Jumper Assembly Connecting Together Two Powerline Conductor Sections

Abstract

A pair of powerline conductors are connected together by a jumper assembly comprising a tower structure, tension insulator strings connecting the line conductors to the tower, a jumper conductor electrically connecting the line conductors, which jumper conductor consists of rigid and/or flexible conductor members, and one or more support insulator beams secured to the tower in a manner swayable both in the horizontal and vertical directions for holding the jumper conductor from slantwise lower direction.

Description

This invention relates to a jumper assembly for connecting powerline conductors at towers, and more particularly to an improved jumper assembly characterized in that a bending moment applied to supporting insulators secured to a tower for supporting a jumper conductor is greatly reduced and any desired insulating clearance can be ensured without using excessively long support insulators even if the horizontal angle between the two power conductors is large.

In double-circuit towers for a narrowed right of way, a jumper assembly has been used at one of the towers of the transmission line which includes one or more supporting insulator beams secured to the tower so as to extend in a direction substantially perpendicular to a plane passing both the axis of the tower and the powerline conductors to be joined by the jumper assembly. The powerline phase-conductor means to be joined by the jumper assembly are held under tension to the tower by means of suitable tension insulator string or strings, respectively, and a jumper conductor is connected to the phase-conductor means at opposite ends thereof. A suitable conductor clamp is secured to the free end of the supporting insulator beam for holding such jumper conductor at about the middle point thereof.

Such known jumper assembly has a shortcoming in that the base portion of each supporting insulator beam, which portion is secured to the tower, is subjected to a rather high bending moment caused by both the weight of the supporting insulator beam per se and the weight of the jumper conductor. During the operation, the bending moment further increases due to additional loading, such as wind, snow, and ice. As the transmission line voltage is raised to extra-high or super-high voltage level, the minimum line to ground clearance also increases, so that the length of the tension insulator string at the tower increases too, resulting in an increased length of the supporting insulator beam of the jumper assembly. It is apparent that the increased length of such supporting insulator beam acts to intensify the bending moment acting to the base thereof. Furthermore, the jumper conductor at a tower at one of substantially straight portions of a super-high voltage transmission line will become very long, because of the requirement for the increased minimum clearance and the increased length of the tension insulator string. Such increase of the jumper conductor also acts to intensify the bending moment acting on the base of the supporting insulator beam. As a result, with the construction of the known jumper assembly, the requirement on the length and the mechanical strength of the supporting insulator beam will exceed the economically feasible limit. Apart from the economy, there is a limit in the mechanical strength of the insulator. In fact, the applicants have already experienced that the known jumper construction is not practical for certain applications due to the limit of the mechanical strength of the supporting insulator beam.

Therefore, an object of the present invention is to provide an improved jumper assembly consisting of at least one supporting insulator beam holding a rigid and/or flexible jumper conductor in a horizontally and vertically swayable manner, which jumper conductor electrically connects two powerline conductors held under tension by tension insulator strings, respectively. With such jumper assembly of the invention, any desired insulating clearance can be ensured by using comparatively small supporting insulator beams for all transmission line towers having very long tension-insulator strings.

The invention will be more fully understood by reference to the following detailed specification and claims taken in connection with the appended drawings, in which;

FIG. 1 is a perspective view of a jumper assembly according to the present invention;

FIG. 2 is a perspective view, illustrating a modification of the jumper assembly of FIG. 1;

FIG. 3 is a fragmentary schematic view of a metallic fixture for pivotally holding a swayable supporting insulator beam to a tower, which fixture is incorporated in the jumper assembly of FIG. 1;

FIG. 4 is a fragmentary view, showing the details of a metallic yoke held by a tension insulator string for connecting a powerline conductor means to a jumper conductor means, which yoke is incorporated in the jumper assemblies of FIGS. 1 and 2;

FIG. 5 is a diagrammatic illustration, showing in detail the manner in which a jumper conductor means is supported by a swayable supporting insulator beam;

FIG. 6 is a schematic view of a modification of the jumper assembly of FIG. 2; and

FIGS. 7 and 8 are schematic perspective views of two known different jumper assemblies, especially designed for double-circuit towers for narrowed right of way.

Like parts are designated by like numerals and symbols throughout the drawings.

Referring to FIG. 1, a transmission line tower 1, or pole, holds end portions of adjacent sections of powerline conductor means 4 by tension insulator string means 2. In the illustrated embodiment, each powerline conductor means 4 consists of two subconductors and each conductor means 4 is held by a pair of tension insulator string means 2. It is understood that the present invention is not limited to such two subconductor lines using a pair of tension-insulator strings for holding each end of such two subconductor phase lines. Metallic fixtures A, A are secured to the tower at substantially diametrically opposite portions thereof for holding the tension-insulator strings for powerline conductor means to be connected, and another metallic fixture B is secured to the tower at a position midway between the two fixtures A, A below the level of the latter fixtures for pivotally supporting the grounded end of a swayable supporting insulator beam 3.

