US966583A - Insulator-protecting apparatus. - Google Patents

Description

' L. c. monollson. INSULATOE PROTEUTING APPARATUS. APPLICATION FILED SEPT. 10, 1909. 96 53 I Patented Aug. 9 H10.

also liabilitycf the insulatorpuncturing dis To all whom it may concern: I I I 9 Be it known that LLLoYnC. N ICI-IOLSON f LL oYnomIoHoLsoN, F BUFFALO, NEW Q'RK.

a citizen of the United St'ate's Qand a resident of Buffalo, county of Er1e,-btate' of New York, have invented certain new and useful; Improvements inInsulator-Protecting Apparatus, of which the following-fie a specificatiou. 4 i I I My invention relates toiinprovements in protecting apparatus and is more especially designed to prevent injury to insulators used on high potential lines.

In ordinary high potential electricsystems.

when the voltage on theline conductor rises abnormally due to lightning Ior other causes a flash-over current. is apt to take place over I "the surface of the insulator to the pin he-- to the high voltage of; the lightning is I heath it and-thence to theearth] If this dis? charge current 15 ofsufficient value to over come the dielectricisti'ength of ,the medium and break it down an arc .,will 1-follo\'v. whicharcis due to the power curreifor yoltage of the line. That is, the actiial'di'scharge due very short duration but the'heavydischarge which follows is due to the flow of the power current which tollowsthe flash-over when a broken down. The insulators used in such 3O the dielectric strengthof theigair has been high potential electric systems are usually of'gla'ss or porcelain. Therefore when such power arcs occur over the shifts of the insulator the heat is apt to injure or wholly destroy To prevent such."destructioni I placean electrode connected with the earth so that when. a flash-over and powerare occur thereon the whole are is diverted.

away from the insulator to jtlie electrode so that it will not injureflj ch'e insulator.

In such high potentialinsulators thereis rectly from the tie-wire to the pin carrying the insulator, or else only one'lo'r two-of the skirts of the insulator maybe punctured, the

For obviating certam of. above ."dilih culties I have provided an arrangement which is clearly shown and described inmy' application for United States-Letters Patent filed January 25,1909, Serial No.-473,980.

,One object of the present invention is to I Specification of'Letters Patent. I

' msoLa'ron-eno'rnormc'arrpnatrnsi the insulatorffrom such power discharges.

Further objects, features and" advantages will nioreuclearly appear frolnzthegdet ailedf v description g ven below taken. in connection a part of this specification.

View of the same. the samcl;

Referringfto the variousfigures; l r epres- I sents the main line. high potential conductor secured to the insulator 2 by'means-of 'a tie L TO v wire 3 passing around the ne'ck4 atthe head I" 5 ofthe insulator. Th e insulator 23in t-h efi, present instance is made up of three skirts: 6,1; 7 and 8,-and is secured to a pole or. other base 9 by means of aniron pin '10-. Bolted1 5 to the base ,of the iron pin lQ'a remetallic" 3 I members 11 projecting upwardly a nd:out-i; wardlyfa'ntlcarrying at their outer end-sthe guard ring 12.. Guard ring 12 ifs below' or on L-m the same side of the horizontal planeof the" 8.0 conducter l as the insulatorfl a-ndcurves or extends in the form of a circleaboutthe in-I I sulator 2 at a' height between the skirts-7 1 and 8 and is. somewhat larger indianiter I I than any of the shirts sothat. it is spaced. therefrom and "from the insulatorj2. ,The-

conductingmeinberor pin 10 is electrically- I.

connected with the guard-ringXIQ byxrneansl of metallic membersjl l and thelvirhol'e iscon-f nccted with the grounder earth by 'means of a conductor13.; I i I the neck of the insulator I provide an electrode-14 in-the forrnof a ring. i The ring l tjzi's composed of two semi-circu u i lar pieces l 'aving' theiren'ds bent upwardly j as at 15, The corresponding ehdso f-these' semi-circular piecesI' are s,ecur ed;:together,

