US2401017A - Control system - Google Patents

Description

May 28, 1946. -M, E, REAGAN ETAL 2,401,017

CONTROL SYSTEM 'Fileduune 2?, 1944v 2 sheets-sheet -1 WITNESSES:

May 28, 1946. M E REAGAN UAL A ZL? f CONTROL SYSTEM Filed June 27, 1944 2 sheets-sheet' 2 n KY/"- fr Y. LATTORNE Patented May 28, 1946 Maurice E. Reagan and Willard A; Derr, Wilkinsburg, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation ofPennsylvania Application June 27, 1944, Serial No. 542,294'

s claims, (Cl. 1774353) Our invention relates, generally, to supervisory control systems, and it has reference, in particular, to control systems for controlling from a central control station, and providing indications `of the operating position of, apparatus which is located remotely from a remote supervisory con-r trol station.

Generally stated, it is an object of our invend tion to provide a supervisory control system which is simple and inexpensive to manufacture, and which is flexible and positive inoperation.

More specifically, it is an object of our invention to provide for remotely controlling and super` vising the operation of apparatus which is positioned some distance from a remote supervisory control station over a single supervisory and control conductor between the apparatus and remote station.

Another object of our invention is to provide for extending a supervisory control system to include apparatus whichgis relatively distant from the remote station without requiring an excessive number of additional conductors or equipment.

It is also an object of our invention to provide for controlling an automatic reclosing circuit breaker at a location which is relatively distant from a remote supervisory control station and for indicating whether the circuit breaker is open and subject to reclosing, locked open, closed, or whether the control and supervisory channel between the circuit breaker and the remote supervisory control station is in operating condition.

4 Yet another object of our invention is to provide for utilizing afpluralityof point supervision oontrol relays in conjunction with a pair-of supervisory control-relays for effecting operation and supervision of a circuit breaker remotely located from a remote control station over a single conductor and at the same time maintainv supervision' of the conductor so as to obtain an indication when the'conductor is shorted, grounded or open. Still another object of our invention is to provide for maintaining supervision of the condition of a control and indication'channel between an operating station and a circuit breaker remotely located therefrom, as well as effecting operating:

station is effected over a single supervisoryconf trol conductor while maintaining supervision of the operating condition of the conductor. A pair of supervision control relays are used to provide a plurality of different stopping circuits for the counting chain at the remote station. Selective operation ofthe supervision control relays is effected by having a pair of point supervision relays connected to the source of control voltage in cascade with a supervisory control conductor extending intermediate the relays of the pair to the remote circuit breaker location. Auxiliary switch means are provided at the remote circuit` breaker location for controlling the polarities applied to the control conductor in accordance withth'e position of the circuit breaker, thereby selectively controllingthe positions of point supervision relays. Failure of the control conductor results in joint operation of the point supervision relays associated therewith, so as to provide for indicating a conductor fault. Control of the circuit breaker is effected over the saine conductor, the circuit breaker control means Abeing non-operative on` the relatively small currents used by the supervision control relays.`

For a more complete understanding of the nature and slope of our invention, reference may be made to the following detailed description in connection withthe accompanying drawings which, when joined together with Figurel at the left and Figure 2 at the right, provide a diagrammatic tively distant from a remote supervisory control view of a supervisory control system embodying the principal features of the invention, in which: Figure 1 is a diagrammatic view of the central control station apparatus,

Fig. 2 is a diagrammatic view of the remote station apparatus together with the auxiliary equipment used at the remote circuit breaker location; and

Fig. 3 is a diagrammatic view of a control and indicating system embodying the invention in another of its forms.

