CN106936120B - A kind of DC grid line fault protection method - Google Patents
A kind of DC grid line fault protection method Download PDFInfo
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- CN106936120B CN106936120B CN201511021554.0A CN201511021554A CN106936120B CN 106936120 B CN106936120 B CN 106936120B CN 201511021554 A CN201511021554 A CN 201511021554A CN 106936120 B CN106936120 B CN 106936120B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/265—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured making use of travelling wave theory
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/268—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for dc systems
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Abstract
The present invention relates to a kind of DC grid line fault protection methods; it include: each measurement point travelling wave signal of real-time monitoring; if reaching the given threshold of protection; the then corresponding dc circuit breaker of tripping; final all breakers of tripping realize the separation of 3 direct current subsystems, and switch the control model of each subsystem converter station.By fault location logic, judgement is in subsystem area or external area error for the traveling wave obtained according to measurement point and each subsystem.If fault location logic judgment is subsystem external failure, guilty culprit route is determined according to fault location logic；Otherwise it is determined as subsystem internal failure.According to scheduling system command, change the control model and power control instruction of each converter station.The time required to technical solution of the present invention effectively shortens fault location, while DC grid is reduced as far as possible and is latched the transfer of bring power and its influence to ac and dc systems stability on a large scale.The method proposed will not can not be applicable in the complication of DC grid structure.
Description
Technical field
The present invention relates to a kind of fault protecting methods of electric system DC grid technology, and in particular to a kind of DC grid
Line fault protection method.
Background technique
DC grid interconnects the energy transmission system formed, international conference on large HV electric systems by a large amount of DC terminals with DC form
(CIGRE) tissue is for the definition of DC grid: the DC network being made of the converter of multiple netted and radial connection,
It is the Important Platform for implementing new energy strategy and optimization energy resources configuration, covers the links such as transmission of electricity, power transformation, distribution,
Using advanced HVDC Transmission Technology, it can be achieved that the access technology of extensive renewable energy power generation and large capacity are defeated over long distances
It send, improves efficiency of energy utilization, it is ensured that safe and reliable, good power supply.DC grid is there is no AC network intrinsic
Synchronism stability problem, transmission range is substantially unrestricted, can be realized large-scale power flow regulating and control, to renewable energy
Power generation has significant supporting role, and many merits such as small, small to Communication Jamming with via net loss.With the voltage-source type change of current
The development of the technologies such as device, dc circuit breaker, DC converter, direct current cables is increasingly mature, and DC grid technology develops into
May, and in the access of large-scale distributed renewable energy, the power supply of ocean archipelago, send out in marine wind electric field cluster, novel
Urban distribution network building etc., it is considered to be most effective technical solution, it has also become the important directions of the following smart grid development.
DC grid is also required to construct complete protection system to meet the requirement that it runs steadily in the long term.In general,
DC grid needs to realize fault fast positioning, isolation and protection act in 5ms, to prevent locking system collapse.However, compared to
AC system, direct current system damping is much smaller, and fault progression process is faster, higher to requirements such as protection quick-action, selectivity；
On the other hand, compared to two-terminal direct current transmission system, the increase of DC grid route and the complication of grid structure are so that right
Line fault protection demand and require it is higher and higher, existing both ends direct current protecting technology no longer be applicable in.
Specifically, needing to realize the quick positioning of failure within milliseconds firstly, since system damping is low；Meanwhile
Under certain failures, adjacent lines fault stress difference is little, and fault location difficulty further increases.Secondly, in order to guarantee to change
The safety for flowing valve equipment needs to realize that the quick of larger fault current inhibits even in several milliseconds, however according to module
Change multilevel converter, its fault current climbing is up to 5kA/ms under DC bipolar short trouble.Again, circuit network
Cause each branch trouble unbalanced stress to weigh, dc circuit breaker configuration difficulty is caused to increase.Finally, DC grid protection includes the change of current
It stands, the plurality of devices protection such as DC line, bus, various kinds of equipment main protection and back-up protection design and need to redesign；In addition,
The requirements such as various kinds of equipment protection timing are not quite similar, and protection cooperation difficulty is larger.
In view of the Protective strategy of the equipment such as in converter station is relatively mature, the existing research of DC grid is had focused largely on
DC line fault positioning and the protection cooperation of converter station etc..And for DC grid line fault positioning etc.