A metallic connector C having a metallic yoke C1 is provided at the far end of each tension-insulator string means 2 to connect the powerline conductor means 4 to a jumper conductor means 5, which can be rigid, or flexible, or a combination of rigid conductors and flexible conductors. Thus, the jumper conductor means 5 provides an electric connection between two adjacent sections of the powerline conductor means 4 through the connectors C. A metallic jumper holder 6 is secured to the line end of the supporting insulator beam 3 for holding the jumper conductor 5 in a swayable or pivotable manner and the insulator beam 3 is slantwise held in a downwardly inclined position by the fixture B. Such swayable holding of the jumper 5 by the metallic jumper holder 6 cooperates with the pivotal support of the lower end of the supporting insulator beam 3, so as to allow the jumper conductor 5 to sway between the adjacent connectors C.

The fixture A for holding the tension insulator string means 2 is of hingelike construction for allowing the insulator string means 2 to sway vertically and horizontally.

FIG. 2 illustrates a modification of the jumper assembly of FIG. 1, in which a pair of swayable supporting insulator beams 3 are used for holding a jumper conductor means 5. In FIG. 2, the grounded ends, or lower ends, of the two swayable supporting insulator beams 3 are pivotally connected to a common yoke B1, which is in turn pivotally supported by a metallic fixture B secured to a tower 1. Thus, the two swayable supporting insulator beams 3 are disposed in a V-shaped configuration. The remaining portions of the jumper assembly of FIG. 2 are substantially identical with the corresponding parts of FIG. 1.

In the jumper assembly of the invention, as illustrated in FIGS. 1 and 2, the jumper holder 6 is disposed below the level of the yokes C1 of the connectors C, so that a tensile load is always applied to the jumper conductor means 5 by the weight of the swayable supporting insulator beam or insulator beams 3.

FIG. 3 illustrates a typical construction of the metallic fixture B for pivotally holding the supporting insulator beam 3 while allowing the insulator beam 3 to sway in both horizontal and vertical directions about the fixture B. In the example, as illustrated, an eyepiece B4 is pivotally secured to the base B5 by a vertical bolt B2, and a clevis B6 at the lower end of the supporting insulator beam 3 is pivotally secured to a tongue integral with the eyepiece B4 by means of a horizontal bolt B3. Thus, the vertical bolt B2 allows the horizontal swaying of the insulator beam 3, while the horizontal bolt B3 allows the vertical swaying of the insulator beam 3.

If a rigid conductor, solid or hollow, is used as the jumper conductor means 5, or as a part thereof, it is preferable to allow the rigid conductor to sway both horizontally and vertically. FIG. 4 illustrates a typical example of the metallic yoke C1, which is suitable for such purposes. It is apparent to those skilled in the art that a clevis and tongue mechanism with two crossing bolts C2 and C3 ensures the pivotal movement of the rigid member of the jumper conductor means 5 about the yoke C1.

FIG. 5 illustrates an example of the jumper holder 6, which is especially suitable for a jumper assembly incorporating rigid conductors acting as a jumper conductor means 5. In this example, the jumper conductor means 5 consists of two linear sections 5c and a central rotatable portion 5a pivotally connected between the two linear portions 5c by a pair of bolts 5b. The jumper holder 6 consists of a metallic sleeve secured to the support insulator beam 3, so as to rotatably hold the central portion 5a of the jumper conductor means 5.

When rigid members are used in the jumper conductor means 5, such as electrically conductive metallic pipes, it is preferable to integrally mount compression-type terminals 7 and 8 to such rigid members, as shown in FIG. 2. Highly flexible conductor sections 9 may be securely connected to such terminals 7, 8 by compression, so as to provide reliable electric interconnection between different portions of the jumper conductors. As can be seen from FIG. 2, such interconnection with the terminals 7, 8 and flexible conductor sections 9 is necessary between the powerline conductor means 4 and the jumper conductor means 5, provided that such rigid conductors are used.

FIG. 6 illustrates the manner in which a jumper assembly of the present invention is applied to an angle tower, which holds two adjacent powerline sections at a bending corner of the line. As can be seen from the figure, any required insulating clearances can be achieved by using comparatively small supporting insulator beams 3. It is also a feature of the invention that, in such angle towers, excessively large spacing from the tower to the jumper conductor can be dispensed with.

