US2973401A - Conductor spacers - Google Patents

Description

Feb. 28, 1961 J TAYLOR 2,973,401

CONDUCTOR SPACERS Filed June 11, 1956 INVENTOR. JOHN J. TAYLOR ATTORNEY United States Patent CONDUCTOR SPACERS Filed June 11, 1956, Ser. No. 590,662

7 Claims (Cl. 174-40) This invention relates to conductor spacers for high voltage transmission lines.

In the art pertaining to the transmission of electrical energy by means of overhead transmission lines at high voltages, it is known to use the so-called bundled con ductors in order to increase the operating voltages and, hence, the transmission capability of a given line. Such bundled conductors constitute two or more cables which are maintained at the same electrical potential and spaced apart mechanically by devices known as conductor spacers. The conductor spacers are of relatively simple form and usually constitute a spacer member for holding the cables apart, together with suitable clamps for securing' the spacer member to the cables in a prescribed relationship.

In the use of such cable spacer arrangements, there are certain difliculties which have heretofore operated to mitigate against the more extensive adoption of the bundled conductor system. Specifically, it has been found that the relative movement of the cables of the phase conductor due to vibration, ice unloading, and the like, imposes substantial stresses upon the cable at the clamps which are utilized to attach the spacers to the cables. The discontinuities effected by the change in mechanical characteristics of the cable eifected by the clamps upon the cable, results not only in a deteriorating mechanical action between the clamp and the cable, but also in fatigue and dynamic failure of the cable strands.

The present invention is concerned with a particular clamp arrangement for conductor spacers useful to substantially reduce or eliminate the failure of cables in bundled conductors. As disclosed and described herein, a particular configuration of cable contacting members "isutilized in the clamp wherein the compressive force 'applied to the cable is a function of the distance from the clamping point. The contacting members are arranged also to deform from the normal position in a manner such that the resistance to deformation varies inversely with :the'dista'nce from the clamping point.

As disclosed and described herein, the invention is embodied in several forms including a so-called flexible spacer and a semi-rigid spacer-that is, where the spacer is arranged to prevent relative rotational movement of the cables while permitting relative longitudinal movement thereof- Accordingly, it is a general object of the invention to reduce-cable fatigue and failure in bundled conductor systems.

A further general object of the invention is to increase theoperating voltage of bundled conductor systems and to reduce corona effects therein.

Anotherobject of the invention is to provide an improved conductor spacer construction in which the spacer may be clamped to the conductor cables without slippage end yet without producing undue strains and changes in 1 the mechanical characteristics of the cable at the clamps.

--:=1; 9l a je t t invention i to pr de a n w d Patented Feb. 28, 1961 ICC improved spacer construction in which corona effects about the elements of the spacer are minimized.

A still further object of the invention is to provide a new and improved conductor spacer for high voltage transmission lines which incorporates new and desirable features and yet may be produced at a lesser cost than the spacers now being utilized for this purpose.

The invention, together with'further features, objects, and advantages thereof will be more clearly understood with reference to the following detailed specification and claims taken in connection with the accompanying drawings, in which:

Fig. 1 shows, in plan view, the invention as embodied in a flexible spacer;

Fig. 2 is a section view taken in the direction 22 in Fig. 1;

Fig. 3 shows, in plan view, the invention as embodied in a rigid bar spacer;

Fig. 4 is an elevation view, partly in section, of the spacer in Fig. 3; and

Figs. 5, 6 and 7 are enlarged views of a clamp member of the spacer of Figs. 3 and 4 exemplifying the clamp construction of the invention.

Referring now to Fig. l, thespacer 10 therein shown comprises a spacer member 11 with two conductor clamps 12 and 13 attached to two conductors 14 and 15 of a bundled phase conductor. The spacer member 11 comprises a single piece of steel wire wound to form an endless cable which is attached to the conductor clamps 12 and 13. The spacer 10 is called a flexible spacer because of the mechanical characteristics of the spacer member 11.

The two conductor clamps 12 and 13 are of identical construction and comprise, in the case of the clamp 13, an inner clamp member 16, an outer clamp member 17, and a U-bolt 18. The U-bolt 18 passes about the outer clamp member 17 between the ridges 19 through the bosses 20, which are formed integrally with the body of the inner clamp member 16, and through openings in the cross piece 21 of the terminal member 22. Clamp members 22, 16 and 17 are held in clamping relationship with each other and the cable by means of the U-bolt 18 and by the nuts 23 which are threaded on the extreme parts of the Ubolt.

