US3786310A - Hybrid dc circuit breaker - Google Patents

Hybrid dc circuit breaker Download PDF

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Publication number
US3786310A
US3786310A US00346208A US3786310DA US3786310A US 3786310 A US3786310 A US 3786310A US 00346208 A US00346208 A US 00346208A US 3786310D A US3786310D A US 3786310DA US 3786310 A US3786310 A US 3786310A
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Prior art keywords
circuit breaker
connection point
line
direct current
crossed
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US00346208A
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W Long
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Raytheon Co
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Hughes Aircraft Co
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
    • H01H33/02—Details
    • H01H33/59—Circuit arrangements not adapted to a particular application of the switch and not otherwise provided for, e.g. for ensuring operation of the switch at a predetermined point in the ac cycle
    • H01H33/596—Circuit arrangements not adapted to a particular application of the switch and not otherwise provided for, e.g. for ensuring operation of the switch at a predetermined point in the ac cycle for interrupting dc
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/02—Details
    • H02H3/021—Details concerning the disconnection itself, e.g. at a particular instant, particularly at zero value of current, disconnection in a predetermined order

Definitions

  • ABSTRACT [52] US. Cl. .(317/11 C, 307/136, 317/11 E [51 Int. Cl. H02h 7/22 58 Field of Search 317/11 E, 11 (3; DC breaker has both and lme-to-gmlmd 307/136 components to limit in-line and line-to-ground voltages during load breaking and fault clearing. Impe- [56] References Cited dance insertion forces down current.
  • This invention is directed to a hybrid DC circuit breaker which limits in-line and line-to-ground voltage.
  • ln-line circuit breakers are those wherein current to be interrupted is diverted into a resistance in series with the load.
  • One example of this is the sequential switching circuit breaker of K. T. Lian reissue patent RE-27,557.
  • Another example is the series sequential circuit breaker of M. A. Lutz patent 3,660,723.
  • the other fundamental configuration of the prior art is the line-to-ground breaker wherein current is diverted into resistance between the line and ground, and the in-line circuit is open. Examples of this are A. N. Greenwood U.S. Pat. Nos. 3,390,305; 3,435,288; 3,476,978; and 3,489,951.
  • the line-to-ground DC circuit breaker has an in-line switch and a series combination of a switch and a resistor connected to ground on each side of the in-line switch.
  • the disadvantage arises that the voltage applied across the in-line switch is that sum of the voltage drop across the two line-to-ground resistors. This can be avoided by shorting the load side of the in-line switch to ground to eliminate the load side voltage to the in-line switch. However, this is not really acceptable in power systems.
  • a hybrid circuit breaker which comprises a line switch for serial interconnection between a power source and itsload.
  • the line switch is paralleled by a shunt switch whichpermitsthe line switch to open and deionize.
  • a series combination of a switch and a resistor with a connection point therebetween.
  • a series combination of a switch and a resistor so that voltages are limited during off-switching and current is forced down.
  • FIG. 1 is a schematic circuit diagram of a high voltage DC system showing the schematic arrangements of a high voltage DC hybrid circuit breaker connected therein for load breaking and fault protection;
  • FIGS. 2-4 are graphs showing voltages across various parts of the circuit breaker during load breaking
  • FIGS. 5-7 are graphs showing the current through various portions of the circuit breaker during load breaking
  • FIG. 8 is a schematic diagram showing another species of the hybrid circuit breaker of this invention.
  • an electric system 10 is shown therein.
  • the electric system comprises a power source 12 which is connected through power line 14 and ground line 16 to a load 19.
  • the hybrid DC circuit breaker 18 is connected in line 14 and between line 14 and ground 16 to control the flow of power to the load.
  • a power system of this nature is disclosed in more detail in G. A. G. Hofmann U.S. Pat. 3,558,960. That patent describes the power source and load in more detail. Furthermore, that patent illustrates switching can be accomplished in a transmission line by switch 100, and can be accomplished in a side tap arrangement from the main transmission line to a tapped load.
  • Circuit breaker 18 of the present invention is capable of both line and side tap load switching. Furthermore, it is capable of load off-switching as well as fault breakmg.
  • Circuit breaker 18 has in-line switch 20 connected serially in power line 14 between connection points I and 2.
  • In-line switch 20 can be a conventional mechanical switch which has a low impedance when closed, and when open can hold off the peak voltages between connection points 1 and 2.
