WO2019043777A1 - Système de transmission de puissance cc - Google Patents

Système de transmission de puissance cc Download PDF

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Publication number
WO2019043777A1
WO2019043777A1 PCT/JP2017/030896 JP2017030896W WO2019043777A1 WO 2019043777 A1 WO2019043777 A1 WO 2019043777A1 JP 2017030896 W JP2017030896 W JP 2017030896W WO 2019043777 A1 WO2019043777 A1 WO 2019043777A1
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WO
WIPO (PCT)
Prior art keywords
converter
power
transmission system
output
state
Prior art date
Application number
PCT/JP2017/030896
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English (en)
Japanese (ja)
Inventor
崇裕 石黒
卓郎 新井
Original Assignee
株式会社東芝
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Publication date
Application filed by 株式会社東芝 filed Critical 株式会社東芝
Priority to PCT/JP2017/030896 priority Critical patent/WO2019043777A1/fr
Publication of WO2019043777A1 publication Critical patent/WO2019043777A1/fr

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
    • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
    • H02H7/122—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

Definitions

  • the present invention relates to a direct current transmission system.
  • High-voltage direct current transmission (HVDC: High-Voltage Direct Current Transmission) is known as a system for supplying power thus generated to a power receiving facility of a consumer.
  • HVDC is put into practical use all over the world as a method suitable for large capacity and long distance transmission.
  • the conventional HVDC converts the transmitted DC power into AC power by the converter, and supplies the AC power to the power reception facility of the AC system.
  • the problem to be solved by the present invention is to provide a DC power transmission system that can maintain high reliability at lower cost.
  • the DC power transmission system of the embodiment has a first converter, a second converter, and a protection device.
  • the first converter converts input power into DC power of a predetermined voltage.
  • the second converter has a storage device, and converts DC power supplied from the first converter into AC power via a DC link connected to the DC side of the first converter. 2 converter, having a storage device.
  • the protection device is a protection device connected between the second converter and an alternating current system, which opens and closes a connection between the second converter and the alternating current system. And a load that consumes AC power from the second converter when the open / close unit is turned off.
  • FIG. 1 is a diagram illustrating an example to which the DC power transmission system 100 according to the first embodiment is applied.
  • the DC power transmission system 100 is applied to, for example, a power transmission system that transmits large-scale renewable energy such as offshore wind power generation, desert photovoltaic power generation, solar thermal power generation, etc. to a large city.
  • the power transmission system includes, for example, a power generation device 10, a transformer 20, an AC grid 30, and a DC power transmission system 100.
  • the DC power transmission system 100 includes an AC / DC converter 110, an AC / DC converter 120, a protection circuit 130, and a control unit 140.
  • the protection circuit 130 is an example of the “protection device”.
  • power generated by wind power, sunlight, or solar heat is an example of “renewable energy”.
  • the power generation device 10 is, for example, a generator such as a wind power generator.
  • the power generation device 10 generates, for example, AC power with a voltage of about several hundred kilovolts, and outputs the generated power to the DC power transmission system 100.
  • the AC power generated by the power generation device 10 is an example of “input power”.
  • An AC / DC converter 110 of the DC power transmission system 100 converts input power supplied from the power generation device 10 into DC power of a predetermined voltage.
  • the AC / DC converter 110 converts, for example, AC power of a voltage of about several hundred kilovolts supplied from the power generation device 10 into a DC voltage of about several hundred kilovolts.
  • the AC / DC converter 120 converts the DC voltage supplied from the AC / DC converter 110 into AC power.
  • the transmission path L between the AC / DC converter 120 and the AC / DC converter 110 is a DC side of the DC power transmission system 100 that handles DC power and an AC side that handles AC power. And functions as a connection unit. That is, the transmission line L is an example of the “DC link”.
  • the AC / DC converter 120 has a capacitor inside, and adjusts the voltage of AC power output from the AC / DC converter 120 by storing and discharging electric charge in the capacitor.
  • the configuration of AC / DC converter 120 will be described later.
  • the capacitor is an example of the "power storage device”.
  • Protection circuit 130 is connected between AC / DC converter 120 and AC system 30. Although the protection circuit 130 is connected to the AC system 30 via the transformer 20 in the example of FIG. 1, the transformer 20 may not be provided in the present embodiment. In this case, the protection circuit 130 and the AC system 30 are connected without the transformer 20.
