US2668201A - Circuit breaker isolating device - Google Patents

Description

Feb. 2, 1954 W. E. WELSH CIRCUIT BREAKER ISOLATING DEVICE Filed Aug. 9, 1950 2 Sheets-Sheet 1 FIGI INI/ENT@ its; MM n r @lf-C E CJNEY f r i :e

` Filed Aug. 9, 1950 Feb. 2, 1954 w, E, WELSH 2,668,201

CIRCUIT BREAKER ISOLATING DEVICE 2 sheets-smet 2 'FIGZ WILLIAM E.WELSH ATTORNEY Patented Feb. 2, 1954 CIRCUIT BREAKER ISOLATING DEVICE William E. Welsh, Allentown, Pa., assignor to McGraw Electric Company, Milwaukee, Wis., a

corporation of Delaware Application August 9, 1950, Serial No. 178,467

Claims. 1

This invention relates to electrical circuit breaker structures and particularly to a device for temporarily isolating circuit breakers without interruption of line current.

It is an object of this invention to provide a convenient device for ley-passing circuit breaker terminal connections without interruption of line current.

Another object of this invention is to provide a device for by-passing circuit breakers in order to facilitate maintenance of these circuit breakers without necessitating their removal from mounting brackets.

A further object of this invention is to provide a labor saving device for facilitating the disconnection of circuit breaker terminals from line` without interruption of line current, necessitating the easy removal of only one clamping device on either side of the breaker.

Still another object of this invention is to provide a device for by-passing electrical circuit breakers from line without interruption of line current that will permit maintenance of the breaker in the safest possible manner without the necessity for using cumbersome insulating barriers and other protective devices.

A still further object of this invention is to provide a by-pass device for electrical circuit breakers that may be easily and inexpensively 'manufactured and installed.

These and other objects will appear as the description proceeds, and the scope of the invention will be set forth in the appended claims.

In the above as well as in the following description, the term circuit breaker is intended to describe any electrical devices that are equipped with at least two terminals adapted to be connected with the line and means electrically connecting these terminals adapted to interrupt electrical current normally flowing between the terminals; viz., housed and unhoused switches, oil circuit breakers, dry circuit breakers, `fuse cutouts, and the like.

In the drawings:

Fig. 1 is a side elevational View of the novel device as employed with a conventional airbreak switch joining each of the terminals with the line and diagrammatically indicating a temporary parallel circuit connection with the line.

Fig. 2 is a fragmentary top plan view of the device as installed on one side of a conventional airbreak switch.

Fig. 3 is a fragmentary side elevational view of a modification of the novel device as employed Y on a conventional airbreak switch.v

Referring in detail to Fig. 1, reference character I refers generally to a disconnecting switch substantially the same as shown in U. S. Letters Patent No. 2,431,147, granted to Alwin G. Steinvmayer on November 18, 1947, and assigned to the same assignee as the present invention. As mentioned above, the device will work equally well with any circuit breakers having at least two terminals and an interrupting means such as the switch blade, fuses, etc. The following description includes the Steinmayer switch as an eX- planatory aid only, and is not intended to limit the novel switch by-passing device in any1 manner.

The switch I includes three stacks of insulators 2, 3. and 4, supported by a base 5 which is normally grounded or neutralized. The insulator 4 carries a stationary contact 6 and a terminal 1 which is in electrical connection with said contact. Also in contact with the terminal 'I is a pair of flaring arcing horns 8. The insulator stack 3 rigidly carries a terminal 9, which terminal is also supported from the insulator stack 2. The insulator stack 2 and upper member IQ are provided with an upstanding portion I! which is revoluble within the terminal 9, the terminal 9 thereby forming a brace between the insulator stacks 2 and 3. The switch arms I3 are pivoted on pivot support I4 supporting pivot pin I5, which supports are rigid with the terminal 9 and supported by the insulator stacks 3. The interfacing of the pivot supports I 4 act as contact surfaces with the switch arms I3, which switch arms electrically connect said terminals 9 with contact 6 supported by insulator stack 4.

An idler link I6 is pivotally mounted on pivot supports I4 and is pivoted to a connecting link I'I, the link I'I being operatively connected tov the switch arms I3 for raising and lowering the idler link I6 operate to provide a universal joint.'

The stack 2 is revolubly mounted and is rotated by means of a shaft 25 or in any other suitable manner. It is apparent, therefore, that when the insulator stack 2 is rotated, the switch arms I3 will be raised or lowered as desired; thusA disconnecting or connecting the electrical circuit between terminals 9 and 1, respectively.

