US1160960A - Surge-proof transformer. - Google Patents

Description

C. H. THORDARSON.

SURGE PROOF TRANSFORMER.

APPLICATION FILED 00L@4 IsIs.

Patened Nov. 16, M15.

2 SHEETS-sun I,

"lllllralu,

C. H. THORDARSON.

SURGE PROOFTRANSFORMER.

APPLICATION mw ocr. s, 1913.

2 'SHEES-SHEE] 2.

' Iioof Transformers; and I -vice or machine out of commission.

CHESTER H. THORDERSON, 0F CHICAGO, ILLINOIS.

SURGE-PROOF 'IRANSFOBMER.

Y v Specificaton'of Letters Patent.

,Patented Novio, i915.

Appiicat'ion flied october e, 1913. seri-aim. 793,787

To all whom 'it may concern.'

Be it known that Dansox, a citizen 'of the United States, and a resident vof Chicago, in and State of Illinois, have invented certain new and useful Improvements in Surgeclare that the following is a exact description thereof, had to the accompanying drawings,` and to the characters of reference marked thereon, which form a part of this specification.

This invention lrelates to a novel method of protecting electrical machinery and devices used in electrical power transmission service, and especially high potential transmission lines, to safeguard the same from high potential disturbances or surges that may occur on the line and prevent the insulation between the turns of the winding of the electrical device or machine from being burned out, with the result of putting the de- Such potential disturbances may occur from external sources, such as from lightning, or from internal potential changes on the line itself upon the opening of a circuit, or upon the short circuiting of the line or portion of the line in which the electrical device or machine is connected. Such rapidly changing magnetic flux has the effect of producing a potential in all the conductors that lie parallel to it, and, inasmuch as this induced potential is in proportion to the velocity of the surge and its magnetic density, it is evident that such induced pressure in the neighboring conductors, lying near thereto, may become enormously high.

The phenomenon of a break down in tlie insulation ,in high potential coils and trans- `foi-mers from an Velectro-magnetic surge is comparable to that. of rthe receiving instru- 'ment ofi-a wireless*telegraphic system.

The coherer acts as an insulation vair gap in the in the manner ofthe insulation between the turns of the wire in a high potential transformer coil. The magnetic disturbances of a sui-ge in an aerial system set up a potential on the conductor leading to thecohei'er that is sufliciently high to break through the air gap of the coherer or its insulation and thereby furnisha path for the battery' current to flow to transmit a signal. lLikewise, an excessive surgev in the transformer acts to set up aihigh potential difference in the neighboring turns of' its winding and when I, CHESTER H. THoR-' thecounty of Cook do hereby der full, clear, and, reference being` it is suihcientlyhigh to break through the' insulation surrounding these conductors, the exciting potential and current from the magnetic field -of the transformer immediately follow thisvpath through insulation and very quickly heat the con: ductor to such an extent that'the insulation surrounding it is charred. The surgeenergy `bi'eaks down the insulation in the neighboring turns which is quickly transmitted to each of the turns of the coil with the result of ruining the transformer.

It has heretofore been lproposed to protect transformers and other elect/tical devices in high poten-tial power transmission lines by placing choke or impedance coils in the line in series with the'electrical devices or machinery to be protected. This method has not been .found to meet the requirements for the reason that if the surge energy be very high, it may jump around or over the coil, Vand also because it checking to some extent or holding back the energy from the windings of the devices to be protected, so that the surge energy i allowed to surge back and forth on the line until it is dissipated as heat.v Other practical economical disadvantages work against the luse of a choke or impedance coil thus arranged. I propose, as a novel method of safeguarding electrical devices and machine'i'y from such troublesome form of energy, and-neutralizing its effect on the transmission system, to apply afew turns of special .winding about the magnetic circuit of the transformer or equivalentpart of an 'electrical device to which the invention may be applied. said winding being connected to the outside end or ends of the high potential winding of the transformer or other electrical devices or machinery. These special turns .ire intended to lie near or parallel to the high potential windingsof the transformer and like windingsinfsiiiiilar devices to be protected, anda'i'efi'i'i'sulated from each other to protect adjacentyturns against the induced potential due to such external or internal disturbances. By placing an adjustable resistance on the second turn of this special winding, the surge ,energy induce in said winding may be dissipated in t-lie i' in of heat in saidexteri'ial resistance. and any velectro-magnetie energy due to the surge ,which passes still Afarther on may be absorbed in another resistance placed on the third turn, and so on.l The turns of the said the broken down is only efficient m special winding are made of progressively increasing cross section and capacity so as tol s afelytake up the increasing potential impressed thereon by thesurge disturbances, and thereby protect thev electrical device from an overcharge of potential, such Vas wouldbreak through the insulations" between the turns thereof. The number of turns to be used. and the resistance to be employed in connection therewith. maybe ladjusted to 'suit the conditions. and,in any event,will