The existing research achievement of multi-terminal direct current transmission system is used for reference in research mostly.
" time-domain fault location method of multibranch direct current line in multiterminal direct current power transmission system " of Song Guobing, Cai Xinlei et al.
(application number: 201110350573.3), propose a kind of time domain Fault Locating Method of multi-terminal direct current transmission system branch route.
This method is based on distributed parameter model, determines fault branch by calculating comparison circuit end points voltage, then pass through all sound branch
Road voltage and current and another electrical quantity of fault branch realize fault location.However, it is desirable to be pointed out that this method needs will be each
Branch measuring point electrical quantity is collected to fault location protective device and position of failure point is calculated and determined, and substantially still falls within both-end event
Hinder localization method, therefore there are certain call duration times, not in favor of the quick positioning of realization fault point.
" a kind of Modular multi-level multi-terminal flexible direct current system direct current fault handling method " of Lin Chang, He Zhiyuan et al.
(application number: 201210537259.0), propose a kind of inspection bipolar suitable for multi-terminal flexible direct current system direct current, monopole failure
Survey and processing method.This method passes through the power information at real-time detection DC line both ends, passes through the current difference between comparison both ends
The difference of other and positive and negative line voltage cooperates realization to determine faulty line and fault category, then by the locking with inverter
The reconstruction of system.It can be seen that this method is unfavorable for direct current there is still a need for real-time detection, the electrical quantity at comparison route both ends
The fast quick-recovery of net.
" a kind of method of discrimination and device of the fault branch of multiterminal element route protection " of Shi Shihong, Jia Hongzhou et al.
(application number: 201410016024.6), propose guard method and the device of a kind of conventional multiterminal element line fault.Its failure
Localization method is by building travelling waves function, to judge that route occurs for failure.However, this method is with glazing bar branch wave impedance
Condition premised on identical has ignored influence of the velocity of wave to traveling wave detector；In addition, there is still a need for compare each converter station traveling wave for this method
Reach the time, however it remains arbitration unit and longer communication delay；Finally, with the complexity of direct current system line construction
Change, it is still necessary to further verify for the applicability of this method.
The shortcoming of existing DC grid line fault protection method can be summarized as two o'clock: first, there are longer logical
News delay, is unfavorable for the realization of fast failure positioning；Second, the protection of large-scale direct current power grid can not be suitable on implementation
Application demand.
Summary of the invention
To solve above-mentioned deficiency of the prior art, the object of the present invention is to provide a kind of DC grid line fault protections
Method, the time required to effectively shortening fault location using subsystem partition protecting structure and the traveling wave method without communication delay,
It reduces DC grid as far as possible simultaneously and is latched the transfer of bring power and its influence to ac and dc systems stability on a large scale.
The method proposed will not can not be applicable in the complication of DC grid structure.
The purpose of the present invention is adopt the following technical solutions realization:
The present invention provides a kind of DC grid line fault protection method, and the DC grid includes converter station #1, #2, #
3, #4 and #5 and its corresponding DC bus B1, B2, B3, B4 and B5, DC power transmission line L12、L15、L25、L45And L23, direct current
Breaker DB12、DB21、DB15、DB51、DB25And DB52And electric signal measuring device；The DC power transmission line L12Respectively
It is connect with DC bus B1 and B2；The DC power transmission line L15It is connect respectively with DC bus B1 and B5；The direct current transportation
Route L25It is connect respectively with DC bus B2 and B5；The DC power transmission line L45It is connect respectively with DC bus B4 and B5；Institute
State DC power transmission line L23It is connect respectively with DC bus B2 and B3；The DC grid is divided into 3 direct current subsystems, point
It Wei subsystem 1: including converter station #1, dc circuit breaker DB12And DB15And corresponding electric signal measuring device；Subsystem
2: including converter station #2 and #3, dc circuit breaker DB21And DB25And corresponding electric signal measuring device；Subsystem 3: including
Converter station #3, #4, dc circuit breaker DB51And DB52And corresponding electric signal measuring device；Electric signal measuring device is used
In measurement travelling wave signal；
The guard method includes the following steps:
(1) travelling wave signal of real-time monitoring measurement point, if reaching the given threshold of travelling wave signal protection, tripping is corresponding
Dc circuit breaker, final all dc circuit breakers of tripping realize the separation of 3 direct current subsystems, and switch subsystem converter station
Control model；Given threshold carries out comprehensive determination by route traveling wave each during failure；
(2) travelling wave signal and subsystem obtained according to measurement point judges that failure is subsystem by fault location logic
System troubles inside the sample space or external area error；Fault location logic, that is, fault location algorithm, including use Travelling Wave Fault Location algorithm, i.e.,
Guilty culprit route is determined by wavefront size and polarity；
(3) it if it is external area error that fault location logic judgment, which is subsystem, is determined further according to fault location logic
Guilty culprit route；Otherwise it is determined as subsystem troubles inside the sample space；
(4) if failure is subsystem external area error, and it is positioned at faulty line L12, then re-closed after setting time non-
Faulty line dc circuit breaker DB15、DB51、DB25And DB52；If failure is subsystem troubles inside the sample space, and is positioned at faulty line
L23, then the corresponding dc circuit breaker DB of non-faulting subsystem is overlapped after setting time15、DB51、DB12And DB52；
(5) according to scheduling system command, change the control model and power control instruction of converter station.
