CN107565521B - A method of removing flexible direct current power grid dc-side short-circuit fault - Google Patents
A method of removing flexible direct current power grid dc-side short-circuit fault Download PDFInfo
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- CN107565521B CN107565521B CN201710868357.5A CN201710868357A CN107565521B CN 107565521 B CN107565521 B CN 107565521B CN 201710868357 A CN201710868357 A CN 201710868357A CN 107565521 B CN107565521 B CN 107565521B
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- circuit breaker
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Abstract
The present invention provides a kind of methods for removing flexible direct current power grid dc-side short-circuit fault, it is related to flexible DC transmission technology field, it can solve the problems, such as that short trouble caused by dc circuit breaker failure can not thoroughly remove under the premise of avoiding entire flexible direct current power grid from stopping transport.This method comprises: sending trip command to whole first object dc circuit breakers, and spare instruction is sent to all the second target dc circuit breakers and target complete AC circuit breaker；Detect whether each first object dc circuit breaker successfully trips within a preset time, if at least one first object dc circuit breaker does not trip successfully within a preset time, trip command then is sent to the second target dc circuit breaker and target AC circuit breaker of the neighbouring breaker not tripped, and the target DC converter of the neighbouring breaker not tripped is latched.The above method is applied in the flexible direct current power grid based on modularization multi-level converter.
Description
Technical field
The present invention relates to flexible DC transmission technology field more particularly to a kind of removing flexible direct current power grid dc-side short-circuits
The method of failure.
Background technique
In recent years, with based on insulated gate bipolar transistor (English name: Insulated Gate Bipolar
Transistor, abbreviation IGBT) the flexible direct current technology of full-controlled device and the development of engineer application, it is changed based on voltage-source type direct current
The flexible direct current electric power network technique of stream device (full name in English: Voltage Source Converter, abbreviation VSC) receives increasingly
More concerns.Voltage-source type DC converter is there are many structure, wherein modularization multi-level converter (English name: Modular
Multilevel Converter, abbreviation MMC) as a kind of novel 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
The advantages that high, modular construction is convenient for extending and being suitable for high voltage occasion, is the preferred topology of the following DC grid converter station
One of scheme.
Current flexible direct current power grid is mainly using 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
Inverter is made of 6 bridge arms, and each bridge arm is by a reactor L0It is connected in series with n semi-bridge type submodule SM1~SMn,
Two bridge arms are combined together a referred to as phase element 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
The quantity and parameter for changing the semi-bridge type submodule of multilevel converter, can satisfy different capacity, voltage class and harmonic parameters
Requirement, be easy to implement Integration Design, shorten construction period, save the cost.
However, above-mentioned modularization multi-level converter has following defects that since the generation of flexible direct current power grid DC side is short
When the failure of road, feed-in short circuit current can be continued with the antiparallel diode of insulated gate bipolar transistor in semi-bridge type submodule, and
And the dc-side short-circuit electric current rate of climb is fast, does not have natural zero-crossing point, causes flexible direct current power grid dc-side short-circuit fault difficult
To remove.One of the main method of flexible direct current power grid dc-side short-circuit fault is removed at present are as follows: uses 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 since current dc circuit breaker manufacturing process is immature, there is protection
System issues the situation of trip signal and the refusal tripping of dc circuit breaker failure, leads to that short trouble cannot be thoroughly removed, power grid
Middle equipment component continues to bear short circuit current.For this situation, existing Preservation tactics are that all exchange top-cross stream is disconnected for tripping
Road device, but this will lead to entire flexible direct current power grid and stops transport, and the time restarted is longer, the utilization rate and power supply of system
Reliability is lower.
Summary of the invention
For above-mentioned the problems of the prior art, the present invention provides a kind of removing flexible direct current power grid dc-side short-circuit fault
Method, it is former to solve short circuit caused by dc circuit breaker failure under the premise of avoiding entire flexible direct current power grid from stopping transport
The problem of barrier can not thoroughly remove.
