WO2001037299A1 - Commutateur de transfert - Google Patents

Commutateur de transfert Download PDF

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Publication number
WO2001037299A1
WO2001037299A1 PCT/SE2000/002274 SE0002274W WO0137299A1 WO 2001037299 A1 WO2001037299 A1 WO 2001037299A1 SE 0002274 W SE0002274 W SE 0002274W WO 0137299 A1 WO0137299 A1 WO 0137299A1
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WO
WIPO (PCT)
Prior art keywords
transfer switch
switch according
switching device
current
switching
Prior art date
Application number
PCT/SE2000/002274
Other languages
English (en)
Inventor
Lars Jonsson
Per Larsson
Falah Al-Hosini
Magnus Backman
Lars Liljestrand
Harry Frank
Original Assignee
Abb Ab
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
Application filed by Abb Ab filed Critical Abb Ab
Priority to EP00978182A priority Critical patent/EP1230658A1/fr
Priority to AU15667/01A priority patent/AU1566701A/en
Publication of WO2001037299A1 publication Critical patent/WO2001037299A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/54—Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere
    • H01H9/541—Contacts shunted by semiconductor devices

Definitions

  • the present invention relates to a transfer switch for alternating current comprising two electric switching devices adapted to establish and breaking, respectively, a current path between a load and an alternating current supply for transferring the supply of electric power to the load from one alternating current supply to the other, each of said switching devices comprising in a cur- rent path therethrough two branches connected in parallel with each other, the first of the branches comprising a first contact member having two contacts movable with respect to each other for opening and closing and the second comprising a component able to block current therethrough in at least a first blocking di- rection and conduct current therethrough in at least one direction, in which a second contact member having two contacts movable with respect to each other for opening and closing is connected in series with the component, and in which the transfer switch also comprises a unit adapted to control opening of said current path through the switching device being closed by controlling the first contact member of this switching device to open for transferring the current to the component when this is in or is going into the conducting state and then the second contact member to open when the component is in
  • Such transfer switches are usually used for rapidly switching in a spare supply to a load, such as an equipment within any industrial process, should the regular supply fail. Such failure may depend on for example a power failure of the regular supply or any fault thereof, such as a shortcircuit through for example an insulation fault with respect to ground. It is then usually a question of such loads that are sensitive to power failure, and for which power failures could cause high costs or other severe in- conveniences, such as danger for persons.
  • One example of a technical field in which a failure of the supply of electric power to an industrial process would have consequences being devastating from the cost point of view are high temperature processes within the steel industry.
  • Load is here to be given a broad sense and an alternating voltage network is for example also comprised, which in this way through a transfer switch may be provided with supply of electric power from different places.
  • the component is usually a semiconductor device, but it could be of any conceivable type having said ability, such as for example a variable electric resistor according to WO 98/149694.
  • the invention is of course not restricted to any particular range of the operation current through such an electric switching device in the closed state of such a transfer switch, and neither to any particular voltage levels existing in said current path, but it may nevertheless be mentioned that it is particularly useful for intermediate voltage, i.e. corresponding to 1 -52 kV system voltage, in which the operation current in question typically may be 1 kA, but both lower and higher voltages and currents than these are conceivable.
  • conducting state is to be given a broad sense, and it is not necessary that a component going into or in conducting state really conducts, but this is also intended to cover that it may be brought to conduct in that moment if desired , which could be the case for a semiconductor device of turn-on type, such as a thyristor, while a passive semiconductor device in the form of a diode instead always will conduct in the conducting state such as defined here.
  • first contact member and “second contact member” comprise all types of physical appearances of a contact member in which a physical separation of two parts while forming a gap therebetween takes place when opening the contact member, and this may for example take place by moving a movable contact interconnecting two spaced contacts so that these are no longer in connection with each other or by having a movable contact bearing against a fixed contact and this is moved away therefrom.
  • Two movable contacts are also conceivable.
  • “Gap” is also to be given a broad sense. It comprises also that an insulator is brought in between the contacts and this may be a solid body bearing against both contacts .
  • a contact surface may also be followed by an insulating surface in the same body (which may comprise a movable or fixed contact) and in the same plane and "the gap" is then formed by the fact that two bodies forming a contact in a bearing position are displaced with respect to each other so that such in insulating surface forms the bearing surface of one or both bodies.
  • the electric switching devices arranged in the transfer switch defined in the introduction are normally called hybrid breakers, and characterizing for them is that they are able to achieve an arc-free breaking of the current path through the switching device, since this takes place when the semiconductor device is in the blocking state and no current flows through the switching device.
  • the gas pressure inside the breaker used has to be high for achieving a sufficient insulation and breaking performance or a vacuum has to be provided inside the breaker for the same reason. Quite an amount of energy is needed in the first case for blowing out the arc, while in the second case a com- paratively high contact pressure for a good contact is needed , which consumes a not negligible amount of energy.
  • Said first contact member is in transfer switches of the type defined in the introduction already known formed by a vacuum breaker with the inconvenience mentioned above as consequence, while the second contact member is formed by a disconnector. Furthermore, the component is in some cases switched in during normal operation, which results in a great need of cooling thereof. This together with requirements of a comparatively complicated control electronic means that such transfer switches already known get very voluminous and costly.
  • the object of the present invention is to provide a transfer switch of the type defined in the introduction, which may be designed in a considerably simpler way, with substantially lower demand on space and by that to a lower cost than such transfer switches already known discussed above.
  • This object is according to the invention obtained by providing such a transfer switch, which comprises at least one movable part and by designing the unit to control this part to carry out one single mechanical movement for opening the two contact members of the first switching device and close the two contact members of the second switching device.
  • one single movable part By controlling one single movable part to carry out one single mechanical movement for opening the two contact members of one switching device and closing the two contact members of the other switching device this may take place in a perfectly synchronized way, without any requirement of any complicated control apparatus for co-ordinating these openings and closings, respectively, with each other.
  • one single driving arrangement may be used for accomplishing the entire transfer of supply to the load from one alternating current supply to the other by driving the movable part to carry out one movement.
