US2605324A - Line-sectionalized equipment - Google Patents

Description

July 29, 1952 H. MADDEN LINE-SECTIONALIZED EQUIPMENT Filed July 26, 1949 Fig.l.

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WITNESSES: WW

ATTORNEY Patented July 29, 1952 UNITED STATES PATENTOFFICE LINE-SECTIONALIZED EQUIPMENT Henry I. Madden, Marietta, Ga., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 26, 1949, Serial No. 106,853

8 Claims. 1

My invention relates to improvements in linesectionalizing equipment for electrical distribution-systems which may be subject to high-impedance fault-conditions. More particularly, my invention relates to the radial-type rural powerlines of from 2.4 to 15 kilovolts.

Rural power-lines are usually operated under conditions requiring every possible economy in the line-equipment. Such lines are commonly protected by reclosers, which are oil circuitbreakers of the reolosing type, located toward the power-input end of the line, and these reclosers are operated by means of a serially connected coil which responds to predetermined overcurrentconditions in the line, usually having a trip-setting of twice the normal current rating of the recloser. Such rural lines are commonly of considerable length, considering the high impedance of the line-conductor which is frequently used. There comes a point which is far enough away from the recloser so that even a dead short-circuit on the line, or a short-circuit with expectable arc-resistance, will not draw double the current rating of the recloser. This marks the maximum effective reach of the recloser, or the maximum length of line which can be protected against transient faults by said reclosers.

Heretofore, relatively inexpensive sectionalizers have been used, at one or more intermediate points within the protected zone or reach of the recloser, for breaking the system into smaller sections, so that a line-section which does not clear itself of a fault after a relatively small number of opening-operations of the recloser will be disconnected by this sectionalizer, so that the rest of the system can remain in operation without a lockout-operation of the recloser after a predetermined number of reclosing-operations, for which it is set.

An object of my present invention is to provide a system of the type just described, in which all of the sectionalizers do not need to be located at an intermediate point, back from the end of the protected zone or reach of the recloser, My invention uses a sectionalizer which extends the protection of the recloser, to still more remote lengths of the distribution-line, in which both the load-currents and the fault-currents are quite small, and this extended length of the distribution-line can be still further extended, by another one of my special sectionalizers, so that much longer lengths of distribution-line can be protected, by a single recloser, than has heretofore been possible. The advantage of this is obvious, when it is remembered that the recloser is an oil-type circuit-breaker, whereas each sec-,

tionalizer is, or theoretically could be, an airswitch or disconnect-switch type of device, which is not called upon to open heavy currents.

A further object of my invention is to provide a novel type of sectionalizer which will minimize unnecessary burning of the lineconductor due to arcing-faults beyond the sectionalizer, because my sectionalizer bypasses the fault-current,

It is a more specific object of my invention to provide a sectionalizer which has a normally open, shunt-connected fault-imposing contact which is connected across the line, this fault-imposing contact being closed in response to an overcurrent-magnitude in the sectionalizer-coil which is connected in series with the line. This faultimposing contact automatically reopens itself in response to a predetermined drop in the current in the sectionalizer-coil. Thus, when a fault occurs beyond the sectionalizer, the fault-current closes the fault-imposing shunt-connected c0ntact across the line, thus putting an intentional fault on the system at the point of the sectional izer, and this intentional fault draws enough fault-current to cause an opening-operation of the recloser which is farther back in the line, back toward the power-supply means. The openingoperation of the recloser deenergizes the-sectionalizer-coil, and thus reopens the fault-imposing contact within a time which is quicker than the reclosing-time of a recloser. If the fault has cleared itself, the sectionalizer will not again respond after the reclosing operation of the recloser. If fault hangs on, the sectionalizer counts a predetermined number of reopening-movements of its fault-imposing contact, and then opens, and locks open, a series sectionalizer-contact which is connected in series with the line, thus performing the usual function of a sectionalizer such as has been known prior to my present invention.

With the foregoing and other objects in view, my invention consists in the systems, combinations, circuits, structures, parts, and methods'of design and operating, hereinafter described and claimed, and illustrated in the accompanying drawing, wherein Fig. 1 is a single-line diagrammatic view of a simple circuit illustrating my invention, and Fig. 2 is a diagrammatic structural representation of the sectionalizer.

