US1680395A - Relay system - Google Patents

Description

Aug. 14, 1928.

' H. P. SLEEPER RELAY SYSTEM Filed April 11. 1922 R O T N E V m Harvqy E J/eeper ATTORNEY Patented Aug. 14, 1928.

HARVEY r. SLEEPER, or wInKINsnU'ne,

PATENT orr cs.

IPENNSYLVANIA, ASSIGNOR TO \fESTING- HOUSE ELECTRIC 8c MANUFACTURING COMPANY, A CORPORATION 0F PENNSYL- VANIA.

RELAY SYSTEM.

Application filed April 11, 1922. Serial No. 551,448.

My invention relates to electrical pro tective systems and particularly to relay systems for protecting distribution systems.

One object of my invention is to provide a relay system for protecting a plurality of parallel-connected transmission circuits extending between two predetermined points of an electricalsystem. g Z 1 Another object ofmy invention is to provide a system, of the above-indicated character, wherebythe transmission systems may be protected according to a predetermined unbalance between the currents traversing the respective circuits arranged in pairs.

Another object of my invention is to provide a relaysystem, of the above-indicated character, in which a relay,that is associated with two predeterminedcircuits to controlthe disconnection of the circuits upon the occurrence of an unbalance exceeding a predetermined amount between the circuit currents, shall be rendered inoperative to control the associated circuitupon the disconnection of either circuit from the-system by reason of a condition in that circuit producing an unbalance between the currents traversing the associated circuit.

Another object of my invention is to provide a system, of the above-indicated character, in which the relay shall selectively control the disconnection of either associated circuit upon the occurrence of such conditions in either circuit as would cause a variation beyond a predetermined amount between the circuit currents. A further object of my invention-is to provide a system, of the abovedndicated character, in which the control balance relay shallbe not only selective in its operation but shall also embody an inverse-time 616-? ment inits operation. 7 i i i United States Patent-No. 1,286,415, is.

sued Dec. 3, 1918 to F. ERicketts, and as signed to the "Westinghouse Electric and Manufacturing Company, discloses an induction disc-type relay embodying an inverse'time function in its operation that is obtained and controlled bymeans of a saturable transformer that operates to control the torque developed in the relay.

The saturable transformer permits a torque to be developed in the relay that is proportional to the value of the current traversing the relay up to a predetermined value at which the transformer becomes saturated. lVhen the current traversing the relay exceeds the value at which the transformer becomes saturated, the torque de veloped in the relay remains. constant, ir-

respective or increase in the value of current traversing the relay, by reason of the regulating eifect of. the saturated transformer, I V Y In practicing my invention, I employ. a saturable transformer, or "torque. compensator, as it is commonly known and which is described in the above-mentioned'Ricketts patent, and apply it to a relay of the induc-.

' tion type in such manner as to cause therelay to have both a directional and a. timeelement feature. 7

The single figure of the accompanying drawing is a diagrammatic view'of aportion of, an. electrical system illustrating three parallelconnected conductors of respective transmission circuits and a relay system for protecting such circuits upon'the occurrence of such faults in-any one of the conductors as wouldcause an increase, decrease or reversal of current that would tend to disturb a predetermined balance between the currents that might traverse the respective'vcircuits.

As is illustrated in the accompanying drawing, energy is supplied from a source of.

electromotive force 10 to a plurality of transmission circuits 11, 12 and 13 through associated circuit interrupters 14, 15 and 16, respectively. v

The circuit 11 is provided with an overload relay 17 and a balance relay 18.]The circuit 12 is similarly provided with an overload relay19 and a balance relay'20, and the circuit 13 is likewise provided with an over-- load relay 21 and a balance relay 22.- i

Therelays are inductivelyQenergized from the respectivecircuits through current transformers 23, 24 and .25, respectively. Theoverloadrelays 17, 19 and 21 are adapted to, close their respective switches 26, 27 and 28 when energized to a predetermined degree and for a predetermined interval'oftime corresponding thereto, lrrespect ve ofthedirection of power traversing the associated,

circuits. Q i The balance relays 18, 20 and 22 comprise,

respectively, a magnetizable core member' 30, provided with two differentially-acting windings 31 and 32, and a selectively'energized winding 33 that is adapted to 00- llt operate with the difierentially-acting windings to control the direction of movement 01 ,ainovable disc member 34. v V I The disc member 34 controls a bridging member 35 that is adapted, when actuated in one direction, to engage two contact members 36 and, when actuated in the other direction, to engage two contact men'ib'ers 37. The balance relays further comprise, respectively, asaturable transformer 38 that is provided with two dillerentially-actin'g primary-windings 39 and 40 and a single secondary winding 41 that is connected to the relay winding 33.