Further, in the step (1), the travelling wave signal includes voltage and current travelling wave signal, respectively voltage
Travelling wave signal S1、S2And S5And current traveling wave signal S12、S21、S15、S51、S25、S52、S54And S23, using wavelet transformation analysis
Method extracts the characteristic component of traveling wave；It is separated by forward and reverse traveling wave, and Cubic Spline Wavelet Transform is carried out to backward-travelling wave
It decomposes and extracts characteristic component；
The given threshold of the travelling wave signal protection, needs to comprehensively consider the influence of different faults type and abort situation,
And meet the requirement of subsystem reliable separation under step (1) each failure；
The control model of the switching subsystem converter station is the DC voltage stability to guarantee subsystem, and final result is
Each subsystem at least 1 converter station participates in the control of the subsystem DC voltage.
Further, in the step (2), fault location logic are as follows: come by comparing the size and polarity of initial traveling wave
Judgement is subsystem troubles inside the sample space or external area error；When the initial traveling wave signal polarity of electric current is identical, and with route traveling wave in area
Signal polarity is on the contrary, then judge subsystem for troubles inside the sample space；
The initial polarity of traveling wave of each electric current of subsystem on the contrary, and negative polarity amplitude is about 2 times of positive polarity amplitude, then judge
Subsystem is external area error.
Further, in the step (3), in the step (3), for route L12, the initial traveling wave of 1 electric current of subsystem
S12Polarity is anti-, the initial traveling wave S of electric current15It is positive, and the initial traveling wave S of electric current12Wave head amplitude is S15About 2 times, then judge failure
For external area error, and failure is located at route L12；For route L25, the initial traveling wave S of the electric current of subsystem 221Polarity is anti-, electric current
Initial traveling wave S25It is positive, and the initial traveling wave S of electric current21Wave head amplitude is S25About 2 times, then judge failure for external area error, and therefore
Barrier is located at route L25；For route L15, the initial traveling wave S of the electric current of subsystem 351Polarity is anti-, the initial traveling wave S of electric current52It is positive,
And the initial traveling wave S of electric current51Wave head amplitude is S52About 2 times, then judge failure for external area error, and failure is located at route L15。
Further, in the step (4), for subsystem 1, if the initial travelling wave signal S of electric current12And S15Polarity is identical
It is then troubles inside the sample space, is otherwise external area error；For subsystem 2, if the initial travelling wave signal S of electric current21、S25With approximate wave
Head amplitude and identical polarity of traveling wave, and with travelling wave signal S23Polarity on the contrary, be then determined as troubles inside the sample space, be otherwise outside area therefore
Barrier；For subsystem 3, if the initial travelling wave signal S of electric current51、S52With approximate wave head amplitude and identical polarity of traveling wave,
And with travelling wave signal S54Polarity is otherwise external area error on the contrary, be then determined as troubles inside the sample space；
Subsystem restores setting time delay and is adjusted according to the operating status of fault condition and dc circuit breaker；If
It fixes time as 5ms；The dc circuit breaker reclosing action signal is generated by the logic based on each measuring point signal of local converter station,
It is generated including fault distinguishing logic outside area's inner region.
