CN109449894A - A kind of active power distribution network current differential protection method and device - Google Patents
A kind of active power distribution network current differential protection method and device Download PDFInfo
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- CN109449894A CN109449894A CN201811277069.3A CN201811277069A CN109449894A CN 109449894 A CN109449894 A CN 109449894A CN 201811277069 A CN201811277069 A CN 201811277069A CN 109449894 A CN109449894 A CN 109449894A
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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
Abstract
The present invention relates to a kind of active power distribution network current differential protection method and devices, the described method includes: determining the attribute-bit of the protection section before and after failure according to the positive-sequence component of protection section both ends electric current before and after active power distribution network failure, and then differential protection is carried out to the protection section according to the attribute-bit of protection section described before and after the failure, determine whether that carrying out differential protection and different attribute identifies the corresponding specific adjusting threshold for carrying out differential protection according to the positive-sequence component of protection section both ends electric current before and after active power distribution network failure respectively using technical solution of the present invention, improve the sensitivity of that differential protection of active power distribution network, the timeliness of isolated fault is effectively ensured simultaneously.
Description
Technical field
The present invention relates to distribution protection technical fields, and in particular to a kind of active power distribution network current differential protection method and
Device.
Background technique
After smart grid concept propose after, distributed generation resource (Distributed Generation, DG) obtain compared with
It is widely applied, supports development close to the distributed power generation of load side energetically in recent years, promote low capacity distributed generation resource and exist
Access in power distribution network, the permeability of DG gradually increases in power distribution network, and the direction of the active power distribution networks such as Xiang Duoyuan, multiterminal is developed,
Based on trend and the characteristics of fault current two-way flow, the powering mode of active power distribution network is from extensive concentration supply power to collection
Chinese style distribution combines the transition of power supply, and the combination power supply of bulk power grid and DG are with low energy consumption, small investment, high reliablity, spirit
The advantages that activity is high, but the power generation feature of DG and conventional electric power generation are different, when DG accesses power distribution network, can make power distribution network
Become the complex network of more power supplys from the radial simple network of single supply, to influence network structure and direction of tide, finally
Influence selectivity, sensitivity, quick-action and the reliability of protective relaying device.Therefore, in order to which the power supply for ensureing power distribution network is reliable
Property, the effect of DG is played as far as possible, needs the solution for considering to be suitable for current electric grid development environment.
Currently, the conventional current differential protection in active power distribution network uses setting protection to sentence mainly for conventional line
It is the technology of fixed high threshold value according to starting current, it can not be into for the line fault situation in power grid in addition to conventional line
Row protection act has and protects the problems such as coverage is not complete and sensitivity is insufficient.
Summary of the invention
The present invention provides a kind of active power distribution network current differential protection method and device, and the purpose is to according to active power distribution network
The positive-sequence component of protection section both ends electric current determines the attribute-bit of the protection section before and after failure, Jin Ergen before and after failure
Differential protection is carried out to the protection section according to the attribute-bit of protection sections different before and after failure, it is poor in the prior art to solve
The problem of dynamic protection sensitivity deficiency, while the timeliness of active power distribution network isolated fault is improved, it reduces caused by electric network fault
Loss.
The purpose of the present invention is adopt the following technical solutions realization:
A kind of active power distribution network current differential protection method, it is improved in that the described method includes:
The protection of failure front and back is determined according to the positive-sequence component of protection section both ends electric current before and after active power distribution network failure
The attribute-bit of section；
Differential protection is carried out to the protection section according to the attribute-bit of protection section described before and after the failure.
Preferably, described in front of and after determining failure according to the positive-sequence component of protection section both ends electric current before active power distribution network failure
The process of attribute-bit for protecting section includes:
If protecting the sum of the positive-sequence component of section both ends electric current I before active power distribution network failureun.mLess than or equal to not detecting branch
Road attribute adjusts threshold Iset.un, then the attribute-bit of the protection section is that there is no non-detection branch before failure, otherwise, therefore
The attribute-bit of the protection section is to exist for detection branch before barrier.