In order to achieve the above objectives, the present invention adopts the following technical scheme:
The present invention provides a kind of methods for removing flexible direct current power grid dc-side short-circuit fault, and the method includes following
Step:
S1: to whole first object dc circuit breakers send trip command, while to all the second target dc circuit breakers
Spare 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 to be connected bus with the first object dc circuit breaker adjacent to institute
State the dc circuit breaker of first object dc circuit breaker；The target AC circuit breaker be and the first object dc circuit breaker
The connected corresponding AC circuit breaker of DC converter of connected bus.
S2: whether each first object dc circuit breaker of detection successfully trips within a preset time, if described in whole
First object dc circuit breaker successfully trips within a preset time, then terminates this process；If at least one described
One target dc circuit breaker does not trip successfully within a preset time, then enters step S3.
S3: it is 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 provided by the present invention for removing flexible direct current power grid dc-side short-circuit fault, when short trouble occurs
When, dc circuit breaker (the i.e. first object dc circuit breaker) tripping on faulty line is controlled, if first object direct current interruption
At least one does not trip successfully device within a preset time, then the company, first object dc circuit breaker institute for controlling and tripping not successfully
The connected dc circuit breaker of bus, and the DC converter being connected with the connected bus of first object dc circuit breaker to trip not successfully
Device corresponding AC circuit breaker tripping, and control and be connected with the connected bus of first object dc circuit breaker to trip not successfully
DC converter locking, so that the connected bus of first object dc circuit breaker for making faulty line and tripping not successfully is stopped transport, 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 route and the connected bus of first object dc circuit breaker to trip not successfully are just thoroughly removed
Short trouble avoids entire flexible direct current power grid and stops transport, reduces power grid stoppage in transit range, improve network system utilization rate
And power supply reliability.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
Some embodiments of invention for those of ordinary skill in the art without creative efforts, can be with
Other attached drawings are obtained according to these attached 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 transmission system of the flexible direct current power grid based on modularization multi-level converter；
Fig. 4 is the topological diagram of the cathode transmission system of the flexible direct current power grid based on modularization multi-level converter；
Fig. 5 is the process that the method for flexible direct current power grid dc-side short-circuit fault is removed provided by the embodiment of the present invention
Figure.
Specific embodiment
In order to make the foregoing objectives, features and advantages of the present invention clearer and more comprehensible, implement below in conjunction with the present invention
Attached drawing in example, technical scheme in the embodiment of the invention is clearly and completely described.Obviously, described embodiment
Only a part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, the common skill in this field
Art personnel all other embodiment obtained without creative labor belongs to the model that the present invention protects
It encloses.
It should be noted that following embodiment is introduced based on four end flexible direct current power grids of dipolar configuration.Such as Fig. 3
It is shown, it is topological for the positive transmission system of the four ends flexible direct current power grid, in female " P " table of the mark pre-script of its each equipment component
Show that relevant device element is the equipment component of positive transmission system；As shown in figure 4, the cathode for the four ends flexible direct current power grid is defeated
Electric system topology indicates that relevant device element is setting for cathode transmission system 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 grid monopole transmission system include four DC bus and
Four DC power transmission lines (being indicated with " DC "), each DC bus is connected with a DC converter respectively, the DC converter utensil
Body is the modularization multi-level converter (being indicated with " MMC ") based on semi-bridge type submodule, and the both ends of each DC power transmission line are equal
Dc circuit breaker (being indicated with " CB ") is accessed, in addition the exchange side of each DC converter is accessed AC circuit breaker and (used " ACCB "
It indicates).
Embodiment one
The present embodiment introduces flexible direct current power grid and monopole ground short circuit failure, i.e. the anode transmission of electricity of flexible direct current power grid occurs
When ground short circuit failure occurs for certain DC power transmission line in system or cathode 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 detection 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
Spare instruction is sent with target complete AC circuit breaker.Wherein, first object dc circuit breaker is that the direct current on faulty line is disconnected
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 is disconnected
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 condition 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 specifically: 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
Spare instruction is sent with PACCB2.