  • the inline switch is in parallel with crossed-field switch device 22, described in greater detail below, and it is necessary for such crossed-field switch devices to have a voltage impressed thereacross to begin conducting, it is desirable that the in-line switch device 20 be capable of developing adequate arc voltage to permit initiation of conduction in the crossed field switch device 22. At present, about one kilovolt is necessary to start conduction. Therefore, in-line switch device 20 is preferably capable of developing a substantial arc voltage drop.
  • Line 24 is connected from connection point 2 through connection point 6 to connection point 3 on ground line 16.
  • line 26 is connected between connection point 1 through connection point 5 to connection point 4 on line 16.
  • Capacitor 28 is connected between lines 24 and 26 to control the rate of voltage rise when in-line switch 20 or crossed-field switch device 22 are off-switched.
  • crossedfield switch device 22 is connected in parallel to in-line switch 20, between lines 24 and 26.
  • Crossed-field switch device 22 is a switch device which is capable of passing direct current and off-switching direct current against high voltage. Crossed-field switch devices of this nature are disclosed in K. T. Lian U.S. Pat. RE- 27,557, M. A. Lutz and R. C. Knechtli U.S. Pat.
  • the power source 12 is capable of normal line voltages of 400 kilovolts at 2,000 amperes. These values will be considered to be the per-unit in the illustration, which is the 1 pu in this disclosure. For purposes of illustration, the values are normalized, with 1 pu voltage sources and initial currents. System inductance is shown lumped, and no transmission line or filter effect are included in the discussion. The non-linear resistors are considered ideal. With an overvoltage value k 1.5, the non-linear resistors are treated as 1.5 pu DC sources in the voltage analysis.
  • 1.5 pu is chosen as maximum overvoltage. Quite often in modern power transmission practice, an overload factor k of 1.7 is found. However, for purposes of this illustration, a value of 1.5 is chosen for illustrative purposes. If the equipment is designed for a different overvoltage factor, that factor would, of course, be employed in designing the circuit breaker for that system.
  • Modern non-linear resistors are structures which do not obey Ohms Law, but the value of resistance varies with the amount of current. In the present case, a high resistance at low current and a lower resistance at high current is desired.
  • the ideal non-linear resistance would have an infinite resistance value at zero current, but would break down and commence conducting when its breakdown voltage was reached.
  • Modern nonlinear resistors are made of silicon carbide, and do not reach the ideal goal.
  • discussion of the present circuit breaker with ideal resistors therein aids in ease of description. The voltage and current curves would be less ideal, when a real non-linear resistor is employed.
  • crossed-field switch device 22 In the operation, as described below, during offswitching or fault breaking, current is transferred from in-line switch into crossed-field switch device 22, by opening the switch 20 when crossed-field switch device 22 is conditioned to conduct. After in-line switch device 20 is opened and deionized, crossed-field switch device 22 is turned off. If there is too much energy in the circuit for a simple turnoff, a circuit can be connected and paralleled to crossed-field switch device 22 which comprises a series combination of another crossed-field switch device and an energy-absorbing resistor, optionally of non-linear characteristics. Such is shown in FIG. 8. In that case, when crossed-field switch device 22 is turned off, the energy is reduced by diverting the current through the energy-absorbing resistor. Such additional energy-absorbing circuits are shown in K. T. Lian patent RE-27,557 and in M. A. Lutz patent 3,660,723.
  • crossed-field switch device 30 Serially connected in line 24 between connection point 2 and connection point 3 are crossed-field switch device 30, resistor 32, which is illustrated as being nonlinear, and switch 34.
  • switch 34 connected in line 26 between connection point 1 and connection point 4 is a series combination of crossed-field switch device 36, resistor 38, which is illustrated as being non-linear, and switch 40.
  • Capacitors 42 and 44 are respectively connected in parallel around crossed-field switch devices 30 and 36 to control the change of voltage with respect to time across the crossed-field switch devices.
  • Resistor 46 shown as being non-linear, is connected between lines 24 and 26 at connection points 5 and 6.
  • Crossed-field switch devices 30 and 36 are identical to crossed-field switch device 22, while switches 34 and 40 can be identical to in-line switch 20. However, the requirements of switches 34 and 40 are somewhat different than the requirements of in-Iine switch 20, so they could be of different design.
  • Crossed-field switch devices, such as the devices 30 and 36 in the present state of the art, cannot reliably turn on in the proper mode when a voltage is initially impressed across them. For example, if switch 34 were absent from the circuit of FIG. 1, crossed-field switch device 30 would be connected directly between the power line 14 and ground 16. Therefore, the entire 1 pu would be impressed on the crossed-field device 30.