In Fig. 1, I show my invention applied to a rural power-line 5 of the type described, which is fed from a power-source 5' through a diagrammatically indicated recloser having a normally closed breaker-contact 6, and an operating-coil 6', both connected inseries with .the'line 5. I The armature l of the recloser is mechanically connected, at 3, to a block 9 which represents any suitable counter and lockout mechanism, which counts the number of rapidly repeated contactopening-and-reclosing operations, and after a predetermined number of such operations locks out the recloser by thereafter holding the contact 8 in its open position, until the recloser is manually reset. t will be understood that the recloser-contact 6 is normally closed, but opens in response to a predetermined overcurrent-condition in the coil 6. The opening of the contact 6 deenergizes the coil 6, and every time the coil 6 is deenergized, the contact 6 automatically recloses itself (if the fault is still on), until the counter-mechanism 9 becomes effectively operative, and holds the contact 6 in its open position. There are a number of such reclosers on the market, and their specific construction constitutes no part of my present invention, except that I prefer to use at least one such recloser, as shown in Fig. l. t is believed, therefore, that the diagrammatic recloser-illustration in Fig. 1 is sufficiently clear without further explanation or illustration.

The rural power-line may extend out, either in a single branch, or in a plurality of branches I l and [2, each branch usually supplying a number of customers located at various points distributed along the line. At a point R at some distance out, in the branch-line l l, a sectionalizer I3 may be located, and in some instances, still another sectionalizer l4 may be located at a still more remote point S in said branch-line I l. The branch-line I2 is illustrated as containing a single sectionalizer l 5 at some intermediate point T within the length of said branch-line l2.

Each of the sectionalizers l3, l4 and i5 comprises a series, current-responsive coil 2| which is serially connected within the line in which the sectionalizer is located. Each sectionalizer also has a normally closed, series contact 22 in said line, and a normally open, shunt-connected fault-imposing contact 23 across the line, this fault-imposing contact 23 being shown, for illustrative purposes, as being connected in a grounding-circuit 24, although such showing is intended to be illustrative of any circuit which imposes an artificial fault on the line at the sectionalizing point where the sectionalizer is located.

When overcurrent of sufficient magnitude passes through the sectionalizer-coil 2|, this coil picks up its armature 2i and closes the normally open fault-imposing contact 23, thus placing a deliberate fault on the system at the location of the sectionalizer. The recloser then opens its series contact 6, deenergizing the sectionalizercoil 2!, and causing the fault-imposing contact 23 to automatically reopen itself, in response to the dropout-movement of the armature 2'5. The armature 21 is also mechanically connected, as diagrammatically indicated at 23 in Fig. l, to a mechanism which is indicated by a block 29, said mechanism comprising a counter and sectionalizer. This mechanism counts the number of closing-and-reopening movements of the faultimposing contact 23, and after a predetermined number of said movements, trips out the series sectionalizer-contact 22, through a diagrammatically indicated mechanical connection 30, which opens said series contact 22 and holds or looks it open, until the sectionalizer is manually reset.

The sectionalizer-coil 2i may be, and preferably, therefore, will always be, more sensitive than the recloser-coil 6', so that the sectionalizer will reach out to a protected zone which extends out farther from the recloser than the zone which would be covered by said recloser alone. Likewise, the sectionaliz-er-counter 29 will always be set for a smaller number of counts than the recloser-counter 9, so as to prevent a lookoutoperation of the recloser if the fault lies beyond the location of the sectionalizer. If there are two sectionalizers in series with the same line, at spaced points along the line, the second, or more remote, sectionalizer, such as that shown at S, will have a more sensitive coil 2!, and will have a counter 28 which is set to count a smaller number of counts, than the first sectionalizer, such as the sectionalizer R in Fig. 1. When I speak of the number of counts of the counter 29, I mean to include a case in which the counter responds to a single count, or to any prescribed plural number of counts, such as 2, 3, 4, or the like.

An illustrative form of structure of one of the sectionalizers, such as 13, is shown in Fig. 2. The sectionalizer is shown mounted in a casing 13! having two bushings, 32 and 33, with the incoming line H enterin by a conductor 25 through the bushing 32, and leaving by a conductor 26 through the bushing 33. The electrical connections to the coil 2 l, the normally closed series contact 22, and the normally open shunt contact 23, in Fig. 2, are as already shown and described in connection with Fig. 1.

