WO1999026328A1 - Systeme de protection contre les arcs de rupture pour armoire electrique - Google Patents

Systeme de protection contre les arcs de rupture pour armoire electrique Download PDF

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Publication number
WO1999026328A1
WO1999026328A1 PCT/US1998/024289 US9824289W WO9926328A1 WO 1999026328 A1 WO1999026328 A1 WO 1999026328A1 US 9824289 W US9824289 W US 9824289W WO 9926328 A1 WO9926328 A1 WO 9926328A1
Authority
WO
WIPO (PCT)
Prior art keywords
protection system
arcing fault
current
detection signal
source bus
Prior art date
Application number
PCT/US1998/024289
Other languages
English (en)
Inventor
Ruben D. Garzon
Original Assignee
Square D Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US08/974,254 external-priority patent/US5933308A/en
Application filed by Square D Company filed Critical Square D Company
Priority to CA002310619A priority Critical patent/CA2310619C/fr
Priority to AU14593/99A priority patent/AU1459399A/en
Priority to EP98958579A priority patent/EP1034591A4/fr
Publication of WO1999026328A1 publication Critical patent/WO1999026328A1/fr

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Classifications

    • 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
    • H01H33/26—Means for detecting the presence of an arc or other discharge
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H79/00—Protective switches in which excess current causes the closing of contacts, e.g. for short-circuiting the apparatus to be protected
    • 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
    • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
    • H01H33/66—Vacuum switches
    • H01H33/666—Operating arrangements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H1/00—Details of emergency protective circuit arrangements
    • H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
    • H02H1/0015—Using arc detectors
    • H02H1/0023—Using arc detectors sensing non electrical parameters, e.g. by optical, pneumatic, thermal or sonic sensors

