CN107565521A - Method for clearing short-circuit fault on direct current side of flexible direct current power grid - Google Patents

Method for clearing short-circuit fault on direct current side of flexible direct current power grid Download PDF

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Publication number
CN107565521A
CN107565521A CN201710868357.5A CN201710868357A CN107565521A CN 107565521 A CN107565521 A CN 107565521A CN 201710868357 A CN201710868357 A CN 201710868357A CN 107565521 A CN107565521 A CN 107565521A
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circuit breaker
target
direct current
breaker
circuit
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CN107565521B (en
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彭发喜
李明
李岩
许树楷
黄伟煌
郭铸
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China South Power Grid International Co ltd
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China South Power Grid International Co ltd
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Abstract

The invention provides a method for clearing a short-circuit fault on a direct-current side of a flexible direct-current power grid, relates to the technical field of flexible direct-current power transmission, and can solve the problem that the short-circuit fault caused by the failure of a direct-current circuit breaker cannot be thoroughly cleared on the premise of avoiding the shutdown of the whole flexible direct-current power grid. The method comprises the following steps: sending tripping instructions to all first target direct current circuit breakers, and sending standby instructions to all second target direct current circuit breakers and all target alternating current circuit breakers; and detecting whether each first target direct current breaker successfully trips within preset time, if at least one first target direct current breaker does not successfully trip within the preset time, sending a tripping instruction to a second target direct current breaker and a target alternating current breaker which are adjacent to the non-tripped breaker, and locking the target direct current converter which is adjacent to the non-tripped breaker. The method is applied to the flexible direct-current power grid based on the modular multilevel converter.

