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WO2015172825A1 - Agencement de traitement de défaut de courant alternatif - Google Patents

Agencement de traitement de défaut de courant alternatif Download PDF

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Publication number
WO2015172825A1
WO2015172825A1 PCT/EP2014/059862 EP2014059862W WO2015172825A1 WO 2015172825 A1 WO2015172825 A1 WO 2015172825A1 EP 2014059862 W EP2014059862 W EP 2014059862W WO 2015172825 A1 WO2015172825 A1 WO 2015172825A1
Authority
WO
WIPO (PCT)
Prior art keywords
converter
arrangement according
fault
resistor
terminal
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/EP2014/059862
Other languages
English (en)
Inventor
Kanstantsin FADZEYEU
Per-Erik Björklund
Per Holmberg
Rolf OTTERSTEN
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ABB Technology AG
Original Assignee
ABB Technology AG
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 Technology AG filed Critical ABB Technology AG
Priority to CN201480078855.4A priority Critical patent/CN106797124B/zh
Priority to PCT/EP2014/059862 priority patent/WO2015172825A1/fr
Publication of WO2015172825A1 publication Critical patent/WO2015172825A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/4835—Converters with outputs that each can have more than two voltages levels comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage
    • 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 generally relates to power transmission systems. More particularly the present invention relates to an AC fault handling arrangement for handling an AC fault on the AC side of a converter converting between AC and DC.
  • Voltage source converters are known to be connected between an Alternating Current (AC) system, often denoted AC grid, and a Direct Current (DC) system, like a High Voltage Direct Current (HVDC) system.
  • AC Alternating Current
  • DC Direct Current
  • HVDC High Voltage Direct Current
  • the converter may in this case be a modular multilevel converter that employs cells, each providing a voltage that may be used for contributing to the forming of an AC waveform as well as for providing a required DC voltage .
  • This converter is in many instances connected to a local AC bus, for instance a bus within a converter station, which in turn is connected to the AC system via a transformer.
  • a transformer having a primary side coupled to the AC system and a secondary side coupled to the converter.
  • an AC breaker serially connected between the primary windings of the transformer and the AC system in order to protect the AC system from faults on the AC bus or in the DC system.
  • the circuit breaker is serially connected between the secondary side of the transformer and the converter . In relation to the converter, there may occur a number of faults that need to be taken care of.
  • faults on the DC side such a single pole-to-ground faults and pole-to-pole faults.
  • KR 10-20004-0035526 One way of handling faults in a load connected to a voltage source converter converting from AC to DC is shown in KR 10-20004-0035526.
  • a parallel circuit is connected between the converter and load, which parallel circuit comprises a first branch with an inductor and a second branch with a diode and a resistor .
  • faults on the AC side such as over-voltages and phase-to-ground faults.
  • Multi-level converter built up with small cells has become the state of art for HVDC converter.
  • Asymmetrical monopole or bipole configurations are common choices for DC transmission systems.
  • AC bus fault One of the faults that this isolation is necessary for is the AC bus fault. This is because any bus-to-ground fault located between the converter and the transformer can cause very high voltages and high currents. Once the AC breaker is open, the AC source voltage is isolated from the converter, thereby the eventual source for the high voltage and high current is disconnected. Unfortunately, the AC circuit breaker takes about 20-30 ms to open if there is a condition for opening, e-g- a current zero-crossing. If there is no condition for opening, it may take a much longer time than 30 ms .
  • the impedance may have to be designed to be very low in order to guarantee the zero-crossing in the AC breaker current .
  • the present invention addresses this situation.
  • the invention is thus directed towards improving fault handling .
  • an AC fault handling arrangement for handling an AC fault on the AC side of a converter converting between AC and DC, where the arrangement comprises :
  • the converter having a DC side with a first and a second terminal for coupling to pole and ground of a DC system and an AC side with a group of terminals for being coupled to an AC system, a circuit breaker serially connected between the AC side of the converter and the AC system, and
  • the parallel circuit consisting of a resistor in parallel with an inductor.
  • Coupled used is intended to cover the possibility of an indirect electrical connection between two elements. There may thus be one or more elements placed between two elements defined as being coupled to each other.
  • connected is on the other hand intended to mean a direct electrical connection of two entities to each other without any entity between them.
  • the invention has a number of advantages. It provides a zero-crossing in the current running through an AC breaker in case of an internal AC fault in the
  • fig. 1 schematically shows a variation of AC fault handling arrangement between an AC system and an asymmetric monopole DC system
