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
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/02—Details
  • H01H33/59—Circuit arrangements not adapted to a particular application of the switch and not otherwise provided for, e.g. for ensuring operation of the switch at a predetermined point in the AC cycle
  • H01H33/596—Circuit arrangements not adapted to a particular application of the switch and not otherwise provided for, e.g. for ensuring operation of the switch at a predetermined point in the AC cycle for interrupting DC

Definitions

• the present invention relates to a separating arrangement for a high voltage direct current network. Moreover, the present invention relates to a method for operating a separation arrangement for a high-voltage direct current network.
• high-voltage networks usually disconnecting arrangements are used with which the current in case of failure (as well as operating currents) can be switched off.
• mechanical switches can not undertake the switching process on their own. The reason for this is that the, at the contacts of the mechanical switch, usually resulting arc voltage is too low compared to the driving mains voltage. Therefore, so-called hybrid switches or hybrid DC circuit breakers are proposed for the interruption of direct current usually consisting of a combination of power electronic and mechanical switch.
• the electrical current is conducted in the normal state of the mechanical switch.
• the current is first commutated by the mechanical switch to the semiconductor branch.
• the semiconductor switch For the arc to extinguish in the mechanical switch, the semiconductor switch must first be switched to the conductive state. After extinguishing the arc and a time for reconsolidation of the insulation gap, the semiconductor switches are driven accordingly, so that builds up a voltage with which the power is turned off in the DC network.
• the arc voltage generated in the mechanical switch is sufficiently large so that the commutation process can also take place.
• the threshold voltage of today used and massively connected in series semiconductor switches must be overcome statically.
• the over the Stray inductances occurring in the commutation circuit voltage drops are taken into account.
• WO 2011 057 675 AI discloses a device for switching off a direct current in a high-voltage network with a first separator comprising a plurality of series-connected semiconductor switches. Parallel to the first separation device, a second separation device is connected, which comprises a series connection of a mechanical switch and a semiconductor switch. Furthermore, in the publication by J. Häfner and B. Jacobson "Proactive Hybrid HVDC Breakers - A key innovation for reliable HVDC grids" presented on "The electric power system of the future - integration supergrids and microgrids", International Symposium in Bologna, Italy, 2011 a separating arrangement described in which a first separator a plurality of series-connected
• Semiconductor switches includes.
• the second separating device connected in parallel with the first separating device comprises, as a mechanical switch, a so-called quick disconnector, which is connected in series with an auxiliary switching device comprising a semiconductor switch.
• an electrical voltage can be built up which considerably exceeds the voltage drop in the first separating device and thus allows the commutation process to be carried out on the first separating device.
• a disadvantage of such an arrangement is that the current in normal operation always flows through the semiconductor switch in the auxiliary switching device and thus permanent losses are generated, requiring the corresponding permanent cooling effort.
• Furthermore, in the case of failure of the entire separation arrangement and an associated uninfluenced short-circuit current destruction of the auxiliary switching device take place because the then flowing short-circuit current exceeds the saturation current of the semiconductor switch in the auxiliary switching device.
• Another possibility is to build a negative voltage in the semiconductor branch of the first separator for the purpose of commutation.
• This is possible, for example, if so-called full-bridge circuits with energy stores, for example capacitors, are used in the semiconductor branch.
• energy stores for example capacitors
• this requires the use of full-bridge modules, for example, each having four IGBT branches.
• DE 694 08 811 T2 describes a high power DC power circuit breaker for use in a DC high voltage power line.
• a semiconductor element is connected in parallel to a mechanical switch.
• an arc voltage is applied to the contacts of the mechanical switch. If this arc voltage exceeds a predetermined limit value, an ignition signal for the semiconductor element is provided by means of a control pulse generator.
• the semiconductor element is closed and thus the current is conducted through the semiconductor element.
• the separating arrangement for a high-voltage direct current network comprises a first separating device which comprises a first semiconductor switching unit and a second separating device which is connected in parallel with the first separating device and which comprises a first mechanical switching unit and an auxiliary switching device connected in series with the mechanical switching unit wherein the auxiliary switching device comprises a second semiconductor switching unit and wherein the auxiliary switching device comprises a second mechanical switching unit which is connected in parallel to the second semiconductor switching unit.
• the separation arrangement can in particular for switching off
• the first semiconductor switching unit of the first disconnecting means may comprise a plurality of semiconductor switches electrically connected in series, for example as IGBTs (Isolated Gate
• IGBTs Isolated Gate
• the first mechanical switching unit in the second isolating device may be formed by a plurality of mechanical switches connected in series, vacuum switches may preferably be used for the mechanical switches can be used. For example, ten vacuum interrupters are connected in series, each of the vacuum interrupters can isolate a voltage of 30 kV.
• the auxiliary switching device connected in series with the first mechanical switching unit comprises a parallel circuit comprising a second semiconductor switching unit and a second mechanical switching unit.
