US1552664A - Insulator - Google Patents

Description

Sept. 8, 1925.

fdiiii 55 A. o. AUSTIN INSULATOR Filed June 9, 1921 4 Sheets-Sheet Sept. 8, 1925. 1,552,664

A. O. AUSTIN INSULATOR Filed June 9, 1921 4 Sheets-Sheet 2 7 (By flwa Sept. 8, 1925. 1,552,664

A. o. AUSTIN INSULATOR Filed June 9, 1921 4 Sheets-Sheet 3 612%, A? M V524. J

' 2,664 o. AUSTIN I INSULA'IOR Filed June 9, 1921 4 SheetsSh'eet 4 Patented Sept. 8, 1925.

v UNITED STATES 5 1,552,664 PATENT OFFICE.

ARTHUR. O. AUSTIN, OB BABBERTON, OHIO, ASBIGNOB, BY um ASSIQM'IS, TO

THE OHIO BRASS COMPANY, OF MANSFIELD, OHIO, A CORPORATION OF NEW JEE- SEY.

INSULL'I'OB.

Application fled June 8, 1981. Serial Io. 476,170.

To all whom it may concern:

Be it known that I, ARTHUR O. A Us'rm, a citizen of the United States, residing at Barberton, in the county of Summit and State of Ohio, have invented certain new and useful Improvements in Insulators, of which the following is a specification.

This invention relates to electric insulators, and especially to insulators for high potentials, and has for its object the rovision of devices of the class named w 1ch shall be of improved construction and operation, and especially which shall have improved means for controlling the electrostatic flux distribution.

The invention is exemplified in the c0mbination and arrangement of parts shown in the accom anying drawings and described in the ollowing specification, and it is more particularly pointed out in the appended claims.

In the drawings Fig. 1 is a transverse section of a high tension transmission line showing a string of insulators in elevation having one embodiment of the present invention applied thereto;

Fig. 2 is a vertical sectional view of one of the flux control members illustrated in Fig. 1;

Fig. 3 is an elevation of a different form of control member;

Fig. 4 is an elevation partly in section of another modification of the control memher; and

Figs. 5, 6, 7, 8, 9, 10 and 11 show still further modifications of the flux control members.

Fig. 12 shows a side elevation and Fig. 13

-a transverse section of a transmission line and a suspension string having another form of flux distributor connected thereto.

In Fig. 1, the numeral 11 designates a portion of a supporting structure, such as a tower for supporting a high tension line. Suspended from the member 11 is a plurality of insulators 12 connected in series, the insulators being of any well-known and approved construction, such as is shown in my prior Patent No. 1,284,976, granted November 19, 1918. A conductor 13 is supported at the lower end of the string of insulators 12 and is secured to the string by a saddle fitting 14. Connected with the fitting 14 and the conductor 13 are upwardly and outwardly extending flux control rods or horns 15. The horns may extend transversely of the line 13, or may be arranged to extend in the longitudinal direction of the line, or atvarious angles thereto as occasion may require.

As shown in Fig. 2, the horns 15 are provided with caps or attaching members 16 to which is secured an insulator or dielectric member 17 The member 17 is provided with downwardly extending flanges 18 and 19 which prevent flash-over when the insulator is wet or when under a very high voltage. A suitable pin or fitting 20 is secured in a recess in'the upper face of the insulator 17 and carries a. metallic rod orpin 21 extending upwardly above the insulator 17. The upper end of the rod 21 may terminate in a knob 22 which in turn is provided with an insulator 23 having downwardly extending flanges 24 and 25. The insulator 23 may be covered by a metallic cap 23', as shown at theright in Fig. 1, or, this cap may be omitted, as shown at the left in that figure. The horn 15 and the extension 21 may be encased in a sheathing of flexible insulating material, such as a rubber hose 26 shown in Fig. 2, or it may be left bare,

as illustrated in Fig. 1. It will be understood that the particular form of flux control member illustrated is shown merely by way of example and that the member may have a large variety of forms which will readily suggest themselves to those skilled in the art.

In the form shown in Fig. 3, the extension member 21 is illustrated as encased in a tubular dielectric member 27 which is secured to a flange member 28 forming a multiple insulated flux control in which the upper portion of the conducting member is entirely encased in a dielectric cover.

In Fig. 4, the horn 15 is covered at its end by a tubular dielectric member 29 having the upper end closed and enlarged, as shown at 30, thus afi'ording increased insulation at the point where the electro-static stress is greatest. An additional dielectric member 31 is secured to the upper portion of the member 30 by cement 32 providing a multiple control member. The cement 32 acts as a layer of conducting material be tween the two members 30 and 31.

end.

