US1999273A - Conductor - Google Patents

Description

April 30, 1935. A, o, AUSTIN L CONDUCTOR Filed July 20, 1932 INVENTOR Ari/ Ur 0. 41152777. BYWM'OQ km ATTORNEY Patented Apr. 30, 1935 UNITED STATES PATENT OFFICE CONDUCTOR New Jersey Application July 20, 1932, Serial N0. 623,525

2 Claims.

This invention relates to electrical conductors. and has for one of its object the reduction of corona losses at high voltages.

Another object is to providea conductor of such construction that it will tend to damp out vibrations.

A further object is to provide a conductor of improved construction and operation.

Other objects and advantages will appear from the following description.

The invention is exemplified by the combination and arrangement of parts shown in the accompanying drawing and described in the following specification, and it is more particularly pointed out in the appended claims.

In the drawing:

Fig. 1 is an elevation of a sectional conductor showing one embodiment of the present invention.

Fig. 2 is a transverse section of the conductor shown in Fig. 1.

Figs. 3, 5, 7 and 9 are views similar to Fig. l

I showingother forms of the invention.

Fig. 4, 6, 8 and 10 are cross sections respectively of Figs. 3, 5 and '7.

For high voltage transmission lines, it is frequently difficult to provide a conductor of sumcient diameter so that corona discharge will not be excessive, causing economic losses or radio interference. Where the tension in the conductors is high, considerable trouble is also caused by vibration. Since the amount of power which may be transmitted increases very rapidly with increased voltage, it is desirable to use a high voltage without incurring corona losses or causing radio interference, thereby reducing the cost of transmitting power. Increasing the tensions in the conductor makes it possible to reduce the number of supports, increases the effective clearance between conductors for a given span length,

and frequently effects a very material economic saving in the cost of a transmission line.

Most conductor materials which have high strength also have poor electrical conductivity, so that it is generally necessary to use a conductor made up of two parts; one for obtaining high mechanical strength and the other for conductivity. In general, the high strength material is placed in the center of the conductor and usually consists of several strands of galvanized steel. One or more outer layers of low resistance mate'- rial, such as aluminum or copper, is placed outside of the steel core.

In my prior Patent No. 1,626,776, an improved type of conductor is shown in which a large diameter is obtained by the use of a spacer element between the high strength core and the outer low resistance layer. In the present invention, a further improvement is provided over that shown in my prior patent, which increases the diameter 5 of a conductor having a given effective cross section of material so as to permit of higher operating voltage and, in addition, provides a conductor which will have less tendency to vibrate under operating conditions.

In the form of the invention shown in the drawing, a high strength cable I0 is surrounded by a spacer member II wound helically on the cable l0, preferably in the opposite direction from the winding of the cable and with a less pitch. Another layer made up of strands i2 surrounds the spacer member II. The strands I2 have an appreciable separation from one another and from the cable In which is maintained by the member II. The spacing of the strands from one another may be maintained by grooves or notches in the member ll orby raised projections l3 between conductors [2. The spacer member I I may be applied with any desired pitch or lay. The invention not only increases the diameterof the conductor and reduces the amount of material required but also provides passages between the outer conductors I2 and the inner cable in which are open to the surrounding atmosphere. Wind blowing against the conductor will tend to blow through these openings. Any tendency of the conductor to vibrate will also set up eddies of air which tend to dissipate energy and thus damp out vibrations more than is done by air resistance to vibrations of a con- 35 ductor having a relatively smooth outer layer.

The increased diameter will also tend to cause more longitudinal slipping movement between the outer and inner strands produced by flexing of the conductor due to vibration. This slipping will cause a dissipation of energy which also tends to dampen out vibrations. The strands making up the cable may be of any desired shape. The conductor having appreciable separation between the outer strands also has the advantage that water will be thrown oif more readily, which will reduce corona and radio interference under wet conditions.

In the modification shown in Figs. 3 and 4, the core I0 is provided with a spacer winding H, similar to that shown in Fig. l, and outside of the spacer winding H, two layers It and I I of conductor wires are wound in opposite directions. The conductor wires l4 and I5 are given a long pitch so that the distance of travel along these 56 wires is not greatly increased by the fact that the wires are coiled about the cable. It will be seen that an open-work spacing is provided, leaving passages through the conductor, which permits air currents to pass through the conductor and breaks up eddies which in a solid conductor form on the lee side and produce the vibrations of the conductor.

In the form shown in Fig. 5, a series of conductors l6 are braided about the central core 10. This also forms an open-work conductor cage surrounding the core and providing spacing through which air currents may pass. In this form it is not necessary to provide a spacer H as the conductors themselves hold one another in spaced relation to the core by the fact that they are made to cross. Of course, a spacer could be used, as in Figs. 1 and 2, to provide further spacing if desired.

In the form shown in Fig. '7, another form of braiding is used for the conductors, which avoids any winding of the conductors about the central core. The conductors are arranged in pairs; one pair of conductors being designated by the numerals l1 and I8 respectively. It will be seen that these conductors are looped together at I! and then cross over the cable and are again looped together at the opopsite side of the core I0 opposite thepoint 20. There are twelve conductors in all shown in the form of braiding illustrated in the drawing, but of course any number of conductors may be used. Between the points where the conductors are looped together, they are woven in and out so that the conductors space one another away from the core to provide open spaces for the passage of air currents.

In the form of the invention shown in Figs. 9 and 10, the cable III is provided with a spacing wire H, similar to that in Figs. 1 and 3. Heavy strands of wire 2| are wound outside of the spacer wire II and are spaced circumterentially so as to give the wire a triangular shape in cross section. It has been found that a wire of this shape is less apt to vibrate in the wind than cylindrical wire and when the outer strand is spaced away from the central cable so as to permit the currents of air to pass between the outer strand and the central cable, eddies are broken up and the tendency to vibrate is greatly decreased.

I claim:

1. An electrical power transmission line c'onductor having an inner core, a spacer strand wound upon said inner core, conductor strands wound upon said spacer strand, said spacer strand having reversely curved portions, each oi less than a half turn and constituting undulations forming stops thereon spaced longitudinally of said spacer strand and engaging said conductor strands and holding adjacent convolutions of said conductor strands in spaced relation to one another.

2. A conductor comprising a central cable. a spacer disposed outside of said cable and three comparatively large strands of conductor wire wound about said cable outside of said spacer, adjacent strands being circumferentially spaced from one another approximately 120 degrees to give the entire conductor a triangular shape in cross section.

ARTHUR O. AUSTIN.

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