  • the switching devices of the transfer switch according to the invention in this way may ensure arc-free breaking of the current through the first contact member without arranging any vacuum breaker, so that instead the corresponding amount of energy may be used for making the breaking faster.
  • Different types of electrical equipment connected to said current path may by that be better protected upon occurrence of a fault and material wear of the contacts included in the switching devices may be reduced. All this means that the transfer switch according to the invention may be made considerably more compact than such transfer switches already known and it may also be provided to a lower cost.
  • the transfer switch comprises at least two contacts consecutively arranged along the path of the movable part for said mechanical movement, the movable part is adapted to form a galvanic connection between said two contacts in the closed state of the re- spective switching device, the respective switching device is adapted to be switched in in a current path going through the switching device through one of the contacts and the movable part, the component of the respective switching device connects the two contacts with each other, and the control unit is adapted to control opening of said current path through the respective switching device by controlling the movable part to move along such a path and in such a direction that the galvanic connection between one of said two contacts and the movable part is broken for opening the first contact member and then the galvanic connection between the second of said two contacts and the movable part is broken for opening the second contact member
  • each switching device since each switching device only has to include two fixed contacts, one movable contact part in common with the
  • At least one of said switching devices comprises at least three contacts consecutively arranged along the path of the movable part for said mechanical movement, and the component of this switching device connects a first and second adjacent of these three contacts with each other, the movable part is adapted to form a galvanic connection between said three contacts in the closed state of said at least one switching device, and the control unit is adapted to control the movable part to move along such a path and in such a direction for breaking the current through this switching device that first the galvanic connection between the first contact most far away from the third of the contacts and the two other contacts is broken for opening the first contact member and then the galvanic connection between the second and the third contact is broken for opening the second contact member
  • This embodiment requires also only one semiconductor device per switching device, which makes it worth its price
  • said at least one switching device of the transfer switch comprises at least two said components in the form of semiconductor devices connected between an outer contact each with respect to the movement path of the movable member and a contact located next to the latter, the movable part is adapted to form a galvanic connection between all contacts between and including said outer contacts in the closed state of this switching device, this switching device comprises members for detecting the direction of the current through the switching device in the closed state, and the control unit is adapted to control the movable part on the basis of information from said detecting members when breaking the current through the switching device to move in one or the other direction along the movement path thereof so as to open the first contact member by breaking the galvanic connection between a first outer contact and a first contact adjacent thereto and then open the second contact member through continued movement.
  • the movable part may in principal instantaneously upon arising of a desire to interrupt one alternating current supply be accelerated for opening the first contact member of the switching device in question, since the movement direction may be chosen so that the semiconductor device intended to have the current transferred thereto is in the conducting state.
  • the harmful influence that a fault along the current path in question may procure may be reduced to a minimum at the same time as the time period during which the load is without supply may be made very short.
  • the movable part is connected to the load, which enables a transfer of the supply of the load from one alternating current supply to the other by very simple means and while using a minimum number of contacts
  • the two switching devices have a contact in common along the movement path of the movable part, so that the contacts along this movement path on one side of the contact in common belong to a first of the switching devices and those on the other side belong to the other of the switching devices, and the con- tact in common is adapted to be connected to the load
  • control unit is adapted to control the movable part along a substantially arc-shaped movement path along which the contact members of both switching devices are arranged
  • this may by this be brought to the closed state through a movement in the direction desired by ro- tatmg the movable part, so that the closed state may be obtained in the fastest possible way, so that in the case of opening and closing in two different directions according to above the rotation direction providing possibility to the fastest opening with respect to the position of the alternating voltage across the switching device in question may always be chosen
  • both switching devices are arranged substantially 180° displaced with respect to each other along said arc, since this makes a transfer of the supply to the load through one switching device to the other possible in the short- est possible maximum time irrespectively of the position of the alternating current of the switching device closed in the moment for occurring of a need of transfer It also gets simpler to operate the switching device by for example an electric motor
  • the movable part is rigidly connected to an axle, and the control unit is adapted to control a driving arrangement to drive the axle for moving the movable part along said path.
  • the transfer switch comprises a driving member being electrically controlled and adapted to carry out said single mechanical movement, and it is particularly advantageous if this driving member is an electromagnetic machine in the form of an electric motor.
  • this driving member is an electromagnetic machine in the form of an electric motor.
  • control unit of the device in the form of an electronic unit is adapted to control the driving member it is also possible to influence the movement of the movable part also when this has already started for making ad- aptations to values of parameters newly measured, such as current and voltage, and possibly interrupt the entire procedure, should it be discovered that there is no longer any need thereof or the movement should for example better take place in the opposite direction.
  • this embodiment is suitable for co-ordination with a prediction of the future development of the current through the respective switching device of the transfer switch, such as a coming zero crossing of the current, so as to co-ordinate a breaking or closing of the current path through the respective switching device with such a prediction, so as to for example ensure that said component with ability to block current only will conduct current during a so-called short half wave.
  • said component which usually is a semiconductor device, such as a diode
  • this component has not to be dimensioned for being able to over a longer time withstand op- eration currents, but it may instead be allowed to be considerably overloaded once it is conducting, since this only takes place during a very short period of time.
  • the transfer switch comprises members adapted to substantially continuously detect the direction and magnitude of the current through the switching device being closed for the moment and send information thereabout to the control unit. This means that the control unit all the time “knows” how transfer from one supply to the other shall take place, so that this may be carried out in the quickest and most flexible way as soon as a need thereof arises.