The preferred embodiment of our invention is shown and described herein as applied to the supervisory control system disclosed in the Boswau Patent No. 2,091,301 issued August 31,J 1937,

and assigned to the assignee of the present invention. For thepurpose of simplification, most of the elements of the system of the Boswau patent are shown herein in the same cooperative rela- `tion as in the Boswau patent and bearing the same reference characters as in the Boswau patent drawing. Certain relays, conductors and other elements of structure havebeen omitted, and others have been added, and certain relay contact elements have been added to the relays of the Boswau patent in order to perform different functions. These elements have been designated by reference characters, not found in the Boswau patent. Since no changes were made in the control station coding, selecting, and control apparatus, shown in Fig. 2 of the Boswau patent, this portion of the system has been shown boxed in Fig. 1 with the same conductors connecting it to other portions of the system, as shown in the` Boswau patent. changes were made in connection with the circuit breaker control relay lill` of Fig.'4 of the Boswau patent, the substation coding, selecting, `and control apparatus of Fig. 4 thereof hasV been shown herein as boxed in Fig. 2 with the circuit breaker control relay 4M, illustrated as boxed therein, in orderto show the changed circuit connections.

While it is common to control remotely located circuit breakers from a control station by a supervisory 'control system such as that shown in the Boswau patent hereinbefore referred to, the circuit breakers, thus controlled, are usually located relatively close to the supervisory control apparatus at the remote station. Hence, it is usually noproblem to provide the necessary control and supervisory circuit between the supervisory apparatus and the circuit breakers. However, in many instances the circuit breakers to lbe controlled by means of a supervisory control system are not all located close to a single location but are scattered over a relatively wide area. One example of this situation is in the case of the power supply to a subway system wherein the circuit breakers may be scattered along the length of the subway line. In such case it becomes necessary to select one or more remote control stations for the supervisory control system and then further provide for extending the supervisory control system from the remote stations to the individual circuit breaker locations.

Referring to Fig. 2 of the drawings, the reference numerals 500 and 502 may denote generally circuit, breaker locations which may be relatively distant from the remote control station and the rest of the supervisory and control apparatus shown in the ngure. The circuit breakers (not shown) at these locations may be of the auto matic reclosing type and of the non-reclosing type respectively, in order to illustrate the different features of the invention.

In order to provide for extending the operation of the supervisory control equipment from ythe remote substation to the circuit breaker location at 552 where a non-reclosing circuit breaker may be located, a single supervisory and control conductor 553 may be provided in connection with the circuit breaker location 552 which may be designated as point i on the supervisory control system where it may be desired to control and supervise the operation of the circuit breaker associated with that point, andat the same time maintain `supervision of the control conductor 553.

In order to provide for indicating not only when the circuit breaker is open or closed but also whether the supervisory control conductor 503 is free from faults, the supervision control relays 551 and 508 may be added to the system of the Boswau patent. These relays have a plurality of contact members cooperativeto provide a plurality of different stopping circuits for the point selecting relays 353 through 358 of the counting chain at the remote station. tact members may be added to the relays 355 and Additional con! Since only relatively minor 351, ln order to provide additional stopping points for the chain. f

Control of the supervision control relays 55? and 558 may be eiTected by means of a pair of point supervision relays 559 and 5m, which also control the operation oi the point relay 3l3, and which may be connected in cascade across the common source of direct current control voltage so as to be normally operated to the energized position. A connection may be provided from therebetween to the supervisory control conductor 553 so that either one or the other of the point ysupervision relays may be shunted down and the other picked up, depending on the polarity .of :the control voltage applied to the supervisory control conductor 553.

The polarity ofthe supervisory control conductor 553 may be varied by connecting the circuit breaker end thereof to either negative or positive polarity through either the tripping relay 3I9 or the closing relay 320 by means of an auxiliary circuit breaker switch 32|. For this reason the connections of the circuit breaker control relay M4 may be changed by adding an additional armature 53| for placing negative polarity on the closing relay 325 to operate it.

In order to providefor electing operation of the point supervision relays without `at the same time operating either of the tripping or the closing relays, the point supervision relays may be disposed to operate on relatively small control kcurrents which are insui'icient to operate the tripping or closing relays. The resistance of the point supervision relays may be suihciently high, so as to limit the control current therethrough to a value less than that required for operating either of the tripping or closing relays.