In Fig. 2, the coil 2| is shown as pulling down? wardly on the armature 2'1, against the force of a compression-spring 34, so as to move a lift-rod -35 downwardly against the force of said spring 34. The bottom of the lift-rod 35 is connected, through a tension-spring 36, to the pivoted contact-arm of the grounding or fault-imposing contact, the connec ions being such as to for: a toggle, which serves to hold the arm 23 either open or closed, according to the position of the lift-rod 35. Thus, when the lift-rod 35 is in its normal upper position, as shown, the bottom of o the lift-rod is above the pivot-point 3'! of the arm 23, so that the spring 38 holds the contact-arm 23 open, but when the lift-rod 35 is in its lowermost position, its bottom end falls sufficiently below the pivot-point 31 to break the toggle, and to cause the spring 38 to pull the contact-arm 23 closed and hold it closed as long as the lift-rod 35 is in said lowermost position. The fault-imposing contact-arm 23 is thus open or closed, according to the position of the lift-rod 35, and that position depends, in turn, upon energization or non-energization of the current-coil 2!.

The lift-rod 35, in Fig. 2, is provided with a pivoted ratchet .6, which is so disposed that, when the lift-rod moves upwardly, the ratchet 40 will engage a notched integrator-arm 4! and move it upwardly one notch. The bottom end of the integrator-arm 4! is disposed in a kind of dashpot 42, having a valve 43 which permits the integrator-arm 41 to move upward freely, but retards the downward return of said arm. The dashpot-timing is such that if the successive notching-operations, due to successive upward movements of the lift-rod 35 occur in rapid succession, as would be the case during a normal operation of the recloser in Fig. 1, the integratorarm will not appreciably drop backwardly, in its position, between successive notching operations, but if the notching-operations are interrupted, the integrator-arm 4| slowly drifts back to its normal lowermost position, and thus resets itself.

The integrator-arm 4| is provided with a stoppin 44, which can be inserted in any one of positions 1, 2, 3 or 4, in order to make the sectionalizer lock out in 1, 2, 3 or 4 operations, respectively.

The normally closed series-contact arm 22, in Fig. 2, is shown as being lifted, or opened, by means of a spring-pressed contact-rod 46, which is normally pressed upwardly toward open position, by means of a compression-spring 41. The contact-rod 46 is normally latched closed, against the, pressure of its opening-spring 41, by means of a trip-lever 48, which extends out over the integrator-arm 4| so that when said arm is being notched upwardly, for the last time, it presses up on the trip-lever 48, and thus releases the contact-rod 46, which thereupon moves upwardly under the pressure of its opening-spring 41. I

The sectionalizer I3 which is shown in Fig. 2 is also provided with an operating-handle 50, which is provided with linkage 5| so that this handle 50 is moved downwardly by the upward or opening movement of the contact-rod 46. The linkage 5! of the operating-handle 50 is also pro vided with a latch 52 which holds the trip-lever 48 in its tripped position, after acircuit-opening operation of the contact-rod 46, so as to lock the series contact 22 in the open position, until the operating-handle 50 is manually reset.

The operation of my device has been explained as the description has preceded. In summary, it may be noted that the first sectionalizer, I3 or 15, in Fig. 1, can be installed anywhere within the reach or protected zone of the recloser. If a second sectionalizer is used, at a still more remote point, as-indicated at 14 in Fig. 1, the first sectionalizer [3, in conjunction with the recloser, may together be regarded as constituting the recloser for the second sectionalizer l4, and this second section sectionalizer 14 may be installed anywhere within the reach or protected zone of the first sectionalizer IS.

It will be noted that my sectionalizer-contacts, 22 and 23, are never called upon to open a circuit which is carrying current, except in the case of a manual operation of the operating-handle 5i] (Fig.2), which will cause its latch 52 toactuate the trip-lever 48 and open the main series contact 22.