  • the switching device comprises a voltage limiting device connected in parallel with the semiconductor device, and the device is adapted to start conducting at a voltage thereacross close to the maximum voltage withstood by the semiconductor device. This is possible thanks to the fact that in the closed and open state of the switching device no voltage will be applied across the semiconductor device and by that neither across the device, so that this will not be heated up by any leakage currents therethrough.
  • the device which may be a varistor, but also could be of any other type, for example a resistor, snubber or the like
  • the first voltage peak occurring across the semicon- ductor device through the returning voltage after opening the first contact member may be limited, which in the case of one single semiconductor device makes it possible to dimension it for being able to hold a lower returning voltage in the blocking direction thereof and by that gets less costly than otherwise.
  • the number of such components having a determined ability to withstand voltage connected in series may be reduced. It is by that avoided that any individual component gets a higher voltage thereacross than it may with- stand, while other components get a lower voltage thereacross.
  • At least one of the switching devices comprises means adapted act increasingly upon the voltage when separating two contacts in connection with opening the first contact member.
  • the voltage at the contact separation is normally in the order of 12-15 V, and it drives the transfer of the current to the component connected in parallel. The higher this voltage is the faster may the current be fed into the component.
  • said means comprises a plurality of first contact members connected in series adapted to be opened substantially simultaneously for transferring the current to the component.
  • said means are formed by the fact that the contacts included in the first contact member have at least a part of ablating material adapted to be heated and evaporated to gases for gas blowing on an arc when separating two contacts when opening the first contact member, which also achieves a higher arc-voltage and a faster commutation of the current to the component.
  • the semiconductor device of at least one of the switching devices is a diode, which often would be preferred, since such a solution is cheap compared to other controllable semiconductor devices and also very reliable.
  • the semiconductor device is controllable, such as a thyristor, and it could also be of turn-off type, such as a GTO or an IGBT, so as to enable a quicker breaking procedure of the closed switching device. It could also in some situations be advantageous to ar- range a bi-directional semiconductor device, i.e. a semiconductor device being able to block and conduct in both directions, such as a BCT (bi-directionally controlled thyristor).
  • a bi-directional semiconductor device i.e. a semiconductor device being able to block and conduct in both directions, such as a BCT (bi-directionally controlled thyristor).
  • Comparatively high voltages may be handled by the two switch- ing devices of the transfer switch and by that by the transfer switch while using a low number of semiconductor devices, when a semiconductor device of a material having a wide energy gap between the valence band and the conduction band is used, i.e. an energy gap exceeding 2.5 eV, such as SiC and diamond.
  • the transfer switch comprises means adapted to continuously or intermittently determine which of the two supplies is for the moment the most suitable for the load, and the control unit is adapted to control said movable part on the basis of information from said means for transferring the supply of the load from one alternating current supply to the other if the alternating current supply switched in to the load in that moment does not correspond to said most suitable supply.
  • the transfer switch may by this be used to always ensure that the one of the two alternating current supplies according to certain criterions most suitable is connected to the load.
  • the invention also relates to advantageous uses of a transfer switch according to above in accordance with the appended claims, and the advantages of most of them appear without any doubt from the discussion above, but it may here be mentioned that a particularly advantageous use of the transfer switch is for connecting an electrical equipment to an alternating voltage network through two different current paths, firstly the first one for starting the electrical equipment through closing the first of the switching devices and then the second one for operation of this equipment through opening the first switching device and closing the second one, in which a more specific such use is constituted by reactor start of an electric motor connected to an alternating voltage network for firstly through the first switching device connect the motor to the alternating voltage network through a reactor, i.e. an inductor, and then through the second switching device connect the motor directly to the alternating voltage network. It is by this avoided that a large such motor re- Jerusalem the voltage level of the alternating voltage network to un- acceptably low levels at said start, and a soft start may instead take place through the reactor.
  • the invention also relates to a switch gear for supply of electricity within industry or in distribution and transmission networks provided with a transfer switch according to the invention.
  • the method according to the invention is also well suited for being carried out through a computer program provided with suitable program steps, and the invention also relates to such a program as well as a computer readable medium onto which such a program is recorded .
  • Fig 1 and 3-8 are simplified views illustrating a transfer switch according to a first preferred embodiment of the invention in different operation positions between a load connected to a first alternating voltage supply and the load connected to a second alternating voltage supply,
  • Fig 2 is a simplified circuit diagram illustrating the principle of the operation of the transfer switch according to Fig 1 ,
  • Fig 9 is a simplified view illustrating a transfer switch according to a second preferred embodiment of the invention in a parking position with the load separated from both supplies,
  • Fig 10 and 12-14 are simplified views illustrating a transfer switch according to a third preferred embodiment of the invention in different operation positions between a load connected to a first alternating voltage supply and the load connected to a second alternating voltage supply,
  • Fig 1 1 is a simplified circuit diagram illustrating the principle for the function of the transfer switch according to Fig 10,
  • Fig 15-17 illustrate schematically an electric switching device applicable in a transfer switch according to a fourth preferred embodiment of the invention in closed, temporary closed and open position, respectively,
  • Fig 1 8 and 1 9 illustrates electric switching devices usable in transfer switches according to further preferred embodiments of the invention
  • Fig 20 illustrates how the current I through and the voltage U across the semiconductor devices of a switching device accord- mg to Fig 19 develop over time in comparison with a switching device substantially according to Fig 18,
  • Fig 21 and 22 illustrates a part of a switching device included in a transfer switch according to the invention in two different positions when breaking the current therethrough
  • Fig 23 and 24 are schematical circuit diagrams illustrating two possible ways to arrange a transfer switch according to the m- vention for start of an electric motor
  • Fig 25 is a simplified circuit diagram illustrating a possible use of a transfer switch according to the invention for switching in and switching out capacitors to an alternating voltage network for reactive power compensation
  • Fig 26 is a simplified sketch illustrating an advantageous use of a transfer switch according to the invention.
  • Fig 27-29 illustrate schematically a use of a transfer switch according to a preferred embodiment of the invention in a ring circuit for feeding loads connected to the ring,
  • Fig 30 is a very simplified view illustrating how the two switching devices of the transfer switch according to the embodiment shown in Fig 27-29 may be controlled, and
  • Figs 31 -34 illustrate a transfer switch according to a further preferred embodiment of the invention used in a said ring circuit in different states