Preferably, described in front of and after determining failure according to the positive-sequence component of protection section both ends electric current after active power distribution network failure
The process of attribute-bit for protecting section includes:
If protecting the sum of the positive-sequence component of section both ends electric current to be not zero after active power distribution network failure, the guarantor after failure
The attribute-bit for protecting section is troubles inside the sample space, and otherwise, the attribute-bit of the protection section is external area error after failure；
Wherein, Iun.m=| Im.pre+In.pre|, Im.preFor the positive-sequence component for protecting section head end electric current before failure, In.preFor
The positive-sequence component of section end current, I are protected before failureset.unThreshold is adjusted for non-detection branch attribute.
Preferably, the attribute-bit according to protection section described before and after the failure carries out the protection section poor
Dynamic protection, comprising:
If protecting the attribute-bit of section after failure is troubles inside the sample space, protect before failure section attribute-bit be there is no
Non- detection branch, then when the positive-sequence component of the protection section both ends electric current meets following formula after failure, protection section carries out differential
Protection:
If protecting the attribute-bit of section after failure is troubles inside the sample space, it is to exist not that the attribute-bit of section is protected before failure
Detection branch, and meet and voltage signal is not present in the non-detection branch, then protection section both ends electric current after failure
When positive-sequence component meets following formula, protection section carries out differential protection:
If protecting the attribute-bit of section after failure is troubles inside the sample space, it is to exist not that the attribute-bit of section is protected before failure
Detection branch, and meet in the non-detection branch that there are voltage signals, then the protection section both ends electric current is being just after failure
When order components meet following formula, protection section carries out differential protection:
If the attribute-bit for protecting section before failure is external area error, the protection section is without differential protection；
Wherein, Iset1=0.1KmIN, Krel1∈ [0.275,0.45], Iset2=max (KunIun.m,0.1KmIN), Krel3=
Krel2∈ [0.35,0.45], Δ Im1For the positive-sequence component for protecting section head end electric current after failure, Δ In1For protection zone after failure
The positive-sequence component of section end current, Iset1It is to open there is no the protection section of non-detection branch is corresponding for attribute tags before failure
Streaming current threshold, KmIt is that there is no the corresponding safety factor of protection section of non-detection branch, I for attribute tags before failureNFor
Feeder line rated current, Krel1For attribute tags before failure be there is no the corresponding restraint coefficient of protection section of non-detection branch,
Iset2For attribute tags before failure be in the presence of non-detection branch and the protection section correspondence of voltage signal is not present in non-detection branch
Starting current threshold, Krel2For attribute tags before failure be in the presence of non-detection branch and non-detection branch there is no voltage letters
Number the corresponding restraint coefficient of protection section, KunFor the protection section correspondence that attribute tags before failure are in the presence of non-detection branch
Safety factor, Iun.mFor the sum of the positive-sequence component for protecting section both ends electric current before failure, Iset3It is for attribute tags before failure
In the presence of non-detection branch and non-detection branch there are the corresponding starting current threshold of the protection section of voltage signal, Krel3For event
Hinder before attribute tags be presence non-detection branch and non-detection branch there are the corresponding braking systems of protection section of voltage signal
Number, UφφTo appoint two-phase voltage poor in three-phase voltage, UsetThreshold is adjusted for the voltage of active power distribution network after failure.
A kind of active power distribution network current differential protection device, it is improved in that described device includes:
Determining module, for determining failure according to the positive-sequence component of protection section both ends electric current before and after active power distribution network failure
The attribute-bit of the front and back protection section；
Protective module, for being carried out according to the attribute-bit of protection section described before and after the failure to the protection section
Differential protection.