Where the circuit breaker at the remote location is provided with automatic reclosing means so that the circuit breaker will reclose after tripping due to a fault, it will be necessary for the operator at the central control station to know not only whether the circuit breaker is open or closed, but Whether it is open and subject to reclosing by the automatic reclosing means upon the removal of the fault or whether it is locked open. This indication is necessary so that the `operator may know whether it is safe for a repairman to Work on circuits controlled by a circuit breaker which is open.

In order to provide this additional indication and also maintain supervision of the control rchannel between the lcircuit breaker location and the remote substation, a pair of supervisory control conductors 5i2 and 5l3 may be provided lbetween the circuit breaker location 550 and the remote station. At the remote station, two pairs of cascade connected point supervision relays 5l 5, 5|5 and 5H., 5l8 may be provided in connection with the supervisory control conductors 512 and 5l3, respectively. Associated make-and-break contacts of these point supervision relays may be interposed in the energizing circuit of the point relay 3H to provide for dcenergizing it upon a change in the operating condition of any one of the point supervision relays. Additional contact members may be provided on the point supervision relays for providing diierent control circuits for the supervision control relays 501 and 508 which determine the different stopping points of the counting chain, comprising` relays 353 through 308.

In order to provide for selectively operating the point supervision relays 5I5 through 5l8 in accordance with the condition of the circuit breaker and the supervisory control conductors, an auxiliaryswitch 3|8' on the circuit breaker at the remote'location 500 may be utilized for connecting either positive or negative polarity to the lsupervisory control conductor 5|3, depending on' whether the circuit breaker is open or closed. The auxiliary switch 3|8' may also beused to connect one or another of the terminals ofthe closing relay 3|1 to the positive or negative ter.-` minal of the source. i j For thepurpose ofsupervising whether` or not the circuit breaker is merely open and subject to reclosing upon the removal of a fault condition, or whether it is locked open, a circuit breaker control switch 520 may be used for controlling the connection of the supervisory control conductor 5|2 to either positive or negative polarity throughltheIoperating Winding of the trip relay 3|6. The circuit breaker control switch may be of toggle or latch type having tripand close operating windings 522 and 523, respectively, for operating the armature 524' to either the trip or close position wherein it remains until operated to the other position. i

The circuit breaker may be locked out by operating the circuit breaker control'switch 520 to the trip position whereupon the reclosing circuit for the circuit breaker-may be interrupted by the opening of contact members 520 at the same time a supervisory signal is sent to the control station in a manner which will be described hereinafter.

In order to provide for supervision of the additional functions at the central control station, the'lamp relays |28 and |30 of the BosWau patent at points and 4 `may be replaced by associated pairsof lamp relays |28', 'I2-8", and |30' and |30", respectively. Additional contact members may be added to the point selecting relays |40, |4|, |142 and |43 and an extracontact may beadded to the signal relay |32 in order to provide for selectively 4controlling the operation of these point lamp relays to' light both the red and green lamps when the supervisory control con-n ductors between the circuit breakers and the remote stations are subject to afault condition. In the case of the circuit breaker at location 500 which is designated as point on the system, the point lamp relays also perform the additional function of lighting an amber lamp 526 when the circuit breaker is open but not locked open.`

Referring to Figs. 1 and 2, it will be seen that theapparatus associated with the circuit breaker at the location 500 is shown for the closed position ofi the circuit breaker with the point supervision relays 5|5 and 511 up and the point supervision relays 5|6 and 5|8 down. The circuit breaker control switch 520 is in the close position. Accordingly. the point lamp relay |28' at the control station is up, providing an energizing circuit for the red lamp |03 which indicates that thecircuit breaker is closed. Should the circuit breaker open due to afault condition, the auxili'ary switch 3|8 moves to the open position, connecting the supervisory control conductor 5|3 to the positive terminal through the operating winding of the closing relay 3|1. Thepoint supervision relay 5|1 is thereby shunted down and the point supervisionfrelay 5|8 picks up momentarily interrupting the holding circuit for the point supervisory relay 3| I, deenergized.