In Fig. 6, the. insulator covering 35 is replaced by a metallic ball 36.

In Fig. 'l', the horn 15 is provided with an insulator -38 of a still difl'erent shape which carries a metallic rod 39 having a knob 40 on its upper end. The knob 40 may beof insulating material encasing the upper end of the rod 39, or it may be a metallic member similar to the ball 36 in Fig. 6. 1

In Fig. 8, the horn 15 carries a compound or built-up insulator 41 su porting a metallic extension 42 of the flux istributing member, upon the upper end of which is carried a built-up insu ator 43.

The insulator 43 may be covered with a rounded metallic cap 43on the outer surface of the insulator. The metallic cap pro vides a flux distributing surface and prevents concentration of the flux at any one oint on the outer surface of the insulator.

t acts in a manner similar to the metallic terminal ball shown in Figs. 6 and 7 and its use in combination with the insulator 43 provides an effective means for preventing arcing due to concentration .of the flux. The metal cap has advantages as outlined and is particularly important in increasing the reliability for one piece insulators or controls of weak or poor dielectric strength. .18. crack in the control insulator due to shooting, depreciation or other causes may lower the pluming voltage like a sharp point since the control extends into a strong field. If the end of the control has a surface of large curvature, the danger of pluming will not be so great but this necessitates a large internal diameter in the insulator greatly increasing the size and cost of the insulator. Where a cap is placed on the outside of the insulator, the concentration of the flux is prevented and the desired result is secured without the necessity of increasing the size of the insulator. Even where a large internal control is used, a defect in the outer dielectric covering will cause a concentration of stress and lower the plumin voltage. A metallic cap, however, will re istribute the stress and tend to maintain a high pluming voltage even where the control insulator is punctured.

In Fig. 9, the horn 15 carries an elongated dielectric covering member 44, the upper end of which is closed and encases the end of the horn 15. H

The upper end of the dielectric member 44 is enclosed in a metallic cap 44 similar to the cap 43 shown in Fig. 8 and operating in a similar manner.

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In Fig. 10 the horn 15 is covered at its end by an insulator 45 and the upper portion of the insulator 45 is enclosed in a metallic .cap 46 similar to those shown in Figs. 8

46 having well rounded surfaces between the two dielectric members of a compound control insulator will have particular advantage in that the metallic cover or cap insures a distribution of the lines of force and the outer dielectric cover forms an insulation to prevent excessive discharges or pluming.

In Fig. 11 a member 48 similar to member 44 in Fig. 9 covers the end of the horn 15 and secured to the upper end of the member 48 is a plurality of dielectric members 49 and 50 cemented to one another to provide a multiple flux control member.

In the form of the invention shown in Figs. 12 and 13, the lowermost insulator 12 supports an inverted bowl shape member 51 within which the saddle 14 is suspended by -a pin 52 and U bolts 53. The member 51 constitutes a flux shield for the saddle 14 and the supporting members and also rovides anattachment for upwardly pro ecting horns 54 secured to the member 51 by rivets 55. The horns 54 may be formed from hollow pipe and at their upper ends are shaped to receive insulating members 56. The insulating members 56 are built up multiple insulators having a plurality of dielectric members cemented together in a manner similar to pin type insulators. It will be seen that the horns 54 constitute flux distributing members which serve to regulate I the electrostatic gradient in the main string and the multiple insulators 56 serve to prevent danger of excessive discharges from th ends of the horns. The multiple insulator provides added security against discharge by increasing the insulation and providing reserve insulation in case one of the members should break down or be injured in any way.

Owing to the fact that it is possible to have less drop in voltage for a given distance along the control than for the same distance in the main insulator, the higher voltage of the control compared with that portion of the insulator adjacent thereto will permit a feeding in of electric flux, or a discharge from the control to the insulator which would tend to take the stress off the lower portion of the main insulator nearest the conductor and increase the stress on the upper portion of the insulator, thereby tending to equalize the stress.

n my prior application, Serial No. 428,- 438, an insulated flux control member .is shown having a single insulating cover. As explained in that application, the flux control member provides a ver eflicient means for regulating the electrica gradient in an insulating member and for preventing pluming that is the formation of streamers into.