Preferably, the determining module, comprising:
First determination unit, if for the sum of positive-sequence component of protection section both ends electric current I before active power distribution network failureun.m
Threshold I is adjusted less than or equal to non-detection branch attributeset.un, then the attribute-bit of the protection section is that there is no not before failure
Detection branch, otherwise, the attribute-bit of the protection section is to exist for detection branch before failure.
Second determination unit, if for protecting the sum of the positive-sequence component of section both ends electric current not to be after active power distribution network failure
Zero, then the attribute-bit of the protection section is troubles inside the sample space, and otherwise, the attribute-bit of the protection section is external area error；
Wherein, Iun.m=| Im.pre+In.pre|, Im.preFor the positive-sequence component for protecting section head end electric current before failure, In.preFor
The positive-sequence component of section end current, I are protected before failureset.unThreshold is adjusted for non-detection branch attribute.
Preferably, the protective module, is used for:
If protecting the attribute-bit of section after failure is troubles inside the sample space, protect before failure section attribute-bit be there is no
Non- detection branch, then when the positive-sequence component of the protection section both ends electric current meets following formula after failure, protection section carries out differential
Protection:
If protecting the attribute-bit of section after failure is troubles inside the sample space, it is to exist not that the attribute-bit of section is protected before failure
Detection branch, and meet and voltage signal is not present in the non-detection branch, then protection section both ends electric current after failure
When positive-sequence component meets following formula, protection section carries out differential protection:
If protecting the attribute-bit of section after failure is troubles inside the sample space, it is to exist not that the attribute-bit of section is protected before failure
Detection branch, and meet in the non-detection branch that there are voltage signals, then the protection section both ends electric current is being just after failure
When order components meet following formula, protection section carries out differential protection:
If the attribute-bit for protecting section before failure is external area error, the protection section is without differential protection；
Wherein, Iset1=0.1KmIN, Krel1∈ [0.275,0.45], Iset2=max (KunIun.m,0.1KmIN), Krel3=
Krel2∈ [0.35,0.45], Δ Im1For the positive-sequence component for protecting section head end electric current after failure, Δ In1For protection zone after failure
The positive-sequence component of section end current, Iset1It is to open there is no the protection section of non-detection branch is corresponding for attribute tags before failure
Streaming current threshold, KmIt is that there is no the corresponding safety factor of protection section of non-detection branch, I for attribute tags before failureNFor
Feeder line rated current, Krel1For attribute tags before failure be there is no the corresponding restraint coefficient of protection section of non-detection branch,
Iset2For attribute tags before failure be in the presence of non-detection branch and the protection section correspondence of voltage signal is not present in non-detection branch
Starting current threshold, Krel2For attribute tags before failure be in the presence of non-detection branch and non-detection branch there is no voltage letters
Number the corresponding restraint coefficient of protection section, KunFor the protection section correspondence that attribute tags before failure are in the presence of non-detection branch
Safety factor, Iun.mFor the sum of the positive-sequence component for protecting section both ends electric current before failure, Iset3It is for attribute tags before failure
In the presence of non-detection branch and non-detection branch there are the corresponding starting current threshold of the protection section of voltage signal, Krel3For event
Hinder before attribute tags be presence non-detection branch and non-detection branch there are the corresponding braking systems of protection section of voltage signal
Number, UφφTo appoint two-phase voltage poor in three-phase voltage, UsetThreshold is adjusted for the voltage of active power distribution network after failure.
Compared with prior art, the invention has the following beneficial effects:
Using technical solution of the present invention, according to the positive-sequence component of protection section both ends electric current before and after active power distribution network failure
The attribute-bit for determining the failure front and back protection section, the electric current positive-sequence component acquisition before and after being applauded according to protection section are protected
The corresponding attribute-bit of section is protected, ensure that the reliability of criterion source data, and then lay base for the sensitivity of differential protection
Plinth carries out differential protection, base of the present invention to the protection section according to the attribute-bit of protection section described before and after the failure
The corresponding differential adjusting threshold of protection is respectively adopted in the different protection section of attribute-bit, solves and protects in the prior art
The infull problem of coverage, ensure that the timeliness of power distribution network differential protection, while reduce the loss of distribution network failure, have
Conducive to power grid operation.
