WO2023284216A1 - 一种并联多端直流系统 - Google Patents

一种并联多端直流系统 Download PDF

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Publication number
WO2023284216A1
WO2023284216A1 PCT/CN2021/131689 CN2021131689W WO2023284216A1 WO 2023284216 A1 WO2023284216 A1 WO 2023284216A1 CN 2021131689 W CN2021131689 W CN 2021131689W WO 2023284216 A1 WO2023284216 A1 WO 2023284216A1
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WO
WIPO (PCT)
Prior art keywords
converter station
sending
end bipolar
bipolar converter
submarine cable
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PCT/CN2021/131689
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English (en)
French (fr)
Inventor
赵晓斌
卢毓欣
李岩
辛清明
邹常跃
徐迪臻
Original Assignee
南方电网科学研究院有限责任公司
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Publication of WO2023284216A1 publication Critical patent/WO2023284216A1/zh

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    • 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
    • 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
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • H02J1/10—Parallel operation of dc sources
    • 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
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • 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
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/28—The renewable source being wind energy
    • 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
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/76—Power conversion electric or electronic aspects
    • 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 invention relates to the technical field of direct current transmission, in particular to a parallel multi-terminal direct current system.
  • the existing offshore wind power DC transmission projects are DC projects using symmetrical unipolar DC projects.
  • the symmetrical unipolar structure may not meet the equipment requirements and reliability requirements, and a bipolar structure needs to be used.
  • the neutral line of the converter station of the onshore bipolar DC system is generally grounded by the grounding pole, that is, the flow can be carried out through the earth return line during unipolar operation; while the offshore wind power transmission DC system has a special application environment. If the seawater grounding pole is used, the seawater The flow of current is generally not allowed, so the offshore wind power bipolar DC transmission project generally requires the use of neutral line DC submarine cables.
  • the offshore wind power DC transmission project adopts a symmetrical unipolar DC system, only two DC cables, a positive DC cable and a negative DC cable, are required; while a bipolar DC system is used, a positive DC cable, a negative DC cable and Metal neutral cable three-circuit DC cable; for large-capacity offshore wind power transmission projects, a bipolar power transmission structure with multiple sending ends and one receiving end may be used. Due to the limitation of the flow capacity of the DC submarine cable, it needs to be connected in parallel at the receiving end DC. At this time, the number of DC submarine cables is 2n back-to-pole submarine cables and n-back neutral submarine cables, and the power transmission cost and sea area caused by submarine cables are relatively high.
  • the embodiment of the present invention provides a parallel multi-terminal direct current system.
  • An embodiment of the present invention provides a parallel multi-terminal DC system, the system comprising: a first sending-end bipolar converter station, a second sending-end bipolar converter station and a receiving-end bipolar converter station;
  • the positive converter of the first sending-end bipolar converter station is connected to the positive converter of the receiving-end bipolar converter station through a first positive DC submarine cable, and the first sending-end bipolar converter station
  • the negative converter of the station is connected to the negative converter of the receiving-end bipolar converter station through the first negative DC submarine cable, and the neutral lines of the first sending-end bipolar converter station pass through the first
  • the neutral line DC submarine cable is connected to the neutral line of the receiving end bipolar converter station;
  • the positive converter of the second sending-end bipolar converter station is connected to the positive converter of the receiving-end bipolar converter station through a second positive DC submarine cable, and the second sending-end bipolar converter station
  • the negative converter of the station is connected to the negative converter of the receiving-end bipolar converter station through the second negative DC submarine cable, and the neutral lines of the second sending-end bipolar converter station pass through the second
  • the neutral DC submarine cable is connected to the neutral line of the first sending-end bipolar converter station.
  • the long-term flow selection of the first neutral line DC submarine cable is max(X 1 , X 2 ); the long-term flow selection of the second neutral line DC submarine cable is X 2 ;
  • X 1 is the rated current of the first sending-end bipolar converter station
  • X 2 is the rated current of the second sending-end bipolar converter station.
  • the long-term operating current of the first neutral line DC submarine cable does not exceed the long-term current selection of the first neutral line DC connection submarine cable, specifically: max(X 1 , X 2 ) ⁇ (Y 1 +Y 2 ); where, max(X 1 , X 2 ) is the long-term current selection of the first neutral line DC submarine cable, X 1 is the rated current of the first sending-end bipolar converter station, X 2 is the rated current of the second sending-end bipolar converter station, Y 1 and Y 2 are respectively the first sending-end bipolar converter station and the second sending-end bipolar run long run current.
  • the current selection of the first neutral line DC connection submarine cable has a second-level overload capability, specifically: when a DC unipolar fault occurs at the receiving end bipolar converter station, the first neutral line
  • the second-level current capacity of the line DC submarine cable is (X 1 +X 2 ), where X 1 is the rated current of the first sending-end bipolar converter station, and X 2 is the rated current of the second sending-end bipolar converter station. rated current.
  • the AC side of the first sending-end bipolar converter station is used to connect the wind turbines of the first wind farm
  • the AC side of the second sending-end bipolar converter station is used to connect the wind turbines of the second wind farm
  • the AC side of the receiving-end bipolar converter station is used for connecting loads.
  • Another embodiment of the present invention also provides a parallel multi-terminal DC system, the system includes: a sending-end bipolar converter station and a receiving-end bipolar converter station;
  • the sending-end bipolar converter station includes M sending-end bipolar converter stations, which are the first sending-end bipolar converter station to the Mth sending-end bipolar converter station;
  • the positive converter of the first sending-end bipolar converter station is connected to the positive converter of the receiving-end bipolar converter station through the first positive DC submarine cable, and the first sending-end bipolar converter station
  • the negative pole converter of the station is connected to the negative pole converter of the receiving-end bipolar converter station through the first negative DC submarine cable, and the neutral line of the first sending-end bipolar converter station passes through the first
  • the neutral line DC submarine cable is connected to the neutral line of the receiving end bipolar converter station;
  • the long-term flow selection of the first neutral line DC submarine cable is max(X 1 , X 2 ,...,X M ); the long-term flow selection of the i-th neutral line DC submarine cable type is X i ;
  • the long-term running current of the first neutral line DC submarine cable does not exceed the long-term current selection of the first neutral line DC connection submarine cable, specifically: max(X 1 , X 2 ,...,X M ) ⁇ (Y 1 +Y 2 +...+Y M );
  • the type selection of the first neutral line DC connection submarine cable has a second-level overload capacity, specifically: when a DC unipolar fault occurs at the receiving end bipolar converter station, the first neutral line DC submarine cable will be in seconds
  • the level flow capacity is 0.5 ⁇ (X 1 +X 2 ...+X M );
  • X 1 is the rated current of the first sending-end bipolar converter station
  • X 2 is the rated current of the second sending-end bipolar converter station
  • X M is the rated current of the M-th sending-end bipolar converter station
  • Y 1 ...Y M are respectively the long-term operating currents from the first sending-end bipolar converter station to the M-th sending-end bipolar converter station while running on the single-pole metal neutral line return line.
  • the AC side of the i-th sending-end bipolar converter station is used to connect the fans of the i-th wind farm;
  • the AC side of the receiving-end bipolar converter station is used for connecting loads.
  • Yet another embodiment of the present invention provides a parallel multi-terminal DC system, the system comprising: a sending-end bipolar converter station and a receiving-end bipolar converter station;
  • the sending-end bipolar converter station includes N sending-end bipolar converter stations, which are the first sending-end bipolar converter station to the Nth sending-end bipolar converter station;
  • the positive converter of the first sending-end bipolar converter station is connected to the positive converter of the receiving-end bipolar converter station through the first positive DC submarine cable, and the first sending-end bipolar converter station
  • the negative pole converter of the station is connected to the negative pole converter of the receiving-end bipolar converter station through the first negative DC submarine cable, and the neutral line of the first sending-end bipolar converter station passes through the first
  • the neutral line DC submarine cable is connected to the neutral line of the receiving end bipolar converter station;
  • the positive converter of the k-th sending-end bipolar converter station is connected to the positive converter of the receiving-end bipolar converter station through the k-th positive DC submarine cable, and the negative pole of the k-th sending-end bipolar converter station
  • the converter is connected to the negative converter of the receiving end bipolar converter station through the kth negative DC submarine cable
  • the neutral line of the kth sending end bipolar converter station is connected to the kth neutral line DC submarine cable through the kth neutral line DC submarine cable.