• the second mechanical switching unit may also include a plurality of mechanical switches connected in series.
• a semiconductor switch which is formed for example as an IGBT, can be used.
• IGBT In practice, for reasons of redundancy but the series circuit less semiconductor switches makes sense.
• the use of two anti-serially connected IGBTs is also conceivable in a bipolar active circuit.
• a half bridge or a full bridge with connected capacitors can be used.
• the separating device preferably comprises a control device for actuating the first mechanical switching unit, the second mechanical switching unit, the first semiconductor switching unit and the second semiconductor switching unit.
• the Control device may include or be connected to a detection device, with which a fault current in the high-voltage direct current network can be detected.
• a detection device with which a fault current in the high-voltage direct current network can be detected.
• the first and the second mechanical switching unit and the first and the second semiconductor switching unit can be controlled independently of each other.
• the IGBTs can be individually controlled in the first semiconductor switch of the first separation unit. By appropriate Abieiter installed parallel to these IGBTs, so a Abschalturginot can be variably adjusted. The path can also be used to limit the current. Thus, reliable operation of the
• a forward voltage of the second semiconductor switching unit is less than an electrical voltage, which rests against contacts of the second mechanical switching unit when the second mechanical switching unit is opened.
• an arc voltage can form. If the second mechanical switching unit is designed as a vacuum interrupter, this arc voltage can be for example 30 volts. This voltage is sufficient to overcome the forward voltage or threshold voltage of the second semiconductor switching unit connected in the forward direction.
• the second semiconductor switching unit may comprise only one or a few IGBTs, which are electrically connected in series.
• control device is designed to close the first and the second mechanical switching unit for normal operation of the high-voltage direct current network.
• the electric current flows in normal operation via the first and the second mechanical switching unit.
• only small electrical losses and the cooling costs can be reduced.
• the separation arrangement can be operated particularly energy efficient.
• control device is designed to open the second mechanical switching unit in the presence of a fault in the high-voltage direct current network. If the direct current in the high-voltage network is to be opened as a result of an error or fault current, the second mechanical switching unit can be opened as quickly as possible. Thus, the shutdown of the electric current can be reliably started.
• the control device is designed to switch the second semiconductor switching unit in the presence of the fault in the forward direction. It can also be provided that the second semiconductor switching unit of the auxiliary switching device is switched to passage in normal operation. At the latest when the current in the high-voltage network is to be switched off, the second semiconductor switching unit is switched in the forward direction.
• the second mechanical switching unit is opened, a voltage is applied between its contacts. It may also be the case that forms an arc between the contacts of the second mechanical switching unit. The electrical voltage between the contacts is sufficient to overcome the threshold voltage of the second semiconductor switching unit. As soon as the electric current flows through the second semiconductor switching unit, a possible arc extinguishes at the contacts of the second mechanical switching unit. Now the mechanical switching unit can immediately absorb electrical voltage.
• control device is designed for this purpose, the first mechanical switching unit of the separation arrangement at the same time as the second mechanical
• the first mechanical switching unit can be opened at the same time as the second mechanical switching unit. It is also conceivable that the second mechanical switching unit is opened for a predetermined period of time, for example 0.1 to a few 10 milliseconds, after the second mechanical switching unit. This allows the first mechanical switching unit individually and independently of the second mechanical
• the control device is designed to switch the second semiconductor switching unit into a blocking operation after opening the first mechanical switching unit.
• the second semiconductor switching unit which is formed by one or more IGBTs
• a blocking voltage for example of 2 kV
• the blocking voltage provided by the second semiconductor switching unit is in series with the arc voltage at the first mechanical switching unit.
• the reverse voltage generated at the second semiconductor switching unit is sufficient to commutate the electric current from the second separator into the first separator.
• the control device may be designed to open the first mechanical switching unit only after an electric current has been commutated by the second separating device into the first separating device. If the first mechanical switching unit is opened only when the electric current is fully commutated in the first separator or the first semiconductor switching unit, the first mechanical switching unit can be ideally opened normally and there is no arc at the contacts of the first mechanical switching unit. As a result, wear of the contacts of the first mechanical switching unit can be effectively prevented.
• the method according to the invention for operating a separation arrangement for a high-voltage direct current network comprises providing a first separation device which comprises a first semiconductor switching unit and providing a second separation device connected in parallel with the first separation device, comprising a first mechanical switching unit and one in series with the first mechanical switching unit
• Switching unit connected auxiliary switching device comprises, wherein the auxiliary switching device comprises at least one second semiconductor switching unit and the provision of a second mechanical switching unit in the auxiliary switching device, which is connected in parallel to the second semiconductor switching unit.
• the single figure shows a schematic representation of a separation arrangement for a high-voltage direct current network.