  • a transfer switch for alternating current is schematically illustrated in Fig 1 and comprises two electric switching devices 1 , 2 adapted to establish and break, respectively, a current path between a load 3 (see Fig 2) here connected to a movable contact part 4 and an alternating current supply 5. 6 each indicated through an electric line for transferring the supply for feeding of the load with electric power from one alternating current supply to the other.
  • One such transfer switch is arranged per phase, so that a three-phase network has three such transfer switches on one and the same location.
  • the movable contact part 4 is arranged on a carrier 7, which is arranged to rotate around an axle 8.
  • Three contacts 9-1 1 and 12-14, respectively, are arranged externally of the carrier 7 with the movable part 4 for the respective switching device along the movement path of the movable part 4. and these contacts are arranged to form good electric contacts when bearing against the movable part 4.
  • the diameter of the circle along which the movable part is adapted to establish electric contacts with the contacts 9-14 is proportional to the alternating voltage of the two supplies.
  • a semiconductor device 1 5-1 8 in the form of a diode connects each outer contact 9, 1 1 , 12, 14 as seen in the movement path with the mid-contact 1 0, 1 3, in which one diode of each switching device has the conducting direction towards the mid-contact and the other the conducting direction away from the latter.
  • the transfer switch has also a driving arrangement in the form of an electric motor 65 adapted to drive the carrier 7 and by that the movable contact 4 to rotate around the axle 8.
  • a driving arrangement in the form of an electric motor 65 adapted to drive the carrier 7 and by that the movable contact 4 to rotate around the axle 8.
  • Each switching device is also provided with a detecting member 19 schematically indicated for the switching device 1 and adapted to detect the direction and the magnitude of the current in the current path through the switching device being closed for the moment and send information thereabout to a unit 20 adapted to control said driving arrangement and by that the movement of the movable contact part 4 on the basis of this information .
  • the control unit will in this way all the time be aware of what the current instantaneously looks like so as to be able to instantaneously control the movable contact part in a desired way.
  • Means 56 of are also arranged to on the basis of other pa- rameters, such as prices of power fed from the two supplies 5, 6, determine which one is the most suitable for the supply of the load at a given time and send information thereabout to the control unit 20.
  • a component 66 increasing the resistance is arranged between the connection of the respective semiconductor device 15-18 to the respective supply 5, 6 and the closest contact 1 0, 1 3. This component increasing the resistance is intended to be controlled to either have a negligible resistance when the respective switching device is closed or get a comparatively high resistance for take voltage thereacross in a way described further below.
  • the component increasing the resistance could be a resistor having a controllable resistance, such as a powder having a very low resistance when applying an outer pressure thereon, but which gets a high resistance when the pressure is removed, or a controllable semiconductor de- vice, which has a low on-state voltage, but which may be brought to turn-off for then considerably increasing the resistance therethrough.
  • a resistor having a controllable resistance such as a powder having a very low resistance when applying an outer pressure thereon, but which gets a high resistance when the pressure is removed, or a controllable semiconductor de- vice, which has a low on-state voltage, but which may be brought to turn-off for then considerably increasing the resistance therethrough.
  • the transfer switch is in the position according to Fig 1 , in which the first switching device 1 is closed, so that the load is connected to the alternating voltage supply 5, while the alternating voltage supply 6 is disconnected, since the elec- trie switching device 2 is open .
  • the alternating current supply 5 is the regular or normal supply
  • the alternating current supply 6 is a spare supply.
  • the control unit 20 firstly decides in which direction the movable contact part 4 shall be moved for being able to break the current path through the first switching device 1 as quick as possible.
  • an electronic unit for controlling thereof and a prediction of a future zero-crossing of the current the opening of this first contact member may be controlled to take place substantially at such a zero-crossing , which means within about 0,5 ms before and about 0,5 ms after such a zero-crossing. That means that the current to be corn- mutated over to flow through the diode is small and the com- mutation may therefore take place quickly without any high demand on means for increasing the voltage across this contact member.
  • the control unit 20 controls then the movable contact 4 to rotate clockwise so as to open a first contact member connected in parallel with the diode 15, which here is constituted by the contacts 1 0, 1 1 and the movable part 4.
  • the temporary closed position shown in Fig 4 is then obtained.
  • a small spark is formed in the gap 22 between the movable part 4 and the contact 10, which results in a voltage of usually 12-15 V, which will drive the transfer of the current through the diode 15, so that the current now instead will flow through the movable part 4, the contact 1 1 and the diode 1 5.
  • a voltage may very rapidly be built up across the diode 15 and thereby the transfer of the current to flow through the diode may be fast.
  • the transfer of the current to the semiconductor device may also be accelerated by switching in a resistance in the regular current path and by that increasing the voltage also across the semiconductor device.
  • the control unit would instead control the movable contact part 4 to rotate counter-clockwise as seen in the figures for utilizing the diode 16 at the breaking instead.
  • a possibility to a very rapid breaking of the current path is obtained in this way, and the switching device may even in the most unfavourable position of the alternating voltage when detecting a need of a breaking be brought between the closed position and the completely opened position according to Fig 8 within a substantially shorter time than one period, usually always within 15 ms for a frequency of 50 Hz of the alternating voltage.
  • the position shown in Fig 8 constitutes also a possible parking position, which may be assumed during a longer period of time should there be a requirement to separate the load from the supplies, for example for carrying out maintenance works between the load and the transfer switch .
  • Voltage increasing means 67 corresponding to the resistance increasing component 66 according to above have also been shown in this figure, which here comprises a charged capacitor adapted to be switched in between the respective outer contact and the mid- contact 1 0, 13 when the connection therebetween through the movable part is to be broken for rapidly transfer the current to flow through the respective diode.
  • the contacts 10, 1 3 and 4 have only to be dimensioned for the operation current, which for example may be 1000 A, while the diodes 15, 16 are dimensioned for a possible shortcircuit current, which in such a case could be 25 kA.
  • the diodes have to be dimensioned for a returning voltage that during a short period of time is applied thereacross after opening said first contact member. This may in the case of a network voltage of 12 kV for example be about 20 kV.
  • the contact gap 23 in Fig 8 has to be able to withstand a considerably higher so-called i mpulse voltage, which in th is case could be 75 kV.
  • the spare sup- ply 2 is immediately switched in should the current direction thereof be so that a temporary current path may be established through the diode 1 7 , and otherwise the switching in of the spare supply is delayed until the position according to Fig 6 is obtained, in which the movable part 4 establish a galvanic con- tact connection with the mid-contact 1 3 of the second electric switching device 2.