' ing the control permits placing of the same in a strong electro-staticfield which could not otherwise be done owing to the danger of the uninsulated control arcing toground or to the main insulator string where. it would cut out or shunt a large part of the insulation. The interposition of dielectric material in the path of such discharges increases the resistance of the path and hence prevents discharge or requires a: higher voltage to cause such discharge. The insulated control can be used to prevent discharge from clamps or from the conductor itself or from any object where the gradient is such that there is danger of discharge into the air or surrounding medium. The further the control extends into the field, the greater" will be the stress on the insulation over the same. Where the stress is very great a single insulating member may not have sufficient dielectric strength to withstand the stress. The present invention, as will be readily understood, provides greater safety in this respect than is afforded by a single insulation. Various attachments may be used to provide multiple insulated-flux control, as shown in the drawings. In Figs. 1 and 2 the multiple flux control ismade up of two elements 17 and 23. In this case the two elements are separated by a conductor 21. The stress tending to break down the element 23 will not be so great as would be the case if the elements 17 were omitted, so there will be less danger of puncture than where a single insulator is used. In Fig. 4

' there is shown a multiple insulated fliix control made up of two dielectric members. This control may be of a variety of shapes, it being possible to use many of the ordinary pin insulators for this purpose. The nearer to the body of the insulating string the conducting element of the control is arranged, the greater will be its effect in in fluencing the stress distribution. Where this control extends well up along the insulator there will be a tendency to are from the control to the string either while the insulator is dry" or when wet. Vhere there are several insulating members in the control, however, the difference in voltage between the different sections of the control and the main body of the insulator can be governed so that arcing from the control to the main body of the insulator can be prevented or controlled as to amount of discharge so as to discharge and cause redistribution of stress. This is of particular advantage in confined places where the distance between the insulator and control orfield is relatively small so thatv there would be danger of the insulator on the flux control breaking down and arcing to ground if extended too far from or along the insulator. I

Where the fluxcontrol has no dircct connection to gkis'ound and is separated by air from any ground connection it will operate under all ordinary conditions even though its dielectric member may be damaged. Theflux control member need not support any other than its own weight. This enables the control member to be much more efficiently designed to obtain 'electro-statie distribution of stresses than is possible with members in the main insulator string.

A much greater influence can be exerted on the main string by connecting intermediate points in the series of flux control mcmbers to the electrodes in the main string by a jumper or conductor, as shown at 48 in Fig. 1. A number of such conductors may be used to connect different points of the control members to various points along the insulator string. The points at which such conductors are attached will depend upon the relative electrical characteristics of the insulator and the control member and the result to be accomplished. This connection 48 may be such that it will be'destroyed in case the power current passes over it to ground. For this purpose the connector may be made of fusible material so that the heat from a power current will cause it to blow. When a connector has been thus destroyed the remaining parts will continue to operate as a flux control without direct connection to the main body.-

It, of course, is evident that the flux con trol members may vary in number and in direction and be placed at either or both ends of an insulator element, such as ordinary transmission insulators, wireless insulators, bushings, or to protect bus bars or conductors which set up a strong field, from arcing to ground or between ends of terminals. The series arrangement of the parts of the control members permits of stepping downthe voltage-much more gradually than can be done where a single control element is used. It is apparent, for instance, that in Fig. l the horn 15 will have the voltage of the conductor 13, but that there will be a drop 111 voltage over the insulator 17 from the horn 15 to'tlre member 21. The member 21 will therefore have a potential lower than the line 13, but considerably higher coverings.

most flexible coverings its use would be the member is provided with a flexible insulating covering.

Where insulated flux controls are used it is not necessary that the end member terminates with an insulating ca This memher may. be covered by a suita le metal covering or have an electrode terminating ina ball or other form, A suitable metal terminal having an extended smooth surface will, of course, be much more e'flicient than would be the. case of an abruptly terminated rod from which the end insulation had been broken or cracked, or in which the end ins'ulation broke down electrically permitting of a concentration of the stress at a point of discharge. When the flux control terminates with an electrode it can be used to charge the main insulator. A discharge may be set up between it and the main string by properly proportioning the gradient for the control and main string and regulating the dis char e between the control and the string. Sucli a discharge can be made to control the stress where a difference between the stress in the insulator and control member is suflicient to cause a discharge between the control electrode and the body of the insulator.

The discharge from the control into the string would tend to cause greater stress to be set up in the portion of the insulator nearest the grounded connection. This would relieve the portion ordinarily under greatest stress nearest the line. This equalization by discharge may be made quite efi'ective and fairlyshort distances used between the control and the main insulator as there would be a strong tendency to discharge at a point in the Wave before the maximum stress -1s applied on the main insulator string.

This is due to the fact that where the distance is such that a discharge may occur early in the wave the difference in potential would be materially reduced by the effective conductivity-in the discharge are. The cur-' rent in the discharge are will reduce as the equalization takes effect. As the current diminishes in the are its resistance will increase greatly so that the arc may die out before maximum stress comes on the main insulator.

