US2525393A - Transfer-tripping carrier-current relaying system - Google Patents

Transfer-tripping carrier-current relaying system Download PDF

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US2525393A
US2525393A US771053A US77105347A US2525393A US 2525393 A US2525393 A US 2525393A US 771053 A US771053 A US 771053A US 77105347 A US77105347 A US 77105347A US 2525393 A US2525393 A US 2525393A
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fault
carrier
terminal
current
line
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John L Blackburn
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Westinghouse Electric Corp
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Westinghouse Electric Corp
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • H02H7/261—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
    • H02H7/262—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations involving transmissions of switching or blocking orders

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  • My invention relates to transfer-tripping carrier-current relaying-systems, and it has particular relation to the use of transfer-tripping carrier-current relaying-means as an adjunct to the prompt or instantaneous reclosure of circuitbreakers.
  • My invention has more particular relation to the protection of a transmission-line section which extends between two electrical buses located at different stations or places, under transmission-line operating-conditions in which one of the buses is a part of a largecapacity system, so that it will supply sufficient fault-current, to a fault, for a reliable instantaneous fault-determination at that terminal, whereas the other bus, at the other end of the protected line-section, is connected to a large load, with little spinning-capacity, so that, under some or all generating-conditions, this bus will have insuflicient fault-current-supplying capacity for reliable instantaneous fault-determination at this terminal.
  • the principal object of my invention is to provide a novel carrier-current means whereby the foregoing difliculties may be avoided.
  • a more specific object of my invention is to provide a normally continuously transmitting carrier-current transmitting-means, at the largecapacity terminal, for transmitting, to the other end of the protected line-section, during nor- 2 mal fault-free operating-conditions within th protected line-section, a continuous distinctive carrier-current signal denoting the continuance of a fault-free condition within the protected line-section, as determined at said large-capacity terminal, this continuous carrier-current transmission being stopped in response to a trippingrelay operation at the large-capacity terminal of the protected line-section, and this stoppage of carrier being utilized, at the low-capacity terminal, for effecting an instantaneous trippingoperation at said low-capacity terminal.
  • my invention consists of the systems, circuits, apparatus, combinations, parts and methods of design and operation hereinafter described and claimed, and illustrated in the accompanying drawing, the single figure of which is a much simplified diagrammatic view of the essential circuits and apparatus necessary to illustrate the novel features of my invention as applied to an illustrative protected line-section.
  • I have illustrated my invention as being applied to the protection of a threephase transmission-line section I, which is connected between a large-capacity west station, which is symbolized by a three-phase electrical bus W having a large generator G connected thereto, and a small-capacity east station, which is represented by a three-phase electrical bus E.
  • the east bus E carries a large load, with little spinning-capacity, so that, in general, it will have, or is likely to have, insufficient capacity to supply enough fault-current for reliable instantaneous fault-response discrimination at said east substation or terminal of the protected line-section I.
  • the line-section is connected to the station-bus W, at this end, by means of a circuit-breaker 2, which is shown as being provided with latched tripping and closing mechanisms, under the control of a trip-coil TC, and a closing-coil CC, respectively.
  • the breaker 2 also has two pole-operated auxiliary make-contacts a, which close when the main breaker-contacts close, a mechanism-operated make-contact aa, which closes in the operative or closed position of the breaker-operating mechanism, and'a mechanism-operated backcontact bb, which closes in an early part of the opening movement of the breaker-operating mechanism.
  • the various relays which make up the protective relaying-system include various relays which are shown, so far as practicable, after the manner of a schematic or across-the-line diagram, which re sults in the various relay-coils and relay-contacts being located, according to their circuits, at separated places in the drawing.
  • the main or operating-coil of the relay is given a letter-designation or legend, and the same letterde signation or legend is applied to all of the contacts of that relay.
  • the reset-coil is distinguished by a subscript R following the letter-designation of the relay.
  • Arrows or dotted lines are also used, to symbolically indicate how the various parts of each relay are connected together.
  • the relays and switches are invariably shown in their open or deenergized positions.