Further, in the step (5), the control model refers to DC voltage control and active power controller；Institute
It states power control instruction and refers to that active power controller instructs.
Compared with the immediate prior art, the excellent effect that technical solution provided by the invention has is:
A kind of DC grid line fault protection method provided by the present invention is protected using the traveling wave fault based on local signal
Shield and Fault Locating Method, avoid causes the converter station long period to bear overvoltage or overcurrent because fault location time is longer
Stress.Meanwhile using subsystem partition protecting strategy, on the one hand facilitate quickly isolating for malfunctioning sub-system；On the other hand then
The continuous service that ensure that DC grid system as far as possible reduces the shadow stopped transport by total system to ac and dc systems stability
It rings.The advantages of present invention designs is summarized as follows:
(1) traveling wave fault protection and Fault Locating Method based on local signal are used, is avoided because of fault location time
It is longer that the converter station long period is caused to bear overvoltage or overcurrent stress；
(2) subsystem partition protecting strategy is used, quickly isolating for malfunctioning sub-system is realized；
(3) continuous service that ensure that DC grid system as far as possible is reduced because total system is stopped transport to ac and dc systems
The influence of stability.
(4) guard method can be extended to more massive DC grid, will not reduce because of the change of DC grid structure
Its applicability.
Detailed description of the invention
Fig. 1 is five end provided by the invention DC grid topology and partition protecting schematic diagram；
Fig. 2 is the flow chart of DC grid line fault protection method provided by the invention.
Specific embodiment
Specific embodiments of the present invention will be described in further detail with reference to the accompanying drawing.
The following description and drawings fully show specific embodiments of the present invention, to enable those skilled in the art to
Practice them.Other embodiments may include structure, logic, it is electrical, process and other change.Embodiment
Only represent possible variation.Unless explicitly requested, otherwise individual component and function are optional, and the sequence operated can be with
Variation.The part of some embodiments and feature can be included in or replace part and the feature of other embodiments.This hair
The range of bright embodiment includes equivalent obtained by the entire scope of claims and all of claims
Object.Herein, these embodiments of the invention can individually or generally be indicated that this is only with term " invention "
For convenience, and if in fact disclosing the invention more than one, the range for being not meant to automatically limit the application is to appoint
What single invention or inventive concept.
The present invention provides five end DC grid topology of one kind as shown in Figure 1 comprising 5 converter stations (#1, #2, #3, #4
And #5), 5 DC bus (B1, B2, B3, B4 and B5) and 5 DC power transmission line (L12、L15、L25、L45And L23), wherein changing
Current more modularization multi-level converter (the Modular Multilevel of prevalence in the world that stream station uses
Converter, MMC), submodule (Sub Module) is semibridge system structure (HalfBridge).Converter station #1, #2 and #3 and straight
Flow Line L12、L15And L25Constitute one it is mesh-structured, any route, which exits, not will lead to converter station #1, #2 or #3
It is detached from power grid.The DC power transmission line L12It is connect respectively with DC bus B1 and B2；The DC power transmission line L15Respectively with
DC bus B1 is connected with B5；The DC power transmission line L25It is connect respectively with DC bus B2 and B5；The DC transmission line
Road L45It is connect respectively with DC bus B4 and B5；The DC power transmission line L23It is connect respectively with DC bus B2 and B3；It is each straight
Flow Line has been equipped with 6 sets of dc circuit breaker (DB12、DB21、DB15、DB51、DB25And DB52) and its protection surveyed with electric signal
Measure device.Wherein, electric signal measuring device is mainly used for measuring the signals (S such as traveling wave1、S2、S5、S12、S21、S15、S51、S25、
S52、S54And S23), to determine the instruction of cut-offfing of dc circuit breaker, current traveling wave is referred to flow out converter station as positive direction.Respectively
Dc circuit breaker and measuring device are integrated in respectively in 3 converter stations corresponding with bus B1, B2 and B5.Entire 5 end direct current
Net is divided into 3 systems, respectively subsystem 1 (only including converter station #1 and its corresponding dc circuit breaker and measuring device),
Subsystem 2 (including converter station #2, #3 and its corresponding dc circuit breaker and measuring device) and subsystem 3 (include converter station #
3, #4 and its corresponding dc circuit breaker and measuring device).