  • the protection circuit 130 includes an open / close unit 132, an open / close unit control unit 134, and a resistor unit 136.
  • the resistance unit 136 is an example of the “load”.
  • the switching unit 132 is connected between the AC / DC converter 120 and the transformer 20, and connects or disconnects the AC / DC converter 120 and the transformer 20.
  • the switch 132 may be a mechanical circuit breaker, or may be a gas circuit breaker or a vacuum circuit breaker.
  • the switch part 132 may be comprised by one switch, and may be comprised by several switch.
  • the switching unit control unit 134 controls the switching unit 132 to cut off between the AC / DC converter 120 and the transformer 20.
  • the specific electrical condition means, for example, that a current (short circuit current) equal to or more than a predetermined threshold flows due to a system fault such as a ground fault in the AC system 30 or the like.
  • switching control section 134 controls switching section 132 by utilizing the magnetic force generated when a short circuit current flows in the conductor through which the internal load current flows, and between AC / DC converter 120 and transformer 20. Is shut off.
  • the switching unit control unit 134 monitors the voltage of the relevant part via the instrument transformer provided at the desired location in the AC system 30, and the switching part 132 is performed when a specific electrical condition is satisfied in the relevant part. Between the AC / DC converter 120 and the transformer 20 may be shut off. When the switching unit control unit 134 disconnects between the AC / DC converter 120 and the transformer 20, the switching unit control unit 134 notifies the control unit 140 to that effect.
  • switch control section 134 controls switch 132 so that there is no gap between AC / DC converter 120 and transformer 20. Even if not physically connected, if the voltage of the AC power output from the AC / DC converter 120 is high, an arc current may flow from the AC / DC converter 120 to the transformer 20. In this case, the electrical connection between the AC / DC converter 120 and the transformer 20 is not cut off even when the switching unit 132 is turned off. When an arc current flows from the AC / DC converter 120 to the transformer 20 after the switching part 132 is turned off, the AC current output from the AC / DC converter 120 needs to be stopped to stop the arc current. There is.
  • Resistor unit 136 is configured such that switching unit 132 shuts off between AC / DC converter 120 and transformer 20, and the AC current output from AC / DC converter 120 is stopped, thereby When the AC power is output again from AC / DC converter 120 after the electrical connection between DC converter 120 and transformer 20 is cut off, AC supplied from AC / DC converter 120 Consume power.
  • the resistance unit 136 is provided in parallel with the switching unit 132 in parallel with the AC / DC converter 120, but the resistance unit 136 is supplied from the AC / DC converter 120. It is sufficient if AC power can be consumed.
  • the resistance part 136 may be comprised by one resistor, and may be comprised by several resistors.
  • the configuration including the resistance portion 136 is illustrated, but in place of the resistance portion 136, it is possible to at least temporarily consume the AC power supplied from the AC / DC converter 120. It is sufficient to have an optional "load". Examples of the load may include both a resistor and an alternating current load, or may be an electric device, a charging device, or the like.
  • Transformer 20 converts the voltage of the AC power supplied from AC / DC converter 120 via protection circuit 130 into a predetermined voltage.
  • Transformer 20 regulates the potential difference between AC / DC converter 120 and AC system 30.
  • the protection circuit 130 and the AC system 30 can be electrically isolated.
  • the AC system 30 is hardware for exchanging commercial power by converting AC power and DC power mutually by the AC / DC converter 120.
  • the AC system 30 is, for example, an AC power supply that supplies AC power, an AC load that consumes AC power, a power transmission network for transmitting AC power to an AC load, or the like.
  • control unit 140 controls AC / DC converter 120 and protection circuit 130 so that the capacitor included in AC / DC converter 120 is not overcharged. Let's do it.
  • the control unit 140 is provided outside the AC / DC converter 120.
  • the distributed control unit 140 and the control unit (not shown) of the AC / DC converter 120 can be operated, so extension is easy. Cost and operating costs can be reduced.
  • control unit 140 may use AC / DC converter 120. It may be provided inside the
  • the control unit 140 monitors, for example, the AC power voltage and current at the predetermined place via an instrument transformer (not shown) provided at a predetermined place of the AC system 30. Then, for example, when a current equal to or greater than a predetermined threshold flows in the transmission line between transformer 20 and AC grid 30 due to a ground fault or the like, control unit 140 determines that a system fault such as a ground fault has occurred. judge. When it is determined that a system fault such as a ground fault has occurred, control unit 140 controls the alternating current output from alternating current / direct current converter 120 to be in the vicinity of 0 (zero). In the following description, making the alternating current output from the AC / DC converter 120 close to 0 (zero) is referred to as “stopping the AC / DC converter 120” or the like.