  • fig. 2 schematically shows currents through the
  • fig. 3 shows a circuit diagram of a parallel circuit used in the AC fault handling arrangement.
  • the present invention is directed towards providing an arrangement for handling Alternating Current (AC) faults on an AC side of a converter concerting between AC and Direct Current (DC) and being provided between a DC system and an AC system, which systems may both be power transmission systems.
  • the arrangement may for this reason be provided in a converter station.
  • the DC system can for instance be a High Voltage Direct
  • HVDC High Volt DC
  • FACTS Transmission System
  • Fig. 1 schematically shows a single line diagram of an arrangement for handling AC faults according to a first embodiment of the invention, which arrangement is provided for being connected between an AC system 10 and a DC system 11.
  • the AC system 10 may be a three- phase AC system.
  • the DC system 11 in turn includes a pole PI coupled to the AC system 10 via the
  • the DC system 11 is an asymmetric monopole system. Therefore there is also a ground potential which may or may not be provided as a neutral conductor in the DC system 11.
  • the arrangement includes a converter 12 for conversion between AC and DC.
  • the converter 12 may function as a rectifier and/or inverter.
  • the converter 12 may be a voltage source converter and in this embodiment it is a cell-based multilevel voltage source converter or a modular multilevel converter. Such a converter is typically made up of a number of cells 14 provided in phase arms of phase legs, where there is one phase leg per AC phase provided in
  • phase leg comprises two phase arms.
  • phase leg There is, in a phase leg, an upper phase arm leading from the first pole PI to an AC terminal or third terminal T3 of the converter 12 and a lower phase arm leading from ground to the AC terminal T3.
  • the cells 14 in the phase leg may be placed symmetrically around the AC terminal T3.
  • the cells 14 may with advantage be connected in cascade in the cell arms.
  • fig. 1 is a single line diagram there is only one phase leg shown. It is furthermore only shown in a general fashion. For the same reason fig. 1 only shows one AC terminal T3. However, the AC terminal T3 is provided in a group of terminals typically
  • the arrangement also comprises a pair of optional capacitors CI and C2 connected between the first and second DC terminals Tl and T2.
  • parallel circuit 16 coupled between the second DC terminal T2 and ground, which parallel circuit 16 comprises and in this case consists of two parallel branches, where a first branch comprises and in this case consists of an inductor and a second branch comprises and in this case consists of a resistor.
  • the parallel circuit thus consists of a resistor in parallel with an inductor.
  • the parallel circuit is thus at one end connected to the second terminal T2 and at the other coupled to a ground potential.
  • the parallel circuit may also be termed an auxiliary parallel circuit or auxiliary neutral equipment.
  • Each cell 14 may be a half-bridge cell, made up of two series connected switching elements having a capacitor connected in parallel with both these elements.
  • the switching elements are typically provided in the form of a semiconductor device of turn off-type, like an Insulated Gate Bipolar Transistor (IGBT), with anti- parallel diode.
  • IGBT Insulated Gate Bipolar Transistor
  • the midpoint between two switching elements of a cell is connected to one end of the capacitor of a following cell. In this way the cells are connected in cascade in the two phase arms between the pole PI and ground.
  • each cell provides a zero or a small voltage contribution that are combined for forming an AC voltage .
  • first and second phase reactors between the cells of the upper phase arm and the lower phase arm, where a first end of the first reactor is connected to the upper arm and a first end of the second reactor is connected to the lower arm and the second ends of these two reactors are interconnected and also connected to an AC bus 17.
  • the converter 12 thus has a DC side for connection to the DC system 11 and more particularly to at least one pole PI of the DC system and an AC side for being coupled to the AC system 10.
  • the arrangement may also include a transformer 18 having a primary side with a first set of primary windings for being coupled to the AC system 10 and a secondary side with a second set of secondary windings coupled to the AC side of the converter 12.
  • the secondary windings are more particularly connected to the phase reactors via the AC bus 17.
  • the bus 17 and AC system 10 are provided for transmission of three phase AC power.
  • the primary side of the transformer 18 includes three primary windings (not shown) , which in this first embodiment are connected in a wye
  • the primary side here furthermore has a neutral point, which is coupled to ground.
  • the neutral point may be directly connected to ground, as shown in fig. 1.
  • the primary side is furthermore connected to the AC system 10 via a circuit breaker 20.
  • the circuit breaker 20 typically comprises three circuit breaking elements, one for each phase.
  • the circuit breaker 20 is more particularly serially connected between the primary side of the transformer 18 and the AC system 10.
  • the circuit breaker 20 is serially connected between the secondary side of the transformer 18 and the AC side of the converter.