Description

A kind of method for removing flexible direct current power network dc-side short-circuit fault
Technical field
The present invention relates to Technology of HVDC based Voltage Source Converter field, more particularly to a kind of removing flexible direct current power network dc-side short-circuit The method of failure.
Background technology
In recent years, with based on igbt (English name:Insulated Gate Bipolar Transistor, abbreviation IGBT) the flexible direct current technology of full-controlled device and the development of engineer applied, changed based on voltage-source type direct current Flow device (English full name:Voltage Source Converter, abbreviation VSC) flexible direct current electric power network technique receive increasingly More concerns.Voltage-source type DC converter has various structures, wherein modularization multi-level converter (English name:Modular Multilevel Converter, abbreviation MMC) as a kind of new voltage-source type DC converter structure, compared to tradition Low level voltage source type DC converter, have switching loss is small, switching frequency is low, to devices switch coherence request not High, modular construction is easy to extend and the advantages that suitable for high voltage occasion, is the preferred topology of following direct current network current conversion station One of scheme.
Current flexible direct current power network mainly uses and is based on semi-bridge type submodule (English name:Half Bridge Sub Module, abbreviation HBSM) modularization multi-level converter.As shown in figure 1, the modular multilevel based on semi-bridge type submodule Transverter is made up of 6 bridge arms, and each bridge arm is by a reactor L0It is in series with n semi-bridge type submodule SM1~SMn, Two bridge arms are combined together a referred to as facies unit to each phase up and down.As shown in Fig. 2 each semi-bridge type submodule includes insulation Grid bipolar transistor T1, T2, respectively with T1, T2 antiparallel diode D1, D2, and capacitor C0.By changing AM access module Change the quantity and parameter of the semi-bridge type submodule of multilevel converter, different capacity, voltage class harmony wave parameter can be met Requirement, be easy to implement Integration Design, shorten construction period, it is cost-effective.
However, there is following defect in above-mentioned modularization multi-level converter:Because the generation of flexible direct current power network DC side is short During the failure of road, feed-in short circuit current can be continued with the antiparallel diode of igbt in semi-bridge type submodule, and And the dc-side short-circuit electric current rate of climb is fast, does not possess natural zero-crossing point, cause flexible direct current power network dc-side short-circuit fault difficult To remove.Removing one of main method of flexible direct current power network dc-side short-circuit fault at present is:Use high voltage DC breaker The selective rhizotomy faulty line in several milliseconds, protection non-fault line power supply are unaffected.This method must be based on direct current Breaker successfully acts this precondition, but because current dc circuit breaker manufacturing process is immature, therefore protection be present System sends the situation of trip signal and the refusal tripping operation of dc circuit breaker failure, causes thoroughly remove short trouble, power network Middle equipment component continues to bear short circuit current.For this situation, existing Preservation tactics are that the exchange of tripping whole AC is disconnected Road device, but this can cause whole flexible direct current power network to be stopped transport, and the time restarted is longer, the utilization rate of system and power supply Reliability is relatively low.
The content of the invention
For above-mentioned the problems of the prior art, the present invention provides a kind of removing flexible direct current power network dc-side short-circuit fault Method, on the premise of avoiding whole flexible direct current power network from stopping transport, to solve short circuit caused by dc circuit breaker failure therefore The problem of barrier can not be removed thoroughly.
To reach above-mentioned purpose, the present invention adopts the following technical scheme that:
The invention provides a kind of method for removing flexible direct current power network dc-side short-circuit fault, methods described includes following Step:
S1:To whole first object dc circuit breakers send trip command, while to all the second target dc circuit breakers Standby instruction is sent with target complete AC circuit breaker;Wherein, the first object dc circuit breaker is straight on faulty line Flow breaker;The second target dc circuit breaker is connected and adjacent to institute to be connected bus with the first object dc circuit breaker State the dc circuit breaker of first object dc circuit breaker;The target AC circuit breaker be and the first object dc circuit breaker AC circuit breaker corresponding to the connected DC converter of connected bus.
S2:Detect whether each first object dc circuit breaker successfully trips in preset time, if described in whole First object dc circuit breaker successfully trips in preset time, then terminates this process;If at least one described One target dc circuit breaker does not trip successfully in preset time, then into step S3.
S3:Exchanged to the second target dc circuit breaker of the neighbouring first object dc circuit breaker to trip not successfully with target Breaker sends trip command, and the target DC converter of the neighbouring first object dc circuit breaker to trip not successfully is closed Lock, terminates this process;Wherein, the target DC converter is connected to be connected bus with the first object dc circuit breaker DC converter.
In the method for removing flexible direct current power network dc-side short-circuit fault provided by the present invention, when short trouble occurs When, dc circuit breaker (the i.e. first object dc circuit breaker) tripping operation on faulty line is controlled, if first object direct current interruption At least one does not trip successfully device in preset time, then controls and connect with the first object dc circuit breaker to trip not successfully The connected dc circuit breaker of bus, and connect the DC converter that bus is connected with the first object dc circuit breaker to trip not successfully AC circuit breaker corresponding to device trips, and controls and connect what bus was connected with the first object dc circuit breaker to trip not successfully DC converter locking, so that faulty line and the first object dc circuit breaker to trip not successfully connect bus stoppage in transit, it is real Now thoroughly remove the purpose of short trouble.Therefore, method provided by the present invention can be in the dc circuit breaker on faulty line Under the situation of failure, only fault of stop circuit and the first object dc circuit breaker to trip not successfully connect bus and just thoroughly removed Short trouble, avoid whole flexible direct current power network and stop transport, reduce power network stoppage in transit scope, improve network system utilization rate And power supply reliability.