  • the long-term flow selection of the first neutral line DC submarine cable is max(X 1 , X 2 ,...,X N );
  • the long-term flow selection of the kth neutral line DC submarine cable is of type max(X k ,...,X N );
  • the long-term running current of the first neutral line DC submarine cable does not exceed the long-term current selection of the first neutral line DC connection submarine cable, specifically: max(X 1 , X 2 ,...,X N ) ⁇ (Y 1 +Y 2 +...+Y N );
  • the type selection of the first neutral line DC connection submarine cable has a second-level overload capacity, specifically: when a DC unipolar fault occurs at the receiving end bipolar converter station, the first neutral line DC submarine cable will be in seconds
  • the level flow capacity is (X 1 +X 2 ...+X N );
  • X 1 is the rated current of the first sending-end bipolar converter station
  • X 2 is the rated current of the second sending-end bipolar converter station
  • X N is the rated current of the Nth sending-end bipolar converter station
  • Y 1 ...Y N are the long-term operating currents from the first sending-end bipolar converter station to the N-th sending-end bipolar converter station while running on the single-pole metallic neutral line;
  • the AC side of the kth sending-end bipolar converter station is used to connect to the fan of the kth wind farm;
  • the AC side of the receiving-end bipolar converter station is used for connecting loads.
  • the DC sides of the bipolar converter station at the sending end and the bipolar converter station at the receiving end are connected through a positive DC submarine cable and a negative DC submarine cable, and the middle of the bipolar converter station at the sending end Neutral line connection, only one neutral line DC submarine cable is used to connect the receiving end bipolar converter station and the sending end bipolar converter station closest to the receiving end bipolar converter station, and the sending end bipolar converter station
  • the neutral line of the pole converter station is connected to the neutral line of other bipolar converter stations at the sending end through other short neutral line DC cables.
  • Fig. 1 is a schematic structural diagram of a parallel multi-terminal DC system provided by an embodiment of the present invention
  • Fig. 2 is a schematic structural diagram of a parallel multi-terminal DC system provided by another embodiment of the present invention.
  • Fig. 3 is a schematic structural diagram of a parallel multi-terminal DC system provided by another embodiment of the present invention.
  • An embodiment of the present invention provides a parallel multi-terminal DC system, the system comprising: a first sending-end bipolar converter station, a second sending-end bipolar converter station, and a receiving-end bipolar converter station;
  • the positive converter of the first sending-end bipolar converter station is connected to the positive converter of the receiving-end bipolar converter station through a first positive DC submarine cable, and the first sending-end bipolar converter station
  • the negative converter of the station is connected to the negative converter of the receiving-end bipolar converter station through the first negative DC submarine cable, and the neutral lines of the first sending-end bipolar converter station pass through the first
  • the neutral line DC submarine cable is connected to the neutral line of the receiving end bipolar converter station;
  • the positive converter of the second sending-end bipolar converter station is connected to the positive converter of the receiving-end bipolar converter station through a second positive DC submarine cable, and the second sending-end bipolar converter station
  • the negative converter of the station is connected to the negative converter of the receiving-end bipolar converter station through the second negative DC submarine cable, and the neutral lines of the second sending-end bipolar converter station pass through the second
  • the neutral DC submarine cable is connected to the neutral line of the first sending-end bipolar converter station.
  • FIG. 1 is a structural diagram of a parallel multi-terminal DC system provided by an embodiment of the present invention.
  • the system includes: a sending-end bipolar converter station 1, a sending-end bipolar converter station Flow station 2 and receiving end bipolar converter station;
  • the positive converter of the first bipolar converter station 1 at the sending end is connected to the positive converter of the bipolar converter station at the receiving end through the positive DC submarine cable 1, and the negative converter of the bipolar converter station 1 at the sending end passes through
  • the negative DC submarine cable 1 is connected to the negative converter of the bipolar converter station at the receiving end, and the neutral line of the bipolar converter station 1 at the sending end passes through the Neutral connection;
  • the positive converter of the bipolar converter station 2 at the sending end is connected to the positive converter of the bipolar converter station at the receiving end through the positive DC submarine cable 2, and the negative converter of the bipolar converter station 2 at the sending end is connected through the negative DC cable 2.
  • the submarine cable 2 is connected to the negative converter of the bipolar converter station at the receiving end, and the neutral line of the bipolar converter station 2 at the sending end is connected to the neutral line of the bipolar converter station 1 at the sending end through the neutral line DC submarine cable 12.
  • the length of the submarine cable between the sending-end bipolar converter station 1 and the receiving-end bipolar converter station is 100 km, and the length of the submarine cable between the sending-end bipolar converter station 2 and the receiving-end bipolar converter station is 120 km
  • the DC sides of the bipolar converter station at the sending end and the bipolar converter station at the receiving end are connected by a positive DC submarine cable and a negative DC submarine cable, and the bipolar converter station at the sending end
  • the neutral line connection of the neutral line, only one neutral line DC submarine cable is used to connect the bipolar converter station at the receiving end and the bipolar converter station at the sending end closest to the bipolar converter station at the receiving end, and the sending end
  • the neutral line of the end bipolar converter station is connected to the neutral line of other sending end bipolar converter stations through other shorter neutral line DC cables.
  • the long-term flow selection of the first neutral line DC submarine cable is max(X 1 , X 2 ); the long-term flow selection of the second neutral line DC submarine cable Type is X 2 ;
  • X 1 is the rated current of the first sending-end bipolar converter station
  • X 2 is the rated current of the second sending-end bipolar converter station.
  • the long-term flow selection of the neutral line DC submarine cable 1 is max(X 1 , X 2 ); the long-term flow selection of the neutral line DC submarine cable 12 is X 2 , and X 1 is the X 2 is the rated current of bipolar converter station 1 at the sending end.
  • the long-term running current of the first neutral line DC submarine cable does not exceed the long-term current selection of the first neutral line DC connection submarine cable, specifically: max(X 1 , X 2 ) ⁇ (Y 1 +Y 2 ); among them, max(X 1 , X 2 ) is the long-term current selection of the first neutral line DC submarine cable, and X 1 is the bipolar commutation at the first sending end
  • the rated current of the station X 2 is the rated current of the second sending-end bipolar converter station
  • Y 1 and Y 2 are the first sending-end bipolar converter station and the second sending-end bipolar Long-term running current for pole metallic neutral return run.
  • the multi-circuit DC adopts the single-pole metal neutral line operation mode
  • the sending-end bipolar converter station and the receiving-end bipolar converter station are connected.
  • the current of the neutral line DC submarine cable will increase, so it is necessary to limit the operating current of the multi-circuit DC long-term homopolar metal neutral line operation mode to ensure that the long-term current of the neutral line DC submarine cable does not exceed the equipment capacity, that is, max (X 1 , X 2 ) ⁇ (Y 1 +Y 2 ), Y 1 +Y 2 is the long-term operation in which the sending-end bipolar converter station 1 and the sending-end bipolar converter station 2 operate simultaneously with a single-pole metal loop current.
  • the type selection of the first neutral line DC connection submarine cable has a second-level overload capability, specifically: when a DC unipolar fault occurs at the receiving end bipolar converter station , the second-level current capacity of the first neutral line DC submarine cable is (X 1 +X 2 ), where X 1 is the rated current of the first sending-end bipolar converter station, X 2 is the second sending-end bipolar converter station The rated current of the pole converter station.
  • the neutral line DC submarine cable needs to have a second-level overload capability.
