned.

Typically the positional elements allow stepwise circumferential repositioning of the arm.

Typically the arms include identical first ends, thereby allowing the arms to be interchangeably mounted to the spigot.

Typically the arm has a dumbbell shaped cross-section.

Typically the mounting includes a clamp located at or adjacent to the second end.

Typically the clamp is C-shaped and includes an opening for receiving the power line in use.

Typically the clamp is rotatably mounted to the arm to allow a position of the opening relative to the arm to be adjusted.

Typically the clamp is rotatable to accommodate left and right orientations of the arm.

Typically the clamp is rotatably mounted to allow the opening to face away from the ground in use.

Typically the arm includes an intermediate section positioned between the first and second ends.

Typically the intermediate section includes an elongate member extending between the first and second ends.

Typically the intermediate section is coupled to the first end and the second end.

Typically the intermediate section includes a bar of insulating material surrounded by a cover. Typically the cover extends over joins between the bar and the first and second ends thereby preventing ingress of material into the joins.

Typically the arm includes a number of sheds arranged along a length of the arm.

Typically the arm includes a two second ends, the first end being positioned between the two second ends, thereby allowing two power lines to be supported.

The present invention seeks to provide a flexible mounting arrangement that is readily assembled from a relatively small number of parts and reduces the degree of requisite assembly skill.

Brief Description of the Drawings An example of the present invention will now be described with reference to the accompanying drawings, in which: -

Figure 1 is an exploded view of an example of apparatus for supporting a power line;

Figures 2 and 3 are side and top views of an example of an arm of the apparatus of Figure 1;

Figures 4 and 5 illustrate an example of a bracket arrangement suitable for connecting the arms of Figures 2 and 3 to a pole;

Figures 6 and 7 are respective cross sectional views through the arm of Figure 3;

Figures 8 and 9 are respective side views and end views of an example of an arm illustrating a clamping arrangement for connection of a power line to the end of the arm;

Figure 10 illustrates a top view of an example of an arm configuration for three power lines; Figures 1 IA to 1 ID illustrate examples of the apparatus for supporting multiple power lines;

Figures 12-14 are respective part longitudinal section, side view and cross-sectional views illustrating a second example of apparatus for supporting power lines;

Figure 15 is an elevation view of a third an example of apparatus for supporting power lines; and, Figures 16A and 16B illustrate examples of the apparatus of Figure 15 in use. Detailed Description of the Preferred Embodiments

An example of apparatus for supporting a power line above ground will now be described with reference to Figure 1.

In this example, the apparatus 10 includes at least one arm 16, 17, 18 (three shown for the purpose of example only), each arm having a first end 16A, 17A, 18A and a second end 16B, 17B, 18B.

The first end 16A, 17A, 18A of each arm 16, 17, 18 is connectable to a support 11, such as a power pole, so as to allow adjustment of a position of each arm 16, 17, 18 relative to the power pole 11. This may be achieved in any suitable manner, but in one example the power pole 11 has a bracket 12 including a spigot 13 extending radially outwardly from the power pole 11, for supporting the arms 16, 17, 18, as will be described in more detail below.

The second end 16B, 17B, 18B of each arm 16, 17, 18 includes a mounting 22, 23, 24 for receiving a power line P (shown in Figure 10). The mounting may be of any suitable form, but in one example, is in the form of a C-shaped clamp.

At least part of each arm 16, 17, 18 is electrically insulating, thereby electrically isolating the power line from the support 11.

Accordingly, the above described arrangement allows one or more arms 16, 17, 18 to be mounted to a support 11 , such as a power pole, thereby allowing one or more power lines P to be supported relative to the power pole. By providing a respective arm for each power line P, with each arm 16, 17, 18 being positionable relative to the power pole, this allows the relative position of the power lines P to be adjusted, and avoids the need for a cross arm that is required in traditional power pole arrangements.

Avoidance of a cross arm, significantly reduces the amount of materials and hence cost required in order to mount the power lines P. Furthermore, this provides a greater flexibility in the mounting arrangement, which can allow for example for a greater separation between the power lines P, or to allow a greater number of lines to be mounted to a common support, whilst maintaining a minimum separation between the power lines P, which is important in preventing shorting between the power lines P. Additionally, the use of arms described above significantly simplify the mounting process. In particular a technician need only mount each arm 16, 17, 18 on the bracket 12, and attach the nut 15, positioning the arms as required during the nut tightening process. Following this, each power line P can simply be dropped into the respective clamp 22, 23, 24, which is then tightened. This is significantly easier than the process of fixing a cross arm to the pole, and then subsequently attaching fittings, before coupling the power lines P to each fitting, and generally requires less components such as nuts, bolts of varying lengths, washers, and the like, as well as less tools to complete the job, allowing for a reduced pole dressing time.