Brief description of the drawings
In order to illustrate more clearly about the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing There is the required accompanying drawing used in technology description to be briefly described, it should be apparent that, drawings in the following description are only this Some embodiments of invention, for those of ordinary skill in the art, on the premise of not paying creative work, can be with Other accompanying drawings are obtained according to these accompanying drawings.
Fig. 1 is the topological diagram of the modularization multi-level converter based on semi-bridge type submodule;
Fig. 2 is the topological diagram of semi-bridge type submodule;
Fig. 3 is the topological diagram of the positive pole transmission system of the flexible direct current power network based on modularization multi-level converter;
Fig. 4 is the topological diagram of the negative pole transmission system of the flexible direct current power network based on modularization multi-level converter;
The flow of the method for the removing flexible direct current power network dc-side short-circuit fault that Fig. 5 is provided by the embodiment of the present invention Figure.
Embodiment
In order to facilitate the understanding of the purposes, features and advantages of the present invention, implement below in conjunction with the present invention Accompanying drawing in example, the technical scheme in the embodiment of the present invention is clearly and completely described.Obviously, described embodiment Only part of the embodiment of the present invention, rather than whole embodiments.Based on the embodiment in the present invention, the common skill in this area All other embodiment that art personnel are obtained on the premise of creative work is not made, belong to the model that the present invention protects Enclose.
It should be noted that four end flexible direct current power networks of the following embodiment based on dipolar configuration are introduced.Such as Fig. 3 It is shown, it is topological for the positive pole transmission system of the four ends flexible direct current power network, in female " P " table of the mark pre-script of its each equipment component Show the equipment component that relevant device element is positive pole transmission system;As shown in figure 4, the negative pole for the four ends flexible direct current power network is defeated Electric system topology, relevant device element setting for negative pole transmission system is represented in the mark pre-script female " N " of its each equipment component Standby element.
Referring again to Fig. 3 and Fig. 4, in the four ends flexible direct current power network monopole transmission system include four dc bus and Four DC power transmission lines (being represented with " DC "), each dc bus is connected with a DC converter respectively, the DC converter utensil Body is the modularization multi-level converter (being represented with " MMC ") based on semi-bridge type submodule, and the both ends of each DC power transmission line are equal Dc circuit breaker (being represented with " CB ") is accessed, the equal incoming transport breaker of the AC of each DC converter (is used " ACCB " in addition Represent).
Embodiment one
The present embodiment introduces the positive pole transmission of electricity that monopole ground short circuit failure, i.e. flexible direct current power network occur for flexible direct current power network When ground short circuit failure occurs for certain DC power transmission line in system or negative pole transmission system, the method for removing short trouble.
As shown in Figure 3, it is assumed that monopole ground short circuit failure occurs for protection system detectio to DC power transmission line PDC12, presses Short trouble is removed according to following methods, as shown in Figure 5:
S1:To whole first object dc circuit breakers send trip command, while to all the second target dc circuit breakers Standby instruction is sent with target complete AC circuit breaker.Wherein, first object dc circuit breaker is that the direct current on faulty line breaks Road device;To be connected with first object dc circuit breaker, bus is connected second target dc circuit breaker and neighbouring first object direct current breaks The dc circuit breaker of road device;Target AC circuit breaker by with first object dc circuit breaker the DC converter station that is connected of company's bus Corresponding AC circuit breaker.
Specific to the operating mode in the present embodiment, faulty line PDC12, faulty line is bus 1 by PDC12 even bus With bus 2.First object dc circuit breaker is PCB12 and PCB21;Second target dc circuit breaker is PCB13 and PCB24;Mesh Mark AC circuit breaker is PACCB1 and PACCB2, then step S1 is specially:To first object dc circuit breaker be PCB12 and PCB21 sends trip command, while to the second target dc circuit breaker PCB13 and PCB24, and target AC circuit breaker PACCB1 Standby instruction is sent with PACCB2.
It is pointed out that to the second target dc circuit breaker and target AC circuit breaker (hereinafter referred to as standby breaker) The purpose for sending standby instruction is the function of making standby breaker possess overcurrent protection on the spot.On the one hand, when some first During target dc circuit breaker trip operation failure, the standby circuit breaker trip near it carries out failure protection, prevents other not Related breaker malfunction, makes the scope of failure protection be only limitted to standby breaker;On the other hand when detect some or When the electric current of certain several standby proximity to circuit breakers is larger, illustrate its still faulty electric current nearby, corresponding first object direct current Breaker failure, now the standby breaker is tripped at once, rather than the current signal detected is sent into protection system, Action command is beamed back again after being judged by protection system, and this needs longer time, is unfavorable for flexible direct current power network and quickly removes event Barrier.
S2:Detect whether each first object dc circuit breaker successfully trips in preset time, if whole first objects Dc circuit breaker successfully trips in preset time, then terminates this process;If at least one first object direct current breaks Road device does not trip successfully in preset time, then into step S3.
Specific to the operating mode in the present embodiment, step S2 is specially:Whether the fault current on detection faulty line PDC12 0 is reduced in preset time, if being reduced to 0, illustrates that short trouble is removed, terminates this process.If not being reduced to 0, explanation At least one tripping operation failure in first object dc circuit breaker PCB12 and PCB21, into step S3, actuating breaker failure protection plan Slightly.