be proportioned as to protect the windings t the electrical devices from any expected maximum surge. The t amount of surge energy that can be thus dissipated may vary nearly as the square of the induced potential or many times higher than the operating potential of the magnetic circuit 'of the said electrical device.

l have shown in the'drawin-gs the adapta titan of my invention -to a high potential transformer. and havel also shown two different forms of special winding referred to. but 'it will be obvious that the details of the application of the invention may be considerably varied within the spirit and scope of the invention.

As shown in drawings: Figure 1 is a vertical section of a high potential transformer equipped with my surge protecting` device Fig. 2 is a fragmentary section of a transformer et uipped with another form of surge protecting device. Fig. 3 is a fragmentaryY section taken on the line 3 3 of Fig. 2. Fig.

' L is a diagrammatic view illustrating the essential electrical elements of the device.v

apart from the mechanical embodiment thereof.

Inthe present instance. said low and high potential coils comprise ribbon like conductors with the turns thereof insulated by strips of paper. or the like. such. for instance. as are shown in my co-pending application for U. S. Letters Patent. Serial No. 776.521 filed on the 30th day of June. 1912)). The magnetic circuit 10 embraces a core member 14 about which the low and high potential windings are wound, together with end members 15 and the side members 16 to complete the magnetic circuit. The low potential winding is insulated from the core meinbei' 1l by an insulating layer 2f) and is insulated from the high potential winding by a thicker insulating layer 21.

Arranged at one or both ends of the core 14 are the lrotective `windings embodying my inventioiil and designated. as a whole, by

One of s1 cli windings is shown diagrammatically in l"ig. 1 and two different forms or modificatibns thereof arei Sliwn mechanically related to other parts inpu'ts 1, 2 and `of the high potential winding 12.

-F ig. 1 comprises five turns, designated respectively as a., b, C, (I and e. with the turn a leading to af terminal 25 adapted for connection to the transmission line and with the last turn e connected to the adjacent turn Y In the form of the protective winding shown in said Fig. 1. the said turns are concentrically related.l That is to say. the center turn a., comprising a solid conductor. is inclosed within the ,next adjacent tubular turn l), with an insulating tube a between them. The said turn b is likewise inclosed within ,the .tubular turn c with an insulating tube 1)',