It should be pointed out that the second target dc circuit breaker and target AC circuit breaker (hereinafter referred to as spare breaker)
The purpose for sending spare instruction is the function of making spare breaker have overcurrent protection on the spot.On the one hand, when some first
When target dc circuit breaker trip operation failure, near spare circuit breaker trip carry out failure protection, prevent other not
Relevant breaker malfunction, makes the range of failure protection be only limitted to spare breaker；On the other hand when detect some or
When the electric current of certain several spare proximity to circuit breakers is larger, illustrate its still faulty electric current nearby, corresponding first object direct current
Breaker failure, the current signal that the spare breaker trips at once, rather than will test at this time are sent to protection system,
By sending back to action command again after the judgement of protection system, this is takeed a long time, and is unfavorable for flexible direct current power grid and is quickly removed event
Barrier.
S2: detecting whether each first object dc circuit breaker successfully trips within a preset time, if whole first objects
Dc circuit breaker successfully trips within a preset time, then terminates this process；If at least one first object direct current is disconnected
Road device does not trip successfully within a preset time, then enters step S3.
Specific to the operating condition in the present embodiment, step S2 specifically: whether the fault current on detection faulty line PDC12
It is reduced to 0 within a 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 failure, enters step S3, actuating breaker failure protection plan in first object dc circuit breaker PCB12 and PCB21
Slightly.
In above-mentioned steps S2, the value of preset time be can be determined according to actual needs, 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 value range of preset time can be set as
3ms~5ms.
S3: it is 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 condition in the present embodiment, target DC converter is PMMC1 and PMMC2.Assuming that first object direct current
Breaker PCB12 trips not successfully, step S3 specifically: to the second target dc circuit breaker PCB13 and target AC circuit breaker
PACCB1 sends trip command, and target DC converter PMMC1 is latched, and makes target DC converter PMMC1 and system
Isolation, so that bus 1 and faulty line PDC12 stop transport, short trouble is removed, and terminates this process.Although being pointed out that
D-c circuit breaker when first object dc circuit breaker PCB12 trips not successfully, on DC power transmission line PDC13
PCB31 nearby can also detect larger current, but standby due to not sending in step sl to d-c circuit breaker PCB31
With instruction, therefore tripping 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 range of system shutdown.
It should be noted that in step s3, although the stoppage in transit of bus 1 will lead to DC power transmission line PDC13 and flow to bus 1
Electric current be 0, but the voltage on DC power transmission line PDC13 is constant, remains to other power supplys accessed on route or negative
Lotus power supply, therefore there is no stop transport by DC power transmission line PDC13.Also, bus 2, bus 3,4 and of bus of positive transmission system
DC power transmission line PDC24, PDC34, and entire cathode transmission system are not also stopped transport.That is, utilizing the failure of step S3
Preservation tactics, only stoppage in transit positive electrode bus 1 and faulty line PDC12 can thoroughly remove short trouble, avoid entire flexibility
DC grid is stopped transport, and stoppage in transit range is reduced, to improve network system utilization rate and power supply reliability.
Embodiment two
The present embodiment introduces flexible direct current power grid and bipolar ground short circuit failure, i.e. the anode transmission of electricity of flexible direct current power grid occurs
When corresponding to DC power transmission line in certain DC power transmission line and cathode 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 detection to DC power transmission line PDC12 and NDC12
Short trouble removes short trouble in accordance with the following methods, as shown in Figure 5:
S1: being 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 spare instruction.
S2: whether the fault current on detection faulty line PDC12 and NDC12 is reduced to 0 within a preset time, if be reduced to
0, illustrate that short trouble is removed, terminates this process.If not being reduced to 0, illustrate first object dc circuit breaker PCB12,
At least one tripping failure, enters step S3, actuating breaker failure protection strategy in NCB12, PCB21 and NCB21.