  • FIG. 2 illustrates the voltage between connection points 2 and l with respect to the time during offswitching.
  • FIG. 3 illustrates the voltage between connection points 2 and 3 with respect to time.
  • FIG. 4 illustrates the voltage between connection points 1 and 4 with respect to time. It is to be noted with respect to FIG. 4 that the connection point 3 is at the same potential as the connection point 4, therefore the curve is labeled as the voltage between points 1 and 3. Furthermore, since the sum of the voltages around the loop between the connection points 1, 2, 3, 4 and 1 must add up to 0, the voltage between points 1 and 3 (FIG. 4) is the difference between the voltages shown in FIGS. 3 and 2.
  • FIG. 2 illustrates the zero voltage drop across in-line switch 20, between connection points 1 and 2, with the l pu voltage drop between connection points 2 and 3, and connection points 1 and 3. It is seen that the voltage of FIG. 3 minus the voltage of FIG. 2 is the voltage of FIG. 4.
  • switches 34 and 40 are open, and crossed-field switch devices 22, 30 and 36 have no voltage thereacross, but crossed-field switch device is conditioned to conduct as soon as sufficient voltage is applied thereto.
  • in-line switch 20 is opened and line current is transferred through crossed-field switch device 22.
  • the crossed-field switch device 22, as presently known has about 500 volts drop, and such would not show on the idealized voltage curves.
  • in-line switch 20 is opened and deionized so that it can withstand its rated 1.5 pu voltage.
  • Crossed-field devices 30 and 36 can be conditioned from t, to t, to conduct so that now, when switches 34 and 40 are closed, they become conductive.
  • the voltage across the breaker, as shown in FIG. 2 rises from t, to t, at a rate determined by the dv/dt limiting capacitance 28. Assuming ideal non-linear resistors that do not conduct until the voltage reaches 1.5 pu, the voltage rise of FIG. 2 from t, to t from to 1.0 pu, is determined by the voltage rate of rise-limiting capacitors, as previously described.
  • the capacitors must carry the current which was in the crossed-field tubes until the resistors conduct. Line current remains constant over this short time span, less than 1 ms.
  • connection points 2 and 3 As the voltage between connection points 2 and 3 reaches 1.5 pu at time t as seen in FIG. 3, the voltage between these connection points is clamped at 1.5 pu .to limit the maximum voltage difference between power line 14 and ground 16. Thus, interline insulation is not overstressed.
  • the voltage between connection points 2 and l rises, the voltage is taken across resistor 46 which begins conducting at time t, to clamp the voltage between points 2 and l at 1.5 pu, as is seen in FIG. 1.
  • the voltage across resistor 38, between points 1 and 3 reduces to zero so that resistor 38 never begins conducting. Switch 40 may just as well have been left open. Thus, in the circuit interruption so far described, the branch between connection points 4 and 5 is not necessary.
  • both power source 12 and load 19 are considered to be voltage sources valued at 1.0 pu.
  • system inductance is shown lumped, and no transmission line filter effects are included.
  • the conducting non-linear resistors are considered ideal and are treated as 1.5 pu DC sources.
  • switches 34 and 40 are opened so that off-switching of the respective crossed-field devices extinguishes the arcs in the switches 34 and 40.
  • Switches 34 and 40 can be triggered vacuum gaps instead of mechanical switch devices.
  • FIG. 8 illustrates circuit breaker 50 connected be tween power source 52 and load 54.Connection is by means of power line 56 and ground line 58. It is recognized that circuit breaker 50 is identical to circuit breaker 18, except for two changes in detail. Gaps 60 and 62 are employed therein in place of switches 34 and 40, respectively. They are precision spark gaps which break down and conduct when they reach a predetermined voltage. A suitable gap is described in an article in IEEE Transactions on Power Apparatus and Systems, Volume PAS-91 No. 5, September-0ctober 1972, at pages 2104-2112 entitled Separation of Gap Functions A New Concept in Station Class Lighting Arrestor Design by Joseph C. Osterhout of Westinghouse Electric Company, Bloomington, Indiana.
  • gap 60 holds off the voltage to prevent conduction through that branch until the voltage rises sufficiently above 1 pu, for example 1.5 pu, to cause the spark gap to are over and conduct. Once conducting, the voltage drop across the branch is controlled by the current through the non-linear resistor in series with the conducting spark gap. Conduction continues until the crossed-field switch in that branch is turned off. Thereupon, the precision spark gap can recover its holdoff properties.
  • FIG. 8 Another difference in detail between FIG. 8 and FIG. 1 is the showing of additional impedance steps to absorb the energy of diverting the line current into resistor 64.