An energizing circuit is thereby provided for the substation starting relay (not shown) of the substation coding, selecting and control appai ratus. The counting chain starts to pulse and which drops and remains sends out -twopulses or one control pulse to select point v| :at .the central control station, relays 303, 302, 304, 30| .picking up in sequence, andrelays303, 302 dropping out. At this point a stopping circuit forithe chain is provided` from the substation coding,` selecting and control apparatus through conductor 521, armature 528 and back contact offthefpointsupervisory relay 3| and front contact and armature 529 of the point selecting relay'304 toreffect energization of the stopping relayfof` the substation control apparatus: f N `1` i. i At the central control station, thepoint selectingrelays |33, |31,l39 and |36 pick up and relays` |38,` |31, dropout in synchronism with the relays 303, 302, 304and 30| of the remote station.' An'energizing circuit for the alarm |05 is provided bythe alarm relay |21 which picks up and the point selecting relay |38 picks up and rings until the release key |03 is depressed. When relay |36 picks up, an energizing circuit is thereby` provided for the point relay |33 at point from negative through the operating winding of relay |33, front contact and armature 530 of point selecting relay |39, conductor 53| through front contact and armature |65 of sequence relay |36, back contact and armature |66 of sequence relay |35, back contact and armature |61 of sequence relay |31, to positive in the control station coding, selecting and control apparatus. Point relay |33 picks up and establishes an energizing circuit for the check lamp |01 through armature 532.

After a short delay when the receiving control relay ofthe coding, selecting and control apparatus of the control station drops, an energizing circuit is established for starting the control station counting chain to pulse and check the point selection operation. Relays 38, |31, |39 and |36 pick up in sequence, relays |38, |31 dropping out as soon as the relay |36 picks up. At this point a stopping circuit is established through front contact members and armature 530 of point selection relay |39 and front contact members and armature 533 of the' point relay |33 to stop the chain from further pulsing,

At the remote station, relays 303, 302, 304 and 30| pick up in sequence, relays 303 and 302 dropping out when relay 30| picks up. An energizing circuit is thus `established for the point relay 300, extending from the negative terminal through the operating winding of relay 309, front contact and armature 534 of 4point selection relay 304, front contacts and armature 334 of sequence relay 30|, back contact and armature 335 of sequence relay 300, back contact and armature 336 ofsequence relay 302 to the positive terminal in the remote station coding, selecting and control apparatus.

Point relay 309 in picking up sets up a circuit which starts the remote station counting chain pulsing to supervise an indication of the changed position of the circuit breaker. Due to point supervision relay 5| 1 dropping and point supervision relay 5|8 picking up, the energizing circuit -for the supervision control relay 501 is intercounting chain `at the remote. station from pulsing' aftery two rcontrol kpulsesto signal that the circuit breaker is` open butnot locked out.

Atthe same time negative polarity is placed on Ythe pointsupervisory relay 31| through front contactand armature 352 Vof relay 35|', conductor 54|, armature 543 and front contact of the point relay` 303, and the armatures and Acontacts of the point supervision-relays 5.15, 516, 511 and 518. At the central control station, the counting chain pulses in synchronism with the remote station chain, and at the second control pulse, an energizing circuit is, established ,for the lamp control relay |32 whichpicks up. .This puts positive volt-age on the point lamp relay |28', through armature 502v and front contact of point selecting relay |40, armature 543 and front contact i of the lamp. control relay |32, and armature 544 14| land .sequence-relay |35 pick up to provide a vstopping circuit from positive through arma.- ture 506 'and front contact of the point relay 133,'armature 550 and back contact of the point supervisory relay |29, contact spring H2 and outer :contact member of the control key |10, conductor |19-andconductor 455|'through front contact anda-armature |90a, of the point selection relay` 14|.

