US3043989A - Reclosing circuit breaker control system - Google Patents

Description

July 10, 1962 w. H. NASH ETAL 3,043,989

RECLosTNG CIRCUIT BREAKER CONTROL SYSTEM Filed Nov. 2s, 1958 l-IIIMIM L INVENTORS. nt/zany Wzn @yan BYl/:Zlziam H. /V'as/z United States Patent O 3,043,989 RECLOSING CIRCUIT BREAKER CNTRL SYSTEM William H. Nash, South Milwaukee, Wis., and Anthony Van Ryan, Ocean Springs, Miss., assgnors to McGraw- Edison Company, Milwaukee, Wis., a corporation of Delaware Filed Nov. 28, 1958, Ser. No. 776,822

4 Claims. (Cl. 317--22) This invention relates to switching devices and more particularly to means for providing power for the operating components of automatic switching devices.

While the invention has application to all types of prior art automatic switching devices, for purposes of illustration it will be described with reference to a selfcontained repea-ting circuit interrupter or recloser which may be characterized as acircuit protective device having fault sensing means operable to open the main interrupting switch upon the occurrence of Van overcurrent or other predetermined circuit condition, reclosing means adapted to reclose the main interrupting switch after a predetermined 'timedelay, operation counting means, and lockout means operable to prevent reclosing of the main interrupting switch after a predetermined number of opening operations. The fault sensing means of one type of circuit recloser comprises an overcurrent relay in series with the main interrupting switch so that it is responsive to and energized by the system current. The reclosing means of such reclosers may include a solenoid and secondary lswitch means adapted to energize the reclosing solenoid when the main interrupting switch has reached its fully opened position. The operation counting mechanisms and the lockout means of this type of recloser are generally coupled in some manner to the overcurrent relay or the reclosing solenoid. It can thus be seen that each of the operative components of such a recloser are aperated by and dependent upon the `system energy.

As a result of their dependence upon system power, this type of prior artrecloser sulered from the disadvantage that they were rendered totally inoperative by complete power loss in the system. Further, because these operating' components were subjected to the full system voltage, they were required -to have voltage ratings greatly in excess kof that actually necessary to operate vthe device, thereby greatly increasing the f-reclosers physical size and cost. Attempts to reduce the size of these components by the use of step down potential transformers has proved equally as costly because these transformers are required to have voltage ratings suiiicient to withstand full system voltage as well as any impulse voltages.

It is yan object of the invention to provide a self-energizing recloser whose operative components are not dependent upon the instantaneous values of system energy.

It is another object of the invention to provide a circuit breaker or recloser having operative components whose voltage ratings are independent of system voltage values.

It is a further object of the invention to provide a circuit breaker or recloser with aneconomical power supply circuit which provides a substantially constant energy supply regardless of instantaneous voltage and current conditions in the line.

It is a still further object of the invention to provide circuit breakers-or reclosesr with an integral power supply means which makes operating power available at all times and whose components do not have to be insulated for full system voltage.

Other objects and advantages of the present invention will become apparent from the followingr detailed description taken in view of the drawing in which schematically illustrates the principal components of a repeating circuit interrupter embodying the present invention.

ICC

In general terms the invention comprises providing a self-contained circuit breaker or recloser having an integral power supply circuit which includes energy storage means such as a storage battery, rectifier means for coupling said energy storage means to a source of alternating current such as a current transformer in circuit with the system to be protected. The invention `also includes providing such reclosers with means for selectively coupling the energy storage means -to the electro-responsive operating components of said recloser or circuit breaker to supply operating energy thereto, so that a predetermined sequence of operation of said operative components may be achieved.

The operating components of a repeating circuit interrupter include electro-responsive means for opening the primary switch means on o'vercurrent or other predetermined circuit condition, electro-re'sponsive reclosing means, and step by step operation counting and lockout means. By supplying energy to these components from the energy storage means rather than from the system, the voltage ratings of these devices can be limited to those necessaiy for operation independent of the instantaneous voltage values of the system, and-the primary switch may be operated independent of system power.