  • the movement of the movable part is then continued to the position according to Fig 7 , so that the transfer switch has assumed a ready position for the quickest possible return to supply of the load through the regular alternating cur- rent supply 5 when a desire thereof arises . It is pointed out that it may for sure be very advantageous, when the movable part 4 reaches the contact 14 , to have the diodes 1 7 and 1 8 directed as shown with respect to the diodes 1 5 and 1 6, but they could also be oppositely directed .
  • the opening of the first switchi ng device 1 and the closing of the second switching device 2 takes place through one single mechanical movement of one sing le movable part, which results in the advantages already mentioned further above.
  • a transfer switch according to a second preferred embodiment of the invention is schematically illustrated in Fig 9, in which the two switching devices 1 , 2 are arranged displaced with respect to each other along and arc of an angle of substantially 120° , which means that the insulation distances 23 between the movable part 4 and the contacts 1 1 , 14 may be increased in the parking position of the transfer switch shown in Fig 9.
  • the transfer switch may by this in the broken parking position withstand higher impulse voltages than in the embodiment according to Fig 1 .
  • this embodiment means that the movable part has a longer distance to move when rotating the movable part 4 counter-clockwise in Fig 9 for transferring the load from one supply to the other.
  • Another possibility to increase said insulation distance is to arrange the two switching devices displaced with respect to each other in the direction of the axle 8.
  • a transfer switch for alternating current is illustrated in Fig 1 0 and 12-14, which functions according to the same principle as the one just described, but the movable contact part 4 is here instead movable along a rectilinear movement path.
  • the two switching devices 1 and 2 have here a fixed contact 24 in common along the rectilinear movement path of the movable part 4. and to this contact 24 in common the load 3 to which the trans- fer switch is intended to accomplish feeding is intended to be connected.
  • the two other contacts 25, 26 and 27, 28, respectively, of the respective switching device are connected with a semiconductor device 29, 30 each in the form of a diode, which is directed with the conducting direction thereof towards the in- ner one of the contacts 26, 27.
  • Fig 12, 1 3 and 14 how firstly the movable part 4 is moved along a rectilinear movement path for obtaining the temporary closed position according to Fig 12, in which the current is transferred to the semiconductor device 29, to the completely open position according to Fig 1 3 of the first switching device 1 and then further to the other completely closed position according to Fig 14 of the switching device 2, so that the spare supply 6 is con- nected to the load 3 through the contact 28, the movable part 4 and the contact 24.
  • a modified electric switching device is schematically illustrated in Fig 1 5, which in combination with an identical such one could form a transfer switch according to a further preferred embodiment of the invention.
  • this switching device will here be described, and it is apparent for a man with skill in the art how two such switching devices could be combined for obtaining a transfer switch while using one and the same movable part 4.
  • the switching device has an inner cylinder 31 , which is rotatably arranged at an axle 32 and has a movable part 4.
  • a second cylinder 33 is arranged externally of the cylinder 31 and has four contacts 34-37 arranged along the movement path of the movable part 4 and adapted to form good electric contacts when bearing against the movable part 4.
  • the switching device is switched in in a current path 38 therethrough through the two outer contacts 34 and 37, respectively.
  • a semiconductor device in the form of a diode 39, 40 is switched in between the two outer contacts and the closest adjacent inner contacts and it has a conducting direction from the outer to the adjacent contact, but it could instead be switched in with the opposite conducting direction.
  • the switching device has also a driving arrangement adapted to drive the inner cylinder 31 to rotate for movement of the movable contact part 4 with respect to the other contacts 34-37.
  • the driving arrangement is in this case an integrated electric motor 41 schematically indicated, which may be of an amount of different types, such as for example a PM-motor, a reluctant motor, a step motor, a DC-motor.
  • the motor is here not located in the same plane as the contacts, but it could be, and it will by that not influence the voltage withstandability.
  • the driving very well may take place in another way, such as through a motor being adapted to act directly upon the axle 32. With respect to the dimensioning of the cylinders with respect to diameter and height this is carried out according to the same criterions as for the embodiment according to Fig 1 .
  • a further switching device of this type having four fixed contacts arranged along the movement path of the movable part 4 by a suitable modification of the outer cylinder in the same way as for the switching device shown for obtaining a transfer switch.
  • this contact could for example be in common for both switching devices.
  • Three additional fixed contacts may then for the rest be arranged following upon each other in the counter-clockwise di- rection from the contact 34 with semiconductor devices switched in the same way between them as for the contacts shown and the last contact as seen in this direction could be connected to an additional alternating current supply, such as a spare supply.
  • Fig 1 8 It is schematically illustrated in Fig 1 8 how a plurality of semiconductor devices 44-46 can be connected in series so as to together be able to take a determined returning voltage after breaking the current path in a switching device included in a transfer switch according to the invention.
  • each diode symbol may be replaced by a number diodes connected in series in this way.
  • the number of semiconductor devices required for a given voltage will be low by choosing a material having a wide bandgap between the valence band and the conduction band, such as SiC or diamond It is also shown in this figure how it is possible to connect semiconductor devices in parallel by here arranging two packages of diodes connected in series in parallel with each other, and this is made for being able to take a certain shortcircuit current or just for redundancy reasons, so that the switching device will function in the desired way even if any diode in any package of the diodes connected in series fails
  • a va ⁇ stor 47 preferably of ZnO
  • the va ⁇ stor is adapted to start conducting at a voltage thereacross close to the maximum voltage that may be withstood by the semiconductor device
  • the va ⁇ stors do not normally conduct any current at all, since no voltage will be applied thereacross but they will only receive a voltage thereacross in connection with the transition between the temporarily closed and the completely open position
  • the voltage U over the semiconductor devices 48 in the reverse direction thereof is developed over time t when the voltage m- creases thereacross in the temporarily closed position at the time zero
  • the dashed line shows how the voltage across the diodes is developed in the absence of va ⁇ stors and the solid line with va ⁇ stors
  • the va ⁇ stors cut the first voltage peak off Are for example four 5 kV diodes arranged in series in a system having a network voltage of 12 kV
  • the first conduct member has two fixed contacts 56, 57, which are adapted to be galvanically connected through a movable part 58 in the closed state
  • the movable part 58 is at one end thereof provided with a portion 59 of a material having a comparatively high resistivity, so that the resistance between the movable part 58 and the contact 56 and by that between the two contacts 56 and 57 is increased in the beginning of said separation (the position according to Fig 22) while allowing current between these contacts therethrough, so that a voltage that will drive the transfer of the current through the semiconductor device will be increased
  • the portion 58 may for example be made of graphite