  • Resistor 64 corresponds to resistor 46 in FIG. 1.
  • Two intermediate resistor-crossed-field switch stages are illustrated.
  • Crossed-field switch 66 and its series resistor are connected in parallel to resistor 64.
  • Crossedfield switch 70 and its series resistor 72 are also connected in parallel to resistor 64.
  • These impedance stages are successively switched off to successively increase impedance to transfer the line current through resistor 64. In most cases, only one such intermediate stage is expected to be needed. However, two are shown as an example.
  • a triggered vacuum gap could be employed in each of the locations of gaps 60 and 62, shown in FIG. 8.
  • the triggered vacuum gap it would not need to precisely break down at a given voltage, but instead, triggering of conduction in the gap would be controlled by appropriate voltage sensors. In that way, the gap begins conducting at an appropriate condition in the breaker.
  • Such a gap is shown in J. M. Lafferty US. Pat. No. 3,290,542.
  • a lightning arrestor structure is a prospective candidate structure for employment in such use.
  • the presently known DC lightning arrestor structures are incapable of adequate energy absorption for the present purpose, and furthermore, they do not reliably isolate when the current is turned off. Thus, as presently known, they are not practical for performing this service.
  • further development in that art may produce DC lightning arrestors of accurate onswitching, adequate energy absorption, sealing off at a proper voltage and proper voltage holdoff recovery when current is stopped.
  • a switch in said first line between a first connection point and a second connection point in said first line for opening said first line between said first connection point and said second connection point;
  • first means capable of conducting direct current and off-switching direct current connected in parallel to said switch in said first line for providing a parallel circuit to said first switch for receiving current when said first switch is opened to permit said first switch to deionize and for off-switching direct current through said first means after said first switch has been deionized;
  • third means for absorbing energy from direct current passing therethrough and for off-switching direct current connected between said first connection point and said second means so that voltage between said first and second connection points can be limited to be maintained below a predetermined value.
  • circuit breaker of claim 2 wherein said second means is a serial connection of a crossed-field switch device for off-switching direct current and means for on-switching and absorbing energy from direct current flowing therethrough.
  • circuit breaker of claim 3 wherein said means for on-switching and absorbing energy comprises an on-switching device and a separate resistor.
  • circuit breaker of claim 1 wherein said second means is a serial connection of a crossed-field switch device for off-switching direct current and means for on-switching and absorbing energy from direct current flowing therethrough.
  • circuit breaker of claim 5 wherein said means for on-switching and absorbing energy comprises an on-switching device and a separate resistor.
  • said third means is a serial connection of a crossed-field switch device and a resistor, said serial connection being connected at one end at said first connection point and at the other end between the crossed-field switch device of said second means and its energy-absorbing means.
  • said third means is a serial connection of a crossed-field switch device and a resistor, said serial connection being connected at one end at said first connection point and at the other end between the crossed-field switch device of said second means and its energy-absorbing means.
  • circuit breaker of claim 1 wherein said circuit breaker has its second connection point connected to a power supply and has its first connection point connected to a load, said power supply and load also being connected to said third connection point.
  • circuit breaker of claim 7 wherein said circuit breaker has its second connection point connected to a power supply and has its first connection point connected to a load, said power supply and load also being connected to said third connection point.
  • circuit breaker of claim 8 wherein said circuit breaker has its second connection point connected to a power supply and has its first connection point connected to a load, said power supply and load also being connected to said third connection point.
  • circuit breaker of claim 9 wherein said circuit breaker has its second connection point connected to a power supply and has its first connection point connected to a load, said power supply and load also being connected to said third connection point.
  • cuit breaker has its second connection point connected to a power supply and has its first connection point connected to a load, said power supply and load also being connected to said third connection point.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
US00346208A 1973-03-29 1973-03-29 Hybrid dc circuit breaker Expired - Lifetime US3786310A (en)