  • my invention contemplates the installation of fault-responsive relays, at each of the line-terminals, which respond only to internal fault-conditions, that is, to a condition in which there is a fault within the protected line-section I, somewhere between the two terminal buses W and E.
  • These internalfaultrelays may be instantaneous or quick-acting relays, and they may even be time-delayed relays, but in general, they will be instantaneous or nondelayed relays, having no substantial delays in their operatingtimes, and in general also, these relays will be carrier-supervised relays, which rely' upon a carrier-responsive blocking-means for blocking an instantaneous fault-response of the local fault-responsive protective-means, this blocking-action being obtained by means of carrier-current which is transmitted, only at times of fault, from the other end of the protected linesection, these transmitted carrier-current signals being utilized to distinguish between internal faults, located somewhere within the protected line-section, and external faults located somewhere beyond one end of the protected linesection.
  • phasecomparison system The other generally accepted carrier-current system, for reliably responding to internal faults within the protected line-section, is the so-cailed phasecomparison system, which is the one which I have chosen for illustration in connection with my present invention.
  • the general features of the illustrated type of phase-comparison system are shown in the Mehring Patent 2,408,868, granted October 8, 1946.
  • a fault-detector initiate the transmission of carrier-current impulses during line-current half-cycles of one polarity, and operating-impulses for a local relay during line-current half-cycles of the opposite polarity, utilizing carrier-current impulses, received from the opposite line-terminal, for blocking a response to the operating-impulses, under through line-current conditions.
  • I utilize a bank of line-current transformers 4, at each terminal of the protected line-section I, to derive, or respond to, the three-phase line-current
  • This line-current is supplied first to some back-up relays, which are symbolically indicated by a rectangle marked BU, because these relays may be of any known or conventional form, their precise details being immaterial to my present invention.
  • the derived line-current is then applied to any suitable network or filter, which is marked HKB, for deriving a single-phase alternating-current voltage which is applied to the primary winding of a saturable transformer ST.
  • the outputvoltage of the HKB network is responsive to a plurality of kinds andseverities of faults, on whatever line-phase a fault may occur, as broadly covered by the Harder Patent 2,183,646, granted December 19, 1939.
  • the secondary winding 6 of the Saturable transformer ST is shunted by a voltage-limiting gas-filled tube 7, as described in the Harder patent.
  • the secondary winding 6 also energizes the operating-coil FD of a fault-de-v tector, which is illustrated as being energized through a rectifier-bridge 8.
  • the secondary winding 6 is further used to energize the primary winding of an input-transformer IT, which is used to control the phase-comparison carriercurrent relaying-system which is shown in my accompanying drawing.
  • the input-transformer IT has two secondary windings II and l2, which are utilized to control the grid-circuits of two alternately triggering gas-filled tubes VI and V2.
  • the cathode-circuits of these gas-tubes VI and V2 include a biasing resistor RB, one terminal of which is connected to the negative bus of a direct-current voltage-source for the tubes, while the other terminal of said resistor is connected to a conductor 15, which is utilized for several purposes.
  • the circuit [5 is used to energizev one terminal of a cathode-circuit loading-resistor RI, the other terminal of which is connected to the cathodeterminal 2
  • the circuit 55 is also used to energize one terminal of another cathode-circuit loading-resistor R2, the other terminal of which is connected to the cathode-circuit 22 of the second gas-tube V2.
  • the two plate-circuits Pi and P2 of the respective gas-tubes VI and V2 are connected together through a capacitor C3, which assists in firingtransfer, as explained in the Mehring patent.
  • the two cathode-circuit loading-resistors RI and R2 are respectively shunted by capacitors Cl and G2, which also assist in firing-transfer, as set forth in the Mehring patent.
  • the two plate or anodecircuits PI and P2 of the two gas-tubes are connected, through resistors R3 and R4, respectively. to a common conductor 24, which is, in turn,
  • the grid-controlling secondaries II and I2 of the input-transformer IT are connected between the grid-circuits and the screen-grid circuits 26 and 21 of the respective gas-tubes VI and V2, these two screen-grid circuits 26 and 21 being connected to different taps on the biasing-resistor RB, so that the gas-tube VI starts firing on a slightly lower fault-current, (as supplied by the input-transformer IT), than the gas-tube V2, because the gas-tube VI has a smaller negative biasing potential applied thereto from the biasing-resistor RB.