  • control unit 140 stops AC / DC converter 120.
  • the control unit 140 can suppress damage to the internal circuit of the AC / DC converter 120 by continuing the excessive current flow to the AC / DC converter 120.
  • the control unit 140 causes the voltage output from the AC / DC converter 120 to decrease to a value close to 0 (zero) by the excess current continuing to flow in the AC / DC converter 120, and the capacitor 140 It becomes possible to suppress falling into a state in which AC power can not be output from AC / DC converter 120 because control can not be performed so that charge is stored.
  • control section 140 stops AC current / DC converter 120 to stop the arc current that may be flowing to open / close section 132, thereby causing AC current / The electrical connection between DC converter 120 and transformer 20 is cut off.
  • the timing when the AC / DC converter 120 is stopped by the control unit 140 and the timing when the opening / closing unit 132 is turned off by the opening / closing unit control unit 134 may be earlier than either.
  • the switch unit 132 is put in the cut off state after the AC / DC converter 120 is stopped by the control unit 140, no arc current flows, and the AC / DC converter 120 and the switch unit 132 are put in the cut off state.
  • the electrical connection between the transformer 20 is also cut off.
  • the AC / DC converter 120 When the AC / DC converter 120 is stopped by the control unit 140, the AC / DC converter 120 does not output AC power, but DC power is supplied from the AC / DC converter 110. If this state continues, charges may continue to be accumulated in the capacitor of the AC / DC converter 120, and the voltage of the capacitor may be damaged beyond the withstand voltage. In order to avoid such damage to the capacitor, control unit 140 is notified that switching on / off unit 132 has been shut off from switching unit control unit 134 and that AC / DC converter 120 is stopped. After both conditions are satisfied, the controller 120 controls the state 120 to return to the state before the AC / DC converter 120 is stopped, that is, the state where the AC / DC converter 120 outputs AC power.
  • FIG. 2 is a diagram showing an example of the configuration of the AC / DC converter 120 according to the first embodiment.
  • FIG. 2A is a diagram showing an example of a modular multilevel converter 120A (MMC).
  • FIG. 2 (b) is a diagram showing an example of the chopper cell C provided in the modular multilevel converter 120 ⁇ / b> A.
  • the modular multilevel converter 120A includes, for example, terminals T (terminals T-1 and T-2) and arm units U (arm units U-1 to U-3), And a transformer 20A.
  • the terminals T-1 and T-2 are terminals connected to a DC system (for example, the power generation device 10 or the AC / DC converter 110).
  • Each of arm units U-1 to U-3 is connected in parallel with each other between terminals T-1 and T-2.
  • the arm unit U includes a positive side arm 121P, a positive side buffer reactor 122P, a negative side buffer reactor 122N, a negative side arm 121N, and terminals T (T-3 to T-5) for inputting and outputting alternating current power.
  • the arm unit U is connected in order of the positive side arm 121P, the positive side buffer reactor 122P, the negative side buffer reactor 122N, and the negative side arm 121N, as viewed from the terminal T-1. Further, in the arm unit U, the terminal T-3 on the connection line between the positive side buffer reactor 122P and the negative side buffer reactor 122N is connected to the transformer 20A.
  • Transformer 20A has the same function as transformer 20 described above. Transformer 20A is connected between arm unit U and an AC system (for example, AC system 30). Moreover, in the modular multi-level converter 120A, the transformer 20A may not be provided, and in this case, the modular multi-level converter 120A and the AC system are connected without the transformer 20A.
  • AC system for example, AC system 30
  • Each of the positive side arm 121P and the negative side arm 121N includes, for example, a plurality of chopper cells C.
  • the plurality of chopper cells C are connected in series between the side of the terminal T-1 in the positive side arm 121P and the side of the positive side buffer reactor 122P.
  • the chopper cell C includes a capacitor 123, a switching element 124 (switching elements 124U and 124X), a diode 125 (diodes 125U and 125X), and terminals T (T-3 and T-4).
  • the switching element 124 is, for example, an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor).
  • Switching element 124 can be turned on / off from the outside (for example, a control unit (not shown) of modular multi-level converter 120A), and is a switching element having a self-extinguishing ability. That is, the modular multilevel converter 120A is a self-excited power converter.