FIGS. 7 and 8 illustrate different known jumper assemblies, respectively. In the construction of FIGS. 7 and 8, supporting insulator beams 3 are used as cantilevers so that the base portion of each supporting insulator beam 3 is subjected to both the bending moment due to the weight of the insulator beam 3 per se and the bending moment due to the weight of the jumper conductor 5. On the other hand, with the construction of the jumper assembly of the invention, either end of the supporting insulator beam 3 is pivotable or swayable so that only the weight of the insulator beam 3 per se produces a bending moment about the center of the insulator beam. Thus, the bending moment acting on the swayable supporting insulator beam of the invention is reduced to a level equivalent to one-fourth of the corresponding bending moment acting on the supporting insulator beam of a known jumper assembly, e.g., that of FIG. 7.

With the construction of the invention, the jumper conductor means 5 is subjected to downward loading caused by the weight of the swayable supporting insulator beam or insulator beams 3 so that the jumper conductor will not be moved excessively by wind. Accordingly, it will never come too close to the tower structure during operation.

In the foregoing disclosure, only a single swayable beam or double swayable beams of supporting insulator or insulators have been described. The present invention, however, is not restricted to such number of beams. For instance, it is apparent to those skilled in the art that three or more swayable supporting insulator beams can be used in the jumper assembly, without departing from the spirit and scope of the present invention.

Claims

What is claimed is:

1. In combination: two sections of powerline conductor means for transmitting electrical power; and a jumper assembly connecting said two sections of powerline conductor means comprising a transmission line tower structure, a pair of tension insulator string means mounted on said tower structure at substantially diametrically opposite portions thereof, a pair of metallic connectors mechanically connecting said power line conductor means to respective ones of said tension insulator string means, jumper conductor means electrically connecting said pair of connectors and including means pivotally connecting said jumper conductor means to said connectors, at least one beam of supporting insulators having one end supportingly connected to the central portion of said jumper conductor means from a slantwise lower direction and the opposite end pivotally secured to said tower structure in a swayable manner at a level below said pair of tension insulator string means at a point between the securing points of said pair of tension insulator string means to said tower structure.

2. A combination according to claim 1, wherein the jumper conductor means consists of a plurality of rigid metallic members pivotally connected together.

3. A combination according to claim 2, wherein the rigid metallic members are pipe conductors.

4. A combination according to claim 1, wherein the jumper conductor means consists of central rigid conductor member held by the swayable supporting insulator beam and flexible conductors electrically connecting the central rigid conductor member to the two powerline conductor means.

5. A combination according to claim 1, wherein the jumper conductor means consists of flexible conductor members.

6. In combination: two sections of powerline conductor means for transmitting electrical power; and a jumper assembly connecting said two sections of powerline conductor means comprising a transmission line tower structure, a pair of tension insulator string means mounted on said tower structure at substantially diametrically opposite portions thereof, a pair of metallic connectors mechanically connecting said powerline conductor means to respective ones of said tension insulator string means, jumper conductor means electrically connecting said pair of connectors and including means pivotally connecting said jumper conductor means to said connectors, a supporting insulator beam having one end supportingly connected to the central portion of said jumper conductor means from a slantwise lower direction and the opposite end pivotally secured to said tower structure in a swayable manner at a level below said pair of tension insulator string means at a point between the securing points of said pair of tension insulator string means to said tower structure.

7. A combination according to claim 6, wherein the jumper conductor means consists of a plurality of rigid metallic members pivotally connected together.

8. A combination according to claim 7, wherein the rigid metallic members are metallic pipe conductors.

9. A combination according to claim 6, wherein the jumper conductor means consists of flexible conductor members.

10. In combination: two sections of powerline conductor means for transmitting electrical power; and a jumper assembly connecting said two sections of powerline conductor means comprising a transmission line tower structure, a pair of tension insulator string means mounted on said tower structure at substantially diametrically opposite portions thereof, a pair of metallic connectors mechanically connecting said powerline conductor means to respective ones of said tension insulator string means, jumper conductor means electrically connecting said pair of connectors and including means pivotally connecting said jumper conductor means to said connectors, a pair of supporting insulator beams disposed in a V-shaped configuration and each having one end supportingly connected to the central portion of said jumper conductor means from a slantwise lower direction and the other end pivotally secured to said tower structure in a swayable manner at a level below said pair of tension insulator string means at a point between the securing points of said pair of tension insulator string means to said tower structure.

11. A combination according to claim 10, wherein the jumper conductor means consists of a plurality of rigid metallic members pivotally connected together.

12. A combination according to claim 11, wherein the rigid metallic members are metallic pipe conductors.

13. A combination according to claim 10, wherein the jumper conductor means consists of a rigid metallic central conductor member held by said supporting insulator beams, and flexible conductors electrically connecting the central conductor member to the two powerline conductor means.