  • the voltage-drop in the cathode-resistor R2 of the second triggering gas-tube V2 is utilized, through the circuit 22, during fault-conditions (under the control of the fault-detector FD), to apply a succession of positive or operating-voltage impulses to the grid-circuit 30 of a relay-tube RT, during alternate half-cycles of the line-frequency output of the HKB network.
  • This is done by having the cathode-circuit 22 of the gas-tube V2 connected to said relay-tube grid, through a loading-resistor R5 and a grid-circuit resistor R6.
  • the voltage-drop in the cathode-resistor RI of the first triggering gas-tube VI is utilized, through the circuit 2 I, as a source of energy for the platecircuit PC! of the main oscillator-tube OSC-l of a carrier-current transmitter, which thus transmits, during fault-conditions (under the control of the fault-detector FD) during the linefrequency half-cycles which have a polarity opposite to the polarity of the half-cycles during which the operating-voltage impulses are generated in the cathode-circuit 22 of the other triggering gas-tube V2.
  • the oscillator-tube OSCI is associated with a tuned circuit 3
  • the output-transformer OT-I has a secondary winding 32 which is provided with a line-tap 33, a receiver-tap 34 and y a grounded terminal 35.
  • the receiver-tap 34 leads to a tuning-capacitor TCI and a tuned-circuit 36, both of which are tuned to the same radio-frequency f1 as the oscillator, and thence a control-voltage is applied to the grid-circuit 31 of a receiver-tube REC-l.
  • the output of the receiver-tube REC-4 is utilized, through a voltage-doubler 38, to apply a negative or restraining-voltage to the loadingresistor R5, thus restraining the relay-tube RT against operation, whenever carrier-current energy, of the frequency fl, is being received by the receiver-tube REC-l,
  • the output of the relay-tube RT is applied, through a relay output-transformer ROT, to the operating-coil of a relay R, which thus responds to the line-frequency component of the outputcurrent of the relay-tube RT.
  • the equipment as thus far described, is included at both ends or terminals of the protected line-section. This constitutes a phase-comparison carrier-current protective relaying-system for quickly tripping the breakers 2, at both terminals,
  • I provide an extra transmitter at the large-capacity terminal W of the protected line-section, and an extra receiver at the limited-capacity terminal E.
  • the second carrier-current transmitter at the large-capacity west station W, is diagrammatically represented by an oscillator-tube OSC-2, which is associated with two amplifier-tubes AI-2 and A22, and an output-transformer OTB-2.
  • This second oscillator-tube OSC-2 is of the continuously transmitting type, that is, a type which is continuously transmitting during normal fault-free conditions on the transmission-system.. This is brought about by energizing the platecircuit PCZ of the oscillator-tube OSC-2, from the positive terminal of the station directcurrent source, through the back-contact 40 of an auxiliary tripping-relay SG which is utilized at this west station, as will be subsequently described.
  • the second oscillator-tube OSC2 is associated with a tuned circuit 42 which is tuned to a second carrier-current frequency f2 which is different from the carrier-current frequency which is used in the phase-comparison protective system, thus causing the second oscillator to transmit at this second frequency.
  • a second receivertube REC-2 is used, the grid-circuit of which is connected to the receiver-tap 34 of the carriertransmitter output-transformer OT-l, at this station, through a tuning-capacitor T02 and a tuned circuit 41, both of which are tuned to the second carrier-current frequency f2, that is, to the frequency of the continuous carrier-current transmitter which is located at the other 1ineterminal W.
  • the output of the second receivertube REC-2, at the east station E, is utilized to energize the operating-coil of a carrier-receiver relay PG, which is utilized as a transfer-tripping relay.
