US1893318A - High tension installation - Google Patents

Description

Jan. 3, 1933. A. o. AUSTIN 1,393,313

HIGH TENSION INSTALLATION Original Filed Oct. 20, 1921 Attorney Patented Jan. 3, 1933 UNITED STATES.

ENT FICE? ARTHUR o. AUSTIN, or. NEABBAJRBERTON, onio, Assmnon, BY nnsnn assicnnnnrs,

TO THE OHIO .BBASS COMPANY, 01E MANSFIELD, OHIO,

JERSEY Original application This invention relates to installations for.

tion and operation and which shall reduce the tendency to discharge of variouscharacters from the highl charged conductors through the control 0 the electrostatic flux in the medium surrounding such conductors.

The invention is exemplified in the combi: nation and arrangement of parts shown in the accompanying drawing and described infthe following specification, and it is more particularly pointed out inthe appended claims.

508,933, filed October 20, 1921, which has resulted in Patent 1,664,190, issued March27,

In the drawing V Fig. 1 is an elevation of an installation embodying one form ofthe present invention. I

Fig. 2 is a section online 2-2 of Fig. 1. t Fig. 3 is an elevation of an installation showing another modification.

Fig. 4 is a section on line of 8.

Fig. 5 is a section on line 5-5of, Fig. 3.

Fig. 6 is a View similar to Fig- 3 showing another form of the invention;

F ig. 7 is a section on line 77 of Fig. 6; a Fig. 8 is a viewsimilar to Fig. 1 showing a different modification of the invention.

In high tension insulators fontransmission and radio work as customarilyzused, a

six or eight section suspension insulator. will ordinarily withstand a greatervoltage at a high frequency without danger of arcing than will the conductor on whichthevoltage is impressed, unless the conductor is of abnormallylarge size. It is, of course, not economical toiuse a conductor which isso large that the first cost and interest on the investment will be excessive, therefore abnormally large conductors are not feasible. Even if there were sufiicient powerto warrant a very large conductor for transmitting power at a high voltage, the line reactance due to the large current necessary forteconomy would be too This is a division of application, Serial'No.

A oonrona r on on NEW men TENSION msTALLArr filed October- 20, 1921, Serial No. 508,932; and in Switzerland April 20, 1922. Divided and this applic ationfiled March 26, 1928. Serial No. 264,906. A

great to-permit of a size suflic'iently' large to prevent arcing of the conductor in the vicinity of the supporting tower where the elec-' tros'tatic field is strong. Spreading or splitting the conductor into several parts so as to increase the effective diameter would be of material benefit, but this is open to serious mechanical objections when carried out throughout the line or in the vicinity of the tower. Y

The insulators or portion of insulators next the transmission'lin'es carry higherelectrostatic stress thanthose farther from the line due to .what'may be'terined the leakage of electrostatic flux to ground from different members in the series. The use of verylarge conductor: in the vicinity of the insulator 7 tends -to prevent or make up for this loss of electrostatic flux, thereby greatly-improving the stress distributionor gradient for the insulating member-or members. The gradient or stress distribution in theseries may be improvedby horns' or flux controls, as shown in my previous application,*Serial" No. 476,179, filed June 19, 1921, which has resulted' in Patent 1,552,664, issued- Sept 8, 1925 or by a large ring or shield vV'here'a ring or shield is used to control the flux, this ring or shield may lower the fiashover owing to its projecting into a'strong field on the tower side so that it may morethan ofiset the advantage of an improvedgradient" in the insulator. I 1

An eight or ten section insulator 'of'good design will usually withstand a higher voltage than that which will start anarc -'from the conductor to the tower, a distance ing the distributionof stress in same.

ofarcihg of the'insulator string by improv- Owing to the comparatively small diameter of the conductor and the comparatively short distance'to the tower, there is a very strong field about the conductor inthe vi cinity of the tower so that by increasing the effective diameter of the conductor by means of a properly formed shield or screen running alon or ad acent to the conductor,

the stress in t e air is lowered and the corona point or voltage necessary to start a plume or are may be greatly raised and the danger of pluming or arcing to ground'under high frequency disturbances may be greatly reduced 'or eliminated. j I v There are two classes of discharge into a the airfrominsulators or high voltage conductors, One class affects the performance OftlflIlSI'nlSSlQIl lines very serlously due to thearcing to ground at voltages much lower than'wouldbe indicated by the voltage which can be carriedoat normal frequency; Where a discharge from a conductor into the air is in thenature of a small streamer, the resistance of the streamer will be greatly reducedby increasing the current in the same. As this currentmay be regarded as a charging current'the air acting as a dielectric in a condenser and a streamer as one of the conductbe carried out further from the conductor.

This will cause a further breakdown of the air, permitting an increase in the electrostatic capacity of the condenser which affects the currentand resistanceof the streamer acting ascone of theelectrodes of the com denser.