• the embodiment described in more detail below represents a preferred embodiment of the present invention.
• the figure shows a generally designated 10 separating arrangement.
• the separation assembly 10 may be used for a high voltage network.
• the high-voltage network may, for example, have a rated voltage of 300 kV.
• the separating device 10 is connected to a line 26 of the high-voltage direct current network.
• the separating arrangement 10 has a first separating device 12 and a second separating device 14, which are electrically connected in parallel.
• the first separating device 12 comprises a first semiconductor switching unit 16.
• the first semiconductor switching unit 16 comprises a plurality of semiconductor switches or semiconductor components connected in series.
• the semiconductor switches can each be designed as IGBT.
• the second separating device 14 comprises a first mechanical switching unit 18, which in the present case is represented by the series connection of two individual switches.
• the first mechanical switching unit comprises a plurality of vacuum interrupters, which are connected in series.
• the second separating device 14 comprises an auxiliary switching device 20, which is electrically connected in series with the first mechanical switching unit 18.
• the auxiliary switching device 20 comprises a parallel circuit comprising a second mechanical switching unit 24 and a second semiconductor switching unit 22.
• the second mechanical switching unit 24 may be formed by one or more vacuum interrupters.
• the second semiconductor switching unit 22 may be formed by one or more IGBTs.
• the second semiconductor switching unit 22 may also be formed by two IGBTs connected in antiseries, by a half-bridge or a full bridge with connected energy stores in the form of capacitors.
• the first mechanical switching unit 18 and the second mechanical Switching unit 24 is closed.
• the second semiconductor switching unit 22 may generally be switched to passage in normal operation of the high voltage network.
• the second semiconductor switching unit 22 is switched immediately in the forward direction. If an error occurs in the high-voltage direct current network, the current flow in the electrical line 26 should be switched off or interrupted.
• first the second mechanical switching unit 24 is opened. When the contacts of the second mechanical switching unit 24 are opened, an arc may form on the contacts. As a result of the arc, an arc voltage of, for example, 30 volts is applied between the contacts of the second mechanical switching unit 24.
• This electrical voltage is sufficient to overcome the threshold voltage of the second semiconductor switching unit 22. Ideally, forms no arc at the contacts of the second mechanical switching unit 24, since the second semiconductor switching unit 22 is switched faster in the passage direction than the second mechanical switching unit 24 is opened. Furthermore, because of the low forward voltage of the second semiconductor switching unit 22, which may be, for example, only a few volts, the necessary minimum arc voltage for an arc can not be achieved at the second mechanical switching unit 24.
• the opening of the second mechanical switching unit 24 and the first mechanical switching unit 18 is opened.
• the arc at the contacts of the second mechanical switching unit 24 is extinguished.
• the second mechanical switching unit 24 can now immediately absorb electrical voltage.
• the second semiconductor switching unit 22 is driven in such a way that a high blocking voltage is applied to it.
• a blocking voltage of 2 kV can be provided with an IGBT.
• the blocking voltage generated by the second semiconductor switching unit 22 is in series with this arc voltage. It is sufficient to commutate the electric current from the second separating device 14 into the first separating device 12. As soon as the electric current has commutated into the first separating device 12 or the first semiconductor switching unit 16, the arc extinguishes at the contacts of the first mechanical switching unit 18 and the actual switching-off of the electric current can begin.
• the first mechanical switching unit 18 is only opened when the electric current is completely commutated by the second separator 14 into the first separator 12.
• the first mechanical switching unit 18 is ideally opened without current and no arc forms at the contacts of the first mechanical switching unit 18.
• wear of the contacts of the first mechanical switching unit 18 due to an arc can be prevented.
• the second mechanical switching unit 24 of the auxiliary switching device 20 is closed again after completion of the switch-off operation.
• the second semiconductor switching unit 22 is protected against overvoltages and overcurrents.
• the semiconductor switching units 16 and 22 may include an IGBT and a semiconductor connected in parallel with the IGBT. Also in the Electrotechnical methods for voltage limiting, such as the parallel connection of voltage-limiting components to the semiconductor switching unit 22, are suitable for protecting the semiconductor switching unit 22 against overvoltages. Suitable voltage-limiting components are, for example
• the separation arrangement 10 has the advantage that the electric current in the normal state exclusively via the first mechanical switching unit 18 and the second mechanical
• Switching unit 24 are closed again, whereby in the case of a high short-circuit current destruction of the second semiconductor switching unit 22 is excluded.
• the error clearing then takes over as part of a so-called backup protection, an additional switch.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
• Electronic Switches (AREA)
• Power Conversion In General (AREA)
• Keying Circuit Devices (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

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Cited By (3)

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Citations (3)

• 2012
  • 2012-09-25 DE DE102012217280.7A patent/DE102012217280A1/de not_active Withdrawn
• 2013
  • 2013-09-10 ES ES13763021.6T patent/ES2606680T3/es active Active
  • 2013-09-10 PL PL13763021T patent/PL2885801T3/pl unknown
  • 2013-09-10 WO PCT/EP2013/068663 patent/WO2014048716A1/fr not_active Ceased
  • 2013-09-10 DK DK13763021.6T patent/DK2885801T3/en active
  • 2013-09-10 EP EP13763021.6A patent/EP2885801B1/fr active Active

Patent Citations (3)

Non-Patent Citations (1)

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