Definitions

  • the present invention relates generally to protective devices for electrical switchgear and, more particularly, to the protection of electrical switchgear from arcing fault currents.
  • Switchgear enclosures are commonly employed in electrical power distribution systems for enclosing circuit breakers and switching equipment associated with the distribution system.
  • switchgear enclosures are comprised of a number of individual stacked or adjacent compartments, each of the switchgear compartments receiving electrical power from a power source and distributing the electrical power through a feeder circuit to one or more loads.
  • each of the switchgear compartments includes circuit breakers for interrupting electric power in a particular feeder circuit in response to hazardous current overloads in the circuit.
  • Switchgear is a general term covering switching and interrupting devices and their combination with associated control, instruments, metering, protective and regulating devices, also assemblies of these devices with associated interconnections, accessories, and supporting structures used primarily in connection with the generation, transmission, distribution, and conversion of electric power.
  • the following paragraphs describe switchgear characteristics in accordance with ANSI/IEEE Standards No. C37.20.2-1987.
  • a switchgear assembly generally refers to assembled equipment (indoor or outdoor) including, but not limited to, one or more of the following: switching, interrupting, control, instrumentation, metering, protective and regulating devices, together with their supporting structures, enclosures, conductors, electrical interconnections, and accessories.
  • a switchgear assembly may be completely enclosed on all sides and top with sheet metal (except for ventilating openings and inspection windows) containing primary power circuit switching or interrupting devices, or both, with buses and connections referred to as metal-enclosed (ME) power switchgear.
  • the assembly may include control and auxiliary devices. Access to the interior of the enclosure is usually provided by doors or removable covers, or both.
  • Metal-enclosed power switchgear may include one or more of the following features: (1)
  • the main switching and interrupting device is of the removable (drawout) type arranged with a mechanism for moving it physically between connected and disconnected positions and equipped with self-aligning and self-coupling primary disconnecting devices and disconnectable control wiring connections.
  • Instruments, meters, relays, secondary control devices and their wiring are isolated by grounded metal barriers from all primary circuit elements with the exception of short lengths of wire such as at instrument transformers terminals.
  • the door through which the circuit interrupting device is inserted into the housing may serve as an instrument or relay panel and may also provide access to a secondary or control compartment within the housing.
  • Metal-clad switchgear is metal- enclosed, but not all metal- enclosed switchgear is metal-clad.
  • the ratings of a switchgear assembly are designations of operating limits under specified conditions of ambient temperature, temperature rise, etc. Where the switchgear assembly comprises a combination of primary and secondary circuits, each may be given ratings.
  • ME switchgear usually has the following ratings:
  • a switchgear assembly may have interrupting or switching capabilities, which are determined by the rating of the particular interrupting and switching devices that are integral parts of the switchgear assembly.
  • the rated maximum voltage of ME switchgear is the highest rms voltage for which the equipment is designed, and is the upper limit for operation.
  • the rated insulation levels of ME switchgear includes two items. (1) Low frequency 1 min withstand voltage
  • the rated frequency of a device, or an assembly is the frequency of the circuit for- which it is designed. (Ratings are usually based on a frequency of 60 Hz).
  • the rated continuous current of ME switchgear is the maximum current in rms amperes at rated frequency, which can be carried continuously by the primary circuit components, including buses and connections, without causing temperatures in excess of specified limits for (1) Any primary or secondary circuit component
  • the continuous current ratings of the main bus in ME switchgear are listed in ANSI/IEEG C37.20.2-1987.
  • the continuous current rating of the individual circuit-breaker compartment shall be equal to the ratings of the switching and interrupting devices used, except as may be modified by lower continuous current ratings for current transformers, power fuses etc.
  • the rated momentary current of ME switchgear is the maximum rms total current that it shall be required to withstand.
  • the current shall be the rms value, including the direct-current component, at the major peak of the maximum cycle as determined from the envelope of the current wave during a test period of at lease 10 cycles unless limited to a shorter time by the protective device.
  • the momentary current ratings of the individual circuit-breaker compartments of ME switchgear shall be equal to: The circuit breaker close and latch, switch fault close, or asymmetrical momentary current ratings of the switching devices used.
  • the rated short-time current of the ME switchgear is the average rms current that it can carry for a period of 2 sec. unless limited to a shorter time by the protective device or current transformer ratings.
  • the short-time current ratings of the individual circuit-breaker compartments of the ME switchgear shall be equal to the short-time ratings of the switching and protective devices used or the short time rating of the current transformers (see ANSI/IEEE C57.13- 1978 (R 1986) [10]).
  • the limiting temperature for ME switchgear is the maximum temperature permitted.
  • the switchgear enclosure may encounter other hazardous conditions known as arcing faults.
  • Arcing faults occur when electric current "arcs" or flows through ionized gas between conductors, between two ends of broken or damaged conductors, or between a conductor and ground in the switchgear enclosure.
  • Arcing faults typically result from corroded, worn or aged wiring or insulation, loose connections and electrical stress caused by repeated overloading, lightning strikes, etc.
  • the ionized gas associated with arcing faults may be released at pressures and temperatures sufficient to damage the switchgear equipment.
  • the most commonly employed method for enhancing the durability of switchgear enclosures in the event of arcing faults is to provide arc-resistant metal switchgear compartments to the above-described MC (metal clad) standards, with a means for venting the gases from the compartments in the event of an arcing fault.
  • These compartments are designed to withstand the pressures and temperatures of the gases associated with an arcing fault and reduce the likelihood or extent of damage to switchgear equipment by preventing the gases from entering adjacent switchgear compartments.