  • the secondary side of the transformer 18 also comprises three secondary windings (not shown) connected in a delta configuration. It should however be realized that it is also possible with a wye configuration.
  • the second set of secondary windings may thus be connected either in delta or in wye configuration.
  • the arrangement may also comprise a fault handling unit, which blocks the switching elements of the cells if a fault is detected, such as an AC bus fault.
  • a fault handling unit may also be set to instruct the circuit breaker 20 to open based on the detection of a fault.
  • Such a fault handling unit may be implemented through a computer or a processor with computer program instructions providing the fault handling functionality that acts on current and voltage measurements made in the system.
  • the arrangement may be provided in a converter station. Therefore the parallel circuit 16, converter 12, capacitors CI and C2, transformer 18 and possibly also the circuit breaker 20 may be provided in such a converter station.
  • the present invention is provided for handling faults in the arrangement like an AC bus fault, where at least one of the phases of the AC bus gets grounded.
  • Fig. 2 shows fault currents of such a fault F in the converter 12 connected to the transformer 18, where two phase legs are shown. There is also a surge arrester between the pole PI and ground. In the drawing only one cell is shown in each phase arm. The situation depicted in fig. 2 is furthermore the situation without the parallel circuit.
  • the cells of the converter are controlled, for instance using pulse width modulation (PWM) , for obtaining an AC voltage at the AC bus 17. It is then possible that a fault F on one of the AC bus phases occur . In this case the cells are blocked, which is done through the transistors of the cells being turned off, for instance through the control performed by a fault handling unit. It can be seen that this situation causes the first current II to flow from the pole PI through the cells of the upper phase arm. In these cells the current II flows through an anti-parallel diode of a switching element when it is forward-biased, through the cell capacitor and then to the AC bus via the upper phase reactor. The situation also causes the second current 12 to flow from ground and through the cells of the lower phase arm.
  • PWM pulse width modulation
  • the current 12 flows through an anti-parallel diode of a switching element when it is forward-biased and then to the AC bus via the lower phase reactor and the secondary winding of the transformer 18.
  • the second current 12 does thus not pass through any cell capacitor.
  • the first current II is a current that overcharges the cell capacitors and the second current 12 is a diode surge current.
  • Fig. 3 shows the parallel circuit 16 with resistor R and inductor L.
  • the resistor R is selected to have a value that damps the DC component of the AC current through the circuit breaker to a level where zero crossings are present despite the fact that there is an AC fault.
  • the resistor value may depend on the damping capability of the circuit formed from the grounding point up to the fault e.g. losses in this circuit.
  • the resistor value may then depend on the number of diodes connected in series between the second terminal T and the AC side of the converter, which may be the same as the number of cells in a lower phase arm. It may also depend on grounding resistance, electrode line
  • the impedance, equipment at neutral bus, converter reactor resistance, transformer impedance, etc. may also be set based on the driving voltage and currents rating. After a suitable resistor value has been chosen, the inductance value may be chosen as low as possible that is capable to drive a current through the resistor R when there is an AC bus fault.
  • the resistor R may therefore have a value in the range between 0.1 ⁇ and 10 ⁇ and preferably between 0.5 and 1 ⁇ , while the inductor may have a value in the range between 5 mH and 500 mH and preferably between 10 and 150 mH.
  • the inductance L makes it possible to not affect losses in the main circuit during normal operation when there is only DC current in the neutral bus. This means that in normal operation all the current will run through the inductor L essentially without losses.
  • the inductor L creates an impedance against the AC component that leads to at least part of the current being driven into the resistor R. Thereby the resistor R damps the DC- offset during AC bus faults so that the zero-crossing current in the AC breaker is created without any or with only limited delay.
  • the parallel-circuit is thus placed in the neutral connection of the converter.
  • This placing has another advantage and that is that it will assist in creating a zero-crossing independently of in which phase the fault occurs. Furthermore, since only passive elements are involved in the creation of a zero-crossing, there is no need for any control logic to activate such a creation. This simplifies the fault handling in the converter.
  • the DC system was an asymmetric monopole system. It should be realized that the invention may just as well be implemented in a bipole system or multi-terminal system.
  • the DC system may essentially be any system where asymmetric monopole may be a building block.
  • the cells are furthermore not limited to half-bridge cells, but may as an