Detailed description of the invention
Fig. 1 is the flow chart of active power distribution network current differential protection method of the embodiment of the present invention；
Fig. 2 is the active power distribution network structural schematic diagram of active power distribution network current differential protection method of the embodiment of the present invention；
Fig. 3 be active power distribution network current differential protection method of the embodiment of the present invention there is no the feeder line knots of non-detection branches
Structure schematic diagram；
Fig. 4 is the feeder line structure of the non-detection branches of presence of active power distribution network current differential protection method of the embodiment of the present invention
Schematic diagram；
Fig. 5 is the structural schematic diagram of active power distribution network current differential protection device of the embodiment of the present invention.
Specific embodiment
It elaborates with reference to the accompanying drawing to a specific embodiment of the invention.
In order to make the object, technical scheme and advantages of the embodiment of the invention clearer, below in conjunction with the embodiment of the present invention
In attached drawing, technical scheme in the embodiment of the invention is clearly and completely described, it is clear that described embodiment is
A part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, ordinary skill people
Member's all other embodiment obtained without making creative work, shall fall within the protection scope of the present invention.
The present invention provides a kind of active power distribution network current differential protection method and devices, are illustrated below.
Technical solution provided by the invention is determined not using the current amplitude and phase information protected in section before and after failure
With situation, corresponding Protection criteria implements differential protection in turn, and for active power distribution network, protection section is interior, and there may be do not detect
Branch causes partial picture sensitivity insufficient, and the distribution in conjunction with distribution protection section both ends electric current positive sequence fault component is special
Sign considers that DG accesses the influence after power distribution network to original protection, proposes active power distribution network self-adaptive current differential protection side
Case.
Embodiment one:
Fig. 1 shows the flow chart of active power distribution network current differential protection method in the embodiment of the present invention, as shown in Figure 1,
The method may include:
101. described in front of and after determining failure according to the positive-sequence component of protection section both ends electric current before and after active power distribution network failure
Protect the attribute-bit of section；
102. carrying out differential protection to the protection section according to the attribute-bit of protection section described before and after the failure.
Failure data for the previous period are recorded by protective device, acquire the phase current of protection section both ends electric current before failure
Or positive-sequence component, phasor operation is carried out to data before the failure of both ends using Kirchhoff's current law (KCL), according to detection branches criterion
Compare data phasor and adjusting threshold size before two sections of current failures, judges to protect section that whether there is or not non-detection branches；
Fig. 2 shows the active power distribution network structural representations of active power distribution network current differential protection method of the embodiment of the present invention
Figure, as shown in Fig. 2, being protection section between the node M and node N of setting feeder line, Load1 is area's internal loading, and DG is not detect
Branch, f1Point is troubles inside the sample space, f2Point and f3Point is external area error.
Wherein, the failure front and back guarantor is determined according to the positive-sequence component of protection section both ends electric current before active power distribution network failure
The process of attribute-bit for protecting section may include:
If protecting the sum of the positive-sequence component of section both ends electric current I before active power distribution network failureun.mLess than or equal to not detecting branch
Road attribute adjusts threshold Iset.un, then the attribute-bit of the protection section is that there is no non-detection branch before failure, otherwise, therefore
The attribute-bit of the protection section is to exist for detection branch before barrier, wherein the non-detection branch attribute adjusting threshold is pressed
The adjusting of section both ends maximum imbalance current is protected, is mainly the detection error of TA in power distribution network.
By self-adaptive current differential protection scheme operating criterion identify internal fault, compare distributed electrical source electric current with
Starting current size is protected, judges whether to execute trip signal isolated fault.
