US3188430A - High-voltage fuse construction with transient grounding feature - Google Patents

Description

June 8, 1965 c. H. WALSH ETAL 3,188,430

HIGH-VOLTAGE FUSE CONSTRUCTION WITH TRANSIENT GROUNDING FEATURE Filed Jan. 2, 1962 VVII/IIIIIIIII INVENTORS CARROLL l-LWALSH AGENT United States Patent @fifice 3,188,430 i a tented June 8, 1965 3,188,430 HIGHeVOLTAGE. FUSE. CONSTRUCTION 1TH TRANSIENT GRUUNDIWG FEATURE Carroll H. Walsh and Raymond W.Toler, both Arkansas Power & Light Co Pine Bluff, Ark. Filed Jan 2, 1%2, Ser. No. 163,582 3 Claims. c1. Milk-414) This invention relates generally to fuses for electric circuits, and more particularly to a fuse suitable for use in connection with high-voltage transmission circuits, such as those operating at alternating current voltages of 115 kv. or higher. 2

The invention herein embodys certain elements in common with the construction shown in Patent No. 2,945,108, dated July 12, 1960, and issued to one of the inventors herein, being distinguished therefrom by a new concept enabling operation in a simpler, less expensive and more efiectivema'nner. However, the construction herein is intended and suitable for operation in connection with the commonly-used neutral-grounded electric transmission system illustrated in the above-mentioned patent.

Among the objects of the present invention are (l) the provision of a fuse which will rupture upon passage of a predetermined current therethrough and in response to such rupture will subject the connected circuit to only a short-time transient fault; (2) the provision of a fuse construction requiring after operation the replacement of only one small and inexpensive fuse link, all of the other components being suitable for repetitive operation; (3) a construction embodying means for guiding a re-usable fuse terminal member along a predetermined path to a final blown latched position and (4) a construction capable of elongating the arc attending the fusing of the fuse link to a transfer point for causing the transient fault on the connected circuit and consequent extinguishrnent of the arc. Otherobjects will become obvious or pointed out hereinafter. l V V In the drawing:

FIG. 1 is an isometric view of the invention in the normal operating position.

FIG. 2 is a fragmentary view of a fuse link suitable for use in the device, shown partly in section.

Referring first to FIG. 1 of the drawing, a metal base 10, which in common practice in high voltage installations is maintained at ground potential, as by means of the connection to ground indicated symbolically at 28, has mounted thereon near its ends the insulator stacks 11, the height of the stacks being related to the voltage-to-ground rating of the device. One of the insulator stacks 11 has rigidly mounted at its top a source terminal pad 14 and an integral laterally extending conducting member 16;

, similarly, the other insulator stack 11 supports the load terminal pad 13 and the laterally extending conducting member 15. The conducting members 15 and 1 6 preferably extend outwardly in parallel relationship in the same directon and are of substantially equal length.

A first relatively fixed fuse terminal member 17, also of conducting material, is rigidly secured to the outer end of the conducting member 15, extending upwardly therefrom and longitudinally with respect to the base 10, and is provided at its outer end with the fuse terminal fastener 19. A second swingably movable fuse terminal member 18 is pivotally mounted by means of the hinge 31 at the outer end of the other conducting member 1a, and normally extends toward and in spaced relationship with respect to the first terminal member 17, being provided at its outer end with the fuse terminal fastener 24) and the arcing tip 37.

retaining clip of latch 33, the latter extending downwardly At the hinged end of the fuse terminal member 18 a I clamp 34 rigidly fastens the resilient motion limiting and from the outer end of the conducting member 16 and in the path of movement of the swingably movable fuse terminal member 18. A spring 32, fastened at its respective ends to the retaining clip 33 and the movable fuse terminal member 18, continuously urges the latter toward swingable movement, thismovement being normally restrained by the fuse link 23, bridging the space between and mechanically joining the adjacent ends of the fuse terminal members 17 and 18.

An inexpensive fuse link having requisite mechanical strength and effective corona shielding is satisfactory for use in the device. FIG. 2 illustrates one structure which has proven satisfactory,being formed from aluminum stranded cable indicated by the end portions 25 and 26, with strands cut away to provide the single strand fusible element 27. The insulating tube 24 mechanically joins the ends portions, being pressed thereon, and any conducting material having suitable weathering qualities will provide effective corona shielding.

Near the midpoint of the base 10 is mounted the insulator 12, which extends upwardly therefrom fora relatively short distance in comparisonu to the height of the insulator stacks 11, and'supports, at its upper end by means of the clamp 22, the transversely extending conducting member 21 in spaced insulated relationship with respect to the fuse terminal'members 17 and 18. 'The conducting member 21 is positioned very close to but not neces'sarily'in the path of movement of theouter end of the swingable fuse terminal member 18, and is grounded as indicate-d bythe symbolic ground 30 through the primary winding of the current transformer 29.

When connected for normal operation, a source conductor extending from a normally grounded source is connected to the source terminal pad 14, and the current path through the'devic e'is sequentially through the conducting member 16, the movable fuse terminal member 18, the fuse 1ink23, the fixed fuse terminal member 17 and the conducting'member' 15 to the load terminal pad 13.