and surrounding 4concentric turns are connectedtogether to constitute a continuous coil or winding bythe connecting conductors a2, b2, c2, and (Z2 as shown in Fig. 1, this arrangement constituting in effect a continuous spiral coilV which is diagrammati-` cally illustrated in Fig. l as aA conventional winding or coil but of progressively increasing diameter as it approaches the high tension winding. The said tubular conductors vare preferably made of copper tubing of proper gage. Shunted between the second and third turns of this winding. as well as the fourth and fifth turns. and between like relationed turns of` a longer winding, if employed. are resistance elements 28. 28. shown diagrammatically in Fig. l. In the mechanical application of these resistance elements to the turns shown in Fig. 1. they each comprise upper and l-ower conductor plates 26. 2T. connected at their peripheries by resistance elenient-sl 28. The plates associated with one pair of resistance elements. (the upper plates as-herein shown) are in velectrical contact with conductors f that are sliunted across the turns 7) and c of the protective winding by the conductors b3 and cf. rllhe plates 26, 27 of the other pair herein shown are likewise in electi'i 'al contact with other tubular conductors f2, fr. rf lpectively. which latter are in like manner shnnted i across the turns and c of the protective winding by the conductors f7". c". These conductors of the resistance circuit are concentrically arranged. in the saine manner as are the turns of the protective winding. the outer conductors being made hollow to inclose the progressively smaller inner conductors and the central conductor which is connected to the terminal of the coil. is a solid wire. The several conductors are insulated from each other by tubular insulating sleeve shown The outer conductor f3 is surrounded by a' insulating sleeve or'tube f4, and is finally protected by a porcelain'or other insulating inclosure f5 that is screw-threaded in the top wall 30 of the casing 31 that inclosesthe transformer elements, and also a body of ,cooling liquid, as oil, in which the transformer elements are immersed. The turn e of the protective winding isconnected to the adjacent winding 12 `by a conductor e4.

In the construction shown in` Figs. 2 and 3, the turns of the protective winding 35, instead of being arranged concentrically with respect to each other, are arranged in flatwise relation to each other, the initial turn g being of smallest cross section and the turns toward the high potential winding being of progressively increasing cross section and capacity. This relation is best shown in Fig. 3wherein g, g', g2, g3 and g4 designate the respective turns of the protective winding, the initial turn g being made smallest, and the' last turng4L of the winding being'made widest to take care of the progressively increasing potential from the 'initial to the lastturn of the winding, in the same general manner as the concentric .turns of the winding shown in Fig. 1. The several turns of the winding are insulated from each other by suitably heavy insulation. The group of windings is inclosed in a heavy insulating sheath that also serves to hold them together. The turn q of the winding 35, last described, is adapted to lead to a suitable terminal of the transmis` sion line. The several'turnsof the said protective winding are connected together to complete the coil by the conductors g, g?, g8 and g5" and are also connected by shunt conductors to the conductors h, h', h2 and h3 of external resistance circuits, herein shown as made of the same constructionas in the type shown in Fig. .1.

The construction shown in Figs. 2 and 3. while efficient for the purpose designed. does not reach the theoretical efficiency of the construction shown in Fig. 1, inasmuch as the potential generated between the .turns of the windings acts from a given turn in all directions, and is, therefore, taken up in a more efficient degree in the concentric relation than in the construction whereinthe turns are arranged side by side. as shown in Figs. 2 and 3. The concentric form is also preferable for mechanical reasons linasmuch as it is stronger and the windings are not subject to the liability of spreading apart under the electro-magnetic stresses which occur in a winding made of flat strips. rl`he same electrical and mechanical advantages appear in the arrangement of the terminal end of the protective winding and .the conductors of the resistance circuits. However. it isto be understood that the latter construction may be varied within the broader aspect of the inve.n ti on is shown'diagrammatically in order to'clearly trace the connections. Itwill be understood, however, that all parts of the turns of the windings and' said conductors at said connections will be suitably covered by heavy insulation andthat the connections between said parts may follow any approved practice.

It will, of course, be understood that the protective winding may and usually will be arranged at both ends of the windings to lbe protected in order to protect the latter winding from s urges entering the coil from either direction.

It will be understood that the details of applying myV novel surge proof method or means to the protection of electrical devices or machines in transmission lines may be varied within the scope of the invention, such details depending to an extent upon the specific character of the. machine or device to be protected.

I claim as my invention:

1. The method of protecting the secondary winding of electrical Vtransformers which consists in arranging in series with said winding a protective impedance winding and connecting an external'resistance across the turns of said protective winding.

'2. A surge-proof electro-magnetic device comprising, in combination with a magnetic circuit, and a winding thereon, of a plurality of protective turns connected in series with said windings, wound also upon said circuit. and means for dissipating' the energy generated in said protective turns.

3. A surge-proof electro-magnetic device comprising. in combination with a magnetic circuit. and a winding thereon. of a plurality of protective turns of progressively increasing capacity connected in series with said windings and wound also upon said circuit and means to dissipate-the energy generated in said protective turns.