  • these systems do not eliminate the generation and release of hot gases associated with arcing faults, they do not eliminate the risk of damage to the switchgear equipment.
  • Cronin U.S. Patent No. 4,130,850 is directed to a high speed fault diverter switch for a gas-insulated substation.
  • the switch referred by Cronin is a High Voltage switch which would be used in a GIS (Gas Insulated Substation).
  • GIS Gas Insulated Substation
  • the lowest typical voltage application for this type of system would be at 60-145 kV which requires an impulse voltage level of up to 650 kV.
  • the open gap of the contacts would be typically around 4 inches.
  • Cronin discloses only a conventional switch, which would require 3 to 4 cycles (i.e., 48- 64 in sec.) to operate.
  • Cronin speaks of the rise of the high pressure being extremely rapid; indeed, experience has shown that the arc should be controlled within 4 milliseconds.
  • the conventional switch will not work, because the contacts must travel 4 inches in 4 milliseconds which gives an approximate average velocity of 25 meters per second. Since, the acceleration time is 4 ms. and the initial velocity is 0 then the required constant acceleration is about 12,500 meter second squared.
  • the discharge pulse is generally in the order of 1 to 2 milliseconds.
  • the discharge pulse described in Diebold U.S. Patent No. 2,971,130 is a 1 millisecond pulse.
  • C 30,000 newton-meters.
  • a reasonable voltage to charge the capacitor would be 3,000 volts in which case a capacitor of 0.0033 farads is needed (this is a rather large capacitor) or if a more common capacitor of 100 micro-farads is used then the charging voltage would be 300 kV.
  • an arcing fault protection system for a switchgear enclosure accommodating a plurality of feeder circuits.
  • Each of the feeder circuits is electrically connected to a source bus and carries an electric current through the switchgear enclosure toward one or more loads downstream of the switchgear enclosure.
  • the arcing fault protection system comprises one or more arcing fault detectors for monitoring the feeder circuits for the presence of arcing fault currents and for producing an arcing fault detection signal upon detecting arcing fault currents in any of the feeder circuits, and an arc diverting device for rapidly diverting the current from the source bus in response to the production of an arcing fault detection signal.
  • the arc diverting device diverts current carried on the source bus to ground, or to another phase in an ungrounded three phase system, and rapidly eliminates arcing fault currents occurring on any of the feeder circuits.
  • the rapid elimination of arcing fault currents substantially reduces or eliminates the generation of hot gases associated with arcing faults and obviates the need to provide an arc-resistant switchgear enclosure or to vent gases from the enclosure.
  • the arc diverting device comprises a mechanical switch rapidly movable from an open position to a closed position.
  • the mechanical switch includes a movable contact and a stationary contact.
  • One of the contacts is electrically connected to the source bus and the other of the contacts is electrically connected to ground or to another phase in a three phase ungrounded system.
  • the movable contact In the open position of the mechanical switch, the movable contact is in a first longitudinal position, apart from the stationary contact. In the closed position of the mechanical switch, the movable contact is in a second longitudinal position, electrically connected to the stationary contact.
  • a latching mechanism comprises a portion of the mechanical switch. The latching mechanism holds the movable contact in the first longitudinal position, defining a latched position, or releases the movable contact from the first longitudinal position, defining an unlatched position, depending on the status of the mechanical switch.
  • a driving mechanism rapidly drives the latching mechanism from the latched position to the unlatched position and accelerates the movable contact toward the second longitudinal position in response to activation of a triggering mechanism.
  • the latching mechanism includes a latch core oriented adjacent to the driving mechanism, the latch core being movable coincident to the driving mechanism and communicating movement to the movable contact in response to activation of the triggering mechanism.
  • An outer surface of the latch core defines a holding surface and a recessed releasing surface.
  • a stationary latch support is oriented transverse to the latch core and has an inner surface defining a retaining member.
  • a plurality of ball bearings are disposed between the latch core and the latch support. The ball bearings are held into engagement with the retaining member by the holding surface of the latch core when the latching mechanism is in the latched position, and collapse inwardly toward the releasing surface and become released from the retaining member when the latching mechanism is in the unlatched position.
  • the arc diverting device comprises a first and second thyristor connected from the source bus to ground.
  • the first and second thyristors include respective first and second gate terminals responsive to the arcing fault detection signal.
  • the first and second -thyristors block current flow when the arcing fault detection signal is not applied to their respective gate terminals and permit current flow when the arcing fault detection signal is applied to their respective gate terminals.
  • FIG. 1 is a block diagram of an arcing fault protection system for a switchgear enclosure according to one embodiment of the present invention
  • FIG. 2 is a block diagram illustrating one embodiment of a portion of the circuit of FIG. 1 which generates an arcing fault detection signal
  • FIG. 3 is a side sectional view of a prior art vacuum interrupter which forms a portion of a mechanical switch which may form part of the arc diverter in the system of FIG. 1;
  • FIG. 4 is a side sectional view of another portion of a mechanical switch which may be used in conjunction with the vacuum interrupter of FIG. 3, illustrating both an open and closed position of the mechanical switch;
  • FIGS. 5a through 5d are schematic diagrams of solid-state switches which may form part of the arc diverter in the system of FIG. 1 ;
  • FIG. 6 is a schematic diagram of an additional circuit which may be added to the mechanical switch of FIGS. 3 and 4 or the solid state switches of FIGS. 5a-5d; and FIG. 7 illustrates a hybrid mechanical/solid state switch.
  • FIG. 1 there is shown a switchgear enclosure, generally designated by reference numeral 10, including individual compartments 10a, 10b, 10c and lOd for housing various components of an electrical distribution system 12.
  • a power source 14 which may comprise, for example, a utility company power transformer, supplies power for the distribution system 12 through a main circuit 16.
  • the main circuit 16 is typically routed through a main breaker, designated here by reference numeral 18.