  • switching elements 124U and 124X connected in series are connected in parallel with capacitor 123. Further, in the chopper cell C, diodes 125U and 125X are connected in anti-parallel to the switching elements 124U and 124X, respectively.
  • the terminal T-3 is connected to the terminal T-4 of the other chopper cell C.
  • the terminal T-3 is connected to the terminal T-1.
  • the terminal T-4 is connected to the terminal T-3 of the other chopper cell C.
  • the terminal T-4 is connected to the terminal T-2.
  • Chopper cell C sets the voltage at terminal T-3 by connecting or blocking switching elements 124U and 124X under control of the control unit (not shown) of modular multi-level converter 120A. Is a predetermined unit voltage (positive side), a zero voltage, or a predetermined unit voltage (negative side).
  • Each of the arm units U-1 to U-3 outputs a multilevel voltage waveform by adjusting the voltage of the terminal T-3 of each of the plurality of chopper cells C which each has.
  • the modular multi-level converter 120A which is an example of the AC / DC converter 120, includes a plurality of chopper cells C, and the chopper cell C includes a capacitor 123.
  • FIG. 3 is a diagram showing another example of the configuration of the AC / DC converter 120 according to the first embodiment.
  • FIG. 3 is a diagram showing an example of the two-level converter 120B.
  • the two-level converter 120B includes terminals T (terminals T-8 and T-9), a capacitor 126, units V (units V-1 to V-3), and an AC filter 129. , And a transformer 20B.
  • the terminals T-8 and T-9 are terminals connected to a DC system (for example, the power generation device 10 or the AC / DC converter 110).
  • a DC system for example, the power generation device 10 or the AC / DC converter 110.
  • Each of units V-1 to V-3 is connected in parallel with one another between terminals T-8 and T-9.
  • the unit V includes a switching element 127 (switching elements 127U and 127X), a diode 128 (diodes 128U and 128X), and terminals T (T-10 to T-12) that input and output AC power.
  • switching elements 127U and 127X are connected in series, and diodes 128U and 128X are connected in anti-parallel to switching elements 127U and 127X, respectively. Further, in each of units V-1 to V-3, a terminal T-10 on a connection line between switching element 127U and 127X is connected to transformer 20B via AC filter 129.
  • the unit V sets the voltage of the terminal T-3 to the connection state or the disconnection state of each of the switching elements 127U and 127X based on control from a control unit (not shown) of the two-level converter 120B. Or a predetermined unit voltage (positive side), a zero voltage, or a predetermined unit voltage (negative side).
  • the AC filter 129 smoothes the voltage at the terminal T of the unit V. As a result, the AC filter 129 outputs a voltage close to a sine wave, that is, a voltage of AC power.
  • Transformer 20B has the same function as transformer 20 described above. Transformer 20B is connected between AC filter 129 and an AC system (for example, AC system 30).
  • the capacitor 126 is included in the two-level converter 120 B which is an example of the AC / DC converter 120.
  • the accident in the DC power transmission system 100 here is, for example, a case where the power transmission line between the transformer 20 and the AC grid 30 is grounded due to lightning strike or the like.
  • FIG. 4 is a diagram showing a normal state where no accident has occurred in the power transmission system.
  • switching unit 132 brings AC / DC converter 120 and transformer 20 into a connected state. For this reason, the current D of the AC power output from the AC / DC converter 120 flows to the transformer 20 through the switching unit 132, and the current D does not flow to the resistance unit 136.
  • FIG. 5 is a diagram showing an initial state in which an accident has occurred in the power transmission system.
  • the current D flows from the accident point (the point where the ground fault occurs) between the transformer 20 and the AC system 30 to the ground or the like.
  • the effective voltage of the AC power output from AC / DC converter 120 to transformer 20 has a value of 0 (zero) or a value close to 0 (zero), which is smaller than the state before the accident occurs. It becomes a value. If the voltage is in the state of 0 (zero), the AC / DC converter 120 can not output AC power.
  • FIG. 6 is a diagram illustrating a medium-term state in which an accident has occurred in the power transmission system.
  • the control unit 140 controls the AC / DC converter 120 to stop.
  • the switching unit 132 is controlled by the switching unit control unit 134 so as to cut off the AC / DC converter 120 and the transformer 20.
  • the power generation device 10 and the AC / DC converter 110 may continue to operate regardless of whether or not an accident has occurred.