Referring now to the drawing in greater detail, the schematically illustrated repeating circuit interrupter is generally designated by the numeral 1 and the operating power supply unit is generally designated by the numeral 2. The circuit interrupter 1 and the power supply circuit 2 may be disposed in their own individual casings 3 and 4 respectively or that they may comprise a selfcontained unit.

The operating power supply circuit includes energy storage means 6 such as a storage battery. Energy is supplied to the battery 6 by means of a current transformer 7 which is a component part of the repeating circuit interrupter and whose primary is in circuit with the system supply line 8 and whose secondary is coupled `to the terminals of the storage battery 6 through a'rectilier 9 by means of conductors 1t), 11, 12, 13, and 14. It can thus be seen that the storagebattery 6 maybe continuously supplied with energy 8 `as long as system current continues to ow. The storage battery l6 may be protected against overcharging, however, by means of la protective relay 16 'whose coil 17 is connected to the battery terminals by conductors 18 and 19 so that when the battery voltage reaches the predetermined value, relay 16 will operate closing normally open contacts 20 to complete the circuit betwen conductors 10 and 14 to thereby short-circuit the secondary of the current transformer 7.

In order to protect the rectifier 9 from excessive currents, a second protective relay 22 may be provided. The latter includes a high impedance winding 24, a low impedance winding 26 and normally open contacts 27. High impedance winding 24 is in circuit between conductors 10 and 14, and low impedance winding 26 is in series with contacts 27, the series combination being in parallel with high impedance winding 24. When the current in the secondary of current transformer 7 reaches a predetermined value, high impedance winding 24 closes normally opened contacts 27 thereby shunting a portion of the current through low impedance winding 27 and around rectier 9.

The main operating components of the recloser 1 int' clude main interrupting contacts 30 in series with the determined number of opening operations. The recloser operating components above enumerated are supplied with energy from storage battery 6 through power supply conductors 42 and 44.

Reclosing solenoid 38 includes a coil 46 and a magnetic plunger 48 operatively connected to the main interrupting switches 30. 'Solenoid plunger 48 and the main interrupting switches 30 are biased toward open position by opening spring 50, but are retained in closed position by latch means 34 which includes a latch lever 52 -whose tip 52 engages a lug 54 carried `by an extension of solenoid plunger 48. Opening spring G acting on lug 54 urges bell crank 52 to rotate around pivot point 56 in a clockwisedirection, but such rotation is prevented by a stop 60 so that the main interrupting switch is held in closed position. Latch means 34 is tripped to allow the main interrupting switch to open by means of a tripping relay 36 having a coil 62 which upon being energized, causes magnetic plunger 64 to move upward, as viewed in the drawing, rotating bell crank 52 in acounterclockwise direction against the force of biasing spring 65, thereby disengaging tip 52 from lug 54 and allowing opening spring Si) to open the main interrupting contacts 30.

Trip coil 62 of tripping relay 36 is placed in circuit with the power supply conductors 42 and 44 by 4overload sensing means 32 upon the occurrence of a predetermined overload condition. More specically, overload sensing means includes an overload relay 66 whose coil 63 is in circuit lwith the secondary of a current transformer 70 coupled to the system supply line 8. Upon the occurrence of apredeterrnined overload in the system, overload relay 66 will operate to close normally open contacts 72 and thereby place trip coil 62 in circuit with the power supply conductors 42 and 44 through conuctors 73, 74, 75, 76, 77 and normally closed contacts 78. Tripping of the main interrupting switch 30 may be delayed by coupling a suitable time delay device 80 to the overload relay 66.