  • Each of the feeder circuits 24 typically supplies power to one or more loads (not shown) downstream of the switchgear enclosure 10. It will be appreciated that the number of feeder circuits 24 shown here, as well as the number of switchgear compartments 10, is exemplary only, and may be varied according to the particular type and/or application of the switchgear enclosure 10.
  • the switchgear enclosure 10 typically includes switching and monitoring equipment associated with the respective feeder circuits 24.
  • the switchgear enclosure 10 includes a plurality of circuit breakers 26a,b,c and a plurality of optical sensors 28a,b,c.
  • the circuit breakers 26 and optical sensors 28 comprise devices known in the art which are mounted within the respective switchgear compartments 10a,b,c and are associated with one of the feeder circuits 24a,b,c.
  • the circuit breakers 26 are provided for interrupting electric power in the respective feeder circuits 24 in response to current overloads and the optical sensors are provided for monitoring the respective feeder circuits 24 for the presence of arcing faults.
  • the electrical components shown here are exemplary only; they may be replaced, eliminated or supplemented with other components, according to the particular type and/or application of the switchgear enclosure.
  • an arc diverter 32 is connected between the source bus 22 and ground.
  • an ungrounded i.e.
  • the arc diverter 32 is connected between the phase lines of the system.
  • the arc diverter 32 upon receipt of an arcing fault detection signal 34, quickly connects or "crow-bars" the source bus 22 to ground (or to another phase line in an ungrounded system), thereby extinguishing arcing fault currents which may have occurred on any of the feeder circuits 24 before they are permitted to generate gases at dangerous pressures and/or temperatures.
  • the arcing fault currents are extinguished in less than about 4 milliseconds, effectively eliminating the generation of dangerous gases associated with the arcing fault.
  • the present invention therefore can eliminate the need to manufacture the switchgear enclosure 10 according to conventional metal-clad (MC) arc-resistant designs or to vent gases from the enclosure 10.
  • MC metal-clad
  • the arc diverter 32 may comprise a mechanical switch, a solid-state switch or a hybrid mechanical and solid-state switch.
  • the arc diverter 32 may be mounted in one of the switchgear compartments, as shown here, or may be mounted in a separate compartment external to the switchgear enclosure 10.
  • FIG. 2 illustrates one embodiment in which the arcing fault detection signal 34 is generated by a combination of a current sensor 20 monitoring the main circuit 16, and optical sensors 28 monitoring the feeder circuits 24. It will be appreciated, however, that the arcing fault detection signal 34 may be generated by any of several other configurations of sensors including, for example, a system where optical sensors 28 and current sensors 20 are employed in each feeder circuit 24, or a system including only optical sensors or only current sensors.
  • the sensor 20 comprises an instantaneous current (or voltage) sensor, such as a current transformer (C.T.), for sensing the instantaneous magnitude of the current (or voltage) in the monitored line.
  • the sensor 20 produces an arcing fault detection signal, designated in FIG. 2 by reference numeral 36, if it determines that an arcing fault is present on the main circuit 16 or a feeder circuit 24.
  • the optical sensors 28 may comprise any type of optical sensor known in the art such as, for example, the optical sensor described in U.S. Patent No. 4,369,364 and commercially available from BBC Brown, Boveri & Company Limited, Baden,
  • the optical sensors 28 are sensitive to light impulses representing the occurrence of arcing faults within the switchgear enclosure 10 and produce an arcing fault detection signal, designated in FIG. 2 by reference numeral 38, if they determine that an arcing fault is present on any of the feeder circuits 24.
  • the respective arcing fault detection signals 36,38 are fed to an AND gate 40, which produces a consolidated arcing fault detection signal 34 to trigger arc diverter 32 only when arcing fault detection signals are provided by both the current sensor 20 and optical sensor 28. This arrangement minimizes the chance that switching will occur due to "false" signals because it is unlikely that false signals will be detected by both the current sensor 20 and the optical sensor 28.
  • FIG. 1 comprises a mechanical switch for rapidly shorting or "crow-barring" the source bus 22 to ground in response to the receipt of an arcing fault detection signal 34.
  • One portion of the mechanical switch may consist of a standard, commercially available vacuum interrupter 52, also known as a "vacuum bottle,” such as the one shown in FIG. 3.
  • the vacuum interrupter 52 is oriented generally about a longitudinal axis 65 and comprises a cylindrical chamber 54 for housing a movable contact 56 and a stationary contact 58.
  • the vacuum interrupter 52 may include a set of contacts immersed in an insulating medium such as, but not limited to, sulfurhexaflouride gas (SF 6 ) or oil.
  • SF 6 sulfurhexaflouride gas
  • the stationary contact 58 is electrically connected to the source bus 22 (FIG. 1) by a connecting rod 60.
  • the movable contact 56 is connected via a connecting rod 62 to a driving mechanism, one example of which will be described in detail later, and is shown in FIG. 4.
  • a driving mechanism one example of which will be described in detail later, and is shown in FIG. 4.
  • the separation or gap between the artifacts 56, 58 when in the open position is from about 6 mm to about 10 mm, for example, about 8 mm.
  • the movable and stationary contacts 56, 58 are engaged, defining a closed position of the mechanical switch.
  • the closing of the vacuum interrupter 52 is accomplished very rapidly so as to substantially eliminate the generation of gases associated with arcing faults. More specifically, the movable contact 56 is rapidly moved toward the stationary contact 58, from a first longitudinal position in which the movable contact 56 is separated from the stationary contact 58 (i.e., in the open position of the vacuum interrupter 52), to a second longitudinal position in which the movable contact 56 is engaged with and electrically connected to the stationary contact 58 (i.e., in the closed position of the vacuum interrupter 52, which is shown in FIG. 3).
  • the closing of the switch is accomplished in less than about 4 milliseconds.
  • FIG. 4 illustrates a structure, designated by reference numeral 64, that may be used to drive the movable contact 56 into engagement with stationary contact 58 according to one embodiment of the present invention.
  • the structure 64 is oriented generally about longitudinal axis 65 and aligned with the vacuum interrupter 52.
  • the left-hand half of FIG. 4 shows the structure 64 as it would appear when the vacuum interrupter 52 is in an open position, in the absence of an arcing fault detection signal 34.
  • the right-hand half of FIG. 4 shows the structure 64 as it would appear when the vacuum interrupter 52 is in a closed position, after having shorted or "crow-barred" the source bus 22 to ground in response to receipt of an arcing fault detection signal 34.