  • the rated current of the two bipolar converter stations at the sending end is 1500A
  • the rated current of the bipolar converter station at the receiving end is 3000A
  • the DC cables of each pole can pass current for a long time 1500A
  • the long-term current of the neutral line DC cable 1 is also 1500A.
  • the neutral line DC submarine cable needs to have an overload capacity of 3000A (1500A+1500A) in seconds to improve system stability sex.
  • the AC side of the first sending-end bipolar converter station is used to connect the wind turbines of the first wind farm; the AC side of the second sending-end bipolar converter station is used for The fan connected to the second wind farm; the AC side of the receiving-end bipolar converter station is used to connect the load.
  • the AC side of the bipolar converter station 1 at the sending end is connected to the wind turbine WT of the wind farm 1, and the wind turbine WT is used to generate power, and is supplied to the bipolar converter station 1 at the sending end;
  • the AC side of the bipolar converter station 2 at the sending end is connected to the wind turbine WT of the wind farm 2 , and the wind turbine WT is used to generate power to supply the bipolar converter station 2 at the sending end.
  • the AC side of the bipolar converter station at the receiving end transmits AC power to the load.
  • the DC sides of the bipolar converter station at the sending end and the bipolar converter station at the receiving end are connected by a positive DC submarine cable and a negative DC submarine cable, and the bipolar converter station at the sending end
  • the neutral line connection of the neutral line, only one neutral line DC submarine cable is used to connect the bipolar converter station at the receiving end and the bipolar converter station at the sending end closest to the bipolar converter station at the receiving end, and the sending end
  • the neutral line of the end bipolar converter station is connected to the neutral line of other sending end bipolar converter stations through other shorter neutral line DC cables.
  • the length of the neutral line submarine cable can be reduced, and To reduce the sea space, by limiting the operating current of the neutral line DC submarine cable and utilizing the short-term overload capacity of the cable, it is possible to meet the operating mode requirements of the parallel multi-terminal DC system with a more economical cable selection and improve the safety of the system and economy.
  • Another embodiment of the present invention provides a parallel multi-terminal DC system, characterized in that the system includes: a sending-end bipolar converter station and a receiving-end bipolar converter station;
  • the sending-end bipolar converter station includes M sending-end bipolar converter stations, which are the first sending-end bipolar converter station to the Mth sending-end bipolar converter station;
  • the positive converter of the first sending-end bipolar converter station is connected to the positive converter of the receiving-end bipolar converter station through the first positive DC submarine cable, and the first sending-end bipolar converter station
  • the negative pole converter of the station is connected to the negative pole converter of the receiving-end bipolar converter station through the first negative DC submarine cable, and the neutral line of the first sending-end bipolar converter station passes through the first
  • the neutral line DC submarine cable is connected to the neutral line of the receiving end bipolar converter station;
  • FIG. 2 is a structural diagram of a parallel multi-terminal DC system provided by another embodiment of the present invention.
  • the system includes: sending-end bipolar converter station 1, sending-end bipolar pole converter station 2, sending-end bipolar converter station 3 and receiving-end bipolar converter station;
  • the positive converter of the first bipolar converter station 1 at the sending end is connected to the positive converter of the bipolar converter station at the receiving end through the positive DC submarine cable 1, and the negative converter of the bipolar converter station 1 at the sending end passes through
  • the negative DC submarine cable 1 is connected to the negative converter of the bipolar converter station at the receiving end, and the neutral line of the bipolar converter station 1 at the sending end passes through the Neutral connection;
  • the positive converter of the bipolar converter station 2 at the sending end is connected to the positive converter of the bipolar converter station at the receiving end through the positive DC submarine cable 2, and the negative converter of the bipolar converter station 2 at the sending end is connected through the negative DC cable 2.
  • the submarine cable 2 is connected to the negative converter of the bipolar converter station at the receiving end, and the neutral line of the bipolar converter station 2 at the sending end is connected to the neutral line of the bipolar converter station 1 at the sending end through the neutral line DC submarine cable 12.
  • the positive converter of the bipolar converter station 3 at the sending end is connected to the positive converter of the bipolar converter station at the receiving end through the positive DC submarine cable 3, and the negative converter of the bipolar converter station 3 at the sending end is connected through the negative DC cable 3.
  • the submarine cable 3 is connected to the negative converter of the bipolar converter station at the receiving end, and the neutral line of the bipolar converter station 3 at the sending end passes through the neutral line DC submarine cable 13 and the neutral line of the bipolar converter station 1 at the sending end.
  • the long-term flow selection of the first neutral line DC submarine cable is max(X 1 , X 2 ,...,X M ); the i-th neutral line DC submarine cable The long-term current flow selection of the cable is X i ;
  • the long-term running current of the first neutral line DC submarine cable does not exceed the long-term current selection of the first neutral line DC connection submarine cable, specifically: max(X 1 , X 2 ,...,X M ) ⁇ (Y 1 +Y 2 +...+Y M );
  • the type selection of the first neutral line DC connection submarine cable has a second-level overload capacity, specifically: when a DC unipolar fault occurs at the receiving end bipolar converter station, the first neutral line DC submarine cable will be within seconds
  • the level flow capacity is (X 1 +X 2 ...+X M );
  • X 1 is the rated current of the first sending-end bipolar converter station
  • X 2 is the rated current of the second sending-end bipolar converter station
  • X M is the rated current of the M-th sending-end bipolar converter station
  • Y 1 ...Y M are respectively the long-term operating currents from the first sending-end bipolar converter station to the M-th sending-end bipolar converter station while running on the single-pole metal neutral line return line.
  • the long-term flow selection of the neutral line DC submarine cable 1 is max(X 1 , X 2 , X 3 ); the long-term flow selection of the neutral line DC submarine cable 12 is X 2 , the long-term flow selection of the neutral DC submarine cable 13 is X 3 ;
  • the long-term running current of the neutral line DC submarine cable 1 does not exceed the long-term current flow selection of the neutral line DC connection submarine cable 1, specifically: max(X 1 , X 2 , X 3 ) ⁇ (Y 1 +Y 2 +Y 3 );
  • the current selection of the neutral line DC connection submarine cable 1 has a second-level overload capacity, specifically: when a DC unipolar fault occurs at the receiving end bipolar converter station, the second-level flow capacity of the neutral line DC submarine cable 1 is X 1 +X 2 +X 3 , where X 1 is the rated current of the sending-end bipolar converter station 1, X 2 is the rated current of the sending-end bipolar converter station 2, and X 3 is the rated current of the sending-end bipolar converter station The rated current of the converter station 3, Y 1 ... Y 3 is the long-term operating current from the sending-end bipolar converter station 1 to the sending-end bipolar converter station 3 while running on the unipolar metal neutral line.
  • the AC side of the i-th sending-end bipolar converter station is used to connect the fans of the i-th wind farm
  • the AC side of the receiving-end bipolar converter station is used for connecting loads.
  • the AC side of the bipolar converter station 1 at the sending end is connected to the wind turbine WT of the wind farm 1, and the wind turbine WT is used to generate power and supply the bipolar converter station 1 at the sending end;
  • the AC side of the sending-end bipolar converter station 2 is connected to the wind turbine WT of the wind farm 2, and the wind turbine WT is used for power generation, which is supplied to the sending-end bipolar converter station 2;
  • the AC side of the sending-end bipolar converter station 3 is connected to the wind farm
  • the wind turbine WT of 3 is connected, and the wind turbine WT is used for power generation, which is supplied to the bipolar converter station 3 at the sending end;
  • the AC side of the bipolar converter station at the receiving end transmits alternating current AC to the load.