Spaced about above the conductor 1 by; mksztnsQOt ring electrode curving aboi spaced trom the insulator at all points but are a PatentedAugLQ, unto; Y 7 Application filed se temberlo, 1999'. Serial nol '517,159.. Y I I thoroughly protecting the top and" neck of with the accompanying drawing which forms 'ni'einberslG'. The-corresponding ends-15; of the semi-circular members are also secured to ether belowjthe conductor 1 byniean s ofm l su table clamps 17 ,{It willthus'be seen-that. f "the niemherscol'nposin the ring 14 -for mgan- I tvhe;heck;.of the insulatonnear the top thereofi WhichQaI- ePM S j clamped to the conductor" so thatcthey are shown and described in said} prior ap'plication and especially to prov de means for I provide improvementsin the arrangementsv electrically connected .withthe 'oof dflbm 'lly. 51 i the main line conductor 1 thesame voltage- 1 10- When'a'n abnormal voltageiexists'iipon 7 exists upon the tie wire and the electrode 14. This tendsto increase the leakage current over the surface of the insulator and if to the conductor 13 and to earth. This heavy discharge which follows is however due to the power current which flows from the conductor tothe ground over the patli which has been broken down because of the initial high voltage to which it has been subjected. The power discharge, however, immediately forms into a flaring are which will now take the more favorable path through the surrounding air from elect-rode 14 to the guardring 12, in which position it is far enough removed from the insulator parts so that they will not be injured by heat. If the electrode 14; were not present,- the upper terminal of the arc would remain at-some point'on tie-wire 3 and would cause intense heat to exist at that point, so much so that the head piece 5 of the insulator would be broken, and the tie-wire itself severely burned.

By placing the ring electrode 14 as de-.

scribed, a meansis-prov-ided for taking the upper terminal of the are off of the tie-wire away'from the neck and providing an, electrode which is at every oint separated suiticiently from the neck 0 the insulator to prevent damage thereto. .Thus, immediately .afterthe power are forms between tie-wire 1 3 and the pin 10, its upper end flares and I attaches '-to electrode 14, while itslower end transfers to theguard ring 12, assuming the position shown by dotted line 18 in Fig. 2, the current supplying this are passing through the members 15in its passage from the conductor I'to the electrode 14.

In order that the presence of,.the guard rings 12 and, 14 may not cut down the resistance offered by the insulator or increase the flashover liability they are so arranged that the initial resistance through the surrounding medium between these electrodes is greater than the initial resistance over the surface offthe insulator. This is accomplished by proper proportioning and placing rings 123ml 14 with reference-to the size and height o f the :i sulator, By the term initial resistance intend to comprehend the tendency of the air gaps to resist the discharge'of current and not break down as vwell as the tendency of the conductors to resist the passage of current. 'The guard ring or electrode 12 is thusso situatedthat the initial resistancethrough the air between it and theelectrode 14 r the tiewire 3 is so great that the initial discharge will not pass directly through the air, but will take place over the surface of the insulator to thcpin 10-and thence to earth. However, im-

- the skirts of the insulator out lowering the fiashover value ofthe, in-, i i 130 mediately the arc has been formed its flaring in various directions causes it to shift to the neck ring 14 and the guard ring 12 so that the arc is not only drawn away from M is also drawn away from the neck of the insulator so that no part of the insulator will becomeunduly heated and damaged. i In insulators constructed as shown in the figures it is a necessary condition that the electrostatic capacity of a shellor part be less than that of the shell or part into' which it fits. This is true because the activedielectric area of the inner shell is smaller than the active area of the outershell into which 'it, engages. This condition causes more'voltage to act upon the inner shell per unit thickness than upon the outer shell or shells when two or more shells are assembled as shown. For this reason when an abnormally high potential exists on an insulator the inner part will have to resist more -vol-- tage per unit thickness than any of the other parts. Thus, when a high voltage actsthe inner part is more liable to puncture than the others.- Also, if the inner part punctures the other arts may puncture also because of the ine ectiveness of the inner part when punctured. If the dielectric strength of the skirt 6 is great enough and its electrostatic capacity is large enough the discharge will take/ place over its surface, but may puncture the skirts? and 8 on account of the lower electrostatic capacity of these parts.