By taking advantage of the phase angle and the insulation in the air gap between the control member and main body of the insulator a very efiicient arrangement may be made with a small amount of insulation in the controlmember, even where insulators are subject to storm or fog conditions causing heavy surface leakage. It is evident that if the effective insulation of the control Owing to the deterioration of plus the efiective insulation of the air gap at e portion of the insulator between the' line and the dischar e point the total insulation is not diminis ed by the presence of the control members. In other words, by utilizin the phase angle and the air gap between t e control electrode and the body of the insulator the control may have much less insulation than the portion of the main insulator shunted by the discharge from the control.

The amount of discharge will be regulated by several factors, one of which will be the completeness ofdischarge of the control to the adjacent insulator member. Where this member is not covered by a metal cap orelectrode the discharge may be very incomplete, even under wet conditions. Where the insulator is covered by a metal electrode more current will flow in the discomplete. It is evi cut that under wet or severe conditions the dischar" e between the control and the main body 0 the insulator may be utilized -to.throw added stress on the upper or round portion of the string or insulating Sement. While this arrangement may be used for normal operation, its greatest value would probably be for controlling unusual conditions, as its use in nor- ..mal operation would necessitate some loss of energy, and considerable noise.

The series insulation in the control permits of a more extended use not only in controlling the flux, but in controlling the path of arcs of certain lines of discharge by placing the controls in position where it is not desired to permit the arc to start. Where the insulation terminates on a control or surface positioned in a strong field so that there is brush discharge, the danger of arcing to ground will be increased, as there will be a greater concentration of stress and more current in the streamers which stand out at the end of the insulation. This is due to the fact that the streamers tend to affect each other mutually limiting their respective currents to a considerable extent. The danger of arcing to ground where there is a persistent wave is greatly aggravated under conditions of this kind. Consequently where a single insulating element is used in the control, the hazard is much greater than where two are used in series, or where the end is terminated, or where the portion which may puncture is covered by an electrode, which will reduce the stress in the surrounding medium.

By the covering of the insulator on the control by a well rounded metal cap of proper design, a high concentration of stress at a puncture in the control insulator can be cap or covering which will be at a much hi her voltage. a

This covering rmits of controls having small sections wit comparatively sharp corners being used for mounting the control insulators. The result being that much smaller and cheaper insulators may be used which will have the higher pluming voltage where a control of large sizeis used but which would necessitate a large and more ex ensive insulator.

claim 1. The combination with an insulator having a mechanical load supported thereon, of a flux control member therefor insulated by a plurality of dielectric members arranged in series and positioned one beyond the other in the electro static field surrounding said insulator said flux control member being entirely supported from one end thereof and free from said mechanical load.v

2. The combination with an insulator, of a flux control therefor, and a plurality of insulators for said flux control arranged in series with one another and separated from one another by conducting material said flux control member having a supporting connection at one end thereof.

3. The combination with an insulator, of a flux control therefor comprising a member having sections of conducting material positioned adjacent said insulator and separated from one another by a dielectric mem- I ber said flux control member having a supporting connection at one end only thereof.

4. The combination with an insulator having a conductor connected thereto, of a flux control member for said insulator having supporting connection at one end only thereof and comprising a member of conducting material connected with said conductor and projecting therefrom into the electro-static field adjacent said insulator. said flux control member having a plurality of insulating members arranged in the path of the lines of force emanating therefrom. said insulating members being positioned one beyond the other in the direction of said lines of force.

5. The combination with an insulator having a conductor connected thereto and supported thereby, of a flux control member therefor comprising a member of conducting material connected with said conductor and extending therefrom into the field of'force adjacent said insulator, a dielectric member arranged to cover a portion of said conductor, and a second conducting member positioned beyond said dielectric member in said electro-static field said flux control member being offset from the conductor supporting insulator and supported entirely at the end thereof connected with said conductor. 6. The combination with an insulator having a conductor connected thereto, of a flux control member for said insulator free from the load imposed by said conductor and comprising alternating, conducting, and dielectric members arranged in series.

7. The combination with an insulator having a conductor secured thereto, of a flux control member connected with said conductor and extending into the. electro-static field adjacent said insulator, said control member comprising a plurality of conducting members arranged in series and insulated from one another, said control member being free from stresses due to the load on said insulator.

8. The combination with an insulator having a conductor carried thereby, of a flux control member for said insulator having supporting connections at the end only thereof adjacent said conductor and comprising a plurality of conducting members insulated from one another and arranged in series so that the various conductin members of said series will have potentlals difiering from one another due to their different positions in said electro-static field.