  • a parallel multi-terminal DC system includes: a sending-end bipolar converter station and a receiving-end bipolar converter station;
  • the sending-end bipolar converter station includes N sending-end bipolar converter stations, which are the first sending-end bipolar converter station to the Nth sending-end bipolar converter station;
  • the positive converter of the first sending-end bipolar converter station is connected to the positive converter of the receiving-end bipolar converter station through the first positive DC submarine cable, and the first sending-end bipolar converter station
  • the negative pole converter of the station is connected to the negative pole converter of the receiving-end bipolar converter station through the first negative DC submarine cable, and the neutral line of the first sending-end bipolar converter station passes through the first
  • the neutral line DC submarine cable is connected to the neutral line of the receiving end bipolar converter station;
  • the positive converter of the k-th sending-end bipolar converter station is connected to the positive converter of the receiving-end bipolar converter station through the k-th positive DC submarine cable, and the negative pole of the k-th sending-end bipolar converter station
  • the converter is connected to the negative converter of the receiving end bipolar converter station through the kth negative DC submarine cable
  • the neutral line of the kth sending end bipolar converter station is connected to the kth neutral line DC submarine cable through the kth neutral line DC submarine cable.
  • FIG. 3 is a structural diagram of a parallel multi-terminal DC system provided by another embodiment of the present invention.
  • the system includes: sending-end bipolar converter station 1, sending-end bipolar pole converter station 2, sending-end bipolar converter station 3 and receiving-end bipolar converter station;
  • the positive converter of the first bipolar converter station 1 at the sending end is connected to the positive converter of the bipolar converter station at the receiving end through the positive DC submarine cable 1, and the negative converter of the bipolar converter station 1 at the sending end passes through
  • the negative DC submarine cable 1 is connected to the negative converter of the bipolar converter station at the receiving end, and the neutral line of the bipolar converter station 1 at the sending end passes through the Neutral connection;
  • the positive converter of the bipolar converter station 2 at the sending end is connected to the positive converter of the bipolar converter station at the receiving end through the positive DC submarine cable 2, and the negative converter of the bipolar converter station 2 at the sending end is connected through the negative DC cable 2.
  • the submarine cable 2 is connected to the negative converter of the bipolar converter station at the receiving end, and the neutral line of the bipolar converter station 2 at the sending end is connected to the neutral line of the bipolar converter station 1 at the sending end through the neutral line DC submarine cable 12.
  • the positive converter of the bipolar converter station 3 at the sending end is connected to the positive converter of the bipolar converter station at the receiving end through the positive DC submarine cable 3, and the negative converter of the bipolar converter station 3 at the sending end is connected through the negative DC cable 3.
  • the submarine cable 3 is connected to the negative converter of the bipolar converter station at the receiving end, and the neutral line of the bipolar converter station 3 at the sending end passes through the neutral line DC submarine cable 23 and the neutral line of the bipolar converter station 2 at the sending end.
  • the long-term flow selection of the first neutral line DC submarine cable is max(X 1 , X 2 ,...,X N ); the kth neutral line DC submarine cable The cable long-term flow selection is max(X k ,...,X N );
  • the long-term running current of the first neutral line DC submarine cable does not exceed the long-term current selection of the first neutral line DC connection submarine cable, specifically: max(X 1 , X 2 ,...,X N ) ⁇ (Y 1 +Y 2 +...+Y N );
  • the type selection of the first neutral line DC connection submarine cable has a second-level overload capacity, specifically: when a DC unipolar fault occurs at the receiving end bipolar converter station, the first neutral line DC submarine cable will be in seconds
  • the level flow capacity is (X 1 +X 2 ...+X N );
  • X 1 is the rated current of the first sending-end bipolar converter station
  • X 2 is the rated current of the second sending-end bipolar converter station
  • X N is the rated current of the Nth sending-end bipolar converter station
  • Y 1 ...Y N are the long-term operating currents from the first sending-end bipolar converter station to the N-th sending-end bipolar converter station while running on the single-pole metallic neutral line;
  • the AC side of the kth sending-end bipolar converter station is used to connect to the fan of the kth wind farm;
  • the AC side of the receiving-end bipolar converter station is used for connecting loads.
  • the long-term flow selection of the neutral line DC submarine cable 1 is max(X 1 , X 2 , X 3 );
  • the long-term flow selection of the neutral line DC submarine cable 23 is max( X 1 , X 2 ), the long-term flow selection of the neutral DC submarine cable 13 is X 3 ;
  • the long-term running current of the neutral line DC submarine cable 1 does not exceed the long-term current flow selection of the neutral line DC connection submarine cable 1, specifically: max(X 1 , X 2 , X 3 ) ⁇ (Y 1 +Y 2 +Y 3 );
  • the current selection of the neutral line DC connection submarine cable 1 has a second-level overload capacity, specifically: when a DC unipolar fault occurs at the receiving end bipolar converter station, the second-level flow capacity of the neutral line DC submarine cable 1 is (X 1 +X 2 +X 3 ), where X 1 is the rated current of sending-end bipolar converter station 1, X 2 is the rated current of sending-end bipolar converter station 2, and X 3 is the rated current of sending-end bipolar converter station 2.
  • the rated current of the pole converter station 3, Y 1 ... Y 3 is the long-term operating current from the sending-end bipolar converter station 1 to the sending-end bipolar converter station 3 while running on the single-pole metal neutral line and return line.
  • the AC side of the sending-end bipolar converter station 1 is connected to the wind turbine WT of the wind farm 1, and the wind turbine WT is used for power generation, which is supplied to the sending-end bipolar converter station 1; sending-end bipolar converter station 2
  • the AC side of the wind farm 2 is connected to the wind turbine WT of the wind farm 2, and the wind turbine WT is used for power generation, which is supplied to the sending-end bipolar converter station 2;
  • the AC side of the sending-end bipolar converter station 3 is connected to the wind turbine WT of the wind farm 3, and the wind turbine WT It is used for power generation and supplied to the bipolar converter station 3 at the sending end;
  • the AC side of the bipolar converter station at the receiving end transmits alternating current AC to the load.
  • the DC sides of the bipolar converter station at the sending end and the bipolar converter station at the receiving end are connected through a positive DC submarine cable and a negative DC submarine cable, and the middle of the bipolar converter station at the sending end Neutral line connection, only one neutral line DC submarine cable is used to connect the receiving end bipolar converter station and the sending end bipolar converter station closest to the receiving end bipolar converter station, and the sending end bipolar converter station
  • the neutral line of the pole converter station is connected to the neutral line of other bipolar converter stations at the sending end through other short neutral line DC cables.