Assuming that first object dc circuit breaker PCB12 trips not successfully, then:
S3: it is sent to second target dc circuit breaker PCB13, NCB13 and target AC circuit breaker PACCB1, NACCB1
Trip command, and target DC converter PMMC1, NMMC1 are latched, make target DC converter PMMC1, NMMC1 and is
System isolation, thus the bus 1 of positive transmission system, the bus 1 and faulty line PDC12, NDC12 of cathode transmission system are stopped transport,
Short trouble is removed, this process is terminated.
In the method for removing flexible direct current power grid dc-side short-circuit fault provided by the present embodiment, work as faulty line
When first object dc circuit breaker PCB12 on PDC12 trips not successfully, the bus 1 for positive transmission system of only stopping transport, cathode is defeated
The bus 1 and faulty line PDC12, NDC12 of electric system can remove short trouble, the bus 2 of positive transmission system, mother
Line 3, bus 4 and DC power transmission line PDC13, PDC24, PDC34 and the bus of cathode transmission system 2, bus 3,4 and of bus
DC power transmission line NDC13, NDC24, NDC34 do not stop transport, and so as to avoid the stoppage in transit of entire flexible direct current power grid, reduce
Stoppage in transit range, to improve network system utilization rate and power supply reliability.
It should be noted that, although the above various embodiments is introduced by taking four end flexible direct current electric network models as an example,
But this is not offered as the method provided by the present invention for removing flexible direct current power grid dc-side short-circuit fault and is only applicable to four ends
Flexible direct current power grid, those skilled in the art have the ability to pass through this method suitable under the enlightenment of method provided by the present invention
When deformation application in other flexible direct current power grids there are technical problem involved in background technique.
The foregoing is merely a specific embodiment of the invention, but scope of protection of the present invention is not limited thereto, any
In the technical scope disclosed by the present invention, any changes or substitutions that can be easily thought of by those familiar with the art, all answers
It is included within the scope of the present invention.Therefore, protection scope of the present invention should be with the scope of protection of the claims
It is quasi-.
Claims (3)
1. a kind of method for removing flexible direct current power grid dc-side short-circuit fault, which is characterized in that the method includes following steps
It is rapid:
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 spare instruction；Wherein, the first object dc circuit breaker is that the direct current on faulty line is disconnected
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 for company, the first object dc circuit breaker institute
The connected corresponding AC circuit breaker of DC converter of bus；
S2: whether each first object dc circuit breaker of detection successfully trips within a preset time, if whole described first
Target dc circuit breaker successfully trips within a preset time, then terminates this process；If at least one described first mesh
Mark dc circuit breaker does not trip successfully within a preset time, then enters 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 the target DC converter of the neighbouring first object dc circuit breaker to trip not successfully is latched,
Terminate this process；Wherein, the target DC converter by with the first object dc circuit breaker company's bus be connected
DC converter.
2. the method according to claim 1 for removing flexible direct current power grid dc-side short-circuit fault, which is characterized in that described
The value range of preset time is 3ms~5ms.
3. the method according to claim 2 for removing flexible direct current power grid dc-side short-circuit fault, which is characterized in that described
Preset time is 4ms.
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| CN201710868357.5A CN107565521B (en) | 2017-09-22 | 2017-09-22 | A method of removing flexible direct current power grid dc-side short-circuit fault |
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| 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 |
| CN110672972B (en) * | 2019-09-09 | 2021-05-04 | 华北电力大学 | Fault positioning and isolating method for flexible direct current distribution network |
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| CN204118714U (en) * | 2014-06-21 | 2015-01-21 | 中国能源建设集团广东省电力设计研究院 | The alternating current-direct current mating protection device of flexible direct current transmission converter station circuit breaker |
| 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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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN204118714U (en) * | 2014-06-21 | 2015-01-21 | 中国能源建设集团广东省电力设计研究院 | The alternating current-direct current mating protection device of flexible direct current transmission converter station circuit breaker |
| 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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| 直流电网中直流断路器失灵保护方案研究;彭发喜 等;《机电工程》;20170820;第34卷(第8期);908-910 |
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