It is again to be emphasized that the novel TheV device is not to be limited to the switch shown and described. The Steinniayer switch is shown for illustrative convenience. It will be apparent that the device may be employed on the terminals of any circuit breaker connected with the power line.

Any convenient manner of dead-end clamping may be used with the novel by-pass device. iowever, a preferred manner is disclosed in Figs. l, 2 and 3, wherein a dead-end clamp is suspended from the base and insulated therefrom by a string of suspension insulators 3i. A string of two @levis-tongue type insulators is shown, but any number may Abe vused depending on the desired flashover insulation requirements. Also, the insulators Si may be of any of well-known types used for suspension purposes.

The insulator on the opposite end of the string from the dead-end clamp 3) is fastened to an extension link 32, which is in turn electrically connected to the grounded or yneutralized base 5.. The extension link may -be omitted Aif desired, ibut is preferably provided for use with standard circuit breakerl structures without requiring modification thereof. The link 3E is conveniently fastened to the base 5 by a vrivet and clevis-bolt kassembly 33. Since .a ground or neutralconnection is all that is desired, the ele-ctrical contact between the link and base will be sufficient for the purpose as shown. Rather than using the rivet and clevis-bolt assembly 33, the .well-known practice of using a hook may be provided.

The extension link 32 is provided with a protruding bolt 'or stud 34 `secured thereto with lock-nuts 35. 'This bolt may be 4positioned. as desired one of the various openings S5 provided for this purpose.

The novel by-pass device is designed to be used on both sides of the switch i Without modification-of any of vthe parts. 'The device includes a .conductor 'which is generally referred to at lid. and which is electrically connected to either of the terminals .9 or I .by a terminal lug di. The lug M is clamped to a rigid extension arrn di. Fastened to the extension arm, vat the opposite end, is a length of flexible conductor cable lli. The opposite or free lend ofthe cable 43 is fastened fto a terminal link 411, which is in turn securely fastened to a removable hot-line clamp 45. The hot-line clamp shown is one of many well-known varieties. Circumjacent to the conductor cable 43 is a helical spring i5 which is preferably cci-extensive with the cable Op posite ends of the spring d5 are secured to the arm 42 and ternnnal link dal, respectively. This may Abe conveniently done by forming an e 'elet at :both ends of the spring and holding it in place with a bolt and :nut combination Kil.

The :hot-line clamp dii is normally held in electrical vconnection with the dead-end clamp 30. This is conveniently provided for by casting va double-headed rivet or rod Sii to the deadend clamp. The rod or rivet be preferably eX- tends from both sides :ci Vthe dead-end clamp for a purpose hereinafter described. It will be apparent that a stud threaded on both ends may be substituted for the rivet. lThis stud (not shown) would be provided with washers and stop nuts on either end as a substitute for the rivet heads. rThis hot-line clamp @iii is secured to the rivet Eil by tightening the fastening eyelet 5I with a hot stick (not shown).

As was stated above, substantially identical by-pass devices are used for both sides Qf. the

switch i. Suspended from, and in electrical engagement with, the deadend clamps 3Q are incoming and outgoing lines and t6, respectively.

The novel by-pass device operates as follows: When maintenance operations are required on the switch I, the lineman installs a by-pass jumper 6G from dead-end clamp 3o on the incoming line 55 to the dead-end clamp 2i) on outgoing line 56, as is diagrammatically shown in Fig. i.. Releasable hot-line clamps (not shown) are fastened to both ends of the jumper 6d. The jumper may then be conveniently attached to both dead-end clamps 3@ by engaging the jumper hot-line clamps (not shown) with rivets 5% on the portion opposite the portion supporting the hotdine clamps d5. The by-pass jumper Si! is generally protected with a length of fiber duct El to protect the insulation of the jumper cable from gafng by linemans climbers, since these jumpers run underneath the circuit breaker structure.

With the jumper 6d now in place, the switch is opened and hot-line clamps l5 on each side of the switch are removed by means of a hot-line stick (not shown) and fastened to the protruding bolt 3d on the link extension 32 as shown by dotted lines in Fig. l. The machine bolt .34 may be 'fastened to the link in any of the openings '36, which are provided as a convenient means for adjusting to desired lengths of conductor iil.