9. The combination with an insulator hav ing a conductor supported thereby, said insulator constituting the entire support for the conductor at the point of connection therewith of a flux control member for said lnsulator comprising a member of conducting material secured to said cpnductor and projecting into the electro-static field surrounding said insulator, a dielectric member carried by said member of conducting material, and a second member of conducting material carried by said dielectric member and supported in said electro-static field in a position beyond said first member of conducting material so that said second member of conducting material will have a potential difi'erent from said first member of conducting material due to its position in i said field.

10. The combination with an insulator having a conductor supported thereby, of a flux control member connected with said conductor and extending into the electro-static field adjacent said insulator, said flux control member having the end thereof opposite said conductor unsupported except by its connection with said conductor, and a dielectric member arranged to separate said control member into sect-ions insulated from one another.

11. The combination with. an insulator having a conductor supported thereby, of a flux control horn projecting from said conductor in the general direction of said insulator, said horn comprising a plurality of sections of conducting material, said sections being insulated from one another by dielectric material.

12. The combination with an insulator having a conductor supported thereby, of a flux control member for said insulator comprising a rod connected with said conductor and entirely supported from the end thereof adjacent said conductor, a dielectric memlber arranged to cover a portion of said rod -fiux control member being entirely supported from the end thereof connected to 'saidconductor and comprising a lurality -of alternating, conductin and ielectric members arranged in series with one another.

14. In combination, an insulator having a conductor connected therewith, and a flux distributor for feeding flux to'said insulator at points removed from said conductor to regulate the otential gradient along said insulator, sa1d distributor comprisin a series of conductor and insulator mem ers alternating with one another said insulating members bein graded in size.

15. In combination, an insulator havin a conductor connected therewith, a flux tributin member extending from said conductor into the surrounding electro-static field and being sup rted from the end thereof connected witfi said conductor, a dielectric member interposed in the path of lines of force emanating'from said distributing member, and a member of conducting material extending beyond said dielectric member in series with said first-mentioned distributing member and insulated therei from.

16. In combination, an insulator having conductors of different otentials connected therewith, and a flux distributor connected with one of said conductors and extending toward but free from the other thereof, said distributor comprising a series of alternating, conductor and insulator members.

17. In combination, an insulator having conductors of different potentials connected therewith, and means for regulating the potential gradient along said insulator between said conductors, said means comprising a flux distributor having a series of alternately arranged conductor and insulator members, said distributor having a conductor member thereof connected with one of said first-mentioned conductors and extending from said conductor in the general direction of said insulator but free from the other first-mentioned conductor and ar- I ranged to feed flux to said insulator at "points along its length.

18. The combination with an insulator having conductors of different tentials connected with opposite portions t ereof, of

from one another, and an electrical connection between one of the units of said insulator "and a conducting member of said flux control, said flux control being supported independent of said electrical connection.

20. The combination with an insulator having a plurality of units and connected with a conductor, of a flux control connected with said conductor and extending into the electrostatic field adjacent said insulator, said flux control comprising a plurality of conducting members insulated from one another, and means for electrically connectin one of the conducting members for said ux control with one of the units of said insulator, said conducting member having a covering of dielectric material for the extremity thereof, the connecting members being insulated from the conductor supported by said insulator.

21. The combination with an insulator comprising a plurality of units and a conductor supported thereby, of a flux control comprising a pluralit of alternately arranged conductor an insulator members, one of which is connected with said conductor, and means for electrically connecting a conductor member of said control removed from said supported conductor with a unit of said insu ator also removed from said supported conductor, the conductor member so connected being superimposed by one of the insulator members of said control.

22. The combination with an insulator having a plurality of units and a conductor su ported thereby, of a flux control connecte with said conductor and extending into the electro-static field adjacent said insulator, said flux control comprising alternately arranged conductor and dielectric members in series, and means for electrically connecting one of said conductor members removed from said supported conductor with said insulator at o1nt removed from said conductor, said e ectrical connectin means being composed of material whicfi will be broken by excessive current.

. 23. The combination with an insulator of a control member therefor comprising a conducting body, a dielectric member enclosing a terminal portion of said body and a metallic cover for said dielectric member having an extended outer surface.

24. The combination with an insulator of a control member therefor comprising a con,

' ducting body, arranged adjacent said insulator, a dielectric member for insulating a portion of said conducting body and a metallic cap on said dielectric member having a rounded extended outer surface for distributing lines of force emanating therefrom. v

- In testimony whereof I have signed my name to this specification on this 26th day of May, A. D. 1921.

ARTHUR O. AUSTIN.

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