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US34620873A 1973-03-29 1973-03-29

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US (1) US3786310A (ro)
JP (1) JPS49129150A (ro)
AU (1) AU461656B2 (ro)
CH (1) CH564266A5 (ro)
DE (1) DE2407168A1 (ro)
FR (1) FR2223810B3 (ro)
IT (1) IT1003938B (ro)
NL (1) NL7404186A (ro)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3963960A (en) * 1974-09-18 1976-06-15 Hughes Aircraft Company Bipolar crossed-field switch tube and circuit
US4300181A (en) * 1979-11-28 1981-11-10 General Electric Company Commutation circuit for an HVDC circuit breaker
US9042071B2 (en) 2010-06-14 2015-05-26 Abb Research Ltd Breaker failure protection of HVDC circuit breakers
US9054530B2 (en) 2013-04-25 2015-06-09 General Atomics Pulsed interrupter and method of operation
US20150372474A1 (en) * 2013-02-13 2015-12-24 Alstom Technology Ltd Circuit interruption device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS626464Y2 (ro) * 1981-04-30 1987-02-14

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3641358A (en) * 1970-06-10 1972-02-08 Hughes Aircraft Co Consecutive crowbar circuit breaker
US3660723A (en) * 1971-03-09 1972-05-02 Hughes Aircraft Co Current transfer circuit as part of high voltage dc circuit
US3678289A (en) * 1971-08-18 1972-07-18 Hughes Aircraft Co Magnetic field control circuit for crossed field switching devices

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3641358A (en) * 1970-06-10 1972-02-08 Hughes Aircraft Co Consecutive crowbar circuit breaker
US3660723A (en) * 1971-03-09 1972-05-02 Hughes Aircraft Co Current transfer circuit as part of high voltage dc circuit
US3678289A (en) * 1971-08-18 1972-07-18 Hughes Aircraft Co Magnetic field control circuit for crossed field switching devices

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3963960A (en) * 1974-09-18 1976-06-15 Hughes Aircraft Company Bipolar crossed-field switch tube and circuit
US4300181A (en) * 1979-11-28 1981-11-10 General Electric Company Commutation circuit for an HVDC circuit breaker
US9042071B2 (en) 2010-06-14 2015-05-26 Abb Research Ltd Breaker failure protection of HVDC circuit breakers
US20150372474A1 (en) * 2013-02-13 2015-12-24 Alstom Technology Ltd Circuit interruption device
US9054530B2 (en) 2013-04-25 2015-06-09 General Atomics Pulsed interrupter and method of operation

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NL7404186A (ro) 1974-10-01
FR2223810A1 (ro) 1974-10-25
IT1003938B (it) 1976-06-10
FR2223810B3 (ro) 1977-01-07
DE2407168A1 (de) 1974-10-10
AU461656B2 (en) 1975-06-05
CH564266A5 (ro) 1975-07-15
JPS49129150A (ro) 1974-12-11
AU6610174A (en) 1975-06-05

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