At the remote station, counting chain relays 303, 302 through 306, 336, 334 and 335 pulse in synfchronism with the relays of the control station providing an energizing circuit for the cirand iront contact of the point relay |33, dropping V it and extinguishingv the red lamp. At the same time positive voltage isput on the point lamp relay |28" through armature 545 and front contacts of the point selectingrelay |40, armature 17|! and front contact of the lamp control relay |32, armature 543 and i'ront cont-acts of the point relay |33, dropping the point lamp relay |28" and completing an energizing circuit for the amber lamp 526 which indicates that the circuit breaker isropen but not locked out. The green lamp |13 is extinguished due to its energizing circuit being opened when the point lamp relay 1 20" drops. After a predetermined time delay, the supervisory control system automatically restores itself to the deenergized or normal condition,

In order for the operator tc lock the circuit f.

breaker at location 500 open and make it safe for a -repairman to Work on the circuits controlled thereby, the operator must go through a manual tripping operation, rst turning the twist key |10 to trip position so that springs and |12 engage their outer contacts, and depressing the point key |14 which shunts the individual point relay |29 through spring |15 and establishes an energizing circuit through spring |16 for starting the central control station counting chain to pulse. Relays |38, 1-31, |39 and |36 pick up in sequence, relays |38 and |31 dropping out when relay |33 picks up, to send out a selection code of one control impulse. An energizing circuit is thereby provided for'stopping the selection Code through armature 541 and front contact members -oi the point relay |29, and front contact members and armature 548 of the point selection relay |39.

At the remote station, the point selection relays 303, 302, 304 and 301 pick up and relays 303, 3512 drop out in synchronism with the relays 138, |31, |39 `and |35 of the controlstation, providing an energizing circuit for thepoint point relay 309 associated with the circuit breaker at location 500. vAfter a predetermined time delay, the relays 303, 302, 300 and again pulse to send a check code 'of one control impulse and check the selection of the point relay 309. At the control station the relays 38, |31, |39 and 13:` pulse and the point relay |33 picks up, lighting the check lamp |01 when the check code is received.

v The operator then depresses the master control key |02 closing contact 10|, which starts the countingchain pulsing to send out three operation Vcontrol pulses 'for operating the circuit breaker control switch to the trip position. 'Ihe counting chain of the control station stops at three control impulses when point selection` relay Yrelay 315 .picks up and establishes an obvious energizing circuit for the trip winding 522 of the circuit breaker controlswitch 520, which operates to the trip position and opens Ycontact members 520a to interrupt the reclosingcircuit of the circuitbreaker and lock the circuit breaker out.

A positive Voltage is thereby placed on the supervisory control 'conductor 5|2 V'through contact members, 520e, dropping point supervision relay 515 andpickingup point supervision relay 511, so that supervision control relay 501 is now up, and supervision control relay 508 is down. The changed position of the point supervision relays 515 and 516 interrupts momentarily the energizing circuit for the individual point relay 311 so that itdrops and starts the remote station counting` .chain pulsing to rsend a supervision code. vThechain pulses until-positive voltage is put on the stopping relay through the front contacts ofv supervision control relay 501, back contactsof supervision control relay 508 and front contacts and armature 354 of point selection relay 3.06. Three control impulses are thus sent to indicate that the circuit breaker is open and locked out.y

At the control station, the relays |38, |31, |39 and |36 through |41 pick up and drop out in synchrcnism with the relays of the remote station counting chain, providing an energizing circuit for the signal control relay |32. The relay 32 in turn' places positive and negative on the point lamp relays |28. and 128"'respectivelythrough armatures 503 and |11 of the relay |32 and armatures .180 and 551 of point selection relay 14| respectively. The point supervision relay |29 is also picked up by negative polarity being applied through armature |14 of relay |32 and armature 553-and front contact of the point relay |33.

The point lamp relay |28 stays down and the point lamp relay |28" picks up. The circuit for the amber lamp 525 is interrupted by armature 550 which engages its front contact and places positive polarity on the green lamp, indicating that the breaker is open and locked out so that it is safe to work on the circuits associated therewith.

Closure of the circuit breaker may be effected over the supervisory control system inthe -usual manner, rst depressing` the point key |10 to select poi-nt I, then operating the twist key |10 to the close position. and depressing the master key |02',` The circuit breaker control relay 414 is operated :in` response to the close code of ve control impulses` and negative polarity is applied to the operating winding of the closing relay 3H over thesupervisory control conductor 5|3. The circuit breaker control switch 520 is thereupon actuated to the close position and the circuit breaker is closed. The usual supervisory signals are sent and the indications of a closed breaker appear at the central control station.