After latch means 34 has been tripped by tripping relay 36 in the above described manner, the main contacts 30 will move to their fully open position under the inuence of yopening spring 50, at which time normally open contacts 81 will be closed, placing `closing coil 46 of reclosing solenoid 38 in circuit with the power Supply conductors 42, 44 through conductors 73, 74, 82, 84 and normally closed contacts 78. Upon the energization of reclosing coil 46 magnetic plunger 48 is attached downwardly, as viewed in the drawing, to reclose the main interrupting switch 30 and re-set latch means 34. If it is desired to'delay the reclosing operation, a suitable time delay device 85 may be provided. Final movement of magnetic plunger 48 towards closed position revopens contacts 81 thereby opening circuiting reclosing coil 46 so that the main interrupting switches are free to reciprocate toward open position under the influence of opening spring should the fault persist and latch means 34 again be tripped.

Upon the opening of main interrupting switch 30, system supply line 8 will be open circuited whereby coil 68 of relay 66 will be vde-energized allowing normally open contacts 72 to reopen. The opening of contacts 72. open circuits tripping coil 62 and allows tripping plunger 64 to return to its initial position under the inuence of biasing spring 65 so that it will be in position for another operation. Should the system fault persist after the reclosing of main interrupting switch 30, normally Aopen ycontact 72 will again be closed lplacing tripping coil 62 in `circuit with the energy supply conductors 42, 44 resulting in the reopening of main contacts 30 in the above described manner.

1f the fault has not cleared after a predetermined number of such opening operations, usually four, it is considered permanent and the recloser must be locked open. For this reason counting and lockout means 40 ,oas een are provided to prevent the interrupting switch 30 from again reclosing. The counting and lockout means 40, illustrated in the drawing, includes a motor mechanically coupled to normally open switch means 92 through a speed reduction box 94. Motor 90 is normally de-energized but is placed in circuit with `battery 6 by overload sensing means 66 which also operates a second pair of normally opened contacts 96, so that upon the occurrence of an overload, motor 90 is placed in circuit with power supply conductors 42 and 44 through conductors 73, 98, 99, 77 and normally closed contacts '78. When the motor 90 is energized, it will move normally open switch means 92 towards closed position. Energy is supplied to the motor 90 in this manner until the main interrupting switch 30 is' tripped open, whereupon relay 66 is de-energized and contacts 96 open thereby interrupting the circuit to motor 90. -While the motor 98 is open circuited, biasing spring 100 tends to move contacts 92 toward open position "but rapid movement thereof, is prevented by time delay dash pot means 162. It will be understood by those skilled in the art, that by proper selection of the reduction ratio of the gear box 94, the speed of the motor 90, the constant of biasing spring 160 and dash pot 102, the movement necessary to close contacts 92 and the time delay between the opening and closing lof main interrupting switch 30, contacts 92 can be made to close after any desired number ot opening operations of the main interrupting -switch 39. For example, if 3.9 seconds of continuous motor operation would close contacts 92, and contacts 96 are normally closed for one second between the sensing of a fault and the opening of the main interrupting switch 30, then four cycling operations would be required to close contacts 92. The closing of contacts 92 places relay coil 104 in circuit with the battery conductors 42, 44

through conductor 106, normally closed contacts 78, conductors 77, contacts 96, motor 90, and conductors 98 and 73. Y

Upon the energization of relay coil 104, normally closed contacts 78 are opened so that the opening of the main interrupting switch 3G is ineffective to energize reclosing coil 46 and the interrupter is prevented from again reclosing. The opening of normally closed contacts 78 also open circuits the motor 90 thereby allowing biasing spring to return contacts 92 to their original position in preparation for another series of operations. Normally open contacts 78, however, remain closed until reset by manual means (not shown). If the fault clears after the first few opening operations so that the number of such operations are not suticient to cause lockout, biasing spring 100 will return contacts .92 to their original position after a sufficient time delay.

The schematically illustrated operation counting and lockout assembly 4t) is merely intended as an example and it will be understood by those skilled in the art that any well known device of this type may be utilized.

It can thus be seen that the occurrence of a fault in system supply line 9 causes electromagnetic latch trip means 36 yto be placed in circuit with battery 6 whereupon it trips latch 34 allowing the interrupting switch 30 to open. This results in the coupling of reclosing solenoid 38 to the battery 6 so that it is actuated to reclosed the interrupting switch 30; It the fault does not clear after a predetermined number of such operations, counting and. lockout means 40 operated to prevent the re-energizing of reclosing solenoid 38 so that the interrupting switch 30 remains open until manually reset.