Specifically, described in front of and after determining failure according to the positive-sequence component of protection section both ends electric current after active power distribution network failure
The process of attribute-bit for protecting section may include:
If protecting the sum of the positive-sequence component of section both ends electric current to be not zero after active power distribution network failure, the guarantor after failure
The attribute-bit for protecting section is troubles inside the sample space, and otherwise, the attribute-bit of the protection section is external area error after failure；
Wherein, Iun.m=| Im.pre+In.pre|, Im.preFor the positive-sequence component for protecting section head end electric current before failure, In.preFor
The positive-sequence component of section end current, I are protected before failureset.unThreshold is adjusted for non-detection branch attribute.
The attribute-bit according to protection section described before and after the failure carries out differential protection to the protection section,
May include:
Fig. 3 show active power distribution network current differential protection method of the embodiment of the present invention there is no the feedbacks of non-detection branches
Cable architecture schematic diagram can obtain as shown in figure 3, non-detection branch is not present between protection section MN according to the data before failure
The load current amplitude on Load1 is about 260A out, then Iset1Amplitude be about 312A, restraint coefficient Krel1Take 0.4；
If protecting the attribute-bit of section after failure is troubles inside the sample space, protect before failure section attribute-bit be there is no
Non- detection branch, i.e. protection section design active power distribution network without branch power supply or when load, based on electric current positive-sequence component after failure
Current differential protection criterion sets starting current threshold and current differential protection restraint coefficient, then protection section after failure
When the positive-sequence component of both ends electric current meets following formula, protection section carries out differential protection, executes trip signal and realizes that distal end is tripped:
Fig. 4 shows the feeder line of the non-detection branches of presence of active power distribution network current differential protection method of the embodiment of the present invention
Structural schematic diagram, as shown in figure 4, protection section is MN section, and MN section includes non-detection load branch, and DG is not detect
Branch, there are non-detection branches in protection section, when not introducing voltage signal, consider non-detection branches feeder line power swing, really
Constant current differential protection criterion determines that protection scheme completes Fault Isolation by adjusting criterion；If protecting the category of section after failure
Property be identified as troubles inside the sample space, it is there is non-detection branch, and meet and described do not detect branch that the attribute-bit of section is protected before failure
Voltage signal is not present in road, designs active power distribution network current differential protection criterion, setting based on electric current positive-sequence component after failure
Starting current threshold and current differential protection restraint coefficient, then the positive-sequence component of the protection section both ends electric current is full after failure
When foot formula, protection section carries out differential protection, executes trip signal and realizes that distal end is tripped:
It introduces voltage signal and copes with motor self-starting process, by voltage fluctuation situation when detection failure, take electricity
Differential protection locking is flowed, current differential protection malfunction is prevented；If protecting the attribute-bit of section after failure is troubles inside the sample space, therefore
The attribute-bit of protection section is there is non-detection branch, and there are voltage signals in the satisfaction non-detection branch before hindering, i.e.,
Protect section there are a large amount of motor, voltage fluctuation is obvious when failure, introduces voltage as current differential protection locking item
Part, voltage is adjusted in setting maximum fluctuation, then when the positive-sequence component of the protection section both ends electric current meets following formula after failure, is protected
It protects section and carries out differential protection, execute trip signal and realize that distal end is tripped:
If the attribute-bit for protecting section before failure is external area error, the protection section is without differential protection；
Wherein, Iset1=0.1KmIN, Krel1∈ [0.275,0.45], Iset2=max (KunIun.m,0.1KmIN), Krel3=
Krel2∈ [0.35,0.45], Δ Im1For the positive-sequence component for protecting section head end (end M) electric current after failure, Δ In1To be protected after failure
Protect the positive-sequence component of segment ends (N-terminal) electric current, Iset1It is that there is no the protection zones of non-detection branch for attribute tags before failure
The corresponding starting current threshold of section, is mainly used to prevent to protect starting under normal circumstances, the adjusting for starting current threshold,
One will consider differential protection area maximum imbalance current, be adjusted by TA detection error, and two will consider load (distributed electrical
