US2112740A - High tension gas filled cable - Google Patents

Description

March 29, 193& I HUMPH'REY 2,112,740

HIGH TENSION GAS FILLED CABLE Filed June 9, 1937 lnvento 1*.-

Daul El'iurnphw ey,

by z/ a JMZM His Attohrwey Patented Mar. 29, 1938 UNITED. STATES HIGH TENSION GAS FILLED CABLE Paul E. Humphrey, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application June 9, 1937, Serial No. 147,292

' 6 Claims. (01. 173-265) The present invention relates to cables for transmitting high tension electric current wherein bare or uninsulated conductors are located within a pipe and the latter filled with high pressure insulating gas. In such a cable, it is necessary to provide mechanical and insulating support for the conductors so as to hold them in proper spaced relation to each other and to the inner wall of the pipe. The dielectric strength of highly compressed gas per unit of thickness is much greater than that of solid insulations of the same thickness now available. To keep the cost of the pipe within reasonable limits, its diameter must necessarily be restricted. This means that if insulators of any ordinary or usual design are interposed directly between the conductors and the pipe in a plane transverse to the axis of the pipe. they will be ineffective to properly insulate the conductors, although as me- 20 chanical supports such insulators would be quite satisfactory. One of the problems is to provide suitable means for properly insulating the conductors one from the other and from the pipe, and a further problem is to provide means where- 25 by the properly insulated conductors can be inserted into the pipe or removed therefrom when necessary or desirable.

The object of my invention is the provision in a high tension gas filled cable of improved means 30 for supporting bare or uninsulated conductors within a pipe containing insulating fluid, such as gas, under a determined pressure whereby such conductors may be readily inserted or withdrawn from the pipe.

35 For a consideration of what I believe to be novel and my invention, attention is directed to the accompanying description and the claims appended thereto;

In the drawing, which is illustrative of my in- 40 vention, Fig. 1 is .a view partly in section 01 a length of high tension gas filled cable; Fig.2 is a cross-sectional view of said cable; Fig. 3 is a diagrammatic view showing the relation of the conductors and their-insulating supports; Fig. 4

45 is a perspective view oi! the parts associated with one of the conductors; and Fig. 5 is a sectional view of a modification.

Referring especially to Figs. 1 and 2, 5 indicates a pipe which may be made of any suitable 50 material either insulating or non-insulating. Desirably, it is made of steel. Inside of the pipe are three conductors 6, I and 8 spaced 120 apart 101" carrying current under high potential which are bare or have such a thin covering of insu- 56 lation as not to effectively insulate them. The

conductors are supported on relatively long solid rods 9 of insulation which form chords that are inclined to the axis of the pipe. Instead of dividing the rod into relatively short lengths, it may be made in a single piece and bent to conform to the desired shape. The rods may be made of any suitable material which has a relatively high dielectric strength and is capable of supporting the weight of the conductors without undue bending. The rods are arranged in end to end rela- 16 tion and held in place by means to be described later. The conductors are fastened to the rods by suitable means such as clamps i0. Inclining the rods in the manner shown permits of relatively wide spacing between the clamps and the ends of the rods, and in this manner an amount of solid insulation is interposed between conducting parts which is comparable in its insulating effect to that of the high pressure insulating gas which fills the pipe. 20

As will be seen from the drawing and particularly from Fig. 4, each conductor has its own insulating support. In order to facilitate the introduction of the conductors and their supports into the pipe 5, special means are provided in the form of segmental members which when assembled define a cylinder. These members extend longitudinally of the pipe and desirably are made of preformed thin metal but which may be of insulation if desired. When assembled, they make a reasonably good fit with the inner wall 0 of the pipe but should not fit too tightly because of the fact that they have to be moved endwise into the pipe and some allowance has to be made for irregularities in the inner surface of the pipe. Each member covers an arc of 120 degrees and has curved or inturned longitudinally extending edges I2, and also inturned projections l3 to form clamps. The rods 9 extend diagonally between the said curved edges and are anchored at their ends thereby, each projection l3 serving to hold the adjacent ends of two rods. The members may extend the full length of each pipe length or section or a number of such members may be provided and arranged end to end. The members may; if desired, be lightened by removing material as indicated at it. From Fig. 4, it will clearly be seen that eachconductor with its insulating supports and member H form an element which is mechanically independent of the others By reference to Fig. 2, it will be seen that when the three elements are assembled to form a cylinder with the curved edges I2 of the members in en'- ga'gement, they may be slipped endwise into the pipe, either by pushing or pulling, after which the ends of the conductors of one pipe length may be united with those of the adjacent length or lengths.

As shown in Fig. 5 each of the rods may under certain conditions support more than a single conductor, provided adequate spacing is provided between the conductors I5 and between said conductors and its supporting member Ii.

vAfter the conductors and their supports are assembled within the pipe and the lengths of the pipe and conductors properly united, the pipe is filled with dry insulating gas under high pressure by any suitable means and maintained in such condition. Prior to filling the pipe with such gas, it is desirable to remove air and any moisture contained therein, as for example by blowing a heated neutral gas, such as CO2,

clined to the axis of the pipe, a means which supports the rods at points remote from the conductors and itself is supported by the inner wall of the pipe, and a filling of insulating fluid under positive pressure for the pipe.

2. A cable comprising uninsulated conductors, an enclosing pipe therefor, diagonally extending rods of solid insulation for supporting the conclusters at points midway of their length, members for independently supporting the rods of said conductors located between said rods and the pipe and forming a cylinder, and a filling of insulating fluid under positive pressure for the 3. A cable comprising a plurality of uninsulated conductors, an enclosing pipe therefor, insulating rods of solid insulation for supporting the conductors, a supporting means for the rods comprising segmental members corresponding in niunber to those of the conductors, said memtears when assembled with abutting edges formr ing a cylinder located within and supported by each conductor which is supported at points remote from the conductor by the inturned edges of a member, and a filling of insulating fluid for the pipe under superatmospheric pressure.

5. A pipe cable having a support for a high tension electric conductor located inside of the pipe comprising a segmental member having inturned longitudinal edges and rod means 01' insulation extending diagonally oi the member to form chords which are supported by the said inturned edges.

6. A pipe cable having a support for a high tension electric conductor located within a pipe, comprising a relatively long segmental member having inturned longitudinal edges, clamping means located at said edges, and straight rods of insulation defining chords arranged in end to end relation and secured in place by the clamping means.

' Q PAUL E. HUMPHREY.

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