US1376418A - Relay system - Google Patents

Description

C. LE G. FORTESCUE.

RELAY SYSTEM.

APPLICATION FILED SEPT-9,1916. 1,376,418. at ted May 3, 1921.

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g BY ,1 9 ATTORNEY UNITED STATES PATENT OFFICE.

CHARLES LE G. FORTESCUE, OF IITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 WEsT- INGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA.

RELAY SYSTEM.

Specification of Letters Patent.

Patented May 3, 1921.

To all whom it may concern:

Be it known that I, CHARLES Ln G. FoR'rnscUE, a subject of the King of England, and a resident of Pittsburgh, 1n the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Relay Systems, of whlch the following is .a specification.

invention relates to relay systems and particularly to means for protectlng parallel-connected feeder circuits.

One object of my invention is to provide a system of the above indicated character that shall have means for selectively disconnecting a feeder circuit when a ground or an overload occurs thereon.

Another object of my invention is to rovide a system of the above indicated 0 aracter that shall have means for disconnecting a feeder circuit when the product of the current traversing that circuit and the total current traversing all of the circuits exceeds a predetermined value.

A further object of my invention is to provide a system of the above indicated character that shall operate correctly irrespective of the direction of flow of energy therein.

In the carrying out of my invention, I provide a relay for each interrupter of a parallel-connected feeder circuit and cause one winding of each relay to be sup-plied with current proportional to the total current traversing all'of the circuits and the other Winding of each relay with current proportional to the current traversing its respective feeder circuit. The windings of the relays are so arranged that each relay develops sufficient torque to trip its interrupter only when the current traversing its respective feeder circuit bears a predetermined relation to the total current traversing all of the feeder circuits, such as may render the rents traversing the circuits are equal and less than a predetermined value. or, when the currents are unequal but the product of the sum of the currents by the value of the current in any circuit is less than a predetermmed value, the interrupter will not be tripped. Thus, if one feeder circuit becomes grounded, the current will increase in one of the windings of the relay to permit t to operate. Also, if one feeder circuit is excessively overloaded, the torque of the relay in the overloaded circuit will increase to such value as to cause its interrupter to trip.

' f the direction of flow of energy in all the parallel-connected feeder circuits reverses because of the regeneration of energy the relays will not operate until a ground or overload occurs-on one or more of the circults. Thus, the system is particularly adaptable to railway systems in which the energy 1s frequently regenerated and returned to the system.

' In the accompanying drawings, Figure 1 1s a dlagrammatic view of a relay system embodylng my lnvention, and Fig. 2 is a diagrammatic view of a system of distribution embodying myinvention.

A system in connection with which my invention may be used comprises a generator 1 that is operatively connected to the primary winding 2 of a transformer 3 the secondary winding 4 of which is connected to a transmission circuit 5. Transformers 6, 7 and 8 are operatively connected to the adapted to be normally traversed by equalamounts of current. However, since they are connected, at predetermined points, to a trolley conductor (not shown), occasions arise when one conductor is traversed by relatively more current than the others. Also, any one or more of the conductors may become grounded, and, if such. conditions obtain, it is advisable to disconnect the faulty conductor or the faulty portion of it from the circuit. In view of the above, the feeder conductors are arranged in sec.-

tions 14, 15 and 16 the respective ends of which are provided with circuit interrupters 17, 18, 19, 20 and 21..

In order to cause the circuit interrupters 17, 18, 19, 20 and 21 to be selectively tripped when a ground occurs upon any one or more of the feeder conductors, or when any one or n feeder conductor.

more of the feeder conductors becomes excessively overloaded, I provide a relay system 22 for each set of interrupters that comprises, in

general, four relays 23, 24, 25 and 26 and four transformers 27, 28, 29 and 30.

The relays 23, 24, 25 and 26 severally comprise a magnetizable core member 31, two cotiperating windings 32 and 33, and an armature 34 that is mounted upon a shaft 35 upon which is also mounted a bridging contact member 36 and one end of a spring 41 the other end of which is connected to a stationary member 42. The windings 32 are connected in series and adapted to be so connected to the transformers 27, 28, 29 and 30 as to be supplied with current proportional to the sum of the currents traversing the feeder conductors 10, 11, 12 and 13, and the winding 33 of each of the relays-is adapted to be so connected to its respective transformer as to be supplied with current proportional to the current traversing its respective That is, the winding 33 ofthe relay 23 is connected to the transformer 27, the winding 33 of the relay 24 is connected to the transformer 28 and, similarly, the windings 33 of the relays 25 and 26 are connected to transformers 29 and 30, respectively.

The bridging contact member 36 of the relay 23 is adapted to engage stationary contact members 37 for the purpose of completing a circuit through a source 38 of electromotlve force and the trip coil 39 of its respective circuit interrupter. Similarly, the other bridging contact members 36 are ada ted to engage stationary contact members 3 for the purpose-of completing the circuit of their respective trip coils 39. Each group of circuit interrupters 17, 18, 19, 20 and 21 is provided with a relay system 22 in order that one or both ends of the conductors may be selectively and automatically disconnected from the remainder of the system under predetermined conditions.