Source) transfer influence, it is contemplated that the electric current of non-detection branches feeder line is not too big, by consider transfer load rated capacity be
The 10% of place feeder line rated current is adjusted, KmIt is that there is no the protection zones of non-detection branch for attribute tags before failure
The corresponding safety factor of section, INFor feeder line rated current, Krel1It is that there is no the guarantors of non-detection branch for attribute tags before failure
The corresponding restraint coefficient of section is protected, protects section both ends electric current positive sequence failure after considering the maximum braking angle of TA saturation and failure
The phase difference of component, Iset2For attribute tags before failure be in the presence of non-detection branch and voltage signal is not present in non-detection branch
The corresponding starting current threshold of protection section, consider non-detection branches feeder line power swing, also need to consider under normal circumstances not
The case where detection branches feeder line power swing, Krel2It is in the presence of non-detection branch and non-detection branch for attribute tags before failure
There is no the corresponding restraint coefficients of protection section of voltage signal, other than needing to consider area outside the influence of TA saturation current, also
It need to consider to shunt in the non-detection branches of external area error and influence of the power swing to protection on non-detection branches feeder line, KunFor event
Attribute tags are the corresponding safety factor of protection section in the presence of non-detection branch, I before hinderingun.mTo protect section two before failure
Hold the sum of the positive-sequence component of electric current, Iset3For attribute tags before failure be in the presence of non-detection branch and non-detection branch has electricity
The corresponding starting current threshold of protection section for pressing signal usually escapes protection section current transformer (TA) detection error
Bring maximum imbalance current, without the concern for the influence of load fluctuation, only by escape protection section TA detection error bring
Maximum imbalance current adjusting, Krel3For attribute tags before failure be in the presence of non-detection branch and non-detection branch has electricity
Press the corresponding restraint coefficient of protection section of signal, UφφTo appoint two-phase voltage poor in three-phase voltage, as A, B, C three-phase wantonly two
Phase voltage is poor, UsetThreshold is adjusted for the voltage of active power distribution network after failure, by the maximum fluctuation escaped under normal operation
Range is adjusted.
If protecting section MN attribute tags after failure is to be identified as troubles inside the sample space, and the protection of the side N can not be opened because electric current is too small
It is dynamic, then it needs to design by specific logical, trip signal occurs to realize the tripping of N-terminal switch to N-terminal by the end M, is finally completed
The isolation of failure.
Compared to conventional current differential protecting technology, self-adaptive current differential protection provided by the invention is as active distribution
One of the important protection technique of net, has the advantages that cost is relatively low, is easily achieved, only need to be on the basis of original protection is matched
It installs a small amount of directional element additional, and adjusts the setting program of original protection, can preferably realize the distribution network protection containing DG；Movement
Speed is fast, can adapt to the variation of network change and the DG method of operation to a certain extent.The key of adaptive guard scheme is
The operation conditions of automatic identification protecting section, i.e., whether there is or not non-detection branches.
Current differential protection protects in section active power distribution network using the amplitude and phase information in protection section
There may be non-detection branches, cause partial picture sensitivity insufficient, in conjunction with distribution protection section both ends electric current positive sequence failure
The distribution characteristics of component proposes active power distribution network self-adaptive current differential protection scheme.Self-adaptive current proposed in this paper is poor
The adaptivity of dynamic protection scheme is mainly reflected in protection scheme and is capable of the operating condition of join protection section itself (whether there is or not
Detection branches, the introducing whether there is or not voltage) the adaptive reasonable setting program of selection, it is adapted to distribution protection section
Situations such as feeder line structure variation and power swing.
Embodiment two:
Fig. 5 shows the structural schematic diagram of active power distribution network current differential protection device of the embodiment of the present invention, such as Fig. 5 institute
Show, the apparatus may include:
Determining module, for determining failure according to the positive-sequence component of protection section both ends electric current before and after active power distribution network failure
The attribute-bit of the front and back protection section；
Protective module, for being carried out according to the attribute-bit of protection section described before and after the failure to the protection section
Differential protection.