  • the structure 64 consists generally of a latching mechanism 66, a driving mechanism 68 and a triggering mechanism 70.
  • the latching mechanism 66 includes a latch core 72, a latch support 74 and a plurality of ball bearings 76 disposed between the latch core 72 and the latch support 74.
  • a piston 78 is positioned between the latching mechanism 66 and the connecting rod 62.
  • the driving mechanism 68, latch core 72, ball bearings 76 and piston 78 are adapted for rapid upward movement along longitudinal axis 65 when the vacuum interrupter 52 is actuated by the triggering mechanism 70, as will be described in detail hereinafter, to drive the movable contact 56 into engagement with the stationary contact 58.
  • the outward-facing surface of the latch core 72 includes a holding surface 80, an inclined surface 82 and a recessed surface 84.
  • the inward-facing surface of the latch support 74 includes a retaining groove 86.
  • the ball bearings 76 are adapted to move in both longitudinal and transverse directions relative to the latch core 72 and latch support
  • the latching mechanism 66 is shown in a latched position, in which the ball bearings 76 are held between the retaining groove 86 of the latch support 74 and the holding surface 80 of the latch core 72. In this position, the piston 78 (and hence connecting rod 62 and movable contact 56) is restrained from longitudinal movement, maintaining the vacuum interrupter 52 in the open position.
  • the latching mechanism 66 is shown in an unlatched position, in which the piston 78 (and hence movable contact 56) is released and permitted to move along longitudinal axis 65 toward the stationary contact 58.
  • the release of the latching mechanism 66 occurs in response to upward movement of the latch core 72. More specifically, when the latch core 72 is moved upwardly along the longitudinal axis 65, the holding surface 80 of the latch core 72 is advanced beyond the longitudinal position of the ball bearings 76, causing the ball bearings 76 to collapse inwardly toward the recessed surface 84 of the latch core 72. The inward movement of the ball bearings 76 causes them to become released from the retaining groove 86 of latch support 74, thereby
  • the driving mechanism 68 is a cylindrical disk oriented about the longitudinal axis 65 and adjacent to a bottom surface of the latch core 72.
  • the driving mechanism 68 comprises a metal disk, but it will be appreciated that other materials may be employed.
  • the driving mechanism 68 is adapted for rapid upward movement along the longitudinal axis 65, in response to production of an accelerating force by the triggering mechanism 70.
  • the driving mechanism 68, in conjunction with triggering mechanism 70, must accordingly be capable of developing significant velocities over a short distance. For example, in one embodiment, it is expected that the closing of vacuum interrupter 52 will be accomplished in two to four milliseconds.
  • the driving mechanism 68 must be capable of producing an average velocity of about 4 to 5 meters per second.
  • this operating speed is exemplary only. The operating speed required for any particular application is dependent on the distance between contacts as well as the pressure and type of insulating medium (if any) between contacts.
  • the driving mechanism 68 is shown adjacent to the triggering mechanism 70, as it would appear when the vacuum interrupter 52 is open.
  • the driving mechanism is shown as it would appear when the vacuum interrupter 52 is closed, having traveled a distance corresponding to the separation distance of the movable and stationary contacts 56, 58.
  • the upward movement of the driving mechanism 68 causes corresponding movement of latch core
  • the triggering mechanism 70 comprises a flat (pancake-type) radially wound coil having a face located adjacent to the driving mechanism 68.
  • the coil 70 is connected to an energy source (not shown) which is activated in response to production of an arcing fault detection signal by the protection system.
  • the energy source comprises one or more capacitors (not shown) charged to a voltage in the range of hundreds or thousands of volts, depending on the particular application or rating of the vacuum interrupter 52.
  • a 700 microfarad capacitor may be charged to 800 volts; where the gap between the open contacts 56, 58 is from about 6 to about 8 millimeters.
  • the presence of electrical current in the coil 70 causes a repulsion force to be produced which is proportional to the number of turns of the coil 70 and the current carried by the coil 70.
  • the repulsion force is directed along the longitudinal axis 65 toward the driving mechanism 68, imparting a high instantaneous acceleration to the driving mechanism 68 and causing a quick release of the latching mechanism 66, in the manner heretofore described.
  • the accelerating force may be supplemented by an additional force associated with the mechanical switch.
  • the supplemental force may be provided by a compressed spring (not shown), or by pneumatic or hydraulic operation.
  • the movable components of the mechanical switch of FIGS. 3 and 4 are relatively low mass components so as to minimize the amount of energy required to close the contacts 56, 58.
  • FIGS. 5a through 5d there is shown a series of solid-state switches which may be used in the system of FIG. ' 1. Components common to the various switch embodiments will be designated by common reference numerals throughout, although the different switch embodiments shown in FIGS. 5a through 5d will be designated by different reference numerals. Generally, each of the respective solid state switch embodiments of FIGS.
  • each of the thyristors 90, 92 illustrated diagramatically in FIGS. 5a-d. may comprise a number of thyristors coupled in series and parallel arrays to meet the voltage and current handling requirements of the system.
  • Gate terminals of thyristors 90, 92, designated respectively by reference numerals 94 and 96, are connected to the AND gate 40 (or, alternatively, directly to the arcing fault sensors 20 and/or 28) to receive an arcing fault detection signal 34 upon the detection of an arcing fault by the protection system.
  • the thyristors 90, 92 are "off and do not permit current to flow through the thyristor.
  • an arcing fault signal 34 applied to the gate terminals 94,96 the thyristor is turned “on” and current is permitted to flow through the thyristor, thereby effectively short-circuiting the source bus 22 and extinguishing any arcing fault currents present in the system.
  • the current flow through the thyristors 90, 92 does not generally shut off, even if the gate signal is removed, until the current flow is reduced below a threshold level, most likely by the main breaker 18 (FIG. 1) in the distribution system.
  • the present invention is not limited to the use of thyristors, but may utilize other forms of solid-state devices such as, for example, insulated-gate bipolar transistors (IGBTs).
  • IGBTs insulated-gate bipolar transistors
  • FIG. 5a illustrates a solid-state switch 98 in a basic embodiment including a pair of thyristors 90, 92 connected in parallel between the source bus 22 and ground, as heretofore described. With no arcing fault signal 34 provided to the gate terminals 94,96