In above-mentioned steps S2, the value of preset time can be decided according to the actual requirements, for example network system needs first Target dc circuit breaker PCB12 and PCB21 successfully trip in 3ms, disengagement failure electric current, remove dc-side short-circuit fault, then Preset time can be set as 4ms, reserve certain reaction time, even detect first object dc circuit breaker PCB12 and PCB21 trips not successfully in 4ms, then actuating breaker failure protection strategy.Preferably, the span of preset time can be set as 3ms~5ms.
S3:Exchanged to the second target dc circuit breaker of the neighbouring first object dc circuit breaker to trip not successfully with target Breaker sends trip command, and the target DC converter of the neighbouring first object dc circuit breaker to trip not successfully is closed Lock, terminates this process.Wherein, target DC converter by with first object dc circuit breaker the direct current that is connected of company's bus change Flow device.
Specific to the operating mode in the present embodiment, target DC converter is PMMC1 and PMMC2.Assuming that first object direct current Breaker PCB12 trips not successfully, and step S3 is specially:To the second target dc circuit breaker PCB13, and target AC circuit breaker PACCB1 sends trip command, and by target DC converter PMMC1 lockings, makes target DC converter PMMC1 and system Isolation, so as to which bus 1 and faulty line PDC12 are stopped transport, short trouble is removed, and terminates this process.Although it is pointed out that When first object dc circuit breaker PCB12 trips not successfully, the d-c circuit breaker on DC power transmission line PDC13 PCB31 nearby can also detect larger current, but due to standby not to d-c circuit breaker PCB31 transmissions in step sl With instruction, therefore tripping operation malfunction can't occur because of overcurrent for d-c circuit breaker PCB31, so as to avoid direct current Transmission line of electricity PDC13 stops transport, and reduces the scope of system shutdown.
It should be noted that in step s3, although bus 1 is stopped transport DC power transmission line PDC13 can be caused to flow to bus 1 Electric current be 0, but the voltage on DC power transmission line PDC13 is constant, remains to other power supplys or negative accessed on circuit Lotus is powered, therefore DC power transmission line PDC13 does not stop transport.Also, bus 2, bus 3, the and of bus 4 of positive pole transmission system DC power transmission line PDC24, PDC34, and whole negative pole transmission system are not also stopped transport.That is, the failure using step S3 Preservation tactics, only stoppage in transit positive electrode bus 1 and faulty line PDC12 just can thoroughly remove short trouble, avoid whole flexibility Direct current network is stopped transport, and stoppage in transit scope is reduced, so as to improve network system utilization rate and power supply reliability.
Embodiment two
The present embodiment introduces the positive pole transmission of electricity that bipolar ground short circuit failure, i.e. flexible direct current power network occur for flexible direct current power network When corresponding to DC power transmission line in certain DC power transmission line and negative pole transmission system in system ground short circuit failure occurs, clearly Except the method for short trouble.
As shown in Figure 3 and Figure 4, it is assumed that bipolar ground connection occurs for protection system detectio to DC power transmission line PDC12 and NDC12 Short trouble, short trouble is removed in accordance with the following methods, as shown in Figure 5:
S1:It is PCB12, NCB12, PCB21 and NCB21 transmission trip command to first object dc circuit breaker, while to Second target dc circuit breaker PCB13, NCB13, PCB24 and NCB24, and target AC circuit breaker PACCB1, NACCB1, PACCB2 and NACCB2 sends standby instruction.
S2:Whether the fault current on detection faulty line PDC12 and NDC12 is reduced to 0 in preset time, if be reduced to 0, illustrate that short trouble is removed, terminate this process.If not being reduced to 0, illustrate first object dc circuit breaker PCB12, At least one tripping operation failure in NCB12, PCB21 and NCB21, into step S3, actuating breaker failure protection strategy.
Assuming that first object dc circuit breaker PCB12 trips not successfully, then:
S3:Sent to second target dc circuit breaker PCB13, NCB13, and target AC circuit breaker PACCB1, NACCB1 Trip command, and by target DC converter PMMC1, NMMC1 locking, make target DC converter PMMC1, NMMC1 with being System isolation, so as to the bus 1 of positive pole transmission system, the bus 1 of negative pole transmission system, and faulty line PDC12, NDC12 stop transport, Short trouble is removed, and terminates this process.
In the method for the removing flexible direct current power network dc-side short-circuit fault that the present embodiment is provided, work as faulty line When first object dc circuit breaker PCB12 on PDC12 trips not successfully, the only bus 1 of stoppage in transit positive pole transmission system, negative pole is defeated The bus 1 of electric system, and faulty line PDC12, NDC12 can just remove short trouble, the bus 2 of positive pole transmission system, mother Line 3, bus 4 and DC power transmission line PDC13, PDC24, PDC34, and the bus 2 of negative pole transmission system, bus 3, the and of bus 4 DC power transmission line NDC13, NDC24, NDC34 do not stop transport, and stop transport, reduce so as to avoid whole flexible direct current power network Stoppage in transit scope, so as to improve network system utilization rate and power supply reliability.
It should be noted that, although various embodiments above is introduced by taking four end flexible direct current electric network models as an example, But this method for being not offered as removing flexible direct current power network dc-side short-circuit fault provided by the present invention is only applicable to four ends Flexible direct current power network, those skilled in the art are under the enlightenment of method provided by the present invention, and having the ability, it is suitable to pass through this method When deformation application in other flexible direct current power networks for depositing technical problem involved in the introduction.
The embodiment of the present invention is the foregoing is only, but protection scope of the present invention is not limited thereto, it is any Those familiar with the art the invention discloses technical scope in, the change or replacement that can readily occur in, all should It is included within the scope of the present invention.Therefore, protection scope of the present invention should using the scope of the claims as It is accurate.