  • FIG. 23 A possible application of a transfer switch according to the invention for motor starts is also illustrated in Fig 23 and 24 It is illustrated in Fig 23 how a transfer switch of the type according to the invention (see the principle sketch according to Fig 2) is switched in between a motor 49 and an alternating voltage network 50
  • a transfer switch of the type according to the invention see the principle sketch according to Fig 2
  • This way of consideration is even more understandable when study- ing the embodiment according to Fig 24, which differs from that according to Fig 23 by the fact that the transfer switch 52 has there been arranged in direct connection to the motor.
  • the motor 49 will then start to act as a generator and contribute with power to the fault place be- fore the fault gets disconnected. It is here a possibility to limit the effect of this by closing the switching device 2 and opening the switching device 1 in such a case, so that the shortcircuit contribution from the motor to the fault place is restricted and breaking of the motor is at the same time reduced.
  • the switching device 1 will then be opened.
  • a possible application of a transfer switch according to the invention for switching in capacitors 60 to a three-phase alternat- ing voltage network 61 for reactive power compensation is illustrated in Fig 25.
  • a transfer switch according to the invention may then be replaced by two breakers 62, 63, such as illustrated in Fig 25
  • the breaker 62 may firstly be closed Thy ⁇ stors 64 connecting the breaker 62 to the phase in question are then turned on so that the capacitor 60 is switched in at a desired time
  • the breaker 63 is then closed
  • the breaker 62 is then opened, so that the thy ⁇ stors not have to conduct any longer, while the breaker 63 is closed and the switching in of the capacitor is completed
  • This advanta- geous sequence for switching in reactive power compensation may be comfortably realised by suitably designing a transfer switch according to the invention
  • a transfer switch ac- cording to the invention may be arranged in a ring circuit 70 for feeding loads connected to the ring circuit, which are indicated through a load line 71 .
  • the ring has two parts 72, 73 arriving to the location for feeding the loads for opposite directions.
  • the two electric switching devices 1 , 2 of the transfer switch are arranged to function as circuit breakers, while also a load breaker 80 is arranged in the line to the load. Two preferred embodiments according to the invention of a transfer switch used in this way will hereinafter be described.
  • a transfer switch according to the invention formed by two elec- trie switching devices 1 , 2 of the type being described in detail in the Swedish patent application 9904166-7 of the applicant is illustrated in Fig 27, and reference is made to that application for more details with respect to the function of such a switching device.
  • Characterizing for this switching device is that only one single rectifying semiconductor device 68 is required for enabling an immediate start of a breaking operation independently of the current direction through the switching device.
  • the movable parts 4 have here an arc-like or banana-like shape and are connected to each other, for example like a wheel with a hub. Thus, they may be rotated about a centre point 69 for breaking or closing the current through the respective switching device.
  • This transfer switch is arranged in a ring circuit 70 emanating from an electric power central and is intended for feeding loads connected to the ring with alternating current.
  • 71 indicates the line to a load, while 72 and 73 indicated the ring parts meeting at the location for the output to the load.
  • the two electric switching devices are preferably controllable completely in- dependently of each other, and the following alternative may then be obtained: Both electric switching devices are closed and the load gets feeding from the two ring parts 72 and 73 of the ring circuit. Only one of the switching devices are closed, and the load then gets feeding only from the ring part connected to the switching device in question.
  • a load breaker is normally also arranged in the line 71 for making it possible to break away the load there and simultaneously enable feeding in the ring beyond the transfer switch It is illustrated by the sequence according to Fig 27-29 how the feeding to the load may be shifted from one ring part 72 to the other ring part 73 In the position according to Fig 27 current flows through the first switching device 1 to the load line 71 , while the second switching device 2 is open
  • the movable parts 4 of the electric switching device 1 are rotated as shown in Fig 28, so that the current through that switching device is transferred to go through the diode 68, while the second switching device 2 is transferred to a position so that the current thereof also flows through the diode thereof
  • the rotation of the movable parts 4 of the first switching device 1 is then continued so that the contact with the diode branch is left when the current has become zero and a voltage has started to be built up across the diode, so that an
  • An electric motor 65 is intended to control a rotation of a hollow axle 74 connected to the movable part of one switching device and an axle 75 inserted therein and connected to the movable parts of the second switching device
  • the function of the motor and the function of a magnet clutch 76 schematically indicated for optionally interconnecting the two axles 74, 75 is intended to be controlled by an electronic unit 20
  • a transfer switch according to another preferred embodiment of the invention is very schematically illustrated in Fig 31 -34, and this transfer switch is also built in in a ring circuit 70 having ring parts 72, 73 and a load connection 71 .
  • the two electric switching device 1 , 2 here share the diode branch 77 by arranging an elongated contact member 78 controllable through a driving member not shown and which may optionally connect one of the electric switching devices or none of them to the diode branch 77.
  • the two ring parts 72, 73 may in the position according to Fig 31 feed alternating current to the load line 71 through the movable contact parts thereof.
  • the ring part 73 shall be switched out and the feeding after that only takes place through the ring part 72.
  • the movable part 4 of the electric switching device 2 is then operated to turn while opening the contact member 79 preceded by a displacement of the contact component 78 into contact with the movable part, so that the current through the switching de- vice 2 may be commutated over to flow through the diode branch 77.
  • the rotation of the movable part 4 of the switching device 2 is continued to the position according to Fig 33 for breaking the current through the switching device 2.
  • the rotation of the movable part may then be continued to the position according to Fig 34 for grounding the ring part 73 through a ground or earth contact 81 , should this be desired .
  • Preferred uses of a transfer switch according to the invention is as current limiter or connected in series with a current limiter or as breaker, as protection for obtaining current breaking and/or disconnection of parts in an electric circuit located on both sides thereof upon occurrence of faults, such as shortcircuits, for switching in and/or out normal operation currents of an eiectric circuit, as disconnector, as grounder for grounding an electric circuit, for switching in and out a generator with respect to an alternating voltage network, for switching in and switching out a resistive load with respect to an alternating voltage network, for switching in and switching out a resistive, eapacitive or inductive load with respect to an alternating voltage network, for breaking current paths in switch gears for supply of electricity in industry or in distribution or transmission networks and for reactor start of an electric motor connected to an alternating voltage network.
  • Preferred is also a transfer switch according to claim 1 comprising current measuring members, an electronic unit adapted to carry out a current prediction algorithm and an electrically controlled driving member, such as a motor, for obtaining opening of the first contact member substantially at a zero-crossing of the current through the switching device being closed.