It is not necessary to make any ground connections for grounding or neutralizing the switch assembly, since the metal base 5 is ordinarily grounded or neutralized `with the link extension 32 electrically connected thereto. The lupper switch assembly will be automatically vgrounded or neutralized when the hot-line clamps '5 are clamped to each of lthe .respective protruding bolts 3b on the connecting links 32.

It will be apparent that an expeditious and safe means has been provided for isolating circuit breakers during maintenance operations. Heretofore, it took linemen nearly an entire day to isolate switches preparatory -to` making maintenance operations upon them. Also, it was necessary for linemen to install large rectangular insulated barriers (not shown) at each end of a gang of switches. These barriers were lnstalled so that the linemen could work on top of the switch structure in complete safety without rany possible contact with the incoming or outgoing lines or any parts of the structure which were energized. The insulating barriers are no longer necessary with the novel 4by-pass device, vinasmuch as all live lines and parts on live lines are 'now at a safe working distance from the isolated circuit breakers. Three to four feet away from the base of the circuit breakers is considered to be a safe working distance for 12 to 22 kv. lines. Linernen using the novel device are now able to disconnect, maintain and reconnect at least four sets of three phase airbreak switches per day, or twice the number maintained by the procedure used heretofore.

Another embodiment of the novel device is disclosed in Fig. 3. This modification includes pantagraph links ifi and 'H substituted for the helical spring d5 shown in the preferred embodiment. The links offer a flexible support to the cable d3. Two or more links may be used if so desired. A terminal lug 'i2 is secured lto the terminal e. The end links 'H are pivotally supported by this lug at pivot bolt '13. The links are preferably of parallel steel strips held to- '-g'ether with bolts and spacers 16, and hingedly jointed at pivot bolt 14. The cable 43 is threaded over and under the spacers and pivotally secured at either end to bolts 13 and 15, respectively. The bolt 15 is also pivotally secured to 4hot line clamp 45.

This modification offers a more rigid support to the cable than the spring would, but it will beapparent that it is of a heavier structure than the preferred embodiment disclosed in Figs. 1 and 2. This modication readily lends itself to substation circuit breaker installations, and `the like. Substation circuit breaker structures are of heavier ratings and are mounted on steel supports rather thanon poles. The embodiment shown in Figs. 1 and 2 is preferred for circuit breakers mounted on'pole brackets where one man may do all of the work with a ten foot hotline stick. Y

The modified pantagraph' link device is operated in substantially the same manner as the preferred embodiment using the helical spring. That is, a by-pass jumper, substantially as di agrammed in Fig. l, is installed between both dead-end clamps 30. The hot-line clamps 45 are then unfastened from the dead-end clamps 39 and moved over to the protruding bolt 34 on the link extension 32, thus grounding or neutralizing the switch.

It will be apparent that a safe and inexpensive means for by-passing a circuit breaker has been described. The novel by-pass device Vmay be installed on existing circuit breakers without necessitating modification thereof.

Although only one switch has been disclosed in the drawings, the device readily lends itself to gang-operated switches ordinarily used in three phase connections, and may also be used in a variety of circuit breaker types. These types may include oil operated reclosers, various types of disconnect switches, fuse cutouts, or any type of circuit breakers that have at least two terminals and a means for electrically connecting or disconnecting the terminals.

I claim:

l. In an electrical circuit breaker structure including a stationary terminal, a grounded support including a dead-end anchoring means insulated therefrom and supporting said terminal in insulated relationship thereto, and a ground or neutral connection on said support; a flexible conductor including a releasable clamping means at one end on said dead-end and normally providing exclusively an electrical circuit between said stationary terminal and said dead-end anchoring means, said releasable clamping means releasably engaged with said dead-end anchoring means to temporarily disconnect the electrical circuit and releasably engageable with said ground or neutral connection.

2. In an electrical circuit breaker structure including a stationary terminal, a grounded support including a dead-end anchoring means and supporting said terminal in insulated relationship thereto, a ground or neutral connection on said support, a flexible conductor electrically connected with said stationary terminal and including a releasable clamping means normally electrically connected with said dead-end anchoring means, said clamping means releasably engaged with said dead-end anchoring means to temporarily disconnect from said deadend anchoring means and releasably engageable with said ground or neutral connection.

3. In an electrical circuit breaker structure including a stationary terminal, a grounded support including a dead-end anchoring means insulated therefrom and supporting said terminal in insulated relationship thereto, and a ground or neutral connection on said support; a conductor normally providing exclusively an electrical circuit between said stationary terminal and said dead-end anchoring means, said conductor comprising a flexible section, a circumjacent resilient means and a releasable clamping means releasably engaged with said deadend to temporarily disconnect the electrical circuit and releasably engageable with said ground or neutral connection.