The terminal 22 is formed with the cross part 21 and a center part 24 including two bosses 25 and 25a in a single piece. The spacer member 11 is received in an opening through the center part and the bosses 25 and 25a are'compressed upon the cable to form a compression joint.

The construction of the clamp members 16 and 17 is such as to produce a particular cooperation between the spacer member and each of the cables and between the two cables. The spacer itself functions'to permit relative movement of the cables, each with respect to the other, while providing a restoring force tending to return the cable to its normal position, all as set forth in co-pending application, Serial No. 590,661, filed June 11, 1956 by. J. J. Taylor, now abandoned. The novel features of the clamp members 16 and 17 are described hereinafter in connection with Figs. 5, 6 and 7.

The various clamp members may be formed of mallc able iron, although other metals, having the necessary elastic properties, may be utilized.

The spacer 26 of Figs. 3 and 4 comprises a spacer bar 27 together with two conductor clamps 28 and 29. Each of the conductor clamps 28 and 29 comprises, as e.g. the conductor clamp 28, two clamp members 30 and 31 having inwardly projecting integral flange parts 32 and 33 respectively. The clamp members are arranged to pivot along the inner extremity 34 of the flanges and are 3 provided with set screws 35 .for drawing the clamp members together upon the cable.

The flange 33 of the lower clamp member 31 projects inwardly beyond the flange 32 of the upper clamp member 30 and supports a bolt 35a for attaching the spacer bar 27 to the conductor 28. The bolt 35apasses through aligned openings in the spacer bar 27 and the flange 3-3 and is provided with a spring 36' which bears upon the spacer bar 27 to hold thespacer bar against the flange 33 and thereby provide a measure of rotational rigidity as well as static friction resisting relative movement of the conductor clamp with respect .to the spacer bar. A nut 37 is threaded on the lower end of the bolt 35a and serves to adjust the compression of the spring36 as well as hold the spacer bar 27 and flange 33.

The spacer bar 27 comprises-a single rigid piece which has suflicient strength to maintain theclamps 28 and 29 in spaced apart relationship under the forces encountered in a conductor cable assemblage. The spacer of Figs. 3 and 4 functions to hold the cables 38 and 39 in spaced apart relationship and sustain the cables against separate rotational movement while permitting relative longitudinal movement thereof.

Referring now to Figs. 5, 6 and 7, the construction of the clamp member 30 of the conductor clamp 28 is there shown. The body 40 of the clamp member 30 typifies the construction, both of the clamp members of the spacer of Figs. 3 and 4, and the spacer of Figs. 1 and 2, the spacer members differing only in the disposition and arrangement of the flanges 32 and 33 and the ridges 19 and the bosses 20. The body 40 is constructed with a central portion 41 having a maximum thickness relative to the remainder of the parts of the body, two elongated parts 42 and 43 extending oppositely from the central part 41, and two end parts 44 and 45 extending from the ends of the intermediate parts 42 and 43. The outside of the body 40 tapers at first slowly along the central part 41 and then more rapidly along the intermediate parts 42 and 43 to forrn the indrawn portions 46 and 47 having a relatively thin vertical section adjacent the end parts 44 and 45. The interior of the body 40 is formed with a cable receiving groove 47 which has a symmetrical drooping configuration along the length of the body with the uppermost portion of the groove along the center part 41 of the body and the lowermost parts of the groove toward the end parts 44 and 45.

The functioning of the body construction shown is such that when the clamp member is compressed against a cable with the cable received in the groove 47, either .by the arrangement of Figs. 3 and 4 or by the arrangement of Figs. 1 and 2, the intermediate and end parts 4 2 and 44 and 43 and 45 are deflected so as to bring the groove 47 into conformance with the exterior of the cable. That is, the extremity 4-8 of the groove will be disposed along a. straight line. The cross sections of the central part 41 and intermediate parts 42 and 43 is such that the resistance to bending, incurred by the cable, various inversely as the distance of the point of bending from the center of the cable clamp. Hence, the cable assumes a relatively gentle arc centered on a line through the center of the clamp member and sharp bending cannot take place at the ends of the clamp member. Further, the pre-stressing brought about by the modification of the initial configuration when the spacer is installed, causes the clamp member to follow the conductor cable when the cable moves away from the clamp member so that cable slapping and the attendant wear of the cable and clamp parts is eliminated. 'The end parts 44 and 45, with the ear- like projections 49 and 50, function to restrain the ends of the clamp member with respect to the cable and prevent the cable member from slipping sidewards out of the cable groove.