4. A surge proof electrical transformer comprising` in combination with the 'inagnetic circuit thereof, and a high potential winding thereon, of a plurality of imped- A ance windings in series with said high potential winding comprising a plurality of turns of progressively increasing capacity. and means to dissipate the energy generated in the turns of said protective winding.

A surge proof electrical transformer comprising. in combination with 'themagnetic circuit thereof, and a high potential windingthereon. of a plurality of impedance windings in series with said high potential winding comprising a plurality of turns of progressively increasing capacity. and external resistance elements connected across the turns of said protective windings.

6. A surgeproof electro-magnetic device gressively comprising` in combination with a magnetic circuit, and a winding thereon, of a plural-` ity of protective'turns of progressively in-v creasing capacity connected lin series with -said windings and also vvound upon said circuit. and external resistanceelements connected across the turns of the protective' Winding.

7. A surge proof electro-magnetic device comprising. in combination with a magnetic circuit. and a high tension Winding thereon, of an impedance winding consisting of a plurality of protective turns. arranged concentrically one ivithin the other and of pro-. increasing capacity and separated by tubular insulation and means to dissipate the surge induced energv generated in said protective turns. y

S. A surge proof electro-magnetic device comprising'. in combination With a magnetic circuit. and a hil of an impedance winding consisting of a plurality of protective turns` arranged concentrically one Within the other and of progressively increasing capacity and separated by tubular insulation and external resistance elements connected.across the turns of saidv protective Winding.

9. A surge proof electro-magnetic device comprising. in combination vwith a magnetic circuit. and a Winding thereon, of a plurality of protective turns of progressively increasing' capacity connected in series with said Winding and Wound also upon said circuit. and means to dissipate the energy generated in said protective turns, said protective turns being arranged concentrically one Within another and separated by tubular insulation.

10. A surge proof electro-magnetic device comprising, in combination with a magnetic circuit, and a Winding thereon, of a plurality `ofprotective turns ofvprogressively increasing capacity connected in series with the said Winding and' wound also upon said circuit, means to dissipate the energy generated inT said protective turns and external resistances connected in .shunt betvveen the protective turns. the conductors of said external resistances being concentrically related with one conductor `within another and suitably insulated.v v

1l. A surge proof electro-magnetic device gh tension winding thereon,

comprising, in combination with a magnetic circuit. and a windingthereon, ot' a plurality of protective turnsfof progressively increasing capacity connected in series with the said winding and wound also upon said circuit, means to dissipate the energy generated in said protective turns, said protective turns being arranged co-ncentrically one Within another and separated by tubular insulation. and external resistances connected parallel betvveen the protective turns, the conductors of said external resistances being concentrically related, with one conductor Within another and suitably insulated.

l2. A surge proof electro-magnetic device comprising. in combination with a magnetic circuit, and a Winding thereon. ofv a plurality of protective turns of progressively increasing capacity connected infseries with said Winding and wound also u'pon said circuit. and external resistances connected `in shuntbetu'een the protective turns, the conductors of said external resistances being concentricallv related. with one conductor within another and suitably insulated, and the resistance elements comprising conducting members that are severally attached to the tubular conductors of the resistance circuit. With resistance elements between them.

r 13. A surge proof electrical transformer comprising. in combination With the magnetic circuit thereof and a high potential Winding thereon, of a plurality of protective turns wound also on said circuit and in series with said winding, and means to dissipate the surge energy generated in said turns.

14. A surge proof electrical transformer comprising. in combination \v-ith the magnetic circuit thereof and a high potential winding thereon. of a plurality of protective turns Wound also on said circuit and in series With saidjvinding. and external resistances connected to the said turns to dissipate the surge energy generated in said turns.

ln testimony. that I claim the foregoing as my invention l atlix my signature in the presence of two Witnesses. this 1st day of October. A. D. 1913. i

CHESTER H. THORDARSO. lVitnesses lV. L. HALL.

G. E. Downs.

Images