Related description is carried out to the DC grid partition protecting method detailed step in conjunction with Fig. 1:
(1) each measurement point travelling wave signal of real-time monitoring, if reaching the given threshold of protection, the corresponding direct current interruption of tripping
Device, final all breakers of tripping realize the separation of 3 direct current subsystems, and switch the control model of each subsystem converter station.
Travelling wave signal described in step (1) includes voltage and current travelling wave signal, can be using existing wavelet transformation etc.
Analysis method extracts the characteristic component of traveling wave.
Protection threshold value described in step (1), needs to comprehensively consider the influence of different faults type and abort situation, and meets
The requirement of subsystem reliable separation under step (1) each failure.
Each subsystem converter station control model of switching is in order to which the DC voltage for guaranteeing the system is steady described in step (1)
Fixed, final result is the control that each subsystem at least 1 converter station participates in the subsystem DC voltage.
(2) according to the traveling wave that obtains of each measurement point and each subsystem by fault location logic, judgement is subsystem
In area or external area error.
The outer fault distinguishing of subsystem area inner region described in step (2) can come true by comparing the size and polarity of initial traveling wave
It is fixed: for subsystem 1, if the initial traveling wave S of electric current12、S15Identical polarity is then troubles inside the sample space, is otherwise external area error；For son
System 2 is, if the initial traveling wave S of electric current21、S25With approximate wave head amplitude and identical polarity of traveling wave, and and S23Polarity phase
Instead, then it is determined as line fault in area (such as F2), is otherwise external area error；For subsystem 3, if the initial travelling wave signal of electric current
S51、S52With approximate wave head amplitude and identical polarity of traveling wave, and with travelling wave signal S54Polarity is on the contrary, be then determined as area
Otherwise internal fault is external area error；
(3) if fault location logic judgment is subsystem external failure, event is determined further according to fault location logic
Route where barrier；Otherwise it is determined as subsystem internal failure.
The method of external area error route is further determined that described in step (3): with route L12For, at the beginning of 1 electric current of subsystem
Begin wave S12Polarity is anti-, S15It is positive, and S12Wave head amplitude is S152 times or so, then failure is located at route (such as failure
F1)；Similarly, according to the initial traveling wave S of the electric current of subsystem 221And S25Also guilty culprit route is determined；After failure F1 generation, son
The initial traveling wave S of 3 electric current of system51And S52Difference is little.All other routes failure has similar differentiation logic.
(4) if failure is subsystem external failure, and it is positioned at faulty line L12(such as failure F1), then restore according to system
Logic after setting time (5ms or so) re-closes non-fault line dc circuit breaker DB15、DB51、DB25And DB52；If failure
For subsystem internal failure (such as failure F2 of subsystem 2), then logic (5ms or so) weight after setting time is restored according to system
Close the corresponding dc circuit breaker DB of closure non-faulting subsystem15、DB51、DB12And DB52。
System described in step (4) restore setting delay can according to the operating status of fault condition and dc circuit breaker into
Row appropriateness is adjusted.Sufficiently let out energy if low current fault or dc circuit breaker arrester, then the setting time can suitably be compressed,
To be further reduced system recovery time.
Dc circuit breaker reclosing action signal described in step (4) is by the logic based on each measuring point signal of local converter station
It generates, long-time communication delay is not present.
(5) according to scheduling system command, change the control model and power control instruction of each converter station.
Control model described in step (5) refers to DC voltage control and active power controller；The power control refers to
Order is primarily referred to as active power controller instruction.
Illustrate be if without the outer fault distinguishing logic of step (2) area's inner region, just can not be to faulty line
It is accurately cut off, and realizes the reconstruction of direct current system；If there is the outer fault distinguishing logic of step (2) area's inner region
It lays the foundation for further determining that for faulty line.
What is illustrated is that just cannot achieve if further positioned without step (3) the external area error route to event
Hinder the accurate excision of route, and then the selectivity of protection can be reduced；If there is step (3) the external area error route is further fixed
Position, maximizing guarantee the integrality of direct current system.
The present invention proposes a kind of DC grid line fault point on the basis of existing DC circuit protection technique is studied
Area's guard method.According to ac and dc systems design requirement, the configuration of direct current system subdivision and dc circuit breaker is realized；Using
The methods of traveling-wave protection realizes that the subregion of fault point substantially positions, and the quick separating of subsystem is realized by dc circuit breaker；Most
Afterwards, closure non-fault line dc circuit breaker realizes re-establishing for DC grid.The present invention uses subsystem partition protecting knot
The time required to structure and the traveling wave method without communication delay effectively shorten fault location, while it is big to reduce DC grid as far as possible
Range is latched the transfer of bring power and its influence to ac and dc systems stability.The method proposed will not be with DC grid
The complication of structure and can not be applicable in.