  • the power generation device 10 is a power generation using renewable energy such as wind power generation or solar power generation, it is difficult to immediately stop the power generation device 10. For this reason, the power generation device 10 may generate DC power, the AC / DC converter 110 may convert DC power into DC power of a predetermined voltage, and the converted power may continue to be supplied to the AC / DC converter 120. .
  • the AC / DC converter 120 receives the supply of the DC power regardless of the output stop, and the balance of the exchange of the power in the AC / DC converter 120 is I can not take it.
  • the balance of the exchange of electric power in the AC / DC converter 120 is lost, and as a result, charge is continuously accumulated in the capacitor of the AC / DC converter 120, resulting in damage to the storage function of the capacitor, causing AC / DC conversion.
  • Device 120 may become out of control. Therefore, in the embodiment, the output of AC power by AC / DC converter 120 is restarted as described below.
  • FIG. 7 is a diagram illustrating a late state in which an accident has occurred in the power transmission system.
  • the control unit 140 restarts the output of AC power by the AC / DC converter 120.
  • the current D of the AC power output from the AC / DC converter 120 is returned to the state before the occurrence of the accident by the control unit 140, the current D flows to the resistance unit 136, and the AC / DC converter 120
  • the output AC power is consumed by the resistor of the resistor unit 136.
  • overcharging of the capacitor of the AC / DC converter 120 can be suppressed, and the AC / DC converter 120 can be prevented from becoming uncontrollable.
  • FIG. 8 is a timing chart for explaining the operation of the DC power transmission system 100 according to the first embodiment.
  • FIG. 8A shows an example in the case where the open / close unit 132 is cut off before the AC / DC converter 120 is stopped when a ground fault occurs.
  • FIG. 8B shows an example in which the open / close unit 132 is cut off after the AC / DC converter 120 is stopped when a ground fault occurs.
  • each of FIGS. 8A and 8B shows the state of the AC / DC converter 120
  • the lower part shows the connection state between the AC / DC converter 120 and the converter.
  • the horizontal axes at the top and bottom of each of FIGS. 8A and 8B indicate time.
  • a state in which normal AC power is output from AC / DC converter 120 is shown as a “normal state”
  • AC power from AC / DC converter 120 is shown. Is indicated as "stopped” when it is stopped.
  • a state in which the AC / DC converter 120 and the transformer 20 are connected is shown as a “connected state”, and the case where it is cut off is Shown as "blocked state”.
  • a ground fault occurs at time T1, and first, the opening / closing unit 132 is put into the interruption state by the opening / closing unit control unit 134. Next, at time T2, the AC / DC converter 120 is stopped by the control unit 140. Then, at time T3, control unit 140 returns AC / DC converter 120 to the normal state. The arc current may continue to flow through the switching unit 132 at time T1, but the arc current is stopped at time T2. At time T3, the AC power of AC / DC converter 120 is consumed by resistance unit 136.
  • a ground fault occurs at time T11, and the AC / DC converter 120 is stopped by the control unit 140 first.
  • the open / close unit 132 is put in the shutoff state by the open / close unit control unit 134.
  • control unit 140 returns AC / DC converter 120 to the normal state. Since the current from the AC / DC converter 120 is stopped at time T11, no arc current flows in the switching part 132 at time T12. At time T3, the AC power of AC / DC converter 120 is consumed by resistance unit 136.
  • time during which AC / DC converter 120 is stopped (time from time T2 to T3 in the example of FIG. 8A, and time from time T1 to T3 in the example of FIG. 8B) is restricted. Although it is not, it is desirable to be as short as possible. This is because the longer the time from time T1 to time T3 is, the more charge is accumulated in the capacitor of the AC / DC converter 120 and the possibility of being overcharged increases.
  • the DC power transmission system 100 includes the AC / DC converter 110, the AC / DC converter 120, and the protection circuit 130.
  • the AC / DC converter 110 converts DC power generated by the power generation device 10 into DC power of a predetermined voltage.
  • the AC / DC converter 120 has a capacitor, and converts DC power supplied from the AC / DC converter 110 via the transmission path L into AC power.
  • Protection circuit 130 is connected between AC / DC converter 120 and AC system 30.
  • the protection circuit 130 further includes an open / close unit 132 and a resistor unit 136.
  • the switching unit 132 brings the connection between the AC / DC converter 120 and the AC system 30 into a connected state or a disconnected state. Resistor 136 consumes AC power from AC / DC converter 120 when switch 132 is turned off.