" again reduces the resistance so that an ac-.

cumulated effect is produced which is very serious when a highfrequency is impressed upon the line'or insulator. This may be better understood when we consider that don high at a normal frequency of twenty-five or sixty cycles, the same length of streamer would have almost a negligible resistance if the frequency is increased several thousand times, 'whichmight [easily occur on the transmission line. This increase in frequency over the normal frequency may come from av number ofdifierent causes,such as lightning and arc1ngground,.the effect of corona on the line in producing a harmonicythe harmonics'produced' by connected apparatus, or

other causes. A discharge then which will I cascade because of the accumulative-effect of current,- either due'tothe reaching of a suf This further increase in current V" of the pipes 29, an insulator 30 may be placed ficiently' high voltage, or partially due to the increased current from an increased frequency, ora combination of both, may-cause serious arcingor at least arcing to ground at voltages much lower thanwould otherwise be thecase. or v i V A small diameter of conductor, as was pointed out, permits a highly concentrated field which' tends to produce streamers at comparatively low voltages. These stream-' ers may exist at or even below the-normal transmittingffrequency. While there may be no trouble from the 'same otherthan the lossof power at normal frequency, 'an' i'n "crease inf frequency, particularly when at tended by an increase in voltage, may permit ofgrowth of a streamer resulting inan arc toground, as previously explained. Where though a" streamer starts, the accumulative amma-11m be sogreat and a much higher voltage and frequency may be 1 impressed without producing a plume or are which'will cent the insulator string and similar rings 28 are connected to the conductor 2 at points spaced from the insulator string A series to the periphery of the rings 27 g and 28 and extendalong the-conductor forming a cylindricalca'ge therewith.

In order to prevent arc-ing from the ends over the end of each; of these pipes. It will the size ofthe conductor is increased, the

concentration-of the fieldis reduced, and even v of pipes "29 is welded or otherwise secured be'seen that'this cage greatly increasesthe 1,10

eflective diameter of the conductor .so'that a much higher voltage must be impressed to cause a sufiicient concentration ofstress in the air to start a streamer than in the caseof a" bare. conductor of a relatively v small diameter. p a

By making the conductor guard or cage of open construction, the concentration of drip kept down. water, if permitted, would tend to form a conducting path which would start a plume The concentration of drip water is eliminated and the cost of the guard and lower the flash-0ver,particularly where the cage or guard has a large projectingsurface which accumulates and concentrates considerabledrip water. The use of the' conductor cage or guard permits higher operating voltages 'andfrequency without arcing from insulators, conductors and fittings for a given tower clearance.

go to ground under a disturbance, permitting 99 I Where it is desired to raise the voltage of a llneafter an installation is made, it frequently occurs that there is not suilicient clearance to permit an insulator of suflicient pended from the saddle 3 and these brackets are provided with openings as shown in Fig. 4. Rods or hollow pipes 16 are suspended in the openings 15 and extend along the conductor 2, the rods or pipes 16 with the conductor 2 forming a. cage of approximately cylindrical shape. The outer ends of the pipes 16 aresupported by a fitting 17 comprising a pair of clamp blocks 18 held together by bolts 19. The blocks 18 are clamped over the conductor 2 and are provided with openings in which the pipes 16 are secured in any suitable manner.

The construction shownin Fig. 6 is somewhat similar to that shown in Fig. 3 except that in Fig. 6 a single supporting brack-.

et 20 is suspended from the saddle 3, the bracket being provided with a series of openings for receiving the pipes 21 extended in both directions from the insulator string. The outer ends of the pipes are supported from the conductor by a fitting similar to that shown in Fig. 3. Inthe construction shown in both Figs. 3 and 6 the ends of the pipes are turned inwardly to prevent danger of arcing from their ends. A wire or other suitable holding device maybe threaded through the ends of the pipes as shown at 22 to hold the bent ends in their inwardly turned position.

In the modification shown in Fig. 8, the rods 16 are supportedadjacent the insulator in a manner similar to that shown in Fig. 4 but the ends of the rods are provided with insulators similar to those shown in Fig. 1.

I claim 1. The combination with a conductor of an insulating support for said conductor, a

plurality of bars disposed along said conductor and extending a short distance at opposite sides of said support, spaced brackets for holding said bars and conductor in spaced relation to one another and means at the ends of said bars for minimizing electrical discharge therefrom.

2. The combination with a conductor of an insulating support for said conductor, a

pair of brackets connected with said con-' ductor in spaced relation to each other adacent said support, a plurality of bars of conducting material mounted on said brackets in spaced relation to one another and to said conductor, said conductor being extended away from said support beyond the ends of said bars and means on the ends of said bars ligor minimizing electrical discharge from said ars.

3. The combination with a conductor of an insulating support for said conductor, a bar of conducting material extending along said conductor adjacent said support and electrically connected with said conductor and terminating at a point short of the end of said conductor and an insulator disposed upon and enclosing the end of said bar. 7

4. The combination with a conductor of an insulating support for said conductor, a plurality of bars arranged in spaced relation to one another and to said conductor and extending longitudinally of said conductor adjacent said. support, said bars being terminated at opposite sides of said support while said conductor extends beyond the ends of said bars and coverings of dielectric mate-x rial disposed over the ends of said bars.

5. The combination with a conductor of a bar extending longitudinally of said conductor and electrically connected therewith and terminating at a point between the ends of said conductor, the end of said bar being turned inwardly toward the center of the electrostatic field set up by said bar and said conductor to prevent electrical discharge from said end.

6. The combination with a conductor of a metal ring disposed adjacent said conductor in a plane transverse thereto, a plurality of metal bars carried by said ring and extending longitudinally of said conductor, the ends of said bars being turned inwardly toward the interior of said ring to prevent electrical discharge therefrom.

In testimony whereof I have signed my name to this specification this 24th day of March, A. D. 1928. j

' ARTHUR OQAUSTIN.

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