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Rectifiers (AREA)
  • Inverter Devices (AREA)

Abstract

La présente invention concerne un dispositif de traitement de défaut de courant alternatif pour traiter un défaut de courant alternatif (F) sur le côté CA d'un convertisseur qui convertit entre CA et CC, l'agencement comportant un convertisseur de source de tension (12) pour effectuer la conversion entre courant alternatif et courant continu, le convertisseur ayant un côté CC ayant une première et une seconde borne (T1, T2) pour coupler à un pôle (P1) et à la terre d'un système à courant continu (11) et un côté courant alternatif ayant un groupe de terminaux (T3) devant être couplés à un système à courant alternatif (10), un disjoncteur (20) connecté en série entre le côté alternatif du convertisseur et le système alternatif (10) et un circuit parallèle (16) ayant une extrémité connectée à la seconde borne (T2) et l'autre reliée à un potentiel de masse, où le circuit parallèle est constitué d'une résistance en parallèle ayant une bobine d'induction.
PCT/EP2014/059862 2014-05-14 2014-05-14 Agencement de traitement de défaut de courant alternatif Ceased WO2015172825A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN201480078855.4A CN106797124B (zh) 2014-05-14 2014-05-14 Ac故障处理布置
PCT/EP2014/059862 WO2015172825A1 (fr) 2014-05-14 2014-05-14 Agencement de traitement de défaut de courant alternatif

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2014/059862 WO2015172825A1 (fr) 2014-05-14 2014-05-14 Agencement de traitement de défaut de courant alternatif

Publications (1)

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WO2015172825A1 true WO2015172825A1 (fr) 2015-11-19

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PCT/EP2014/059862 Ceased WO2015172825A1 (fr) 2014-05-14 2014-05-14 Agencement de traitement de défaut de courant alternatif

Country Status (2)

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WO (1) WO2015172825A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017167744A1 (fr) * 2016-04-01 2017-10-05 General Electric Technology Gmbh Appareillage de commutation de courant continu haute tension
EP3747100B1 (fr) * 2018-01-30 2022-03-16 Hitachi Energy Switzerland AG Dimensionnement de parasurtenseur dans un système de transmission de courant continu
EP3635851B1 (fr) * 2017-07-28 2022-03-30 Siemens Energy Global GmbH & Co. KG Unité de convertisseur de courant

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114257076B (zh) * 2021-12-24 2024-04-12 阳光电源股份有限公司 变流器系统及其控制方法、存储介质
CN114977122A (zh) * 2022-04-06 2022-08-30 国网经济技术研究院有限公司 一种高压直流换流站用故障限流装置及方法

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GB2397445A (en) * 2003-01-14 2004-07-21 Alstom Power transmission circuits
GB2459764A (en) * 2008-05-06 2009-11-11 Siemens Ag DC power transmission system
US20110080758A1 (en) * 2008-06-10 2011-04-07 Abb Technology Ag Plant for transmitting electric power

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GB2397445A (en) * 2003-01-14 2004-07-21 Alstom Power transmission circuits
GB2459764A (en) * 2008-05-06 2009-11-11 Siemens Ag DC power transmission system
US20110080758A1 (en) * 2008-06-10 2011-04-07 Abb Technology Ag Plant for transmitting electric power

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STEVEN DE BOECK ET AL: "Configurations and earthing of HVDC grids", 2013 IEEE POWER & ENERGY SOCIETY GENERAL MEETING, 1 January 2013 (2013-01-01), pages 1 - 5, XP055167145, ISBN: 978-1-47-991303-9, DOI: 10.1109/PESMG.2013.6672808 *
XIAOFANG CHEN ET AL: "Research on the fault characteristics of HVDC based on modular multilevel converter", ELECTRICAL POWER AND ENERGY CONFERENCE (EPEC), 2011 IEEE, IEEE, 3 October 2011 (2011-10-03), pages 91 - 96, XP031974626, ISBN: 978-1-4577-0405-5, DOI: 10.1109/EPEC.2011.6070260 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017167744A1 (fr) * 2016-04-01 2017-10-05 General Electric Technology Gmbh Appareillage de commutation de courant continu haute tension
EP3635851B1 (fr) * 2017-07-28 2022-03-30 Siemens Energy Global GmbH & Co. KG Unité de convertisseur de courant
US11368084B2 (en) 2017-07-28 2022-06-21 Siemens Energy Global GmbH & Co. KG Current converter unit, transmission installation having a current converter unit, and method for fault management in a current converter unit
EP3747100B1 (fr) * 2018-01-30 2022-03-16 Hitachi Energy Switzerland AG Dimensionnement de parasurtenseur dans un système de transmission de courant continu

Also Published As

Publication number Publication date
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CN106797124A (zh) 2017-05-31

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