  • switching unit 132 disconnects the connection between AC / DC converter 120 and AC system 30, and output from AC / DC converter 120 A reduction in voltage can be suppressed, and the resistor unit 136 can suppress the overcharging of the capacitor of the AC / DC converter 120 by consuming the AC power output from the AC / DC converter 120, This is because the AC / DC converter 120 can be prevented from falling out of control.
  • a configuration is considered in which a protection circuit 130 is provided on the side of the DC system (for example, between the AC / DC converter 110 and the power generation device 10).
  • the resistor unit 136 of the protection circuit 130 consumes the DC power output from the power generation device 10.
  • the resistor unit 136 needs to be configured of, for example, a large number of resistors that can be switched by a semiconductor switch. In such a configuration, many effective semiconductors must be used, which increases the cost of the apparatus.
  • the protection circuit 130 is not necessary to use an expensive semiconductor switch for the protection circuit 130. Since the voltage value of the AC power output from the AC / DC converter 120 can be controlled by the AC / DC converter 120, for example, the protection circuit 130 is effective for the AC power output from the AC / DC converter 120. It suffices to have a resistor capable of consuming power.
  • the resistor unit 136 is provided in parallel to the switching unit 132 with respect to the AC / DC converter 120.
  • the transformer 20 can be supplied with power even when the switching unit 132 is in the shutoff state, in addition to the effects described above. It is possible to restore the DC transmission system 100 more smoothly if the accident recovers.
  • DC power input to the AC / DC converter 110 is renewable energy.
  • the DC power supplied to the AC / DC converter 120 can not be immediately stopped. Even in this case, alternating current power can be supplied from the alternating current / direct current converter 120 to the transformer 20 via the resistor portion 136.
  • the DC power transmission system 100 further includes a control unit 140 that causes the AC / DC converter 120 to stop outputting AC power when the switching unit 132 is turned off.
  • the controller 140 controls the AC / DC converter 120. By stopping the output of the circuit, it is possible to suppress a drop in voltage output from the AC / DC converter 120 and prevent the AC / DC converter 120 from becoming uncontrollable.
  • the control unit 140 notifies that the output of the AC power of the AC / DC converter 120 has been stopped and that the switching unit 132 has been shut off. After both conditions of receiving (from the switch control unit 134) are satisfied, the AC / DC converter 120 is made to restart the output of AC power. Thus, in the DC power transmission system 100 according to the first embodiment, the control unit 140 outputs the output of the AC / DC converter 120 even when the arc current is generated when the switching unit 132 is turned off.
  • the arc current can be stopped by stopping the Therefore, the output of the AC power from the AC / DC converter 120 can be consumed by the resistor unit 136 by resuming the output of the AC power while the control unit 140 does not generate the arc current. Therefore, overcharging of the capacitor of AC / DC converter 120 can be suppressed, and damage to AC / DC converter 120 can be prevented.
  • the second embodiment is different from the above-described first embodiment in that the control unit 140 controls the open / close unit 132.
  • the control unit 140 monitors the voltage and current of AC power at a predetermined place of the AC system 30, and when the current of the AC system 30 is in a predetermined state, such as when a current equal to or greater than a predetermined threshold flows in the area And instructs the control unit of the AC / DC converter 120 to stop the AC / DC converter 120, and instructs the switch control unit 134 to switch the switch 132 off.
  • the open / close controller 134 may be omitted.
  • the open / close unit control unit 134 is omitted, the open / close unit 132 is put in the closed state under the control of the control unit 140.
  • the control unit 140 is an example of the “control unit”.
  • control unit 140 instructs the control unit of AC / DC converter 120 to resume the output of AC power from AC / DC converter 120.
  • the control unit 140 performs AC / DC conversion when the state of the AC system 30 is a predetermined state, such as when a short circuit accident occurs in the AC system 30.
  • the switch control unit 134 or the control unit 140 shuts off the open / close unit 132 while stopping the switch 120, it is possible to prevent the voltage of the AC power from being lowered.
  • the control unit 140 both stops the output of the AC current of the AC / DC converter 120 and turns the switching unit 132 into the shutoff state. And causes the AC / DC converter 120 to resume output of AC power.
  • the AC power output from the AC / DC converter 120 can be consumed by the resistor unit 136, and the capacitor of the AC / DC converter 120 is excessive. It can be prevented from being charged.