It will be noted that the shunt-contact 23, in Fig. 2, cannot. open until the lift-rod 35 moves upwardly, and this cannot happen until the series current-responsive coil 2| is deenergized, so as to permit the lifting-spring 34 to lift the armature 2'! in Fig. 2. Thus, the shunt-contact 23 cannot be opened until the current-coil 2| is deenergized, and this condition of the coil will not occur except when the recloser-contact 6 is opened. Thus, there is no voltage on the circuit at the time when the grounded or fault-imposing circuit '24 is interrupted by the opening of the shunt-contact 23.

Since my sectionalizer- contacts 22 and 23 are light-duty contacts, they may be operated in air, or in oil, or in any other desired medium, but in any event, their construction is simple and inexpensive, as compared to the recloser, which is called upon to interrupt heavy currents.

It will be noted that my fault-imposing sectionalizer not only serves to extend the possible reach or protected zone of the recloser, but it also results in more positive operation of the recloser, for faults which are only slightly beyond the location of the sectionalizer but still within the furthest limits of the slowest operation of the recloser. This more positive operation of the recloser, for such faults, is brought about by the imposition of a deliberate fault, through the shunt-connected circuit 24 of the recloser, thus virtually eliminating any arc-resistance which may exist in the line.

It will further be noted that my fault-imposing sectionalizer minimizes unnecessary burning of the line-conductor, due to arcing-faults beyond the sectionalizer, because my fault-imposing shunt-circuit 24 short-circuits the line at the sectionalizer and bypasses the fault-current which is flowing to the actual fault, while at the same time reducing the line-voltage substantially to zero, so that the fault is extinguished, even before the recloser-contact 6 can open, at least in some instances.

While I have described my invention in a simple illustrative form of embodiment, I wish it to be understood that my invention is subject to considerable changes in the way of additions, omissions, and substitutions, within the skill of the art, without departing from the essential spirit of my invention. I desire, therefore, that the appended claims shall be given the broadest construction consistent with their language.

I claim as my invention:

1. In an electrical distribution-system having a considerable length of distribution-line which may be subject to high-impedance fault-conditions; a recloser-means interposed at a sendingpoint for feeding power into said length of distribution-line, said recloser-means comprising a series, current-responsive recloser-coil in said line, a normally closed, series recloser-contact in said line, and recloser-operating mechanism for causing said series recloser-contact to open and reclose a predetermined number of times, and then to lock open, in response to rapidly repeated overcurrent-conditions of predetermined magnitude in said recloser-coil, said predetermined magnitude of overcurrent being too low to be sure to include all faults'near the remote end of the liner and a fault-imposing sectionalizer interposed at an intermediate point in the line at a distance close enough to said sending-point so that substantially all fault-currents due to faults within said distance are greater than said predetermined magnitude, said sectionalizer comprising a series, current-responsive sectionalizer-coil in said line, a normally closed, series sectionalizer-contact in said line, a normally open, shuntoonnected fault-imposing contact across said line, and sectionalizer-operating mechanism including a fault-mposing means for causing said faultimposing contact to close in response to an overcurrent-magnitude in said sectionalizer-coil, the minimum overcurrent-magnitude to which said sectionalizer coil will respond being smaller than said predetermined magnitude to which said recloser-coil responds, said fault-imposing contact automatically reopening in response toa substantially zero-current condition in said sectionalizercoil, and said sectionalizer-operating mechanism further including a sectionalizing-ineans for causing said series sectionalizer-contact to open during a substantially zero-current condition in said sectionalizer-coil, and to remain open, in response to a predetermined number of reopening-movements of said fault-imposing contact, less than the predetermined number of rapidly repeated reclosures of said recloser-operating mechanism.

2. A fault-imposing sectionalizer for use on an electrical distribution-line, said sectionalizer comprisin a series, current-responsive sectionalizercoil in said line, a normally closed, series sectionalizer-contact in said line, a normally open, shunt-connected fault-imposing contact across said line, and sectionalizer-operating mechanism including a fault-imposing means for causing said fault-imposing contact to close in response to an overcurrent-magnitude in said sectionalizercoil, said fault-imposing contact automatically reopening in response to a substantially zerocurrent condition in said sectionalizer-coil, and said sectionalizer-operating mechanism further including a sectionalizing-means for causing said series sectionalizer-contact to open during a substantially zero-current condition in said sectionalizer-coil, and remain open, in response to a predetermined number of reopening-movements of said fault-imposing contact.