  • the coupling-transformer GT2 for the second carrier-frequency f2, that is, for the fre quency of the continuous carrier-current transmitter which is stopped by the auxiliary trippingrelay SG, is coupled to the carrier-current lead-in cable 53, by means of an fz-frequency line-tuner 56 and an fi-frequency trap 51.
  • the carriercurrent lead-in-cable 53 is coupled to phase-C of theline I, through a coupling-transformer 58,
  • the limitedcapacity east station E is provided with a bank of potential-transformers 63, which are utilized to energize the operating-coils of three undervoltage fault-detector relays VA, VB and VC, for the three delta line phases
  • These undervoltage relays serve as fault-detectors by responding to a predetermined drop in the line-voltage. They are intended, in the broader aspects of my invention, to be representative of any fault-detector which does not require a magnitude of line-current which is necessary to pick up th cLurent-responsive fault-detector FD at this station E.
  • the direct-current tripping and reclosing circuits for controlling the circuit-breakers 2 at the respective ends of the protected line-section I ,are
  • the basic tripping and reclosing circuits are identical, at both, ends of the line, with certain additional equipment added at the limited-capacity end E, for providing the quick tripping which is necessary, at this station, in order to clear an arcingfault on the protected line-section, so that the breakers at both ends can be reclosed, even though the fault-current at low-capacity end E may b insignificant.
  • I will first describe the basic tripping and reclosing circuit, which is common to both ends of the protected line-section.
  • the fault-detector FD has a make-contact 64 which is connected to the negative station-bus in series with the make-contact R, of the phase-comparison relay R, to energize the circuit B of the operating-coil SX of a reclosingrelay SX, which is preferably a relay of the position-retaining type.
  • the operating-coil SX is connected, through a conductor 66, to the opcrating-coil of the auxiliary tripping-relay SG, which has previously been mentionedin connection with the control of the second carrier current oscillator OSC2 at the station W.
  • the operating-coil SG is connected, through a circuit 57, to an auxiliary make-switch a of the circuit-breaker 2 at the relaying-station, and thence to the positive station-bus
  • the trip-coil TC of the breaker at-this station, is energized by a parallel circuit extending between the conductors 66 and 61, and serially including a makecontact 68 of the auxiliary tripping-relay SG.
  • any desired additional tripping-circuits may-also be provided, as are symbolically represented by aback-up make-contact BU, which is connected 8 between the negative-terminal and the conductor 66, thus providing back-up tripping, without an accompanying reclosing-operation, because the reclosing-relay SX is not energized by the back-up contact BU.
  • aback-up make-contact BU which is connected 8 between the negative-terminal and the conductor 66, thus providing back-up tripping, without an accompanying reclosing-operation, because the reclosing-relay SX is not energized by the back-up contact BU.
  • reclosing circuit or control-system Any suitable reclosing circuit or control-system may be utilized.
  • An illustrative reclosing system is shown, in its simplest elements, as comprising a make-contact SX of the reclosing relay, this make-contact SX being connected to the negative bus in series with a manually controllable switch 10, an auxiliary breaker-contact bb, which closes at an early stage during the opening movement of the breaker-mechanism, and a back-contact TR of a toggle-relay or other position-retaining relay TR, and thence to a conductor H.
  • the conductor H is utilized to energize the operating-coil X of a closing-relay X, the cir'-' cuit of which alsoincludes the back-contact Y of a releasing-relay Y.
  • the back-contacts Y are a little slow in opening, in response to an energization of said releasing-relay Y, as is diagrammatically indicated by means of a dashpot 72.
  • reclosing-relay SX is of the positionretaining type, as has been assumed in the illustrated form of embodiment of my invention, it is provided with a reset-coil SXR, which is energized from the conductor H in series with a make-contact X of the closing-relay X.
  • the conductor TI is also utilized to energize the operating-coil Y of the releasing-relay Y, the circuit of which is completed through an auxiliary breaker-switch aa, which opens at an early stage during the opening-movement of the breaker-mechanism.
  • the time-relay which is introduced by the dashpot 12, or other delayingmeans, on the releasing-relay Y, is sufl'icient to prevent the possibility of the opening of the releasing-relay back-contact Y prior to the opening of the auxiliary breaker-switch contacts aa.