In the arrangement of Figs. 1 and 2, the control of cable deflection in the plane of the conductor cables is achieved by the use of the cable clamps of the invention. The utility of the arrangement resides in the fact that upon longitudinal relative movement of the cables, a couple is formed in which the cable would ordinarily tend to bend about the ends of the conductor clamp and the opposing force exerted by the spacer member 11 accentuates the effect. In the arrangement of Figs. 3 and 4 the principal resistance is in a vertical plane, that is, with regard to vertical deflections brought about by vibrations of the conductor cables or other vertical displacements thereof. In both arrangements, however, the cross section of the cable clamp is such that a measure of grading of the resistance exerted by the clamp member is provided in the remaining direction. For example, in Figs. 3 and 4, the sidewise variation In resistance to deflection is useful upon extreme relative movements of the conductor clamps 28 and 28 wherein the spacer bar 27 abuts the flanges of the clamp members.

The construction of the spacers disclosed and described herein is such that the spacers have characteristics particularly useful for the intended purpose beyond that of the variations in resistance to deflection of the clamp members. Particularly, the shape of the clamp members is such that corona effects are inherently minimized. Further, the design of the clamp member with the relatively heavy middle section permits the exertion of a sufficient clamping action upon the conductor cable to prevent slippage between the spacer and the cable, an important requirement in this art. The arrangement of Fig. I particularly meets the conflicting requirements of an adequate mutual restraining and clamping action between the individual spacer members and the cables, together with reduction of corona effects and simplicity of construction.

It is to be understood that the foregoing description is not intended to restrict thescope of the invention and that various rearrangements of the parts and modifications of the design may be resorted to, giving effect to .a liberal interpretation to the claims as herein set forth.

Iclaim:

1. A conductor spacer for use with two conducto cables comprising two conductor clamps and an interposed spacer member for holding the clamps in spaced apart relationship, the said conductor clamps each comprising two opposed elongated clamp members and each clamp member comprising a unitary piece having a longitudinally directed, transversely arcuate, cable receiving groove with the longitudinal section thereof tapering from the middle part of the clamp outward toward each end thereof for resisting vertical movement of the cable according to the distance from the center of the clamp, and a downwardly arcuate configuration longitudinally along the groove for deformation into a a bstantially straight line configuration upon engagement with a cable, means for securing the clamp members in clamping relation with the cable, and means for securing the spacer member to the conducting clamps.

2. The invention in accordance wtih claim 1 in which the tapering cross section and the downwardly arcuate configuration is symmetric about the center of the clamp member.

3. The invention in accordance with claim 1 in which the spacer member is a flexible elastically deformable curvi-linear member.

4. The invention in accordance with claim 1 in which the spacer member is a rigid bar with rotational movement restraining pivot means between the bar and the conductor clamp.

5. The invention in accordance with claim 1 in which the spacer member is a rigid bar and vertically directed pivot means connecting the bar and a conductor clamp.

6. A conductor spacer for use with two conductor cables comprising two conductor clamps, an elastically deformable curvi-linear spacer member, screw means for securing the conductor clamps in engaging relationship with the cables, and means fixedly securing the spacer member to the conductor clamps, said conductor clamps each comprising two clamp members each in the form of an elongated unitary body having a longitudinally directed transversely arcuate cable receiving groove and a transverse cross section tapering from the middle part outward toward the ends of the body at least in the plane of the cables and spacer member for resisting transverse movement of the cable gradually according to the distance from the center of the clamp and the screw means comprising a U-bolt passing about the clamp members and received in a clamp member part having extending side portions and a socket portion for the flexible part of the spacer member.

7. A conductor spacer for two conductor cables comprising electrically conductive metallic spacer means including a flexible elastically deformable spacer member arranged in the plane of the cables with two terminals at the lateral extremities of the spacer member operatively attached thereto and comprising a socket part and a cross part, two conductor clamps each for connection between a terminal and an associated cable and including an inner clamp member comprising an elongated unitary body part with a longitudinal transversely arenate cable receiving groove and a similar outer clamp member opposed thereto, the inner clamp member having opposed vertically directed ears above and below the body part and the outer clamp member having circumfercntially directed ridges on the outer side thereof, a U-bolt disposed over the clamp members received between the ridges of the outer clamp member and through the openings in the ears and the cross part of the terminal, and screw means threaded on the U-bolts for holding the clamp members and terminal in compressive relationship.

References Cited in the file of this patent UNITED STATES PATENTS 1,902,008 Austin Mar. 21, 1933 2,009,289 Caird July 23, 1935 2,432,635 Van Ryan Dec. 16, 1947 FOREIGN PATENTS 518,441 Great Britain Feb. 27, 1940 724,729 Great Britain Feb. 23, 1955 1,103,932 France June 1, 1955

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