Further features of example arrangements will now be described in more detail.

In one example, the spigot 13 includes a threaded end 14 so that a nut 15 may connect to the spigot 13 and the bracket 12, thereby allowing the arms 16, 17, 18 to be held in position. Three arms 16, 17 and 18 may be secured in selected circumferential positions in stepwise fashion by reason of the co-operating radial locators, as will be described in more detail below.

The arms 16, 17, 18 are typically made from any long life, UV stable, resin or moulding material, and generally have an elongate shape to ensure a minimum separation between the first and second ends 16A, 17A, 18A, and 16B, 17B, 18B, thereby allowing the arm to provide appropriate insulative properties. The elongate arm is typically shaped so as to reduce accumulation of contaminants including dust, salt or other pollutants that might encourage electrical leakage current to form and flow. In one example, this is achieved using a substantially cylindrical cross section.

The arms 16, 17, 18 may also include other insulating technologies, such as a number of sheds 19, 20 and 21 positioned along the length of the arms 16, 17, 18.

A typical arm is shown in more detail in Figures 2, 3, 6 and 7.

As shown, the first end 16A, 17A, 18A, includes a connector 27 for connecting the arm 16, 17, 18 to the support 11 so as to allow adjustment of the position of the arm. In particular, the connector 27 includes an aperture 27 A for receiving the spigot 13, which in turn projects substantially perpendicularly from the support 11 , thereby allowing the connector 27 to be rotatably mounted to the spigot 13. It will be appreciated that this arrangement allows multiple arms 16, 17, 18 to be mounted to the spigot 13 in turn, as shown for example in Figure 10. The nut 15 may then be connected to the spigot 13, and tightened, thereby urging the connectors 27 of each arm 16, 17, 18 together, with an innermost one of the arms 18 being urged against the bracket 12. This allows the relative position of the arms 16, 17, 18 to be maintained by frictional engagement between the connectors 27 and the bracket 12.

However, in one example, the connector 27 also includes a number of positioning elements 27B, which are typically in the form of circumferentially spaced ridges extending radially outwardly from the aperture 27A. In one example one face of the connector may include ridges, with the other face including corresponding apertures. The bracket 12 also has positioning elements in the form of locating apertures 25, or locating ridges. It will be appreciated that the nature of the positioning elements is not important, and any suitable arrangement can be used such as the provision of interlocking teeth provided on the connectors 27 and bracket 12.

In use, the positioning elements 27B on a given connector 27 of an arm 16, 17, 18 co-operate with corresponding positioning elements on at least part of the bracket 12 or the connector 27 of another arm 16, 17, 18 thereby enabling the arm to be selectively positioned. In particular, this allows stepwise circumferential positioning of the arms 16, 17, 18.

It will be appreciated that the use of positional elements 27B is not essential, but can provide additional engagement between the arms 16, 17, 18 and the bracket 12, thereby preventing unwanted relative movement of the arms.

It will be appreciated from the above that each of the arms 16, 17, 18 are substantially identical, thereby allowing the arms to be interchangeably mounted to the spigot 13.

The arms 16, 17, 18 are typically shaped so as to reduce build up of contaminants on the arm in use. An example cross sectional shape is shown in Figure 6. In this example, the arm has a substantially dumbbell shape, with an outer ridge 28, 29 at each end of the dumbbell. In use, the ridge 28, 29 is positioned uppermost, facing away from the ground, so that the sloping surfaces located at 30 and 31 or 32 and 33 are sloping surfaces which thereby inhibit the build up of any contaminants or debris on the arm. This also applies to the surfaces 34, 35, 36 and 37 which are all oblique surfaces to the vertical and consequently contaminants will tend to slide off or be washed of in the next rain event. Alternative shapes may however be used such as a circular cross section.

An example of a mounting for receiving a power line P will now be described in more detail in relation to Figure 8. In this example, the mountings are C-shaped clamps 22, 23, 24 that include an opening 38 for receiving the power line P in use. The clamps 22, 23, 24 are rotatably mounted to the arms 16, 17, 18 to allow a position of the opening 38 relative to the arm to be adjusted. This can be used to allow the clamp to accommodate left and right orientations of the arm, as well as to allow the clamps 22, 23, 24 to be arranged so that the opening 38 is upper most, and therefore facing away from the ground, in use. This allows a power line P to be "dropped in" and supported by the clamp 22, 23, 24. An adjusting nut 39 can be used to close the clamp in order to clamp the power line P into position as illustrated in Figure 10.

In the example of Figure 10 the three arms 16, 17, 18 of Figure 1 are secured into the position illustrated in Figure HA. It will be appreciated from Figures HA to HD that many configurations of the arms may be used to suspend or support wires.