  • These switch-contacts aa are bypassed by a make-contact Y of the releasing-relay Y.
  • the next line of the schematic direct-current diagram shows a holding-circuit T4 for the conductor 1
  • This line of the schematic diagram also shows the utilization of the conductor H to energize a closing-coil circuit 15 in series with another make-contact X of the closing-relay X,
  • the circuit 75 energizes the closing-coil CC of the breaker at this station, and also a parallel-connected operating-coil TB, of the toggle-relay TR.
  • the toggle-relay TR- has a make-contact TR which energizes an alternating-current line-frequency circuit, which is shown inset into the direct-current diagram of the drawing, to energize the winding T of a reclosing-relay timer T, in series with a circuit-breaker make-contact a, in a sixty-cycle timer-circuit marked AC--AC.
  • the timer T has a make-contact T which energizes the reset-coil TRR of the toggle-relay TR.
  • the breaker-trippin and reclosing circuits are the same as have just been described, with the addition of a transfer-tripping circuit for providing another means for energizing the circuit 65 of the auxiliary reclosingrelay SX.
  • the transfer-tripping circuit 80 0perates under the control of a back-contact PG of thepreviously mentioned transfer-tripping relay PG, under the supervision or control of a serially connected, manually controllable switch 8!.
  • the back-contact PG of the transfer-tripping relay PG is supervised by the fault-detectors VA, VB and VC at the station E, so that a transfer-tripping operation will not be eifected, at the station E, unless there is some indication of the existence of a fault, as determined by the undervoltage faultdetectors VA, VB and VC.
  • These undervoltage fault-detectors have back-contacts VA, VB and V0, which are connected in parallel with each other, and in series with the make-contact PG in the transfer-tripping circuit 80.
  • any fault-current which appears in the protected line-section I must come from the limited-capacity station E. If this fault-current is too small to pick up the fault-detectors at the two ends of the line-section, there will be no energization of the triggering gas-tubes VI and V2, at either end of the line-section, and hence there will be no operating-voltage applied to the relay-tube RT, and hence no instantaneous phase-comparison tripping, at either end of the protected line-section I.
  • the fault-current which appears in the protected line-section l is supplied by the large-capacity station W, and this faultcurrent is always large enough to pick up the fault-detectors FD at both ends of the protected line-section, thus blocking tripping, as in any phase-comparison protective system, such as is disclosed in the Mehring patent.
  • a protective carrier-current relaying-system for protecting a line-section of a transmission-system against internal faults within said line-section, comprising fault-responsive relaying-means, at a first terminal of the protected line-section, for reliably determining the existence of an internal fault within the protected line-section, a normailly continuously transmitting carrier-current transmitting-means, at said first terminal, for transmitting, to a second terminal of the protected line-sec;ion, during normal fault-free operating-conditions within the protected line-section, a continuous distinctive carrier-current signal denoting the continuance of a fault-free condition within the protected linesection, as determined at said first terminal, means disposed at said first terminal for stopping the transmission of said distinctive continuous carrier-current signal in response to a response of said fault-responsive relaying-means at said first terminal, and means disposed at said second terminal for providing at internalfault response to a non-receipt of said distinctive 11 continuous carrier-current signal from the first terminal.