4. In an electrical circuit breaker structure including a stationary terminal, a grounded support including a dead-end anchoring means insulated therefrom and supporting said terminal in insulated relationship thereto, and a ground or neutral connection on said support; a conductor electrically connectedwith said stationary terminal and comprising a flexible section, a circumjacent resilient means and a releasable clamping means at the opposite end of said conductcr and normally engaged with said dead-end anchoring means, said clamping means releasably engaged with said dead-end anchoring means to temporarily disconnect the electrical circuit and releasably engageable with said ground or neutral connection.

5. In an electrical circuit breaker structure including a stationary terminal, a grounded support including a dead-end anchoring means insulated therefrom and electrically connected to the line, said support supporting said terminal in insulated relationship thereto, and a ground or neutral connection; a conductor electrically connected on said support with said stationary terminal and comprising a flexible section, a circumjacent resilient means and a releasable clamping means normally electrically connected to the line, said clamping means releasably engaged with said dead-end anchoring means to f temporarily disconnect the electrical circuit and releasably engageable with said ground or neutral connection.

6. In an electrical circuit breaker structure including two stationary terminals, a vmeans for electrically connecting and disconnecting said terminals, and a grounded support including a ground or neutral connection; a dead-end anchoring means electrically connected with the line and positioned in the proximity of each terminal and insulated therefrom, a by-pass conductor adapted to temporarily provide a by-pass circuit between each of said dead-end anchoring means, and fiexible conductors each including a releasable clamping means at one end and normally providing exclusively an electrical circuit between eachV of said stationary terminals and its corresponding dead-end anchor means, said releasable clamping means releasably engaged with said dead-end anchor means to temporarily disconnect the electrical circuit and releasably engageable with said ground or neutral connection.

'7. In an electrical circuit breaker structure including two stationary terminals, a means for electrically connecting and disconnecting said terminals, and a grounded support including a ground or neutral connection; a dead-end anchoring means electrically connected with the line and positioned in the proximity of each terminal and insulated therefrom, a by-pass conductor adapted to temporarily provide a by-pass circuit between each of said dead-end anchoring means, and conductors normally providing an electrical circuit exclusively between each of said terminals and its corresponding dead-end anchor means, said conductors comprising a exible section, a circumjacent resilient means and a releasable clamping means releasably engaged with said dead-end anchoring means to disconnect the` electrical circuit and releasably engageable withsaid ground or neutral connection.

8. In an electrical circuit breaker structure including a stationary terminal, a grounded support including a dead-end anchoring means insulated therefrom and supporting said terminal in insulated relationship thereto, and a ground or neutral connection on said support; a flexible conductor normally providing an electrical circuit between said stationary terminal and said dead-end anchoring means and comprising a current carrying wire, rigid sections extending from said terminal and supporting said wire, said sections each pivotally linked with one another and including a reieasable clamping means at the free end, said clamping means electrically connected with said wire and normally electrically connected with the line, said clamping means releasably engaged with said dead-end anchoring means to temporarily disconnect from the line and releasably engageable with said ground nr neutral connection.

9. A device for isolating a pole top switch or the like from an electric line, comprising a flexible disconnect loop permanently attached to a stationary terminal of said switch, releasable connecting means aixed to the'other end of said loop for engaging the line to said switch, an adjacent grounding connection arranged to receive said releasable connecting means, said adjacent grounding connection being part of the dead-end anchoring means of said line and insulated therefrom.

10. The method of conjointly maintaining service in an electric high tension power line and electrically isolating a circuit breaker having two switching elements movable relative to each other to open and close the line circuit and having line terminals each electrically connected respectively to one of said switching elements and through-a conducting link to said line, said method comprising in sequence, temporarily electrically luy-passing said breaker by means of a jumper shunting said breaker, disconnecting said breaker from said power line at said conducting links, and establishing a connection between said terminals and ground or neutral through said conducting links.

WILLIAM E. WELSH.

References Cited in the file of this patent UN'I'IED STATES PATENTS Number Name Date 1,415,708 Renke May 9, 1922 2,233,826 Allison Mar. 4, 1941 2,363,360 Rawlins Nov. 21, 1944 2,434,315 Froland Jan. 13, 1948 2,438,746 Garrison Mar.. 30, 1948 2,452,285 Rees Feb. 22, 1949

Images