While the invention has been illustrated in relation -to one schematically illustrated repeating circuit interrupter, it is understood that the power supply means according to the invention has application in all types of switching devices which have electro-responsive operating components such as circuit breakers and reclosers.

We claim:

l. A repeating circuit interrupter having primary switch means in circuit with a source of alternating electrical energy, spring means coupled to said primary switch means and biasing the same toward open position, latch means for holding said primary switch means closed `against the force of said spring means, a storage battery, a current transformer in circuit with said source of alternating electrical enregy, a rectier coupling said storage battery to said current transformer whereby the energy stoage therein may be substantially continuous, fault responsive means for opening said primary switch means on overcurrent including a first electromagnetic operator for tripping said latch means and fault sensitive means in circuit with said source of electrical energy for coupling said electromagnetic operator to said storage battery upon the occurrence of a predetermined overcurrent whereby said primary switch means is opened, a second electromagnetic operator having a coil and an armature mechanically coupled to said primary switch means, means for completing an energizing circuit to said coil after said fault responsive means has opened said primary switch means, whereby said primary switch meansis reclosed, and step by step lockout means for maintaining said second coil deenergized after a predetermined number of opening and closing operations whereby said primary switch means remain open.

2. A repeating circuit interrupter having primary switch means in circuit with an alternating current system, fault sensitive means for opening said primary switch means upon the occurrence of a predetermined circuit condition, reclosing means operative to close said switch means after each opening operation, said fault sensingmeans including an electro-responsive operator, a battery, current transformer means in circuit with said system, reetitier means coupling said battery to said current transformer means, means for energizing said electro-responsive operator from said battery upon the occurrence of said condition so that said electro-responsive operator will be enregized to open said primary switch means, whereby low voltage operating energy `for said electro-responsive switch control means may be supplied to said battery from high voltage electrical power systems of the distribution and sub-transmission class, and lockout means operative to prevent the reclosure of said switch means after a predetermined number of opening and reclosing operations.

3. .A repeating circuit interrupter. having primary switch means in circuit with a source of alternating electrical energy, latch means yfor holding said primary switch means closed, a storage battery, a current transformer in circuit with said source of alternating electrical energy, a rectifier coupling said storage battery to said current transformer, electro-responsive means for tripping said latch means to` open said primary switch means, and circuit means for coupling said electro-responsive means to said storage battery upon the occurrence of a fault in Said system so that the opening of said primary switch means will be eifected, reclosing means operative to close said switch means after each opening operation, and lockout means operative to prevent the reclosure of said switch means after a predetermined number of Opening and reclosing operations.

4. A repeating circuit interrupter having primary switch means for interrupting an alternating current circuit, electro-responsive means for opening said primary switch means, current transformer means inductively coupled to said circuit, rectier means coupling said storage 4battery to said current transformer means, condition responsive means coupled to said circuit and operative upon the occurrence `of an overload therein to couple said electro-responsive switch opening means to said storage -battery to effect the opening of said primary switch means, reclosing means operative to close said switch means after each opening operation, and lockout means operative to prevent the reclosure of said switch means after a predetermined number of opening and reclosing operations.

References Cited in the le of this patent UNITED STATES PATENTS 1,308,249 MacGahan July 1, 1919 2,053,445 Rose Sept. 8, 1936 2,259,331 Vedder Oct. 14, 1941 2,362,194 Dodd Nov. 7, 1944 Patent N0. 3,043,989 July lO, 1962 William H. Nash et al.

It is hereby certified that error a ent requiring correction and that the sa corrected below.

ppears in the above numbered patid Letters Patent should read as Column 6, line 24, after "circuit," insert a storage battery,

Signed and sealed this 26th day of March 1963.

(SEAL) Attest:

ESTON G. @'IIINSON DAVID L. LADD Attesting Officer Commissioner of Patents

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