Upon passage'of a currentsufiicient to fuse the fusible element 27,the heat from the consequent arc causes fracture of the fuse link housing, the fuse link being of inexpensive, non-arc-xtinguishing construction, and the arc continues to play between the spaced fuse terminal members 17 and 18. Concurrently the movable fuse terminal, under the bias of the spring 32, swings downwardly and thus elongates the arc until the arcing tip 37 reaches a point in its path of movement closely adjacent to the grounded conductor 21, illustrated by the broken line designated by the numeral 35. At this point the arc is intercepted by the conductor 21, being transferred thereto from the fuse terminal member 17. A line-to-ground fault is thus impressed upon the connected source circuit, causing protective equipment to open the circuit to extinguish the are, following which the circuit may be reclosed automatically, all in accordance with comm-on practice. During this interval, the movable fuse terminal member continues its swingable movement to the position indicated by the broken line numbered 36, at which point the movement is limited and the fuse terminal member latched by engagement with the resilient jaws of the clip 33.

It will be apparent that the passage of line-to-ground current through the current transformer 29 may be utilized to cause operation of various associated equipment, such as high or low tension circuit breakers and alarm circuits, as desired, or as specifically illustrated in theabove-mentioned Walsh patent in connection with polyphase circuits.

The fuse terminal member 13 is of course energized at line potential following reclosure of the connected circuit,

and the latch clip 33 effectively holds this member in insulated spaced relationship with both the grounded conductor 21 and the grounded base 10, thereby precluding circuit interruptions which might otherwise result from a freely swinging fuse terminal member. The only replacement necessary following operation of the device is the small and inexpensive fuse link, and this low re-fusing cost is equally available, for example, to all transmission line voltages from 115 kv. to 460 kv.

The foregoing description is intended to be illustrative, and reference is made to the appended claims to ascertain the scope of the invention.

We claim:

1. A high-voltage fuse construction comprising a conducting base,

insulating means mounted on said base,

spaced insulated load and source conducting members carried by said insulating means,

a fixed fuse terminal member mounted on the load conducting member,

' a swingably movable fuse terminal member hinged at one end on said source terminal member and extending toward said fixed fuse terminal member in spaced relationship therewith,

means biasing said swingably movable fuse terminal member for swingable movement along a predetermined path away from said fixed fuse terminal member,

a fuse link bridging the space between said fuse terminal members and normally restraining movement of said movable fuse terminal member,

said fuse link when unfused normally electrically connecting the fuse terminal members and upon fusing releasing the movable fuse terminal member for movement in response to the are initiated by the fusing of said fuse link and thereby elongating the said fuse link when unfused normally electrically conmeeting the fuse terminal members and upon fusing releasing the movable fuse terminal member for movement in response to the are initiated by the fusing of said fuse link, said movement concurrently elongating the are along the predetermined path of movement of the unhinged end of said movable fuse terminal member,

additional insulating means mounted on said base,

and a grounded conducting member carried by said additional insulating'means,

said grounded conducting member extending to a point adjacent to and space from the path of movement of the unhinged end of said'swingably movable fuse terminal member.

3. The construction recited in claim 2, including latch means mounted at the hinged end of said swingably movable fuse terminal member and positioned in the path of arc along the path of'movement of the unhinged end 7 i adjacent to and spaced from the path of movement 7 a of the unhinged end of said swingably movable fuse terminal member.

2. A high-voltage fuse construction comprising a conducting base,

insulating means mounted on said base,

movement and limiting the movement thereof,

said latch means holding said movable member in the limited position following its movement thereto.

References tCited by the Examiner UNITED STATES PATENTS 438,394 10/90 White 200 X 607,251 7/98 Lewis. 7

2,272,370 2/42 FOX 200117 2,498,575 2/50 Pittman 200l13.3

7 2,945,108 2/60 Walsh 200-114 BERNARD A. GILHEANY, Primary Examiner;

Claims (1)

1. A HIGH-VOLTAGE FUSE CONSTRUCTION COMPRISING A CONDUCTING BASE, INSULATING MEANS MOUNTED ON SAID BASE, SPACED INSULATED LOAD AND SOURCE CONDUCTING MEMBERS CARRIED BY SAID INSULATING MEANS, A FIXED FUSE TERMINAL MEMBER MOUNTED ON THE LOAD CONDUCTING MEMBER, A SWINGABLY MOVABLE FUSE TERMINAL MEMBER HINGED AT ONE END ON SAID SOURCE TERMINAL MEMBER AND EXTENDING TOWARD SAID FIXED FUSE TERMINAL MEMBER IN SPACED RELATIONSHIP THEREWITH, MEANS BIASING SAID SWINGABLY MOVABLE FUSE TERMINAL MEMBER FOR SWINGABLE MOVEMENT ALONG A PREDETERMINED PATH AWAY FROM SAID FIXED FUSE TERMINAL MEMBER, A FUSE LINK BRIDGING THE SPACE BETWEEN SAID FUSE TERMINAL MEMBERS AND NORMALLY RESTRAINING MOVEMENT OF SAID MOVABLE FUSE TERMINAL MEMBER, SAID FUSE LINK WHEN UNFUSED NORMALLY ELECTRICALLY CONNECTING THE FUSE TERMINAL MEMBERS AND UPON FUSING RELEASING THE MOVABLE FUSE TERMINAL MEMBER FOR MOVEMENT IN RESPONSE TO THE ARC INITIATED BY THE FUSING OF SAID FUSE LINK AND THEREBY ELONGATING THE ARC ALONG THE PATH OF MOVEMENT OF THE UNHINGED END OF SAID MOVABLE FUSE TERMINAL MEMBER, ADDITIONAL INSULATING MEANS MOUNTED ON SAID BASE, AND A GROUNDED CONDUCTING MEMBER CARRIED BY SAID ADDITIONAL INSULATING MEANS, SAID GROUNDED CONDUCTING MEMBER EXTENDING TO A POINT ADJACENT TO AND SPACED FROM THE PATH OF MOVEMENT OF THE UNHINGED END OF SAID SWINGABLY MOVABLE FUSE TERMINAL MEMBER.

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