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Abstract

一种并联多端直流系统，送端双极换流站和受端双极换流站的直流侧通过正极直流海缆和负极直流海缆相连，送端双极换流站的中性线连接，仅采用一回中性线直流海缆用于连接受端双极换流站和距离受端双极换流站最近的一个送端双极换流站，并将该送端双极换流站的中性线与其他送端双极换流站的中性线通过其他较短的中性线直流电缆相连，通过该接线方式，可减少中性线海缆长度，并且减少用海空间。

Description

一种并联多端直流系统 技术领域
本发明涉及直流输电技术领域，尤其涉及一种并联多端直流系统。
背景技术
现有海上风电直流送出工程均为采用对称单极的直流工程，当输送容量增大时，对称单极结构可能无法满足设备要求和可靠性要求，需要采用双极结构。
陆上双极直流系统换流站中性线一般采用接地极接地，即单极运行时可通过大地回线进行通流；而海上风电送出用直流系统应用环境特殊，若采用海水接地极，则海水中将流过电流，一般不被允许，因此海上风电双极直流送出工程一般需要采用中性线直流海缆。
海上风电直流送出工程采用一回对称单极直流系统时，仅需正极直流电缆和负极直流电缆共两回直流电缆；而采用一回双极直流系统时，则须正极直流电缆、负极直流电缆和金属中线电缆三回直流电缆；对于大容量海上风电送出工程，可能采用多个送端和一个受端的双极输电结构，由于直流海缆通流能力的限制，需要在受端直流处并联汇集，此时直流海缆数量为2n回极线海缆和n回中性线海缆，由于海缆造成的输电成本和用海面积的较高。
发明内容
本发明实施例提供一种并联多端直流系统，对于送端多个海上风电送出用换流站的并联直流系统，仅采用一回中性线直流海缆，减少总的直流中性线海缆长度和成本，减少用海面积。
本发明一实施例提供一种并联多端直流系统，所述系统包括：第一送端双极 换流站、第二送端双极换流站和受端双极换流站；
所述第一送端双极换流站的正极换流器通过第一正极直流海缆与所述受端双极换流站的正极换流器连接，所述第一送端双极换流站的负极换流器通过第一负极直流海缆与所述受端双极换流站的负极换流器连接，所述第一送端双极换流站的中性线均通过第一中性线直流海缆与所述受端双极换流站的中性线连接；
所述第二送端双极换流站的正极换流器通过第二正极直流海缆与所述受端双极换流站的正极换流器连接，所述第二送端双极换流站的负极换流器通过第二负极直流海缆与所述受端双极换流站的负极换流器连接，所述第二送端双极换流站的中性线均通过第二中性线直流海缆与所述第一送端双极换流站的中性线连接。
作为一种优选方式，所述第一中性线直流海缆长期通流选型为max(X 1，X 2)；所述第二中性线直流海缆长期通流选型为X 2；
其中，X 1为第一送端双极换流站的额定电流，X 2为第二送端双极换流站的额定电流。
作为一种优选方式，所述第一中性线直流海缆的长期运行电流不超过所述第一中性线直流连接海缆长期通流选型，具体为：max(X 1，X 2)≥(Y 1+Y 2)；其中,max(X 1，X 2)为第一中性线直流海缆长期通流选型,X 1为第一送端双极换流站的额定电流，X 2为第二送端双极换流站的额定电流,Y 1和Y 2分别为第一送端双极换流站和第二送端双极换流站同时以单极金属中线回线运行的长期运行电流。
作为一种优选方式，所述第一中性线直流连接海缆通流选型具备秒级过负荷能力，具体为：在受端双极换流站发生直流单极故障时，第一中性线直流海缆的秒级通流能力为(X 1+X 2)，其中，X 1为第一送端双极换流站的额定电流，X 2为第二送端双极换流站的额定电流。
作为一种优选方式，所述第一送端双极换流站的交流侧用于连接第一风电场的风机；
所述第二送端双极换流站的交流侧用于连接第二风电场的风机；
所述受端双极换流站的交流侧用于连接负载。
本发明另一实施例还提供一种并联多端直流系统，所述系统包括：送端双极换流站和受端双极换流站；
所述送端双极换流站包括M个送端双极换流站，分别为第1送端双极换流站到第M送端双极换流站；
所述第1送端双极换流站的正极换流器通过第1正极直流海缆与所述受端双极换流站的正极换流器连接，所述第1送端双极换流站的负极换流器通过第1负极直流海缆与所述受端双极换流站的负极换流器连接，所述第1送端双极换流站的中性线均通过第1中性线直流海缆与所述受端双极换流站的中性线连接；
第i送端双极换流站的正极换流器通过第i正极直流海缆与所述受端双极换流站的正极换流器连接，第i送端双极换流站的负极换流器通过第i负极直流海缆与所述受端双极换流站的负极换流器连接，第i送端双极换流站的中性线通过第i中性线直流海缆与所述第1送端双极换流站的中性线连接,其中，M≥2，i＝2,…,M。
作为一种优选方式，所述第1中性线直流海缆长期通流选型为max(X 1，X 2,…,X M)；所述第i中性线直流海缆长期通流选型为X i；
所述第1中性线直流海缆的长期运行电流不超过所述第1中性线直流连接海缆长期通流选型，具体为：max(X 1，X 2,…,X M)≥(Y 1+Y 2+…+Y M)；
所述第1中性线直流连接海缆通流选型具备秒级过负荷能力，具体为：在受端双极换流站发生直流单极故障时，第1中性线直流海缆的秒级通流能力为0.5×(X 1+X 2…+X M)；
其中，X 1为第1送端双极换流站的额定电流，X 2为第2送端双极换流站的额定电流,X M为第M送端双极换流站的额定电流，Y 1…Y M分别为第1送端双极换流站到第M送端双极换流站同时以单极金属中线回线运行的长期运行电流。
作为一种优选方式，所述第i送端双极换流站的交流侧用于连接第i风电场的风机；
所述受端双极换流站的交流侧用于连接负载。
本发明又一实施例提供一种并联多端直流系统，所述系统包括：送端双极换流站和受端双极换流站；
所述送端双极换流站包括N个送端双极换流站，分别为第1送端双极换流站到第N送端双极换流站；
所述第1送端双极换流站的正极换流器通过第1正极直流海缆与所述受端双极换流站的正极换流器连接，所述第1送端双极换流站的负极换流器通过第1负极直流海缆与所述受端双极换流站的负极换流器连接，所述第1送端双极换流站的中性线均通过第1中性线直流海缆与所述受端双极换流站的中性线连接；
第k级送端双极换流站的正极换流器通过第k正极直流海缆与所述受端双极换流站的正极换流器连接，第k送端双极换流站的负极换流器通过第k负极直流海缆与所述受端双极换流站的负极换流器连接，第k送端双极换流站的中性线通过第k中性线直流海缆与第k-1送端双极换流站的中性线连接,其中N≥2，k＝2,…,N。
作为一种优选方式，所述第1中性线直流海缆长期通流选型为max(X 1，X 2,…,X N)；所述第k中性线直流海缆长期通流选型为max(X k,…,X N)；
所述第1中性线直流海缆的长期运行电流不超过所述第1中性线直流连接海缆长期通流选型，具体为：max(X 1，X 2,…,X N)≥(Y 1+Y 2+…+Y N)；
所述第1中性线直流连接海缆通流选型具备秒级过负荷能力，具体为：在受端双极换流站发生直流单极故障时，第1中性线直流海缆的秒级通流能力为(X 1+X 2…+X N)；
其中，X 1为第1送端双极换流站的额定电流，X 2为第2送端双极换流站的额定电流,X N为第N送端双极换流站的额定电流，Y 1…Y N分别为第1送端双极换流 站到第N送端双极换流站同时以单极金属中线回线运行的长期运行电流；
所述第k送端双极换流站的交流侧用于连接第k风电场的风机；
所述受端双极换流站的交流侧用于连接负载。
本发明提供的一种并联多端直流系统，送端双极换流站和受端双极换流站的直流侧通过正极直流海缆和负极直流海缆相连，送端双极换流站的中性线连接，仅采用一回中性线直流海缆用于连接受端双极换流站和距离受端双极换流站最近的一个送端双极换流站，并将该送端双极换流站的中性线与其他送端双极换流站的中性线通过其他较短的中性线直流电缆相连，通过该接线方式，可减少中性线海缆长度，并且减少用海空间，通过限定中性线直流海缆的运行电流，并利用电缆的短时过负荷能力，可以以较经济的电缆选型满足并联多端直流系统的运行方式要求，提高系统的安全性和经济性。
附图说明
图1是本发明实施例提供的一种并联多端直流系统的结构示意图；
图2是本发明另一实施例提供的一种并联多端直流系统的结构示意图；
图3是本发明又一实施例提供的一种并联多端直流系统的结构示意图。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