Landscapes

  • Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
  • Arc-Extinguishing Devices That Are Switches (AREA)

Abstract

Selon l'invention, dans un commutateur de transfert permettant d'alterner le courant, deux dispositifs de commutation électrique de type hybride sont conçus, respectivement, pour établir et interrompre un parcours de courant entre une charge et une alimentation en courant alternatif afin de transférer l'alimentation de la charge avec de l'énergie électrique d'une alimentation en courant alternatif (5) vers l'autre (6). Les dispositifs de commutation comportent des composants (15-18) qui bloquent le passage du courant au moins dans une direction de manière à établir un parcours de courant temporaire à travers lesdits dispositifs lorsque le parcours de courant à travers le dispositif de commutation est interrompu, et qui permettent l'exécution sans arc électrique de l'interruption. Une unité de commande (20) est conçue pour commander une partie mobile (4) afin d'exécuter un mouvement mécanique unique aux fins d'ouverture d'un des dispositifs de commutation et de fermeture de l'autre pour modifier l'alimentation en courant alternatif vers la charge.
PCT/SE2000/002274 1999-11-18 2000-11-20 Commutateur de transfert WO2001037299A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP00978182A EP1230658A1 (fr) 1999-11-18 2000-11-20 Commutateur de transfert
AU15667/01A AU1566701A (en) 1999-11-18 2000-11-20 A transfer switch