The overload relays 17, 19 and 21 are arranged to control the respective circuits associated therewith. Each of the balan'cerelaysl8', 20 and 22, however, is arranged to control two of the transmission circuits.

The balance'relay 18 controls the circuits 11 and 12, the balance relay 20 controls the circuits '12 and 13 and the balance relay 22 controls the circuits 11 and 13.

Upon the occurrence of faulty conditions i in one ofthe circuits, the relays will selec tively control the operation of the associated interrupter. Each of the interrupters is providedwith a trip coil 42 and three interlock switches 43, 44 and 45'.

In order to indicate to an attendant in the station the automatic disconnection of a circuit by reason of a faulty condition, a bell, or other indicating device, 46 is employed which is operated whenever one of the interrupters is automatically opened. A transfer relay 47 is employed to com-01 the circuit of the bell, or other indicating device. I

The relay 47 comprises a 'sw'tch 48 that normally is closed and a switch 49 that normally is open. The relay fur'the'r com-prises an operating coil 50 which, when energized,

actu'ates the switches 48 and 49 to opposite positions, at which positions the switche'sj'a re maintained by a latching member 51'. The latching niembfer 51 is actuated. to permit the resetting of the relay in its initial posi tio n' upon the ene'rgiz'ation of a resetting coil 52. A push hutt on switch 53 is provided to control the circuit or the resetting co'il.

By tracing the circuits of the operating coils of the balance relays, it will be noted that the relays are energized in accordance with the degree of unbalance between the currentstraversing the associated circuits. In considering the connections of the relay 18, for example, it will be observed that the windihgs 31 and 39 are energized from the current transformer 23, whereas the windings 32, and 40 are energized from the current transformer 24. The windings 39 and 40 are connected in their 'respective'circuits to be difierentially effective in'energizingfthe secondary winding 410i the saturable transformer.

The windings 31 and 32 are similarly differentially effective in maintaining a flux distribution in the magnetizable core member 30. Since the winding 41 is energized in accordance with the ditlerence between the degree of .en'erg'izaabh or the windings ber 34, depending upon which set of windings 31 and 39 or 32 and 40 is energized to agreater degree;

The saturable transformer 38 introduces a time element in the operation of. the balance relay 18 by'reason of its saturable char? a'ct'er andits limiting effect upon the value of the current that may be caused to traverse the circuit including the secondary winding 41. I

, The transf rmer 38 also serves to introduce an electrical angular displacement be tween the flux established by the winding 33 and the resultant flux established by the differentially-acting . windings 31 and 32, thereby rendering the induction .relay 18 operative. The necessity. for shading pole pieces or other corresponding means for introducing an angular displacement between two of the fluxes to produce a rotative torque in the disc member is thus obviated.

The inte'r'rupters 14, 15 and 16, when closed, effect the closing of the associated interlock switches 43, 44 and 45 to complete the various circuits controlled thereby. The switches 43 of the interrupters control, the circuit of the associated trip coil 42. The switches 45 of the interrupters 14 and 16, when closed, control the energizing circuit for the control switch iof the balance relay 22. The switches 44 ofthe interrupters 15 and '16 control the energizing circuittor the control switch of the balance relay 20 and, similarly, the interlock switch 44 of the inte'rrupter 14 and the switch 45 of the interrupter 15 control the energizingcircuit of the balance relay 18. The switch 45 of the interrupter 14 similarly controls the en ergizin circuit for the overload relay 17. Similarly, the switch 45 of the interrupter 15 and the switch 44 of the interrupter 16 control the energizing, circuits "for the switches of the associated overloadrelays 19 and 21, respectively. I I

If the interrupters 14, 1'5 and 16 are all closed to connect the feeder or transmission circuits to thesystemyand a fault should'occur upon the conductor 11 that would cause such an unbalance between the currents traversing the conductors 11 and 12 as to exceed a predetermined ratio between such currents, the windings 39 and 31 would be enercui ts.

gized to a greater degree thanthe windings 32 and 40. The balance relay would thereupon be energized to actuate the disc member 34 to effect the engagement of the contact members 36 by the bridging member 35. A circuit would thereupon be completed from the positive conductor of the control circuitthrough the switch 45 of the interrupter 15, the switch 44 of interrupter 14, the switch 35, the contact members so, thence through two circuits inparallel, one including the trip coil 42 and the other including the operating coil 50of the transfer relay 47, controlling the bell 46, to the negative conductor of the control circuit.