The above embodiments are merely illustrative of the technical scheme of the present invention and are not intended to be limiting thereof, although referring to above-described embodiment pair
The present invention is described in detail, those of ordinary skill in the art still can to a specific embodiment of the invention into
Row modification perhaps equivalent replacement these without departing from any modification of spirit and scope of the invention or equivalent replacement, applying
Within pending claims of the invention.
Claims (6)
1. a kind of DC grid line fault protection method, the DC grid includes converter station #1, #2, #3, #4 and #5, and its
Corresponding DC bus B1, B2, B3, B4 and B5, DC power transmission line L12、L15、L25、L45And L23, dc circuit breaker DB12、
DB21、DB15、DB51、DB25And DB52And electric signal measuring device；The DC power transmission line L12Respectively with DC bus
B1 is connected with B2；The DC power transmission line L15It is connect respectively with DC bus B1 and B5；The DC power transmission line L25Respectively
It is connect with DC bus B2 and B5；The DC power transmission line L45It is connect respectively with DC bus B4 and B5；The direct current transportation
Route L23It is connect respectively with DC bus B2 and B3；The DC grid is divided into 3 direct current subsystems, respectively subsystem
1: including converter station #1, dc circuit breaker DB12And DB15And corresponding electric signal measuring device；Subsystem 2: including the change of current
Stand #2 and #3, dc circuit breaker DB21And DB25And corresponding electric signal measuring device；Subsystem 3: including converter station #4, #
5, dc circuit breaker DB51And DB52And corresponding electric signal measuring device；Electric signal measuring device is for measuring traveling wave
Signal；
The guard method includes the following steps:
(1) travelling wave signal of real-time monitoring measurement point, if reaching the given threshold of travelling wave signal protection, the corresponding direct current of tripping
Breaker, final all dc circuit breakers of tripping realize the separation of 3 direct current subsystems, and switch the control of subsystem converter station
Mode；Given threshold carries out comprehensive determination by route traveling wave each during failure；
(2) travelling wave signal and subsystem obtained according to measurement point judges that failure is subsystem area by fault location logic
Internal fault or external area error；Fault location logic, that is, fault location algorithm, including use Travelling Wave Fault Location algorithm, that is, pass through
Wavefront size and polarity determine guilty culprit route；
(3) if fault location logic judgment is subsystem external area error, failure institute is determined further according to fault location logic
In route；Otherwise it is determined as subsystem troubles inside the sample space；
(4) if failure is subsystem external area error, and it is positioned at faulty line L12, then non-faulting is re-closed after setting time
Route dc circuit breaker DB15、DB51、DB25And DB52；If failure is subsystem troubles inside the sample space, and is positioned at faulty line L23, then
The corresponding dc circuit breaker DB of non-faulting subsystem is overlapped after setting time15、DB51、DB12And DB52；
(5) according to scheduling system command, change the control model and power control instruction of converter station.
2. DC grid line fault protection method as described in claim 1, which is characterized in that described in the step (1)
Travelling wave signal includes voltage and current travelling wave signal, respectively voltage traveling wave signal S1、S2And S5And current traveling wave signal S12、
S21、S15、S51、S25、S52、S54And S23, the characteristic component of traveling wave is extracted using wavelet transformation analysis method；Pass through forward and reverse row
Wavelength-division from, and using Cubic Spline Wavelet Transform method decompose extract characteristic component；
The given threshold of the travelling wave signal protection, needs to comprehensively consider the influence of different faults type and abort situation, and full
The requirement of subsystem reliable separation under each failure of sufficient step (1)；
The control model of the switching subsystem converter station is the DC voltage stability to guarantee subsystem, and final result is each son
System at least 1 converter station participates in the control of the subsystem DC voltage.
