US1110179A - Lightning-arrester. - Google Patents

Description

E. BENNETT.

LIGHTNING ARR-ESTER.

APPLIOATION FILED AUG. 26, 1908. RENEWED FEB. 6, 1914 1,1 10,179. Patented Sept. 8, 1914 3 SHEETSSHEET 1.

I B. BENNETT. MGHTNING ARRBSTER. APPLIUATIOI? FILED AUG. 26, 190B. RENEWED FER- 6, 1914.

1 1 lg l'yg Patented Sept. 8,1914

3 SHEETS*SHEET 2.

E. BENNETT.

LIGHTNING AERESTER.

APPLICATION FILED we. 26, 1908. RENEWED 1 313.6, 1914.

1,1 10,179. Patented Sept. 8, 1914.

3 SHEETS-SHEET 3.

l lowing is a specification.

, UNITED smrns PATENT curios.

EDWARD BENNETT, OF OLMSTED, U'ldlil.

mon'rmne-epsnsrnn.

Specification of hetters Intent.

resented Sept. 8, 1914.

, Application men August 2c, 1905, Serial Not 150,358 neutral-re February rem. semim. 81?,055.

To all whom it may concern: Y

Be it known that L EDWARD Bhnnn'rr, a citizen of the United States, residing at Olmsted, in the county of Utah State of Utah, have-invented or discovered certain new and useful Improvements in Lightning Arresters,' of which improvements the fol The invention herein described relates to certain improvements 1n lightning arresters used for the purpose of protectm powercircuits and apparatus from the a normal potentials resulting "either from lightning disturbances or from. the inherent .charslc teristics of the system under the disturbing influence of switching 'operatiohs, short oir-' cliits, grounds, and o pbrtitions or accidents or alike nature. p

.The invention hasfor its object the rapidand yet gradual suppression of th'e'dynamic current flow whichv always results across in nrrester when the arrester functions in discharging an abnormal potential. The method by which I accomplish this result. is to use in my arrester a spark gap which Will'be broken down at a potential a pre determined amount higher than the normal Operating potential, the passage of the dis charge at the abnormal potential across the arrester is accompanied by the dynamic current arc and 1 cause the motion of this are along the spark gap electrodes to auto matically and rapidly insert or include in the circuit predetermined and fixed resistances of a rapidly increasing value, thus reducing the volume of the current to a point Where the arc is quietly suppressed.

The invention is hereinafter more fully described and claimed.

In the accompanying drawings, forming a part of this specification, Figure (1) illustrates diagrammatically the essential feat tures of What 1 term my arrcstcr unit; Figs. (2), (2):and (2) illustrate the details of one form of arrester unit in which an air blast is used to cause the arc to travel along the electrodes more rapidly, and the inserted resistances consist of sections of a water column: Fig. (3) illustrates another form of the arrester unit in which a magoetic field is used to cause the arc to'inove more rapidly along the electrodes, and the I mounted, preihsrabl in a verticslflposition en insulators (2); mountediadjaceut to this conductor are e number of conductors (3), which are contiectedt'o pcints olon" a suit able res1stunce(d) one end of Whic l is con, inected to ground. The conductors (1) and are. 'preterably mounted inside it shaft 5 of wood or other'meteriahpreferably inon conductingr (10) represents a power station containing transformers (11), "and generating apparatus (12),;which it is delsired to protect," (:13)! represents the trans mission vires'leacing from the station.

In the ructice of my'invention, the conductor (1) is connected to one of the power wvires (l3) and the distances between the conductors (1) andKB) are so proportioned that the lowest gap (6) which is the shortest will break down at a certain predetermined lpotential. \Vhen this gap breaks down; the

dynamo current follows and the are so es :tablished rises along the electrodes due to lthe heating of the air: in rising, one end of the arc travels up the conductor (1) endthe other end jumps up from conductor (3) :toconductor (3) immediately above it and iso on, each time inserti determined amount of t 1e resistance (4) m ;the path of the current and thereby decrees" ting the current. In order to suppress the are more rap- ;idly, I prefer to supplement this natural !draft which causes the arc to jump up from conductor to conductor by a blast up the shaft produced by any suitable means such an aspirator at the bottom of the shaiit fed by a smalljet of compressed air or by Qa fan motor (7) *or by the action offmagnetic. field as illustrated in Fig.

Fig. 2 illustrates the details of an arrester Iunit as constructed for service on a 40,000 -volt,, three phase transmission system. The conductor (1), mouuted on insulators (2), is connected to one of the Wires of the transmission line. The conductors (3) which are formed of iron or copper Wire project into a Water column (4) which; constitutes the an additional pr e-y 3 of the path from (8) to conductor (3) passzthe lower gap (6) is adjusted so that its breaking down potential will be higher than that of the upper gap (8) and the cross section and length of the water column has been so proportioned that the resistance in the columnfrom the gap (6) to ground is low, (in this particular unit 280 ohms) and the resistance from gap (8) to ground is much higher (2500 ohms). With the gap (8) adjusted so that it will break down at a potential above the normal operating potential and the gap (6) set so that it will break down at a potential 7 0% above thenormal operating potential, it the potential of the line wire, due to any cause, rises to a point 50% above the normal operfating potential, the gap (8) will break down and a path to ground is provided through the water column.