The interrupter 14 would thereupon be opened and the relay 47 would be actuated to its biased position to complete the circuit of the bell 46,thereby signalling to the station attendant that a circuit had been automatically disconnected from the system by reason of a faulty condition thereon. By depressing the push-button switch 53, the attendant can reset the relay 47 to render it operable for subsequent operation.

Upon the opening of the circuit interrupt.- er 14 to disconnect the circuit 11 from the source of energy 10, the switch 44 is opened. The balance relay 18 is then, therefore, inoperative to control the interrupter 15 of. the circuit 12. Balance protection is still obtained, however, between the circuits 12 and 13 by means of the balance relay 20, since the windings 31 and 39 of that relay are energized from the current transformer 24 and the windings 32 and 40 are energized from the current transformer 25. If the circuit 13 should now be disconnected by reason of abnormal conditions therein, the

,. interrupter 16 would be opened and the control circuits of all of the balance relays would be open c-irouited and the relays rendered inoperative to control any of the oil Undersuch conditions, the overload relay 19 would provide overload protection for the circuit 12.

So long as balanced current conditions obtain in the three or more transmission circuits, the balance relays will not operate to disconnect any of the circuits, irrespective of the amount of current traversing the same. Under such conditions, the overload relays provide overload protection for the respective circuits.

It will'be noted that a balance relay is associated with each two successive transmission circuits arranged as a pair of circuits to be protected by the associated relay. For the sake of simplicity, I have shown but one phase of the system involved. Similar protection would be provided for the other phases of the circuits to be protected;

l Vhile I have shown a system of protection containing a, particular type of relay, I do not limit my invention to the particular relays that are illustrated orto the particular arrangement thereof, since modilications may be made therein without departing from the spirit and scope of the ap pended claims. q 7 I claim as my invention: I 1Q'1he combination with a plurality of parallel-connected conductors between two points of an electrical system and circuit interrupters for the respective conductors, of an induction relay for selectively controlling either interrupter depending upon the occurrence of a fault thereon affecting a predetermined ratio between the currents normally traversing the conductors, said relay comprising a controlling member movable in two directions, two di'lferentiallyncting windings, a winding co-operating with the differential windings to actuate themovable member in one direction or the other depending upon the degree of energization of the differentially-acting windings and means for energizing the said winding in accordance with the variation from a predetermined ratio of the currents traversing thepair of conductors, said means serving also to introduce an electrical angular displacement between the magnetic flux established by the said winding andthe flux established by the differentially-acting windings, the fluxes cooperating to effect. movement of the movable member, in a time interval dependent upon the degree of energi'zation of said winding.

2. The combination with a plurality of parallel-connected conductors and circuit interrupters for the respective conductors, of means normally balanced when the currents traversing the conductors bear predetermined relations to each other and means comprising a saturated transformer controlled by currents proportional to the main currents traversing the conductors for controlling said balanced means and for introducing a time element and a directional element in the operation thereof.

3. In an electrical system, the combination with a plurality of parallel circuit conductors, circuit interrupters therefor and current transformers energized therefrom, of

means for selectively controlling the interrupters upon the occurrence of a fault in one termined ratio between the currents of the several circuits comprising a balance relay provided with two windings, each energized from a current transformer in eachconducllC of the conductors tending to affect a prede- I tor, and a co-operating winding for actuating the relay to select one or the other circult lnterrupter, and a control element also energized from the same current transformers for controlling the energization of the co-operating windings to introduce a direction selective action and an inverse time interval in the relays responsiveness.

4. In an electrical system, the combination with a plurality of parallel circuit conduc tors, circuit interrupters therefor and cur rent transformers energized therefrom, of means for selectively controlling the interrupters upon the occurrence of a fault in one of the conductors tending to affect a predetermined ratio between the currents of the several circuits comprising a balance relay provided with two windings, each energized from a current transformer in each conductor, and a co-op'erating winding for actuating the relay to select one or the other circuit interrupter, and means for influencing said Winding comprising an element responsive to the difference between the two circuit currents andan element associated therewith for introducing a saturating characteristic to the influence of said element upon I the winding thereby to introduce a selective and time delay action in the co-operation between said winding and the two differential windingz 5. An electric protective relay comprising an electromagnet provided with two windings differentially operative and adapted to be connected to two normally current-balanced circuits, a movable member, a winding for 'co-op'erating with the diiferential windings to actuate the movable member in one direction or the other, and means co-operative with the several windings for influencing theselective action and introducing a time element in the response.

In testimony whereof, I have hereunto subscribed my name this 31st day of March,

HARVEY P. SLEEPER.

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