Claims (3)

  1. A kind of 1. method for removing flexible direct current power network dc-side short-circuit fault, it is characterised in that methods described includes following step Suddenly:
    S1:Trip command is sent to whole first object dc circuit breakers, while to all the second target dc circuit breakers and entirely Portion's target AC circuit breaker sends standby instruction;Wherein, the first object dc circuit breaker is that the direct current on faulty line breaks Road device;The second target dc circuit breaker is connected and neighbouring described the to be connected bus with the first object dc circuit breaker The dc circuit breaker of one target dc circuit breaker;The target AC circuit breaker is is connected with the first object dc circuit breaker AC circuit breaker corresponding to the connected DC converter of bus;
    S2:Detect whether each first object dc circuit breaker successfully trips in preset time, if whole described first Target dc circuit breaker successfully trips in preset time, then terminates this process;If at least one described first mesh Mark dc circuit breaker does not trip successfully in preset time, then into step S3;
    S3:To the second target dc circuit breaker and target alternating current interruption of the neighbouring first object dc circuit breaker to trip not successfully Device sends trip command, and by the target DC converter locking of the neighbouring first object dc circuit breaker to trip not successfully, Terminate this process;Wherein, the target DC converter by with the first object dc circuit breaker company's bus be connected DC converter.
  2. 2. the method according to claim 1 for removing flexible direct current power network dc-side short-circuit fault, it is characterised in that described The span of preset time is 3ms~5ms.
  3. 3. the method according to claim 2 for removing flexible direct current power network dc-side short-circuit fault, it is characterised in that described Preset time is 4ms.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108258727A (en) * 2018-01-24 2018-07-06 许继集团有限公司 A kind of offshore grid-connected wind farm transmission system
CN110672972A (en) * 2019-09-09 2020-01-10 华北电力大学 Fault positioning and isolating method for flexible direct current distribution network

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CN106684841A (en) * 2017-02-03 2017-05-17 许继电气股份有限公司 Flexible direct-current grid system direct-current short-circuit fault protection method and device

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CN106684841A (en) * 2017-02-03 2017-05-17 许继电气股份有限公司 Flexible direct-current grid system direct-current short-circuit fault protection method and device

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108258727A (en) * 2018-01-24 2018-07-06 许继集团有限公司 A kind of offshore grid-connected wind farm transmission system
CN110672972A (en) * 2019-09-09 2020-01-10 华北电力大学 Fault positioning and isolating method for flexible direct current distribution network

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