本发明实施例提供一种并联多端直流系统，所述系统包括：第一送端双极换流站、第二送端双极换流站和受端双极换流站；
所述第一送端双极换流站的正极换流器通过第一正极直流海缆与所述受端 双极换流站的正极换流器连接，所述第一送端双极换流站的负极换流器通过第一负极直流海缆与所述受端双极换流站的负极换流器连接，所述第一送端双极换流站的中性线均通过第一中性线直流海缆与所述受端双极换流站的中性线连接；
所述第二送端双极换流站的正极换流器通过第二正极直流海缆与所述受端双极换流站的正极换流器连接，所述第二送端双极换流站的负极换流器通过第二负极直流海缆与所述受端双极换流站的负极换流器连接，所述第二送端双极换流站的中性线均通过第二中性线直流海缆与所述第一送端双极换流站的中性线连接。
在本实施例具体实施时，参见图1所示，是本发明实施例提供的一种并联多端直流系统的结构意图，所述系统包括：送端双极换流站1、送端双极换流站2和受端双极换流站；
第一送端双极换流站1的正极换流器通过正极直流海缆1与受端双极换流站的正极换流器连接，送端双极换流站1的负极换流器通过负极直流海缆1与受端双极换流站的负极换流器连接，送端双极换流站1的中性线均通过中性线直流海缆1与受端双极换流站的中性线连接；
送端双极换流站2的正极换流器通过正极直流海缆2与受端双极换流站的正极换流器连接，送端双极换流站2的负极换流器通过负极直流海缆2与受端双极换流站的负极换流器连接，送端双极换流站2的中性线均通过中性线直流海缆12与送端双极换流站1的中性线连接。
具体的，若送端双极换流站1与受端双极换流站间海缆长度为100km，送端双极换流站2与受端双极换流站间海缆长度为120km，送端双极换流站1与送端双极换流站2间海缆长度为20km，采用本实施例的接线方式仅需100km+20km＝120km中性线直流电缆，比采用原方式所需220km节约了100km中性线直流电缆，减少用海面积。
本发明实施例提供的一种并联多端直流系统，送端双极换流站和受端双极换 流站的直流侧通过正极直流海缆和负极直流海缆相连，送端双极换流站的中性线连接，仅采用一回中性线直流海缆用于连接受端双极换流站和距离受端双极换流站最近的一个送端双极换流站，并将该送端双极换流站的中性线与其他送端双极换流站的中性线通过其他较短的中性线直流电缆相连，通过该接线方式，可减少中性线海缆长度，并且减少用海空间。
在本发明提供的又一实施例中，所述第一中性线直流海缆长期通流选型为max(X 1，X 2)；所述第二中性线直流海缆长期通流选型为X 2；
其中，X 1为第一送端双极换流站的额定电流，X 2为第二送端双极换流站的额定电流。
在本实施例具体实施时，中性线直流海缆1长期通流选型为max(X 1，X 2)；中性线直流海缆12长期通流选型为X 2，X 1为送端双极换流站1的额定电流，X 2为送端双极换流站2的额定电流。
提高第一中性线直流海缆通流能力，能够承受第一送端双极换流站和第二送端双极换流站的额定电流，满足系统稳定性和安全性能的要求。
在本发明提供的又一实施例中，所述第一中性线直流海缆的长期运行电流不超过所述第一中性线直流连接海缆长期通流选型，具体为：max(X 1，X 2)≥(Y 1+Y 2)；其中,max(X 1，X 2)为第一中性线直流海缆长期通流选型,X 1为第一送端双极换流站的额定电流，X 2为第二送端双极换流站的额定电流,Y 1和Y 2分别为第一送端双极换流站和第二送端双极换流站同时以单极金属中线回线运行的长期运行电流。
在本实施例具体实施时，若多回直流均采用单极金属中线回线运行方式，在多回直流金属中线回线汇流后，连接送端双极换流站和受端双极换流站的中性线直流海缆通流将增加，因此需要限制多回直流长期同极性单极金属中线运行方式下的运行电流，保证中性线直流海缆长期通流不超过设备能力，即max(X 1，X 2)≥(Y 1+Y 2)，Y 1+Y 2为送端双极换流站1和送端双极换流站2同时以单极金属回线 运行的长期运行电流。
在本发明提供的又一实施例中，所述第一中性线直流连接海缆通流选型具备秒级过负荷能力，具体为：在受端双极换流站发生直流单极故障时，第一中性线直流海缆的秒级通流能力为(X 1+X 2)，其中，X 1为第一送端双极换流站的额定电流，X 2为第二送端双极换流站的额定电流。
在本实施例具体实施时，考虑受端发生直流单极故障的暂态情况，短时内直流以单极金属中线回线运行，中性线直流海缆需具备秒级过负荷能力。比如两个送端双极换流站均采用1500A额定电流，受端双极换流站额定电流为3000A的情况下，双极和单极金属中线正常运行方式下，每极直流电缆长期通流为1500A，中性线直流电缆1长期通流也为1500A，当考虑受端直流单极故障时，中性线直流海缆需具备秒级3000A(1500A+1500A)的过负荷能力,提高系统稳定性。
在本发明提供的又一实施例中，所述第一送端双极换流站的交流侧用于连接第一风电场的风机；所述第二送端双极换流站的交流侧用于连接第二风电场的风机；所述受端双极换流站的交流侧用于连接负载。
在本实施例具体实施时，参见图1所示，送端双极换流站1的交流侧与风电场1的风机WT连接，风机WT用于发电，供给送端双极换流站1；送端双极换流站2的交流侧与风电场2的风机WT连接，风机WT用于发电，供给送端双极换流站2。
受端双极换流站的交流侧输交流电AC给负载。
本发明实施例提供的一种并联多端直流系统，送端双极换流站和受端双极换流站的直流侧通过正极直流海缆和负极直流海缆相连，送端双极换流站的中性线连接，仅采用一回中性线直流海缆用于连接受端双极换流站和距离受端双极换流站最近的一个送端双极换流站，并将该送端双极换流站的中性线与其他送端双极换流站的中性线通过其他较短的中性线直流电缆相连，通过该接线方式，可减少中性线海缆长度，并且减少用海空间，通过限定中性线直流海缆的运行电流，并 利用电缆的短时过负荷能力，可以以较经济的电缆选型满足并联多端直流系统的运行方式要求，提高系统的安全性和经济性。
在本发明另一实施例提供一种并联多端直流系统，其特征在于，所述系统包括：送端双极换流站和受端双极换流站；
所述送端双极换流站包括M个送端双极换流站，分别为第1送端双极换流站到第M送端双极换流站；
所述第1送端双极换流站的正极换流器通过第1正极直流海缆与所述受端双极换流站的正极换流器连接，所述第1送端双极换流站的负极换流器通过第1负极直流海缆与所述受端双极换流站的负极换流器连接，所述第1送端双极换流站的中性线均通过第1中性线直流海缆与所述受端双极换流站的中性线连接；
第i送端双极换流站的正极换流器通过第i正极直流海缆与所述受端双极换流站的正极换流器连接，第i送端双极换流站的负极换流器通过第i负极直流海缆与所述受端双极换流站的负极换流器连接，第i送端双极换流站的中性线通过第i中性线直流海缆与所述第1送端双极换流站的中性线连接,其中，M≥2，i＝2,…,M。
在本实施例具体实施时，参见图2所示，是本发明另一实施例提供的一种并联多端直流系统的结构意图，所述系统包括：送端双极换流站1、送端双极换流站2、送端双极换流站3和受端双极换流站；
需要说明的是，在本实施例中以M＝3说明具体连接关系。
第一送端双极换流站1的正极换流器通过正极直流海缆1与受端双极换流站的正极换流器连接，送端双极换流站1的负极换流器通过负极直流海缆1与受端双极换流站的负极换流器连接，送端双极换流站1的中性线均通过中性线直流海缆1与受端双极换流站的中性线连接；
送端双极换流站2的正极换流器通过正极直流海缆2与受端双极换流站的正极换流器连接，送端双极换流站2的负极换流器通过负极直流海缆2与受端双极 换流站的负极换流器连接，送端双极换流站2的中性线均通过中性线直流海缆12与送端双极换流站1的中性线连接。
送端双极换流站3的正极换流器通过正极直流海缆3与受端双极换流站的正极换流器连接，送端双极换流站3的负极换流器通过负极直流海缆3与受端双极换流站的负极换流器连接，送端双极换流站3的中性线均通过中性线直流海缆13与送端双极换流站1的中性线连接。
在本发明提供的又一实施例中，所述第1中性线直流海缆长期通流选型为max(X 1，X 2,…,X M)；所述第i中性线直流海缆长期通流选型为X i；
所述第1中性线直流海缆的长期运行电流不超过所述第1中性线直流连接海缆长期通流选型，具体为：max(X 1，X 2,…,X M)≥(Y 1+Y 2+…+Y M)；