  • the thyristors 90, 92 do not permit current to flow through the thyristor.
  • an arcing fault signal 34 applied to the gate terminals 94,96 the thyristors conduct electric current from the source bus 22 to ground, thereby short-circuiting the source bus 22 and extinguishing any arcing fault currents present in the system.
  • the thyristors 90, 92 are biased in a manner such that the first thyristor 90 begins conducting current from the source bus to ground coincident to a positive half-cyle of alternating electric current on the source bus 22, and the second thyristor 92 begins conducting current from the source bus to ground coincident to a negative half-cyle of alternating electric current on the source bus 22.
  • FIG. 5b illustrates a solid-state switch 100 according to an alternative embodiment of the present invention.
  • the solid-state switch 100 includes respective thyristors 90, 92 having respective gate terminals 94,96 responsive to an arcing fault detection signal, as heretofore described.
  • the solid-state switch 100 further includes a shunt shorting contact 102 connected between the source bus 22 and ground.
  • the shunt shorting contact 102 generally comprises a relatively slow operating switch (e.g., about one-half cycle— 16m sec.) which is also triggered in response to the detection of an arcing fault (e.g., upon receipt of the arcing fault detection signal 34) to provide an alternate current path 104 from the source bus 22 to ground.
  • the shunt shorting contact 102 is triggered to provide the alternate conducting path 104 before the thyristors 90, 92 have conducted for much more than about one half-cyle of alternating electric current. This is an advantageous feature because typical thyristors are rated to withstand high currents for no more than about one half-cycle. The provision of shunt shorting contact 102 prolongs the operable life of the thyristors 90, 92 because it decreases the likelihood that the high current rating of the thyristors 90, 92 will be exceeded.
  • FIG. 5c illustrates a solid-state switch 110 according to another alternative embodiment of the present invention.
  • the solid-state switch 110 includes respective thyristors 90, 92 having respective gate terminals 94,96 responsive to an arcing fault detection signal, as heretofore described.
  • the solid-state switch 11O further includes a current-limiting reactance 112 and a voltage arrestor 114 such as a varistor.
  • the current limiting reactance 112 is connected between the source bus 22 and the thyristors 90, 92 so that, when the thyristors 90, 92 are conducting, the current flowing through the respective thyristors 90, 92 is limited, preferably to a level that does not exceed the current rating of the thyristors 90, 92.
  • the voltage arrestor 114 such as a metal oxide varistor
  • MOV Metal Organic Vapor
  • FIG. 5d illustrates a solid-state switch 120 according to still another alternative embodiment of the present invention.
  • the solid-state switch 120 includes all of the components of the solid-state switch 110 shown in FIG. 5c, with the addition of a shunt shorting contact 122.
  • the shunt shorting contact 122 serves substantially the same function as the shunt shorting contact 102 described in relation to FIG. 5b, providing an alternate conducting path 124 for the current flowing between the source bus 22 and ground.
  • the shunt shorting contact 122 is triggered to provide the alternate conducting path 124 before the thyristors 90, 92 have conducted for more than about one half-cyle of alternating electric current, for the reasons heretofore described in relation to FIG. 5b.
  • any of the solid-state switches described in relation to FIGS. 5a through 5d may be used in combination with a mechanical switch, such as that described in relation to FIGS. 3 and 4, to define a hybrid solid-state and mechanical arc diverter circuit 32 in the system of FIG. 1.
  • a mechanical switch such as that described in relation to FIGS. 3 and 4
  • FIG. 7 One example of this is shown in FIG. 7 and described below.
  • FIG. 6 there is shown an additional circuit which may be added in series between either the mechanical switch shown on FIGS. 3 and 4 or any of the solid state switches shown on FIGS. 5a-d and ground, or another phase line, in an ungrounded three phase system.
  • This additional circuit component comprises the combination of a resistor 125 and a fuse 126 connected in parallel.
  • two such circuits are illustrated for a three-phase system, that is between each of the A and C
  • the fuse 126 will be a relatively fast acting fuse, for example, on the order of VA to Vz milliseconds, and may be rated from 10 to 250 amps, for example 30 amps. Taking into account stray inductance in the circuitry and wiring, it might be expected that about one millisecond will elapse before the current is totally transferred from the fuse 126 to resistor 125, following the opening of the fuse.
  • the resistor When the fuse opens, the resistor will provide an additional resistance in series to limit the current in the circuit, while still clamping the circuit to ground.
  • the resistor value may be selected to limit the current to the circuit on the order of no more then about 2 to 2 Vi times the continuous current rating of the circuit. For example, in a 1200 amp continuous rated circuit, the resistor might be selected to permit a current flow of about 3 K amps.
  • the use of a fuse will avoid the delay which might be experienced with the addition of the resistance alone, that is the time in which it might otherwise take the arc voltage to rise sufficiently to drive significant current through the resistor.
  • the mechanical switch 130 may be of similar design to the switch shown on FIGS. 3 and 4, while the electronic switch 140 may be of similar design to the electronic switches shown on FIGS. 5a through 5d.
  • the mechanical switch 130 and electronic switch 140 are wired in series between the buss 22 or other line to be protected and ground, or, in an ungrounded three-phase system between the protected phase and another phase.
  • the same triggering line 34 carrying the arcing fault detection signal.
  • the solid state and mechanical switches are triggered simultaneously, it will be appreciated that the solid state switch 140 will close faster, thus carrying the initial current. However, the mechanical switch will close shortly thereafter to take most of the voltage off of the solid state switch 140.
  • FIG. 7 may be smaller than that described above, for example, about 4 millimeters rather than about 8 millimeters, such that a smaller, less expensive component may be utilized.
  • the circuit of FIG. 6 may also be used in series with the hybrid switch of FIG. 7. While particular embodiments and applications of the present invention have been illustrated and described, it is to be understood that the invention is not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations will be apparent from the foregoing descriptions without departing from the spirit and scope of the invention as defined in the appended claims.