  • a quick-reclosing carrier-current protective-system for protecting transmission-line section which extends between a first electrical bus and a second electrical bus, said first electrical bus being disposed at a first terminal of the protected line-section and having sufficient fault-current-supplying capacity for reliable instantaneous fault-determination at said first terminal, said second electrical bus being disposed at a second terminal of the protected line-section and, at least at times, having insufficient faultcurrent-supplying capacity for reliable instantaneous fault-deterinination at said second terminal, said quick-reclosing protective system comprising an instantaneous fault-responsive protective-means, at each of said terminals, for
  • said protective-system being characterized by further comprising a normally continuously transmitting carriercurrent transmitting-means, at said first terminal, for transmitting, to said second terminal, during normal fault-free operating-conditions within the protected line-section, a continuous distinctive carrier-current signal denoting the continuance of a fault-free condition within the protected line-section, as determined at said first terminal, means disposed at said first terminal for stopping the transmission of said distinctive continuous carrier-current signal in response to a response of said
  • a protective carrier-current relaying-system for protecting a transmission-line section which extends between a first electrical bus and a second electrical bus, said first electrical bus being disposed at a first terminal of the protected line-section and having sufficient fault-currentsupplying capacity for reliable instantaneous fault-determination at said first terminal, said second electrical bus being disposed at a second terminal of the protected line-section and, at least at times, having insufficient fault-currentsupplying capacity for reliable instantaneous fault-determination at said second terminal, said relaying-system comprising an instantaneous fault-responsive protective-means, at each of said terminals, for responding to an internal fault within the protected line-section, each of said fault-responsive protective-means including a carrier-responsive blocking-means for blocking an instantaneous fault-response of said faultresponsive protective-means, a normally nontransmitting carrier-current transmitting-means, at each of said terminals, for at times transmitting a carrier-current signal for energizing the carrier-responsive blocking-means at
  • a quick-reclosing carrier-current protective-system for protecting a transmission-line section which extends between a first electrical bus and a second electrical bus, said first electrical bus being disposed at a first terminal of the protected line-section and having sufllcient faultcurrent-su'pplying capacity for reliable instantaneous fault-determination at said first terminal, said second electrical bus being disposed at a second terminal of the protected line-section and, at least at times, having insufficient fault-current-supplying capacity for reliable instantaneous fault-determination at said second terminal, said quick-reclosing protective system comprising an instantaneous fault-responsive protective-means, at each of said terminals, for responding to an internal fault within the protected line-section and for effecting a quick interrupter-opening operation for disconnecting the protected line-section from the bus at the terminal where the fault-responsive relayingmeans is located, each of said fault-responsive protective-means including a, carrier-responsive blocking-means for blocking an instantaneous fault-response of

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2991397A (en) * 1957-10-31 1961-07-04 Femco Inc Protective system for detecting breakdown resistance that would cause a short or ground of a power circuit
US3414773A (en) * 1966-08-25 1968-12-03 Wayne Electronic Products Comp Automatic relay carrier circuitry for testing multiple terminal points employing timer sampling means

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB320067A (en) * 1928-06-21 1929-09-23 Reginald Otto Kapp Improvements in or relating to protective arrangements for electric power lines or the like
GB415576A (en) * 1932-08-08 1934-08-30 Siemens Ag Improvements in and relating to protective electrical circuits for power lines and the like
GB418060A (en) * 1932-04-15 1934-10-12 Westinghouse Electric & Mfg Co Improvements in or relating to electric cut-out or protective systems
GB499512A (en) * 1937-08-20 1939-01-25 Gen Electric Co Ltd Improvements in or relating to carrier signalling systems applicable to electric protection systems
US2408868A (en) * 1944-05-10 1946-10-08 Westinghouse Electric Corp Carrier-current phase-angle relaying system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB320067A (en) * 1928-06-21 1929-09-23 Reginald Otto Kapp Improvements in or relating to protective arrangements for electric power lines or the like
GB418060A (en) * 1932-04-15 1934-10-12 Westinghouse Electric & Mfg Co Improvements in or relating to electric cut-out or protective systems
GB415576A (en) * 1932-08-08 1934-08-30 Siemens Ag Improvements in and relating to protective electrical circuits for power lines and the like
GB499512A (en) * 1937-08-20 1939-01-25 Gen Electric Co Ltd Improvements in or relating to carrier signalling systems applicable to electric protection systems
US2408868A (en) * 1944-05-10 1946-10-08 Westinghouse Electric Corp Carrier-current phase-angle relaying system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2991397A (en) * 1957-10-31 1961-07-04 Femco Inc Protective system for detecting breakdown resistance that would cause a short or ground of a power circuit
US3414773A (en) * 1966-08-25 1968-12-03 Wayne Electronic Products Comp Automatic relay carrier circuitry for testing multiple terminal points employing timer sampling means

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