Normally, each conductor of the feeder circuits carries the same amount of current which may be assumed to be I amperes, for purposes of illustration. Under this condition, the torque developed by each of the armatures is proportional to 4P. Hence, the springs 41 are of such dimensions that when the currents traversing any one or more of the windings 32 and 33 are such that the torque developed by the armature exceeds, by a predetermined amount, the

Assume that the section 15 of the feeder conductors is not delivering energy to any apparatus in that section and that the conductor 10 becomes grounded at a point 40 relatively nearer to the transformer 8 than to the transformer 7. When such conditions obtain, the current will increase in that part of the conductor 10 between the point 40 and the interrupter 20 in inverse ratio to the distance of the point 40 from the transformer 8. This will-cause the current traversing the Winding 33 of the relay 23 that is adapted to control the interrupter 20 to' increase. The total current traversing the conductors may remain constant or increase because of the ground, depending upon whether or not load is being taken from the section, and, consequently, the current traversing the winding 32 will either remain constant or increase. Thus, the torque developed by the armature 34 will be relatively greater than the counter torque of the spring 41, and the bridging contact member 36 will engage thestationary contact members 37 to cause the trip coil 39 to open the interrupter 20 of the conductor 10.

When the interrupter 20 of the conductor 10 is opened, the current will greatly increase in the other portion of the conductor 10 in the section 15, and, if the current traversing the conductors 11, 12 and 13 remains constant, increases or slightly decreases, the relay 23 of the system 22 that controls the interrupter 19 will operate to thus completely disconnect the conductor 10 in the section 15.

If a load is connected to one of the conductors of the section 14 and it drawsan excessive current, the interrupter to which it is the closest will trip if the product of the total current and the current through the overloaded conductor exceeds a predetermined value. If the "overload persists, the interrupter at the other end of the conductors will be similarly disconnected, and the other conductors will be successively disconnected, in accordance with the relative the relative direction of currents in the windings 32 and 33 will not be affected and the relays will operate selectively only when a ground or excessive overload occurs upon one or more of the feeder conductors.

I do not limit my invention to the particular structure and application illustrated, as it may be variously modified without departing from the spirit and scope of the invention as set forthin the appended claims.

I claim as my invention:

1. In a system of distribution, the combination with a plurality of parallel-connected conductors and a series transformer for each conductor, of an induction relay for each conductor severally having two w ndings that actuate the relay in accordance with the product of the currents traversing the same, means for connecting one term1- nal of each transformer to one termmal of one winding of the correspondmg relay, and means for connecting the other relay windings in series between the common terminals of the transformers and the common terminals of the first mentioned relay windings.

2. In a system of distribution, the combination with a plurality of parallel-connected conductors and a series transformer for each conductor, of a relay for each conductor severally having two windings that actuate the re ay in accordance with the product of the currents traversing the same, means for connecting one terminal of one winding of each relay to one terminal of. itscorresponding transformer, and means for connecting the other relay windings in series between the common terminals of the transformers and the common'terminals of the first mentioned rela'y windings.

3. In a system of distribution, the combination with a plurality of parallel .connected conductors and a series transformer for each conductor, of a relay for each conductor severally having two cooperating windings that actuate the relay in. accordance with the products of the currents traversing the same, means for connecting one terminal of one winding of each relay to one terminal of its corresponding transformer, means for so connecting the other relay windings in series across the transformers that current proportional to the total current traversing the conductors traverses the same.

4. In a system of distribution, the combination with a plurality of parallel-connect ed feeder conductors and a series transformer for each conductor, of a relay for each conductor having two cooperating windings that actuate the relay in accordance with the product of the currents traversing the same, means for connecting one terminal of one winding of each relay to one terminal of its corresponding transformer, means for connectmg. the other terminals of said. windings together, and means for connecting'the other relay windings in series between the commonterminals of the transformers and the common terminals of the first mentioned relay windings.

5. In a system of distribution, the combination with -a plurality of parallel-connected feeder conductors and a series itransformer for each conductor, of a relay for} each conductor having two windings that" actuate the relay in accordance with the" product of the currents traversing the same, I

means for connecting one winding of each relay in series with its corresponding transformer, means for connectlng the other rethe current traversing that conductor and 9 the total current traversing all of the con ductors exceeds a. predetermined value.

7. In a system of distribution, the combination with a'plurality of parallel-connected feeder conductors, of a current transformer for each conductor and a relay for each conductor energized from the current transformers in accordance with the product of the current traversing all the conductors and the current traversing the respective conductors for effecting the disconnection of'a conductor when the relay of that conductor is energized in excess of a predetermined value.

8. In a system of distribution, the combi- 10 nation with a plurality of parallel-connected feeder conductors, of a plurality of relays each having a winding which is severally energized in accordance with the current traversing a conductor and each having a second winding which is energized in accordance with the sum of the currents traversing all of the conductors and means controlled by the relays for disconnecting a conductor in which the current is such that the product of the effects developed in the corresponding relay exceeds a predeterminedvvalue. A

9. In a system of distribution, the combination with a plurality of parallel-connected feeder conductors, of a relay for each conductor having two cooperating windings, means for energizing one winding in accordance with the current traversing the conductor, means for energizing the other winding in accordance with the sum of the current trayersing all' of the conductors and means for disconnectmg a conductor when the product of the effects developed by the gree greater than a predetermined value, windings in the corresponding relay exand means fort connecting the current transceeds a predetermined value. formers to the windings to energize them 15 10. In a system of distribution, the combirespectively, in accordance ith th r t; nation with a plurality of parallel-connecttraversing the corresponding conductor and ed feeder conductors, and a series transthe sum of the current traversing all of the former for each conductor, of a relay for conductors. each conductor having two cooperating In testimony whereof, I have hereunto 20 windings that actuate the relay in accordsubscribed my name this 23rd day of Auance with the products of the currents travgust, 1916.

ersing the windings and serving to disconnect that conductor when actuated to a de- CHARLES LE G. ORTESQUE.

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