Landscapes

  • Gas-Insulated Switchgears (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

L'invention concerne un système de protection contre les arcs de rupture destiné à une armoire électrique (10), comprenant un dispositif de commutation (32) servant à dériver rapidement le courant en provenance du bus source (22) d'un système de distribution électrique (12), en réaction à la détection d'un arc de rupture à l'intérieur du système. Le dispositif de commutation (32), qui peut comprendre un commutateur mécanique, un commutateur à semiconducteurs ou un dispositif hybride, dérive rapidement le courant porté sur le bus source (22) de manière à souffler efficacement l'arc de rupture se produisant dans le système de distribution (12). On évite ainsi la production de gaz à pressions et/ou températures élevées, ce qui permet de protéger l'équipement de commutation électrique contre d'éventuels dommages.
PCT/US1998/024289 1997-11-19 1998-11-13 Systeme de protection contre les arcs de rupture pour armoire electrique WO1999026328A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
CA002310619A CA2310619C (fr) 1997-11-19 1998-11-13 Systeme de protection contre les arcs de rupture pour armoire electrique
AU14593/99A AU1459399A (en) 1997-11-19 1998-11-13 Arcing fault protection system for a switchgear enclosure
EP98958579A EP1034591A4 (fr) 1997-11-19 1998-11-13 Systeme de protection contre les arcs de rupture pour armoire electrique