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9904165A SE518664C2 (sv) 1999-11-18 1999-11-18 Transferswitch, användning av en sådan transferswitch, anläggning innefattande ett flertal transferswitchar, ställverk och förfarande för överföring av en matning av en last
SE9904165-9 1999-11-18

Publications (1)

Publication Number Publication Date
WO2001037299A1 true WO2001037299A1 (fr) 2001-05-25

Family

ID=20417756

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2000/002274 WO2001037299A1 (fr) 1999-11-18 2000-11-20 Commutateur de transfert

Country Status (4)

Country Link
EP (1) EP1230658A1 (fr)
AU (1) AU1566701A (fr)
SE (1) SE518664C2 (fr)
WO (1) WO2001037299A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1953780A1 (fr) * 2007-02-02 2008-08-06 Abb Research Ltd. Dispositif de commutation électrique, son utilisation et procédé de commutation
US7755872B2 (en) 2006-09-14 2010-07-13 Schweitzer Engineering Laboratories, Inc. System, method and device to preserve protection communication active during a bypass operation
WO2012152345A1 (fr) 2011-05-10 2012-11-15 Abb Research Ltd Procédé utilisé par un contrôleur pour commander un compensateur dynamique, contrôleur, logiciels, et progiciels
EP3116007B1 (fr) * 2015-07-07 2018-10-31 ABB Schweiz AG Dispositif de commutation

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3388295A (en) * 1964-08-20 1968-06-11 Hubbell Inc Harvey Current interrupter
US3395316A (en) * 1966-02-17 1968-07-30 Allen Bradley Co Electric switch with contact protector
US3636292A (en) * 1967-02-21 1972-01-18 Sprecher & Schuh Ag Vacuum switch for alternating current interruption
US3675079A (en) * 1970-07-15 1972-07-04 Merlin Gerin Three phase electric switching system having rectifier shunted contacts
DE2204983A1 (de) * 1972-02-03 1973-08-16 Reinhausen Maschf Scheubeck Lastumschalter fuer stufenschalter von regeltransformatoren
DE2209500A1 (de) * 1972-02-29 1973-09-06 Transformatoren Union Ag Schaltungsanordnung zum unterbrechungslosen lastumschalten bei stufentransformatoren
US4754360A (en) * 1985-05-07 1988-06-28 Nipponkouatsudenki Kabushikikaisha Arc extinguishing apparatus having sensing of initial arc

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3388295A (en) * 1964-08-20 1968-06-11 Hubbell Inc Harvey Current interrupter
US3395316A (en) * 1966-02-17 1968-07-30 Allen Bradley Co Electric switch with contact protector
US3636292A (en) * 1967-02-21 1972-01-18 Sprecher & Schuh Ag Vacuum switch for alternating current interruption
US3675079A (en) * 1970-07-15 1972-07-04 Merlin Gerin Three phase electric switching system having rectifier shunted contacts
DE2204983A1 (de) * 1972-02-03 1973-08-16 Reinhausen Maschf Scheubeck Lastumschalter fuer stufenschalter von regeltransformatoren
DE2209500A1 (de) * 1972-02-29 1973-09-06 Transformatoren Union Ag Schaltungsanordnung zum unterbrechungslosen lastumschalten bei stufentransformatoren
US4754360A (en) * 1985-05-07 1988-06-28 Nipponkouatsudenki Kabushikikaisha Arc extinguishing apparatus having sensing of initial arc

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7755872B2 (en) 2006-09-14 2010-07-13 Schweitzer Engineering Laboratories, Inc. System, method and device to preserve protection communication active during a bypass operation
EP1953780A1 (fr) * 2007-02-02 2008-08-06 Abb Research Ltd. Dispositif de commutation électrique, son utilisation et procédé de commutation
WO2008092815A2 (fr) * 2007-02-02 2008-08-07 Abb Research Ltd Dispositif de commutation, utilisation de celui-ci et procédé de commutation
WO2008092815A3 (fr) * 2007-02-02 2008-10-16 Abb Research Ltd Dispositif de commutation, utilisation de celui-ci et procédé de commutation
US7977824B2 (en) 2007-02-02 2011-07-12 Abb Research Ltd. Switching device, use thereof and a method for switching
WO2012152345A1 (fr) 2011-05-10 2012-11-15 Abb Research Ltd Procédé utilisé par un contrôleur pour commander un compensateur dynamique, contrôleur, logiciels, et progiciels
US8775835B2 (en) 2011-05-10 2014-07-08 Abb Research Ltd. Method in a controller controlling a dynamic compensator, a controller, computer programs and computer program products
EP3116007B1 (fr) * 2015-07-07 2018-10-31 ABB Schweiz AG Dispositif de commutation

Also Published As

Publication number Publication date
SE9904165L (sv) 2001-05-19
SE9904165D0 (sv) 1999-11-18
EP1230658A1 (fr) 2002-08-14
AU1566701A (en) 2001-05-30
SE518664C2 (sv) 2002-11-05

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