所述第1中性线直流连接海缆通流选型具备秒级过负荷能力，具体为：在受端双极换流站发生直流单极故障时，第1中性线直流海缆的秒级通流能力为(X 1+X 2…+X M)；
其中，X 1为第1送端双极换流站的额定电流，X 2为第2送端双极换流站的额定电流,X M为第M送端双极换流站的额定电流，Y 1…Y M分别为第1送端双极换流站到第M送端双极换流站同时以单极金属中线回线运行的长期运行电流。
在本实施例具体实施时，中性线直流海缆1的长期通流选型为max(X 1，X 2，X 3)；中性线直流海缆12的长期通流选型为X 2，中性线直流海缆13的长期通流选型为X 3；
中性线直流海缆1的长期运行电流不超过所述中性线直流连接海缆1的长期通流选型，具体为：max(X 1，X 2，X 3)≥(Y 1+Y 2+Y 3)；
中性线直流连接海缆1通流选型具备秒级过负荷能力，具体为：在受端双极换流站发生直流单极故障时，中性线直流海缆1的秒级通流能力为X 1+X 2+X 3，其中，X 1为送端双极换流站1的额定电流，X 2为送端双极换流站2的额定电流,X 3为送端双极换流站3的额定电流，Y 1…Y 3分别为送端双极换流站1到送端双极换 流站3同时以单极金属中线回线运行的长期运行电流。
本发明提供的又一实施例中，所述第i送端双极换流站的交流侧用于连接第i风电场的风机；
所述受端双极换流站的交流侧用于连接负载。
在本实施例具体实施时，参见图2所示，送端双极换流站1的交流侧与风电场1的风机WT连接，风机WT用于发电，供给送端双极换流站1；送端双极换流站2的交流侧与风电场2的风机WT连接，风机WT用于发电，供给送端双极换流站2；送端双极换流站3的交流侧与风电场3的风机WT连接，风机WT用于发电，供给送端双极换流站3；受端双极换流站的交流侧输交流电AC给负载。
在本发明又一实施例提供一种并联多端直流系统，所述系统包括：送端双极换流站和受端双极换流站；
所述送端双极换流站包括N个送端双极换流站，分别为第1送端双极换流站到第N送端双极换流站；
所述第1送端双极换流站的正极换流器通过第1正极直流海缆与所述受端双极换流站的正极换流器连接，所述第1送端双极换流站的负极换流器通过第1负极直流海缆与所述受端双极换流站的负极换流器连接，所述第1送端双极换流站的中性线均通过第1中性线直流海缆与所述受端双极换流站的中性线连接；
第k级送端双极换流站的正极换流器通过第k正极直流海缆与所述受端双极换流站的正极换流器连接，第k送端双极换流站的负极换流器通过第k负极直流海缆与所述受端双极换流站的负极换流器连接，第k送端双极换流站的中性线通过第k中性线直流海缆与第k-1送端双极换流站的中性线连接,其中N≥2，k＝2,…,N。
在本实施例具体实施时，参见图3所示，是本发明又一实施例提供的一种并联多端直流系统的结构意图，所述系统包括：送端双极换流站1、送端双极换流站2、送端双极换流站3和受端双极换流站；
需要说明的是，在本实施例中以N＝3说明具体连接关系。
第一送端双极换流站1的正极换流器通过正极直流海缆1与受端双极换流站的正极换流器连接，送端双极换流站1的负极换流器通过负极直流海缆1与受端双极换流站的负极换流器连接，送端双极换流站1的中性线均通过中性线直流海缆1与受端双极换流站的中性线连接；
送端双极换流站2的正极换流器通过正极直流海缆2与受端双极换流站的正极换流器连接，送端双极换流站2的负极换流器通过负极直流海缆2与受端双极换流站的负极换流器连接，送端双极换流站2的中性线均通过中性线直流海缆12与送端双极换流站1的中性线连接。
送端双极换流站3的正极换流器通过正极直流海缆3与受端双极换流站的正极换流器连接，送端双极换流站3的负极换流器通过负极直流海缆3与受端双极换流站的负极换流器连接，送端双极换流站3的中性线均通过中性线直流海缆23与送端双极换流站2的中性线连接。
在本发明提供的又一实施例中，所述第1中性线直流海缆长期通流选型为max(X 1，X 2,…,X N)；所述第k中性线直流海缆长期通流选型为max(X k,…,X N)；
所述第1中性线直流海缆的长期运行电流不超过所述第1中性线直流连接海缆长期通流选型，具体为：max(X 1，X 2,…,X N)≥(Y 1+Y 2+…+Y N)；
所述第1中性线直流连接海缆通流选型具备秒级过负荷能力，具体为：在受端双极换流站发生直流单极故障时，第1中性线直流海缆的秒级通流能力为(X 1+X 2…+X N)；
其中，X 1为第1送端双极换流站的额定电流，X 2为第2送端双极换流站的额定电流,X N为第N送端双极换流站的额定电流，Y 1…Y N分别为第1送端双极换流站到第N送端双极换流站同时以单极金属中线回线运行的长期运行电流；
所述第k送端双极换流站的交流侧用于连接第k风电场的风机；
所述受端双极换流站的交流侧用于连接负载。
在本实施例具体实施时，中性线直流海缆1的长期通流选型为max(X 1，X 2，X 3)；中性线直流海缆23的长期通流选型为max(X 1，X 2)，中性线直流海缆13的长期通流选型为X 3；
中性线直流海缆1的长期运行电流不超过所述中性线直流连接海缆1的长期通流选型，具体为：max(X 1，X 2，X 3)≥(Y 1+Y 2+Y 3)；
中性线直流连接海缆1通流选型具备秒级过负荷能力，具体为：在受端双极换流站发生直流单极故障时，中性线直流海缆1的秒级通流能力为(X 1+X 2+X 3)，其中，X 1为送端双极换流站1的额定电流，X 2为送端双极换流站2的额定电流,X 3为送端双极换流站3的额定电流，Y 1…Y 3分别为送端双极换流站1到送端双极换流站3同时以单极金属中线回线运行的长期运行电流。
参见图3所示，送端双极换流站1的交流侧与风电场1的风机WT连接，风机WT用于发电，供给送端双极换流站1；送端双极换流站2的交流侧与风电场2的风机WT连接，风机WT用于发电，供给送端双极换流站2；送端双极换流站3的交流侧与风电场3的风机WT连接，风机WT用于发电，供给送端双极换流站3；受端双极换流站的交流侧输交流电AC给负载。
本发明提供的一种并联多端直流系统，送端双极换流站和受端双极换流站的直流侧通过正极直流海缆和负极直流海缆相连，送端双极换流站的中性线连接，仅采用一回中性线直流海缆用于连接受端双极换流站和距离受端双极换流站最近的一个送端双极换流站，并将该送端双极换流站的中性线与其他送端双极换流站的中性线通过其他较短的中性线直流电缆相连，通过该接线方式，可减少中性线海缆长度，并且减少用海空间，通过限定中性线直流海缆的运行电流，并利用电缆的短时过负荷能力，可以以较经济的电缆选型满足并联多端直流系统的运行方式要求，提高系统的安全性和经济性。
以上所述是本发明的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明原理的前提下，还可以做出若干改进和润饰，这些改 进和润饰也视为本发明的保护范围。

Claims (10)

  1. 一种并联多端直流系统，其特征在于，所述系统包括：第一送端双极换流站、第二送端双极换流站和受端双极换流站；
    所述第一送端双极换流站的正极换流器通过第一正极直流海缆与所述受端双极换流站的正极换流器连接，所述第一送端双极换流站的负极换流器通过第一负极直流海缆与所述受端双极换流站的负极换流器连接，所述第一送端双极换流站的中性线均通过第一中性线直流海缆与所述受端双极换流站的中性线连接；
    所述第二送端双极换流站的正极换流器通过第二正极直流海缆与所述受端双极换流站的正极换流器连接，所述第二送端双极换流站的负极换流器通过第二负极直流海缆与所述受端双极换流站的负极换流器连接，所述第二送端双极换流站的中性线均通过第二中性线直流海缆与所述第一送端双极换流站的中性线连接。
  2. 如权利要求1所述的一种并联多端直流系统，其特征在于，所述第一中性线直流海缆长期通流选型为max(X 1，X 2)；所述第二中性线直流海缆长期通流选型为X 2；
    其中，X 1为第一送端双极换流站的额定电流，X 2为第二送端双极换流站的额定电流。
  3. 如权利要求1所述的一种并联多端直流系统，其特征在于，所述第一中性线直流海缆的长期运行电流不超过所述第一中性线直流连接海缆长期通流选型，具体为：max(X 1，X 2)≥(Y 1+Y 2)；其中,max(X 1，X 2)为第一中性线直流海缆通流选型,X 1为第一送端双极换流站的额定电流，X 2为第二送端双极换流站的额定电流,Y 1和Y 2分别为第一送端双极换流站和第二送端双极换流站同时以单极金属中线回线运行的长期运行电流。