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US08/974,254 US5933308A (en) 1997-11-19 1997-11-19 Arcing fault protection system for a switchgear enclosure
US08/974,254 1997-11-19
US09/190,094 US6141192A (en) 1997-11-19 1998-11-12 Arcing fault protection system for a switchgear enclosure
US09/190,094 1998-11-12

Publications (1)

Publication Number Publication Date
WO1999026328A1 true WO1999026328A1 (fr) 1999-05-27

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ID=26885777

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Application Number Title Priority Date Filing Date
PCT/US1998/024289 WO1999026328A1 (fr) 1997-11-19 1998-11-13 Systeme de protection contre les arcs de rupture pour armoire electrique

Country Status (5)

Country Link
EP (1) EP1034591A4 (fr)
AU (1) AU1459399A (fr)
CA (1) CA2310619C (fr)
MY (1) MY116301A (fr)
WO (1) WO1999026328A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010069011A1 (fr) * 2008-12-19 2010-06-24 Protectelec Pty Limited Unité de surveillance pour un système de distribution électrique en régime it comportant un conducteur de référence flottant
WO2016041730A1 (fr) * 2014-09-18 2016-03-24 Dehn + Söhne Gmbh + Co. Kg Dispositif de protection d'installations et de personnes dans des moyens d'alimentation basse tension polyphasés
WO2018153780A1 (fr) * 2017-02-24 2018-08-30 Bombardier Transportation Gmbh Système électrique
CN111937111A (zh) * 2018-06-08 2020-11-13 菲尼克斯电气公司 具有监控装置的断路器及其方法
DE102022202654A1 (de) 2022-03-17 2023-09-21 Siemens Aktiengesellschaft Verfahren zum Störlichtbogenschutz

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US11239652B2 (en) 2018-12-26 2022-02-01 Eaton Intelligent Power Limited Compliant, hazardous environment circuit protection devices, systems and methods
US11270854B2 (en) 2018-12-26 2022-03-08 Eaton Intelligent Power Limited Circuit protection devices, systems and methods for explosive environment compliance
US11615925B2 (en) 2018-12-26 2023-03-28 Eaton Intelligent Power Limited Hazardous location compliant circuit protection devices having enhanced safety intelligence, systems and methods
US11303111B2 (en) 2018-12-26 2022-04-12 Eaton Intelligent Power Limited Configurable modular hazardous location compliant circuit protection devices, systems and methods

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US4723187A (en) * 1986-11-10 1988-02-02 General Electric Company Current commutation circuit
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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010069011A1 (fr) * 2008-12-19 2010-06-24 Protectelec Pty Limited Unité de surveillance pour un système de distribution électrique en régime it comportant un conducteur de référence flottant
WO2010069012A1 (fr) * 2008-12-19 2010-06-24 Protectelec Pty Limited Système de protection pour un système de distribution électrique en régime it comportant un conducteur de référence flottant
US8953288B2 (en) 2008-12-19 2015-02-10 Iep2 Research Pty Limited Sentinel unit for an IT electrical distribution system having a floating reference conductor
US8953295B2 (en) 2008-12-19 2015-02-10 Iep2 Research Pty Limited Protection system for an IT electrical distribution system having a floating reference conductor
WO2016041730A1 (fr) * 2014-09-18 2016-03-24 Dehn + Söhne Gmbh + Co. Kg Dispositif de protection d'installations et de personnes dans des moyens d'alimentation basse tension polyphasés
WO2018153780A1 (fr) * 2017-02-24 2018-08-30 Bombardier Transportation Gmbh Système électrique
CN110505970A (zh) * 2017-02-24 2019-11-26 勃姆巴迪尔运输有限公司 电气系统
US11358472B2 (en) 2017-02-24 2022-06-14 Bombardier Transportation Gmbh Electric system
CN110505970B (zh) * 2017-02-24 2023-02-21 勃姆巴迪尔运输有限公司 电气系统
CN111937111A (zh) * 2018-06-08 2020-11-13 菲尼克斯电气公司 具有监控装置的断路器及其方法
CN111937111B (zh) * 2018-06-08 2024-05-03 菲尼克斯电气公司 具有监控装置的断路器及其方法
DE102022202654A1 (de) 2022-03-17 2023-09-21 Siemens Aktiengesellschaft Verfahren zum Störlichtbogenschutz

Also Published As

Publication number Publication date
MY116301A (en) 2003-12-31
AU1459399A (en) 1999-06-07
EP1034591A1 (fr) 2000-09-13
EP1034591A4 (fr) 2004-03-10
CA2310619A1 (fr) 1999-05-27
CA2310619C (fr) 2005-02-08

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