It will be further appreciated that in relation to Figures HA to HD that each of the arms there shown are of equal length but even though they are configured as shown, that the wires may be connected and held in position in arms of a different length or a mix of different length arms all of which share a common connector independent of length. Thus, in one example, two or more different length arms may be employed.

It is also noted that in the example of Figure HB, a fourth arm 116, having a second end 116B, is shown. It will be appreciated that this may be used in a configuration in which three arms 16, 17, 18 are used to carry three phase power lines P, with a fourth arm 116 being used to carry an overhead earth line.

Other variations are possible, and in this regard, any number of arms may be mounted to a common spigot, as will be appreciated by persons skilled in the art. Figures HA to HD also highlight how different orientations for the arms 16, 17, 18 can be used to alter separations di, d₂ between the second ends of the arms 16B, 17B, 18B, 116B, which in turn allows the separation between the power lines P to be adjusted.

These figures also highlight how the different orientation of the arms can be adjusted to support power lines P of different configurations. HA, HC and 11D show possible configurations to support a common 3 wire power line P. HB shows a configuration to support 4 wire system. It will be appreciated that these arrangements are for the purpose of example only, and that in practice any number of arms may be used, thereby allowing 3 wire configurations with an overhead earth wire to be provided (using four arms), as well as two 3 wire circuits (using six arms). Many other configurations are possible, as will be mentioned in more detail below.

A further example, will now be described with reference to Figures 12-14, which illustrate another example of an arm assembly 40.

In this example, the arm assembly includes an intermediate section comprising a bar 41 such as a pultruded fibre reinforced cylindrical bar, for interconnecting the first and second ends

4OA, 4OB. The bar 41 is coupled to a metal end piece 42, which forms the first end 4OA.

The coupling may be achieved in any suitable manner, but in one example involves a male/female coupling formed by plugging the bar 41 into a socket provided on the metal hub section 42, which is then crimped to the bar 41. The other end of the bar 41 plugs into a second end piece 43, mounting in a similar manner, thereby forming the second end 4OB.

As in the previous example, the metal end piece 42 includes a connector 47, having an aperture 47 A, and positional elements 47B, allowing the connector 47 to be mounted to a support such as a spigot 13. Similarly, the end piece 43 supports a mounting 44, such as a C- shaped clamp, which is rotatably mounted to the end piece 43, allowing relative rotation of the mounting 44 relative to the arm 40, as in the previous examples.

A cover 46, such as a silicone rubber jacket, is provided about the bar 41, the cover having spaced sheds along substantially the whole of the bar 41. This could be achieved by using either moulding or heat shrink techniques. In this example, the cover 46 is moulded so that it extends over the joins between the bar 41 and the end pieces 42, 43. The use of a moulded silicone cover 46 provides a seal extending over the joins, thereby preventing ingress of material, such as moisture and other pollutants. Ingress of material into the joins can lead to damage of the bar 41 or the end pieces 42, 43, which can in turn have an impact on the electrical properties of the arm, and in particular can reduce the ability of the arm to maintain electrical isolation between the power line P and the support pole 11.

A further example will now be described with reference to Figure 15. In this example, the apparatus includes an arm 156 having two second ends 156B, 156C, with a "notional" first end 156A being provided intermediate the two second ends 156B, 156C.

Again, the first end 156 A includes a connector 157, having an aperture 157A and positional elements 157B, thereby allowing the arm 156 to be supported by a spigot 13, or other similar supporting means. Additionally, each of the second ends 156B, 156C include a mounting 158, 159, such as a C-shaped clamp, allowing two power lines P to be supported by the arm 156.

Example arrangements using arms similar to the arm 156 are shown in Figures 16A and 16B. In the example of Figure 16 A, two arms 156, 166 are provided to allow a five wire configuration to be supported, with an additional single arm 180 being provided to allow an overhead earth wire to be supported. In this instance, the overhead earth wire is not insulated from the bracket 12, and a metallic arm can be used.

In the example of Figure 16B, a third arm 176, which is of a shorter length than the arms 156, 166, is added, allowing two three wire circuits to be supported. In this latter example, the arms 156, 166, 176 are configured so that the power lines P are provided in vertical alignment, as shown by the dotted lines 178, 179, although this is not essential.

The arrangements shown in Figures 16A and 16B could alternatively be implemented using the arms of Figures 1 to 14. In this instance, the arrangement of Figure 16A would require four arms 16, in addition to the earth arm 180, whilst the arrangement of Figure 16B would require six arms. It will be appreciated from this that using the double second ended arm of Figure 15 reduces the number of arms required to support a given number of power lines P. This is particularly advantageous as it reduces the pole dressing time by allowing a single arm to be fitted to support two power lines P.