3. DC grid line fault protection method as described in claim 1, which is characterized in that in the step (2), failure
Positioning logic are as follows: judge subsystem troubles inside the sample space or external area error by comparing the size and polarity of initial traveling wave；When
The initial traveling wave signal polarity of electric current is identical, and with route travelling wave signal polarity in area on the contrary, then judging subsystem for troubles inside the sample space；
The initial polarity of traveling wave of each electric current of subsystem on the contrary, and negative polarity amplitude is 2 times of positive polarity amplitude, then judge subsystem
For external area error.
4. DC grid line fault protection method as claimed in claim 3, which is characterized in that in the step (3), for
Route L12, the initial traveling wave S of 1 electric current of subsystem12Polarity is anti-, the initial traveling wave S of electric current15It is positive, and the initial traveling wave S of electric current12Wave head
Amplitude is S152 times, then judge failure for external area error, and failure is located at route L12；For route L25, the electric current of subsystem 2
Initial traveling wave S21Polarity is anti-, the initial traveling wave S of electric current25It is positive, and the initial traveling wave S of electric current21Wave head amplitude is S252 times, then sentence
Disconnected failure is external area error, and failure is located at route L25；For route L15, the initial traveling wave S of the electric current of subsystem 351Polarity is
Instead, the initial traveling wave S of electric current52It is positive, and the initial traveling wave S of electric current51Wave head amplitude is S522 times, then judge failure for outside area therefore
Barrier, and failure is located at route L15。
5. DC grid line fault protection method as claimed in claim 3, which is characterized in that in the step (4), for
Subsystem 1, if the initial travelling wave signal S of electric current12And S15Identical polarity is then troubles inside the sample space, is otherwise external area error；For subsystem
System 2, if the initial travelling wave signal S of electric current21、S25With approximate wave head amplitude and identical polarity of traveling wave, and and travelling wave signal
S23Polarity is otherwise external area error on the contrary, be then determined as troubles inside the sample space；For subsystem 3, if the initial travelling wave signal S of electric current51、
S52With approximate wave head amplitude and identical polarity of traveling wave, and with travelling wave signal S54Polarity is on the contrary, be then determined as event in area
Barrier, is otherwise external area error；
Subsystem restores setting time delay and is adjusted according to the operating status of fault condition and dc circuit breaker；When setting
Between be 5ms；The dc circuit breaker reclosing action signal is generated by the logic based on each measuring point signal of local converter station, including
Inner region outer fault distinguishing logic in area's generates.
6. DC grid line fault protection method as described in claim 1, which is characterized in that described in the step (5)
Control model refers to DC voltage control and active power controller；The power control instruction refers to that active power controller instructs.
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| EP3711128B1 (en) * | 2017-11-17 | 2022-01-05 | Hitachi Energy Switzerland AG | Fault handling in a dc power system |
| CN108120902B (en) * | 2018-01-31 | 2020-03-27 | 国网浙江省电力有限公司电力科学研究院 | Method for rapidly judging transmission line fault |
| CN108400575B (en) * | 2018-03-19 | 2019-10-11 | 西安交通大学 | DC line fault guard method based on inverter injection characteristic signal |
| CN108551161B (en) * | 2018-03-20 | 2019-05-24 | 西安交通大学 | Utilize the inverter DC line fault guard method that actively injection and traveling wave couple |
| CN108683160B (en) * | 2018-04-28 | 2020-01-14 | 西安理工大学 | Transient energy protection method for fault current of direct-current transmission line |
| CN109188207B (en) * | 2018-09-18 | 2020-12-25 | 四川理工学院 | Bus fault positioning method based on initial traveling wave active power |
| CN111929531B (en) * | 2020-07-20 | 2021-07-27 | 南方电网科学研究院有限责任公司 | Power distribution network fault section positioning method and system based on ground fault transfer |
| CN112083280B (en) * | 2020-08-27 | 2022-07-08 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Method for identifying fault interval of hybrid multi-terminal direct-current power transmission system |
| CN112448374A (en) * | 2020-11-16 | 2021-03-05 | 国网北京市电力公司 | Line protection method, system and device |
| CN114583672B (en) * | 2022-03-28 | 2024-05-24 | 武汉船用电力推进装置研究所（中国船舶重工集团公司第七一二研究所） | Short circuit protection method for ship low-voltage direct-current distribution system |
| CN115411710A (en) * | 2022-10-14 | 2022-11-29 | 国网山东省电力公司东营市河口区供电公司 | Anti-islanding protection device |
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