If the accumulated charge or disturbance is relatively light so that the conductivity ground is sufficient to prevent any further rise of potential, the gap (6) will not break down and the dynamic current which can flow will be greatly limited by the relativel high resistance in the discharge path. -I however, the conductivity of the path provided by the break down of gap (8) is not sufficient to prevent a further rise of potential, the potential will continue to rise until it becomes high, enough to cause gap (6) to break down ,when'a further rise will be fprevented by thevery high conductivity 0 the path to ground so provided. In either case, the are so established isdriven up the-shaft so rapidly that it is difficult to follow it with the eve, the whole operation from the passage oif the discharge across the gap (6) to the time when the are has reached the topmost (from which-point the resistance of the water column is 11,000 ohms) consuming about one tenth of a second. Moreover the are, in traveling up the conductor (1) and in jumping up the conductor (3), does not draw out in length and become thirty or forty feet long as in the ordinary horn arrester under similar conditions but remains quite short (about six inches in length) and springs almost directly across from conductor (1) to the conductor (3) which is about opposite that end of the are which rests onconductor (1).

While I have given certain resistances and proportions, I do not limit myself to these proportions. They have been mentioned forv the purpose of illustrating the principle of my invention and it-must be clearly understood that these proportions areentirely unsuited except for a particular power system ahd set of conditions.

In Fig. 3; 1, 2, 3, 4, 6 and 14: designate the same elements as in the figures previously described. The resistance column (4) is composed of cement and graphite suitably proportioned to obtain the desired steps in the resistances between the projecting conductors (3) which may consist of expanded -metal which has been embedded in the column during its construction. In this case the conductors (3) may be dispensed with entirely and one terminal of the arc may be caused to travel directly up the face of the cement-graphite resistance column. I prefer to make the cross section of the column at the base much greater than at the top to provide a greater thermal capacity for the greater amount of energy which is expended in the base and thus preclude any objectionable rise in the temperature of the column when the arrestcr discharges the line a number of times in rapid succession. To cause the arc to rise rapidly, I combine with this arrester the choke coil which is generally used in the 8 line wires at power stations to reflect incoming surges of potential, and so locate the choke coil (9) with reference to the electrodes (1) and (3) that the magnetic field from the choke coil causes the arc to travel rapidly upward.

While I have mentioned and specifically described certain forms of resistances and certain supplementary means of giving to the are a rapid motion, I do not limit myself to the use of these forms or means; the use of other forms of resistance such as metallic resistances and of other means of imparting to the are a rapid motion comes within the scope of my invention.

The action of my arrester is entirely different from that of the well known horn gap. In the horn gap arrester it is true that the current is diminished somewhat when the arc draws out to a great length but the resistance even of a ten or twenty foot air path is slight and is very uncertaip. Indeed after the arc has drawn out to a great length the current is still so high that the instantaneous extinction which sometimes occurs under these conditions gives rise to disturbances of greater severity than that which initially caused the horn gap to break down. On the other hand, in my arrester I do not attempt to draw out the are but I cause the motion of the arc and more particularly of the two terminals of the arc to insert or include in the circuit predetermined and fixed resistances and I proportion these resistances so that the current is cut down by gradual steps to a point where the extinction of the arc produces no more efiect on the system than the throwing ofi of a motor load.

I claim as my invention:

'1. A lightning arrester including in combination, spaced electrodes forming a spark gap, one of said electrodes including conductors located at a plurality of spaced intervals along said electrodes and suitable regap, one of said electrodes includin sistanee connecting said conductors, whereby the travel ofthe arc along the electrodes inzerts in theucg gcuit' an increasin resistance.

A g figgfjlarrester 'inclu ing in combination, spa electrodes forming a spark projeetin conductors located at a plum ity of 5 seed intervals. throughout the entire length .of the ele'ctrodemand suitable resistance connecting said conductors whereby the travel of the are along the electrodes inmrts in the circuit an increasin resistance.

3. A lightnin arrester inclu in combination, space electrodes one of which is connected with a transmission line, and the other of which is connected with the ground,

. said electrode connected with the ground ining being 0 whereby;

member.

eluding projecting conductors located at a plurality of spaced throughout the length of the; electrode, a casing surrounding said electrode, said casn at the top and bottom, a fan located at t e bottom of the casing for causing a circulation ofair through the casing, the are is caused to travel ra i y along t e electrodes. f

4. A lightnin arrester comprising relativel long an short diverging terminal mom rs, a resistance conn of overlapping conductors that are connected at intervals to the resistance and constitute an extension of the shorter terminal 5. A lightning arr-ester comprising relaintervals extending plurality of to the shorter terminal member, and a plurality tivel long and short diverging terminal mem rs, a resistance connected to the shorter termmal member a plurality of over-lapping conductors t at are connected 'ance support for said over-lapping con ductcrs.

7. A lightning arrester comprising terminal "members one of which consists of a single high-resistance support for said conductors. I

8. A lightning arrester comprising a pair 10f terminal members one of which consists of a refractory high-resistance member and a series of over-lapping conducting members su ported thereby.

n testimony whereof I have hereunto subscribed my name this 29th day of May, 1908.

EDWARD BENNETT.

Witnesses:

H. G. Nien'rmoans, E. A. Tnonmmm.

over-lapping conductors and a

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