  • FIG. 8 is a block diagram showing a configuration example of the DC power transmission system 100A of the third embodiment.
  • the third embodiment is different from the above-described embodiment in that a transformer 20 is provided between the AC / DC converter 120 and the protection circuit 130.
  • the third embodiment is different from the above-described embodiment in that the transformer 20 is not provided between the protection circuit 130 and the AC system 30.
  • the control unit 140 monitors, for example, the voltage at the relevant point via the instrument transformer provided at a desired location in the alternating current system 30, and for an unshown instrument provided between the protection circuit 130 and the alternating current system 30.
  • the voltage and current of AC power supplied to AC system 30 are monitored via a transformer.
  • control unit 140 stops AC / DC converter 120 in a stopped state.
  • the control unit 140 controls the opening / closing unit 132 to be in the disconnection state.
  • control unit 140 resumes the output of AC power of AC / DC converter 120 after the electrical connection between AC / DC converter 120 and AC system 30 is cut off.
  • the transmission connected to the DC side of the AC / DC converter 110 includes the AC / DC converter 110 for converting input power into DC power of a predetermined voltage, and a capacitor.
  • AC / DC converter 120 for converting DC power supplied from AC / DC converter 110 via path L into AC power, and protection connected between AC / DC converter 120 and AC system 30
  • the circuit 130 is a switching unit 132 for connecting or disconnecting the connection between the AC / DC converter 120 and the AC system 30, and the switching unit 132 using the AC / DC converter 120 and the AC system 30.
  • High reliability can be maintained at low cost by having a protection circuit 130 having a resistor portion 136 that consumes AC power from the AC / DC converter 120 when there is an interruption state. Rukoto can.
  • switching unit 132 disconnects the connection between AC / DC converter 120 and AC system 30, and output from AC / DC converter 120 A reduction in voltage can be suppressed, and the resistor unit 136 can suppress the overcharging of the capacitor of the AC / DC converter 120 by consuming the AC power output from the AC / DC converter 120, This is because the AC / DC converter 120 can be prevented from falling out of control.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Direct Current Feeding And Distribution (AREA)

Abstract

Selon la présente invention, un premier convertisseur convertit une puissance d'entrée en une puissance CC d'une tension prescrite. Un second convertisseur comprend un dispositif de stockage d'énergie, et convertit, en puissance CA, la puissance CC fournie par le premier convertisseur par l'intermédiaire d'une liaison CC qui est reliée au côté CC du premier convertisseur. Un dispositif de protection, qui est relié entre le second convertisseur et un système CA, est pourvu d'une unité de commutation qui établit la liaison entre le second convertisseur et le système CA de façon à être dans un état connecté ou dans un état déconnecté, et d'une charge qui consomme le courant alternatif provenant du second convertisseur quand l'unité de commutation atteint l'état déconnecté.
PCT/JP2017/030896 2017-08-29 2017-08-29 Système de transmission de puissance cc WO2019043777A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130200859A1 (en) * 2010-07-30 2013-08-08 Abb Technology Ag Capacitor discharge in a cell based voltage source converter
WO2014132396A1 (fr) * 2013-02-28 2014-09-04 三菱電機株式会社 Dispositif de conversion de puissance
WO2016125376A1 (fr) * 2015-02-03 2016-08-11 三菱重工業株式会社 Dispositif de commande de génération d'énergie électrique, dispositif de commande de convertisseur d'énergie électrique , procédé et programme de commande de génération d'énergie électrique
WO2016194649A1 (fr) * 2015-05-29 2016-12-08 株式会社 東芝 Système de transmission de puissance en courant continu, son serveur central et procédé de rétablissement de la voie de transmission de puissance en courant continu après une panne

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130200859A1 (en) * 2010-07-30 2013-08-08 Abb Technology Ag Capacitor discharge in a cell based voltage source converter
WO2014132396A1 (fr) * 2013-02-28 2014-09-04 三菱電機株式会社 Dispositif de conversion de puissance
WO2016125376A1 (fr) * 2015-02-03 2016-08-11 三菱重工業株式会社 Dispositif de commande de génération d'énergie électrique, dispositif de commande de convertisseur d'énergie électrique , procédé et programme de commande de génération d'énergie électrique
WO2016194649A1 (fr) * 2015-05-29 2016-12-08 株式会社 東芝 Système de transmission de puissance en courant continu, son serveur central et procédé de rétablissement de la voie de transmission de puissance en courant continu après une panne

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