In a like manner it the skirts 6'and 7 have 1-00 v sufiicient dielectric stren th and suflicient electrostatic capacity the discharge will take a place over the surface of the skirts 6 and 7 i and will puncture skirt 8 on account of its relatively low electrostatic capacity. Since the electrostatic capacity of the inner skirt- 8 is necessarily less on account of the size of its top than that of 7 and the capacity of skirt! is for the same'reason less than 'that of' the skirt 6, it is evident that the skirt 8 is'more liable to puncture than the skirt 7 and that the skirt 7 is more liable to puncture than the skirt 6. Hence it. is apparent that if the skirt 8 can be prvented from puncture, the puncture of the ther skirts is likewise prevented. The

puncture of skirt 8 is .prevented by means of the electrode or guard'ring 12 being placed at a position such that the dielectric a strength ofthe surrounding medium. will be broken down between the lower edge of the skirt? and the guard ring 12 before the surrounding medium will be broken down between these points whenthe pathis over the surface of skirts -7 and 8. This result is accomplished, th -:refore, tg causing the. ring 12 to slightly lower the ashover value of the insulator below the skirt 7, but withsulator above that point.

'viding the electrode 14 7 top part or 'neck' of From the above it will appear hat by prospaced ab ut the neck apparent that the neck ring arrangement is 1 sz-mple'and economical in construction and easy to put in place since'the clamps 17 are readily ent over the ends 15 by a suitable tool to securely hold the members of the and at the same time clamp ring 14 together the electrode in place upon the conductor 1.

Although I havedescribed, m improvements in greatdetaill (lo-not esire to be limited to the exact details shownand described except as hereinafter claimed, but Having fully and clearly explained my invention, what'I claim as new and desire to secure by Letters Patent of the United States is Y 1. In an arrangement of the class described an electric conductor, an insulator therefor, .a tie wire for securing the conductor to theiinsulator, an electrode opposite said tie Wire} spaced from the insulator and ele tricallyabonnected with the conductor to pro et the tie wire neck of the insulator, (and a second electi'cde arranged to di-.

vert the fpower arc away from the insulator when a ashover occurs 'overthe surface of the insulator.

-2. In an arrangement of the class. de-

scribed, an electric conductor, an insulator 35 curing the conductor to the insulator, an

of the pin type therefor, a tie wire for se-' electrode opposite said tie wire, spaced from the insulator and electrically connected with the conductor, said ,electrode being formedin the shape of a ring spaced around'the neck of the insulator and a second electrode arranged to divert the power are away from the insulat'or when a flashover occurs over the surface of the insulator, said second electrode being electrically connected with earth.

3. In an arrangement of the class de scribed, an electric conductor, an insulator therefor, an electrode spaced 'from the in-,-

sulator and electrically connected with the conductor, said electrode being formed of two semi-circular members placed aroundcuring them, together on the otlie Q a flashover occurs over the surfacebzf vthe insulator. :4. In an arrangement of -the gclas therefor, an electrode spaced members placed aroundthe insiil'at member having its ends bent-to embrace t conductor, means for securing the co spon'ding ends of the members together one side. of the conductonchiitp the conductor and means-arrangedito the power are away from the insulatorwhe scribed, an, electric conductoran om, lator and electrically connected with Iluctor, said electrode being forme spaced therefrom,-eacli member having-1t endsbent to embrace the conductor, Inean for securing-the corresponding ends 0 members together on'one side of thef'c ductor, clamps for securing them together. on the other side'of the conductor and mean. arranged to divert the. gow'er are away from the insulator when a 'ashover occursfover 7F the surface of the insulator. 1- p 5. In an arrangement of the ;cla ss="de -I" scribed, an electric conductor, an insulator therefor, an electrode spaced from the insu lator and electrically connected with the conductor, said electrode bein v, two member's' placed around t einsulator;-v

and spaced therefrom each member havin' 6. In an arrangeinent g'of the scribed' an' electric condiigtor, a v, therefor and an electrodef' bppositelator and electrically connectedwith the c ductor, said'electrode' bein'g formed 0 members clamped to "th e conductgron e 11. side of the insulatornfi f' In testimony whereof, I have signe name to this specification, in'the presence of two subscribing witnesses.

LLorip' o. NICHOL SO Witnesses: I

H. E; Nronons, A. G. BIERMA.

1 ail the insulator and' spaced liiierefromg eaclf"

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