Should either or both of the supervisory control conductors 5|2 or 5|3 have a fault thereon, being open, grounded or shorted, the control voltage will be removed from either or both of the point supervision relays 5|5, 5|6 or 5| 1, SIB.

Both of the relays of the pair from which the voltage is removed will operate to the energized position. Accordingly, the individual point relay 3| I is dropped to start the remote station counting chain pulsing to select the proper point at the control station. Subsequently, due to the fact ,that both of the supervision control relays 501 and 508 will be deenergized, a supervisory signal ofiour controlimpulses will besent to indicate an open wire or a fault thereon. y

At the control station, the alarm relay `|2'| operates and both the point relay |33 and the signal control relay |32 will energize in order, so that energizing circuits will be established for both of the point lamp relays |28" Vand |28 through front contact members and armatures 543Vand |1| of the signal control relay, and front contacts and armatures 562 and 503, respectively, of the point selection relay |42. Accordingly, both the red and green lamps will be lighted, indicating an open supervisory control line condition. 'I'he disagreement lamp |08 will also be lighted, regardless of whether the control key l I0 isin the close or trip position, throughthe armatureand front contact of either point lamp relay |20",l or |28'.

`In connection with the circuit breaker location 502, which may, for example be denoted as point 4 Vonthe supervisory system, it will be observed that the singlepair of point supervision control relays 509 and `5|0 are selectively operable'depending on the polarity applied to .the control, conductor 503 or the absence thereof, to energize either the supervision control relay 501, or both of the supervisioncontrol relays 501 and` 508, or to deenergize, both of them, in order to provide three different stopping circuits for the remote station counting chain. Since the circuit breaker. at location 502 is not arranged for automatic reclosing, these operating positions of thesupervision control relays may be used to in' dicate that the circuit breaker is tripped, that it is, closed, or that there is a faultysupervisory controlconductor condition. The circuit breaker trip and closing relays are` likewise operated over the supervisory control conductor under the control of the control relay M4 and the auxiliary circuit breaker relay 32 `At the control station, the point lamp relays and |30" associated with point 4 operate in substantially the'same manner as the point lamp relays |20' and |28 of point to control the operation of the associated indicating lamps, except that an amber lamp is not provided, and the redand green lamps are used in the usual manner to merely indicate whether the circuit breaker is closed or open. Since this type of supervisory control `circuit is used on circuitrbreakers not having automatic reclosing, the additional indication of whether the circuit breaker islocked out is not necessary since there isvno danger of the circuit breaker reclosing due to the removal of a fault condition whilethe repairman is working on the circuits.

Supervision of the single supervisory and control conductor is provided in the same manner as set forth in the description in connection with the circuit breaker at location 500. When the control voltage is removed from` the conductor 503, bothv of the point supervision relays 509'and 5|0 operate. Both of the supervisory control relays 501 and 508 are thereby deenergized, and a code of four control impulses is sent to indicate a faulty condition on the conductor. 1

It will be apparent from the above description and from Fig. 3 of lthe drawings that the extended portion of the supervisory control scheme may in itself comprise a useful subcombination Where it is-desired to operate and eiect an operating condition of remotely located apparatus without using the supervisory and control equipment of the Boswau patent, In such instance the control conductor 503 may be used in conjunction with a manual control switch555 which maybe operated'to apply either a negative or a positive control voltage to the single supervisory and control conductor 503 for selectively energizing the trip or close relays 3 I9 or ,320 at a remote circuit breaker location.

