June 2, 1936. I
`
`w_ M, HANNA '
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`2,043,099
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`ELECTRICAL PROTECTIVE SYSTEM
`
`Filed Oct. 26, 1933
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`7
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`7
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`Inventor:
`William M.l-1anna,
`by‘ imtorn ey.
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`

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`Patented June 2, 1936
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`2,043,099
`
`UNITED STATES
`
`PATENT OFFICE
`
`10
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`2,043,099
`ELECTRICAL PROTECTIVE SYSTEM
`William M. Hanna, Schenectady, N. Y., assignor
`to General Electric Company, a. corporation of
`New York
`Application October '26, 1933, Serial No. 695,288
`(Cl. 175-294)
`1 Claim.
`compartment l0, current transformer and cable
`My invention relates to electrical protective
`compartment. ll, potential transformer compart
`systems, more particularly to protective systems
`ment l2 and a reactor compartment I3. It will
`for electrical power distribution circuits and the
`like, and has for its principal object the provi
`be understood, of course, that the above described
`sion of an improved system for instantly detect
`arrangement may be varied to a considerable ex
`tent in accordance with the operating require
`in‘g fault arcs and causing electrical isolation of
`ments and preferred design of the station.
`the same.
`The aforesaid compartments housing the elec‘
`The occurrence of a fault arc, as arcing be
`trical apparatus of the station are normally closed
`tween phases or to ground, in a bus and switch
`and sealed with respect to exterior sources, of
`station of an electrical power distribution system,
`light, access being had in any suitable manner as
`for example, necessitates immediate action in iso
`by a door 14 in the case of the reactor compart
`lating or cutting off the affected part of the cir
`cuit from the remainder of the system. Timely
`ment 13.
`In case-of a fault are within the station, as? for
`isolation of the fault may minimize the damage
`example between one of the phase busbars 2 and
`and prevent the spreading of trouble throughout
`grounded supporting or wall structure, the flash
`the bus and switch station and other parts of the
`system.
`of the are within the normally darkened busbar
`compartment is detected by a light sensitive cell,
`The use of ground fault and over-current re
`as a photo-electric cell l5, suitably located with
`lays and similar electro-responsive devices for
`in the busbar compartment Ill. The photo-elec
`‘ detecting fault currents and isolating the affected
`N) c.
`tric cell l5 coacts with electro-responsive means
`parts of the system is well known practice. In
`l5’ for closing a circuit breaker tripping circuit,
`accordance with the present invention, the fault,
`the source of supply voltage for which is indi
`as evidenced by arcing, is instantly detected by a
`cated at IS. The tripping circuit includes a trip
`light sensitive cell which coacts with electro-re
`ping coil H which may coact in any suitable and
`sponsive means so as to cause tripping of a cir
`well known manner with the tripping and oper
`cuit breaker, or breakers, for isolating the afore
`ating mechanism [8 of the circuit breaker 3. The
`said fault.
`circuit breaker 3 and its operating and tripping
`My invention will be more fully set forth in the
`following description referring to the accompany
`mechanism per se form no part of the present in
`vention and further description thereof is be
`ing drawing, and the features of novelty which
`lieved unnecessary other than to point out that
`characterize my invention will be pointed out with
`operation of the bellcrank l9 e?e-cts vertical
`particularity in the claim annexed to and form
`movement of the oil circuit breaker bridging
`ing a part of ‘this speci?cation.
`member to open and close the circuit through the
`Referring to the drawing, Fig. 1 is a partly di
`breaker.
`agrammatic illustration of a bus and switch sta
`Energization of the trip coil ll from the con
`tion provided with an electrical protective system
`trol source I6 effects tripping and opening of the
`embodying the present invention, and Fig. 2 is a
`diagrammatic illustration of a ring bus arrange
`oil circuit breaker 3 in a manner well known in
`the art. In the event that a plurality of oil cir
`ment to which, by way of example, the aforesaid
`protective system is applied.
`cuit breakers are to be tripped simultaneously in
`response to energization of the control circuit,
`Referring more particularly to Fig. l, the bus
`the trip coils of such breakers may be connected
`and switch station I is provided with a plurality
`of normally closed compartments containing the
`in parallel with the trip coil IT as indicated at
`high tension electrical apparatus of the station.
`20.
`Likewise mounted within the oil circuit breaker
`The bus and switch station, as well known in the
`compartment 9, current transformer compart
`art, comprises part of an electrical power dis
`ment ll, potential transformer compartment l2
`tribution system including the distribution bus
`and reactor compartment l3 are photo-electric
`bars 2, oil circuit breaker 3 and corresponding
`cells 2|, 22, 23 and 24, respectively, coacting with
`disconnecting switches 3’, current transformer
`the corresponding electro-responsive means 2|’,
`4, potential transformer 5 and corresponding dis
`22’, 23’ and 24' which are each related to the oil
`connecting switch or fuse 5’, reactor 6 and feeder
`circuit breaker tripping circuit in the manner of
`or generator circuit 1.
`.
`electro-responsive means l5’. Accordingly, a
`The station as illustrated comprises a centra
`fault, as evidenced by arcing, in any one of the
`operator’s passage 8, an oil circuit breaker and
`aforesaid compartments is instantly detected by 55
`disconnecting switch compartment 9, a busbar
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`40
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`' 2
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`45
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`2,043,099
`the corresponding photo-electric cell which,
`In order to prevent actuation of the circuit
`through its associated electro-responsive means,
`breaker tripping mechanism whenever the sta
`causes energization of the tripping coil I ‘l and
`tion operator opens a door admitting light to a
`opening of the proper circuit breaker, or breakers,
`compartment, a door switch 40 may be connected
`to isolate the fault in that part of the station.