  4. 权利要求1所述的一种并联多端直流系统，其特征在于，所述第一中性线直流连接海缆通流选型具备秒级过负荷能力，具体为：在受端双极换流站发生直流单极故障时，第一中性线直流海缆的秒级通流能力为(X 1+X 2)，其中，X 1为第一送端双极换流站的额定电流，X 2为第二送端双极换流站的额定电流。
  5. 权利要求1所述的一种并联多端直流系统，其特征在于，所述第一送端双极换流站的交流侧用于连接第一风电场的风机；
    所述第二送端双极换流站的交流侧用于连接第二风电场的风机；
    所述受端双极换流站的交流侧用于连接负载。
  6. 一种并联多端直流系统，其特征在于，所述系统包括：送端双极换流站和受端双极换流站；
    所述送端双极换流站包括M个送端双极换流站，分别为第1送端双极换流站到第M送端双极换流站；
    所述第1送端双极换流站的正极换流器通过第1正极直流海缆与所述受端双极换流站的正极换流器连接，所述第1送端双极换流站的负极换流器通过第1负极直流海缆与所述受端双极换流站的负极换流器连接，所述第1送端双极换流站的中性线均通过第1中性线直流海缆与所述受端双极换流站的中性线连接；
    第i送端双极换流站的正极换流器通过第i正极直流海缆与所述受端双极换流站的正极换流器连接，第i送端双极换流站的负极换流器通过第i负极直流海缆与所述受端双极换流站的负极换流器连接，第i送端双极换流站的中性线通过第i中性线直流海缆与所述第1送端双极换流站的中性线连接,其中，M≥2，i＝2,…,M。
  7. 如权利要求6所述的一种并联多端直流系统，其特征在于，所述第1中 性线直流海缆长期通流选型为max(X 1，X 2,…,X M)；所述第i中性线直流海缆长期通流选型为X i；
    所述第1中性线直流海缆的长期运行电流不超过所述第1中性线直流连接海缆长期通流选型，具体为：max(X 1，X 2,…,X M)≥(Y 1+Y 2+…+Y M)；
    所述第1中性线直流连接海缆通流选型具备秒级过负荷能力，具体为：在受端双极换流站发生直流单极故障时，第1中性线直流海缆的秒级通流能力为(X 1+X 2…+X M)；
    其中，X 1为第1送端双极换流站的额定电流，X 2为第2送端双极换流站的额定电流,X M为第M送端双极换流站的额定电流，Y 1…Y M分别为第1送端双极换流站到第M送端双极换流站同时以单极金属中线回线运行的长期运行电流。
  8. 权利要求6所述的一种并联多端直流系统，其特征在于，所述第i送端双极换流站的交流侧用于连接第i风电场的风机；
    所述受端双极换流站的交流侧用于连接负载。
  9. 一种并联多端直流系统，其特征在于，所述系统包括：送端双极换流站和受端双极换流站；
    所述送端双极换流站包括N个送端双极换流站，分别为第1送端双极换流站到第N送端双极换流站；
    所述第1送端双极换流站的正极换流器通过第1正极直流海缆与所述受端双极换流站的正极换流器连接，所述第1送端双极换流站的负极换流器通过第1负极直流海缆与所述受端双极换流站的负极换流器连接，所述第1送端双极换流站的中性线均通过第1中性线直流海缆与所述受端双极换流站的中性线连接；
    第k级送端双极换流站的正极换流器通过第k正极直流海缆与所述受端双极换流站的正极换流器连接，第k送端双极换流站的负极换流器通过第k负极直流 海缆与所述受端双极换流站的负极换流器连接，第k送端双极换流站的中性线通过第k中性线直流海缆与第k-1送端双极换流站的中性线连接,其中N≥2，k＝2,…,N。
  10. 如权利要求9所述的一种并联多端直流系统，其特征在于，所述第1中性线直流海缆长期通流选型为max(X 1，X 2,…,X N)；所述第k中性线直流海缆长期通流选型为max(X k,…,X N)；
    所述第1中性线直流海缆的长期运行电流不超过所述第1中性线直流连接海缆长期通流选型，具体为：max(X 1，X 2,…,X N)≥(Y 1+Y 2+…+Y N)；
    所述第1中性线直流连接海缆通流选型具备秒级过负荷能力，具体为：在受端双极换流站发生直流单极故障时，第1中性线直流海缆的秒级通流能力为0.5×(X 1+X 2…+X N)；
    其中，X 1为第1送端双极换流站的额定电流，X 2为第2送端双极换流站的额定电流,X N为第N送端双极换流站的额定电流，Y 1…Y N分别为第1送端双极换流站到第N送端双极换流站同时以单极金属中线回线运行的长期运行电流；
    所述第k送端双极换流站的交流侧用于连接第k风电场的风机；
    所述受端双极换流站的交流侧用于连接负载。
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN204720999U (zh) * 2015-07-01 2015-10-21 南方电网科学研究院有限责任公司 一种高压直流输电接地极系统
CN105071373A (zh) * 2015-08-27 2015-11-18 中国电力科学研究院 一种柔性直流输电系统中直流开关场的配置系统和方法
US20160036221A1 (en) * 2014-07-31 2016-02-04 Abb Technology Ag Dc connection system for renewable power generators
CN112736977A (zh) * 2020-12-31 2021-04-30 中国长江三峡集团有限公司 多端海上风电柔性直流与储能协同并网系统及其控制方法
CN112986753A (zh) * 2021-02-22 2021-06-18 天津大学 一种经金属回线接地的柔性直流电网双端故障测距方法
CN113489043A (zh) * 2021-07-12 2021-10-08 南方电网科学研究院有限责任公司 一种并联多端直流系统

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108258727A (zh) * 2018-01-24 2018-07-06 许继集团有限公司 一种海上风电场并网输电系统
US11355925B2 (en) * 2018-01-30 2022-06-07 Hitachi Energy Switzerland Ag System design solution for DC grid cost reduction and risk minimization
CN108964111B (zh) * 2018-08-22 2020-06-30 国家电网有限公司 一种具有中压侧直流出线的直流输电系统及其控制方法
CN112152204B (zh) * 2020-09-04 2022-09-16 南方电网科学研究院有限责任公司 多端直流单极故障功率转移方法及装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160036221A1 (en) * 2014-07-31 2016-02-04 Abb Technology Ag Dc connection system for renewable power generators
CN204720999U (zh) * 2015-07-01 2015-10-21 南方电网科学研究院有限责任公司 一种高压直流输电接地极系统
CN105071373A (zh) * 2015-08-27 2015-11-18 中国电力科学研究院 一种柔性直流输电系统中直流开关场的配置系统和方法
CN112736977A (zh) * 2020-12-31 2021-04-30 中国长江三峡集团有限公司 多端海上风电柔性直流与储能协同并网系统及其控制方法
CN112986753A (zh) * 2021-02-22 2021-06-18 天津大学 一种经金属回线接地的柔性直流电网双端故障测距方法
CN113489043A (zh) * 2021-07-12 2021-10-08 南方电网科学研究院有限责任公司 一种并联多端直流系统

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