Additionally however, this also reduces the number of connectors that need to be mounted on the spigot 13 to support a given number of arms. Thus, for a configuration similar to that of Figure 1 IB, as shown in Figure 16A, instead of requiring four arms 16, 17, 18, 116, only two arms 156, 166 are required, meaning that only two connectors 157 need be mounted to the spigot 13, instead of the four connectors 27 that would be required using the single arm arrangement of Figure 2. This therefore reduces the number of connectors that need to be fitted to a single spigot 13 to support a given number of power lines P, thereby allowing shorter spigot lengths to be used, whilst maintaining the number of power lines P that can be supported. It will be appreciated that avoiding the need increase the length of the spigot 13 can avoid difficulties in mounting and stability of the arrangement.

Accordingly, the above described apparatus provides an arm assembly that can be used to support a power line P above ground by connecting the power line P to a support via an arm assembly. The arm assembly includes an arm having a first end and a second connectable to the support for movement relative to the support, and a second end having an insulator and a power line P connection means preferably at or adjacent to the second end.

This allows the position of the power line P relative to the support to be adjusted, whilst avoiding the need for a traditional cross arm. This in turn provides a greater degree of flexibility in the arrangement of the power lines P, which can for example, assist in reducing shorting or other faults, whilst reducing the cost of the mounting arrangement in comparison to traditional mounting techniques.

Whilst the above has been given by way of illustrative example of the present invention many variations and modifications thereto will be apparent to those skilled in the art without departing from the broad ambit and scope of the invention as set out in the appended claims. In particular expressions such as includes, including, comprise and comprising as used herein are to be read as non-limiting, meaning that other elements may be added to the claimed combination and doing so still results in a structure which falls within the claims.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1) Apparatus for supporting a power line above ground, the apparatus including at least one arm having a first end and a second end, the first end being connectable to a support so as to allow adjustment of a position of the arm relative to the support, the second end having a mounting for receiving the power line, and at least part of the arm being electrically insulating.

2) Apparatus according to claim 1, wherein the apparatus includes a plurality of arms, each of the arms being for supporting a respective power line. 3) Apparatus according to claim 1 or claim 2, wherein the second end includes an electrically insulating material for electrically isolating the mounting from the first end. 4) Apparatus according to any one of the claims 1 to 3, wherein the first end includes a connector for connecting the arm to the support so as to allow adjustment of the position of the arm. 5) Apparatus according to claim 4, wherein the connector includes an aperture for receiving a spigot projecting from the support, thereby allowing the connector to be rotatably mounted to the spigot.

6) Apparatus according to claim 5, wherein the apparatus includes a plurality of arms, each of the arms including a connector having an aperture, thereby allowing a number of arms to be rotatably mounted to the spigot.

7) Apparatus according to claim 5 or claim 6, wherein the connector includes a number of positioning elements for co-operating with corresponding positioning elements on at least one of the support and another arm, to enable the arm to be selectively positioned.

8) Apparatus according to claim 7, wherein the positional elements allow stepwise circumferential positioning of the arm.

9) Apparatus according to claim 7 or claim 8, wherein the arms include identical first ends, thereby allowing the arms to be interchangeably mounted to the spigot.

10) Apparatus according to any one of the claims 1 to 9, wherein the arm has a dumbbell shaped cross-section. 11) Apparatus according to any one of the claims 1 to 10, wherein the mounting includes a clamp located at or adjacent to the second end. 12) Apparatus according to claim 11 , wherein the clamp is C-shaped and includes an opening for receiving the power line in use.

13) Apparatus according to claim 12, wherein the clamp is rotatably mounted to the arm to allow a position of the opening relative to the arm to be adjusted. 14) Apparatus according to claim 12, wherein the clamp is rotatable to accommodate left and right orientations of the arm.

15) Apparatus according to claim 12 or claim 13, wherein the clamp is rotatably mounted to allow the opening to face away from the ground in use.

16) Apparatus according to any one of the claims 1 to 15, wherein the arm includes an intermediate section positioned between the first and second ends.

17) Apparatus according to claim 16, wherein the intermediate section includes an elongate member extending between the first and second ends.

18) Apparatus according to claim 16 or claim 17, wherein the intermediate section is coupled to the first end and the second end. 19) Apparatus according to any one of the claims 16 to 18, wherein the intermediate section includes a bar of insulating material surrounded by a cover.

20) Apparatus according to claim 19, wherein the cover extends over joins between the bar and the first and second ends thereby preventing ingress of material into the joins.

21) Apparatus according to any one of the claims 1 to 21, wherein the arm includes a number of sheds arranged along a length of the arm.

22) Apparatus according to any one of the claims 1 to 21, wherein the arm includes a two second ends, the first end being positioned between the two second ends, thereby allowing two power lines to be supported.

23) Apparatus for supporting a power line above ground, the apparatus being substantially as hereinbefore described with reference to the drawings and/or examples.