`in series with the relay 38 so as to open the circuit
`The electro-responsive means 24’ coacting with
`of the relay coil when the compartment door is
`the photo-electric cell 24 in the reactor compart
`opened. When the compartment door is closed
`ment is diagrammatically illustrated and includes
`the switch 40 is likewise closed so that the relay
`an electron discharge device 25 having the usual
`38 may be energized in the normal manner by the
`?lament or cathode 26, grid 21 and plate or
`photo-electric cells. For manual control of the
`anode 28. A primary transformer winding 29 en
`tripping means, a switch 6| is arranged to close
`ergized from a suitable source of alternating cur
`the tripping circuit.
`rent is related to secondary windings 35, 3| and
`Where desirable, the electroresponsive appara
`32 which energize the output, ?lament and con
`tus associated with a photo-electric ‘cell may con
`trol circuits, respectively, of the electron dis
`trol a signal circuit so that there is a visual or
`charge device 25.
`audible indication of the opening of one or more
`The control and output circuits associated with
`breakers when a flashover or fault arc occurs.
`the electron discharge device form per se no part
`Fig. 2 diagrammatically illustrates a ring bus
`of the present invention, and the operation there
`arrangement to which feeder and generator lines
`of is well known in the art. The photo-electric
`may be connected. In the present instance the
`cell 24, which comprises a variable resistance
`ring bus 2 is sectionalized by the reactors 6 and
`when exposed to varying intensities of light, a
`the corresponding series and by-pass circuit
`capacitance 33 and a potentiometer 34 comprise
`breakers 6’. The feeder or generator lines ‘I, as
`a phase shifting bridge connected through a grid
`the case may be, are connected as illustrated
`resistance 35 to the grid 27. The power output
`through the circuit breakers 3 to the ring bus.
`or anode-cathode circuit includes an operating
`If now a fault arc should occur at one of the
`coil 35', and the secondary winding 30 which is
`reactors 6 for example, the photo-electric cell 24
`connected to the secondary winding 3| at 36.
`in that portion of the reactor compartment would
`The operation of the system is as follows: In
`cause tripping of all circuit breakers which could
`the event of the occurrence of a fault are within
`possibly feed current into the fault. In the pres- 9
`the reactor compartment l3, for example, the re
`ent instance two breakers 6' would open at oppo
`sistance of the photo-electric cell 24 instantly
`site sides of the fault as indicated, thereby vcom
`changes in response to the ?ash of the are so as
`pletely isolating the fault.
`to change the phase relation of the grid voltage
`The circuit breakers may, of course, be oper
`with respect to the anode voltage. As is well
`ated in the usual manner by over-current relays “
`known, the electron discharge device 25 is effec
`as indicated in Fig. 2. In order to avoid compli
`tive as an asymmetrical conductor to pass uni
`cation of the drawing, the current transformer
`directional current impulses through the anode or
`4 is shown connected to a relay 4’ for energizing
`output circuit in the event that the grid voltage
`a separate trip coil 43 of the circuit breaker.
`is less negative than a certain critical value.
`40
`It should be understood that my invention is
`When the grid voltage is more negative than the
`not limited to speci?c details of construction
`critical value no current will flow. The charac
`and arrangement thereof herein illustrated, and
`teristics of the photo-electric cell circuit are such
`that changes and modi?cations may occur to one
`that when the ‘compartment is dark the corre
`skilled in the art without departing from the
`sponding resistance of the cell causes the grid
`spirit of my invention.
`voltage to assume such a phase relation with re
`What I claim as new and desire to secure by
`spect to the anode voltage that it is more nega
`Letters Patent of the United States, is:
`tive than the aforesaid critical value during the
`In a bus and switch station for a high tension
`positive half cycles of anode voltage. Accordingly,
`electric transmission and distribution system in
`no current ?ows through the output circuit in
`50
`cluding a normally closed and darkened compart
`cluding the operating coil 35’. When, however,
`ment housing high tension electrical apparatus
`the resistance of the photo-electric cell changes
`having an opening therein and a closure for said
`in response to the ?ash of an arc the phase angle
`opening and a circuit breaker for discomiecting
`of the grid voltage is changed so that the grid
`said electrical apparatus from said system, an
`voltage becomes less negative than the aforesaid
`55
`electrical protective system comprising a light
`critical value during positive half cycles of anode
`sensitive cell mounted in said compartment so
`voltage and current ?ows through the operating
`as to detect a fault at any part of said apparatus
`coil 35' effecting closing of control switch 31 and
`as evidenced by arcing in said compartment, elec
`energization of relay 38 which in turn energizes
`tro-responsive means including a relay coacting
`the circuit breaker tripping ‘circuit through con
`with said light sensitive cell for causing tripping
`tacts 39. It will be apparent that a plurality of
`of said circuit breaker, and means rendering in
`photo-electric cells may be connected in parallel
`operative said relay when said closure is open.
`to the same electroresponsive device where the
`same breaker or group of breakers is to be
`tripped.
`
`WILLIAM M. HANNA’
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`60
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`65
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