Supervision maybe effected by means of green and red signal lamps 5B1 and 568 which may be connected to the common source in cascade and provided with an intermediate connection to the supervision and control conductor 503, or they may be controlled by the point supervision relays 509and 5|0 similarly connected.` i Accordingly, with the circuit breaker open and positive potential applied to the supervisorycontrol conductor 503, pointsupervision .relay will be up and the green lamp 568 `will be lighted. The

breaker may be closed by` moving the switch 565 o to apply negative potential to the conductor 503, thus energizing the close relay 320. The auxiliary circuit breaker switch operates and appliesnega- From the above descriptionand accompanying l drawings, it will be apparent that we have provided a new and novel manner for supervising and controlling circuit breakers or other apparatus units which are located remotely from a remote supervisory station, and at the same time providing for supervision of the supervisory control conductors extending between the remote` station and the circuit breaker location. This extension of the supervisory control system provides positive supervision and control of theremotely located circuit breaker and may be used apart from the supervisory control system for effecting operation of apparatus atfremote locations and-obtaining an indication thereof without the necessity of the usual supervisory coding equipment. i

Since certain changes may be made in the above described construction, and different embodiments of the invention may be madewithout departing from the spirit and scope thereof, it is intended that all matter `contained in the above description` or shown in the accompanying drawings should be considered as illustrative and not in a limiting sense.

We claim as our invention: y

1. In a supervisory control system having a plurality of control points at a remote station associated With apparatus located'remotely therefrom and selectively controllable from a central control station over a supervisory control channel, a chain of counting relays at each station cooperative to select a point to be controlled or indicate an operation of the apparatus associated with said point and check saidoperation, a single control and supervision conductor extending from the remote station to the apparatus location, means at the apparatus'location normally effective to maintain one polarity or the other on the conductor depending on the condition ofk the apparatus, means at the remote station selectively responsive to either polarity or the absence thereof on said conductor Vtofprovide different stopping circuits for the remote station counting chain at different points in the operating sequence, and means at the VcontrolV station controlled by the counting chain thereat for indicating the condition of the apparatusand of the'supervisoryand control conductor.V v

2. A supervisory control system for an apparatus unit distantly positioned from a remotestation comprising, supervisory and control apparatus including a chain'of counting relays locatedV at each of a control station and the remote station operable in synchronisrn in response to changed conditions at either station, a single supervisory and control conductor extending' from the apparatus unit position to the remotev station, auxiliary switch means responsive to the apparatus unit position 'for normally maintaining either positive or negative polarity on said conductor depending on the' position of the apparatus unit, and control means at the remote station normally responsive to the polarity of the conductor to provide different stopping circuits for they remote station counting chain to effect an indication of the apparatus unit position and furtherresponsive to the absence of either polarity n the conductor to provide a still different stopping circuit for the remote station counting chain to effect an indication of a faulty supervisory and control channel.

3, A supervisory control system comprising, su-

pervisory control means including'a chain of relays at each of a remote and a control station operable in synchronism over a single supervisory cont-rol channel in response to an initiating signalr from either station, supervision control means operable to provide different stoppingcircuits for the chain, of relays at the remote station, a pair of point supervision relays. controlling the operation of the supervision control means, a single supervision 'and control channel connecting the point supervision relays toa circuit breaker location removed from the remote station, circuit means at the remote station providing operating circuits for the point supervision relay means to effect operation of the supervision control means to provide indication of a faulty supervision and control. channel, and means normally responsive to the position of the circuit breaker to apply either a. positive or a negative control potential to the supervision and control channel to render one or another of the point supervision relays inoperative andI effect an indication of the circuit breaker position.

fri The combination in a supervisory control system having supervisorycontrolV apparatus at remote and control stationsv including a chain of counting relays at each station operable in synchronism to transmit or receive coded series of impulses, of supervisory control means at the remote station operable to stop the remote station counting chain rat a plurality of diierent points, a pair of point supervision relays providing a plurality of circuits for the supervisory control means, said relays being normally connected in cascadeL to a source of control voltage for providing operation of the supervision control means to effect a predetermined supervisory code signal, and a single supervisory control conductor associated with a circuit breaker and the point super- Vision relays for jointly applying either a positive or a negative control voltage to the point supervision relays in accordance with the position of the circuit breaker to shunt one or another of them and operate the supervisory control means to effect one or another of different predetermined supervisory code signals to indicate the circuit breaker position.