3. In an electrical distribution-system having a considerable length of distribution-line which may be subject to high-impedance fault-conditions; a recloser-means interposed at a sendingpoint for feeding power into said length of distribution-line, said recloser-means being operative to open and reclose said line a predetermined number of times, and then to lock open, in response to rapidly repeated overcurrent-conditions of predetermined magnitude, said predetermined magnitude of overcurrent being too low to be sure to include all faults near the remote end of the line; and a fault-imposing sectionalizer interposed at an intermediate point in the line at a distance close enough to said sendingpoint so that substantially all fault-currents due to faults within said distance are greater than said predetermined magnitude, said sectionalizer comprising means for imposing a deliberate fault on the line in response to a second predetermined overcurrent-magnitude in said sectionalizer, and for removing said deliberate fault during the subsequent no-current period of said recloser-means, the second predetermined overcurrent-magnitude to which the sectionalizer responds being smaller than the first-mentioned predetermined overcurrent-magnitude to which the reclosermeans responds, said sectionalizer further comprising means for counting a succession of rapidly repeated overcurrent-conditions for a number of times which is less than the recloser-times, and for then opening the distribution-line, and 1001 ing it open, during a no-current period of said recloser-means.

4. A fault-imposing sectionalizer for use on an electrical distribution-line, said sectionalizer comprising means for imposing a deliberate fault on the line in response to a predetermined overcurrent-magnitude in said sectionalizer, and for removing said deliberate fault when the sectionalizer current falls to substantially zero, said sectionalizer further comprising means for counting a predetermined number of rapidly repeated overcurrent-conditions, and for only then opening the distributionline, and looking it open, during a no-current period.

5. In a sectionalizer, a casing having a bushing with an incoming conductor and a bushing with an outgoing conductor, contact means disposed in said container operable to connect a fault to said outgoing conductor, electroresponsive means in said casing movable in response to a current of a predetermined value to efiect operation of said contact means, normally closed switch means disposed in said casing in series circuit relation with the electroresponsive means and said incoming and outgoing conductors, and means actuated in response to operation of said electroresponsive means a predetermined number of times for opening said switch means.

6. In a circuit interrupter, a casing having incoming and outgoing conductors, switch means in said casing operable to connect a fault to said outgoing conductor, electroresponsive means connected in series with the conductors between said switch means and the incoming conductor for operating said switch means in response to a predetermined current condition in said conductors, counting means operable to cumulative count only closely succeeding operations of said switch means, separable contact means disposed in said casing intermediate the switch means and the incoming conductor, and means operated by said counting means to interrupt the circuit between the incoming and outgoing circuit connections, only after a predetermined number of operations of the switch means.

7. A circuit interrupter comprising, incoming and outgoing terminal conductors, switch means operable to connect a fault to the outgoing terminal conductor, electroresponsive means connected in series circuit with the terminal conductors operable to effect operation of said switch means in response to predetermined current conditions in said series circuit, separable contact means connected in said series circuit, and counting means operable in response to closely successive operations of said switch means to effect separation of said separable contact means only after a predetermined number of operations of the counting means.

8. A circuit interrupter comprising, switch means operable to connect a fault to a conductor, electroresponsive means operable to effect operation of said switch means in response to predetermined current conditions in said conductor, separable contact means connected in series circuit relation with the electroresponsive means and the conductor, and counting means actuated by the electroresponsive means to count closely successive operations of the switch means, said counting means being operable to effect separation of said contact means, only in response to a predetermined number of closely successiv operations of said switch means.

HENRY I. MADDEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 22,872 Matthews Apr. 29, 1945 1,919,895 Luthi July 25, 1933 1,945,591 Brooks Feb. 6, 1934 1,982,986 Garlingtcn Dec. 12, 1934 2,106,844 Harder Feb. 1, 1938 2,288,953 Matthews 1- July 7, 1942 2,291,350 Scott July 28, 1942 2,334,571 Matthews Nov. 16, 1943 FOREIGN PATENTS Number Country Date 619,875 France -1 Apr. 11, 1927 OTHER REFERENCES Electrical World, page 58, March 4, 1944. Electrical World, pages 50 and 51, April 29. 1944.

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