5. In a supervisory control system having supervisory control apparatus at remote'and'control stations each with a chain of counting relays operable from either station in synchronism to control and indicate the position of an apparatus unit located distantly from the remote station, a pair of supervision control relays selectively operable to provide a plurality of stopping points for the remote station counting chain, a single supervisory and control conductor extending from the remote station to the apparatus unit location, means at the apparatus unit location for applying control potentials of opposite polarities to the conductor depending on the position of the apparatus unit, and a pair of point supervision relays operable in response t0 the-polarity of the control conductor to effect operation of the supervision control relays to indicate theap'- paratus unit position, said relays being connected in cascade to a source of control voltage for effecting operation of the supervision control relays .to indicate a conductor fault when the control voltage on the control conductor is rendered ineffective at the remote station.

6. A supervisory control system comprising, supervisory and control equipment located at remote and control stations including a chain of counting relays at each station operable in synchronism from either station, a circuitybreaker located remotely from the remote station-,a single supervisory and control conductor extending from the remote station to the circuit breaker,

lmeans at the circuit breaker location operable toV apply control voltages of opposite polarities from a source to the control Vconductor depending on whether ther circuit breaker is open or closed, a pair of point supervision relays connected to the source of control voltage andv to the control conductor so as to be jointly operable when th'e control voltage on the'control conductor is reduced below a predetermined value and selectively operable depending on the polarity of the control voltage on the control conductor when it is above the predetermined value, a, plurality of supervision control relays operable under the control of the point supervision relays for controlling the remote station Vcounting chain to produce diierent code signalsI dependingon the positions of the point supervision relays; and indicating means at the controlstation operable under the control of the control station counting ch'ain to indicate Whether' the circuit breaker is open or closed or Whether there is a fault on the control conductor.

7. A supervisory control system comprising, supervisory control equipment located at remote and control stations including a chain of counting relays at each station operable in synchronism from either station, a plurality of supervision control relays at the remote station operable to provide a plurality of stopping circuits for the counting relays at the remote station for indicating dilerent conditions of the system, a cir,- cuit breaker having means for automatically reclosing after tripping due to a fault and located remote from the remote station, supervisory tripping and closing means of the control. systemV associated with a circuit breaker located remote from the remote station and having means for effecting automatic reclosing after tripping, switch means associated with the circuit breaker for connecting one terminal of the closing means to one terminal of a direct current source when the circuit breaker is closed and the other terminal of the closing means to the other terminal of the source when th'e circuit breaker is open, control switch means operable under the control of the supervisory tripping and closing means to control the tripping and closing circuits of the circuit breaker and connect one terminal of the supervisory tripping means to one or the other terminals of the source depending on whether the control switch' is in the trip or the close position, a supervisory control conductor extending from the other terminal of each the supervisory tripping and closing'means to the remote control station, and a pair of point supervision relays for each conductor said relays being connected in cascade across the source and having connections intermediate the relays of one pair to one control conductor and intermediate the relays of the other pair to the other conductor.

8. A supervisory control system comprising, supervisory control apparatus located at remote and control stations and connected by a supervisory control channel, said apparatus including a chain of counting relays at each stai-,ion operable in synchronism from either station, supervisory tripping and closing means operable over the supervisory channel for a circuit breaker distantly located from Ithe remote station means operable to automatically reclose the circuit breaker subsequent to a fault condition, control means operable in response tooperation of the supervisory tripping means to prevent reclosing thereof by the automatic reclosing means, a supervisory control conductor extending from each of the supervisory tripping and closing means, means associated with the control means and the circuit breaker for connecting the conductors to one or the other terminals of a direct current source depending on whether the control'means and the circuit breaker are in Vthetrip or closed position, and a pair of control relays associated with each control conductor cooperative to pro- Yvide different stopping circuits for the remote station counting chain to produce dierent supervisory code signals for eiecting indications at the control station depending on whether the circuit breaker is merely open, locked open or closed, and whether the control conductors have a faul-t condition thereon.

i MAURICE E. REAGAN.

WILLARD A. DERR..y

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