Specifically, the determining module may include:
First determination unit, if for the sum of positive-sequence component of protection section both ends electric current I before active power distribution network failureun.m
Threshold I is adjusted less than or equal to non-detection branch attributeset.un, then the attribute-bit of the protection section is that there is no not before failure
Detection branch, otherwise, the attribute-bit of the protection section is to exist for detection branch before failure；
Second determination unit, if for protecting the sum of the positive-sequence component of section both ends electric current not to be after active power distribution network failure
Zero, then the attribute-bit of the protection section is troubles inside the sample space, and otherwise, the attribute-bit of the protection section is external area error；
Wherein, Iun.m=| Im.pre+In.pre|, Im.preFor the positive-sequence component for protecting section head end electric current before failure, In.preFor
The positive-sequence component of section end current, I are protected before failureset.unThreshold is adjusted for non-detection branch attribute.
The protective module, is used for: if protecting the attribute-bit of section after failure is troubles inside the sample space, protecting section before failure
Attribute-bit be there is no non-detection branch, then the positive-sequence component of the protection section both ends electric current meets following formula after failure
When, protection section carries out differential protection:
If protecting the attribute-bit of section after failure is troubles inside the sample space, it is to exist not that the attribute-bit of section is protected before failure
Detection branch, and meet and voltage signal is not present in the non-detection branch, then protection section both ends electric current after failure
When positive-sequence component meets following formula, protection section carries out differential protection:
If protecting the attribute-bit of section after failure is troubles inside the sample space, it is to exist not that the attribute-bit of section is protected before failure
Detection branch, and meet in the non-detection branch that there are voltage signals, then the protection section both ends electric current is being just after failure
When order components meet following formula, protection section carries out differential protection:
If the attribute-bit for protecting section before failure is external area error, the protection section is without differential protection；
Wherein, Iset1=0.1KmIN, Krel1∈ [0.275,0.45], Iset2=max (KunIun.m,0.1KmIN), Krel3=
Krel2∈ [0.35,0.45], Δ Im1For the positive-sequence component for protecting section head end electric current after failure, Δ In1For protection zone after failure
The positive-sequence component of section end current, Iset1It is to open there is no the protection section of non-detection branch is corresponding for attribute tags before failure
Streaming current threshold, KmIt is that there is no the corresponding safety factor of protection section of non-detection branch, I for attribute tags before failureNFor
Feeder line rated current, Krel1For attribute tags before failure be there is no the corresponding restraint coefficient of protection section of non-detection branch,
Iset2For attribute tags before failure be in the presence of non-detection branch and the protection section correspondence of voltage signal is not present in non-detection branch
Starting current threshold, Krel2For attribute tags before failure be in the presence of non-detection branch and non-detection branch there is no voltage letters
Number the corresponding restraint coefficient of protection section, KunFor the protection section correspondence that attribute tags before failure are in the presence of non-detection branch
Safety factor, Iun.mFor the sum of the positive-sequence component for protecting section both ends electric current before failure, Iset3It is for attribute tags before failure
In the presence of non-detection branch and non-detection branch there are the corresponding starting current threshold of the protection section of voltage signal, Krel3For event
Hinder before attribute tags be presence non-detection branch and non-detection branch there are the corresponding braking systems of protection section of voltage signal
Number, UφφTo appoint two-phase voltage poor in three-phase voltage, UsetThreshold is adjusted for the voltage of active power distribution network after failure.
Embodiment three:
It is as follows using the simulation results after this programme:
(1) non-detection branches load influences external area error
Protection section is MN section, and MN section includes non-detection load branch, and the following table 1 is for verifying external area error (event
Barrier occurs in f2Point and f3Point) when, above-mentioned self-adaptive current differential protecting method action situation and non-detection load branch are to area
The rated capacity of non-detection branches Load1 is adjusted to 3.6MW by the influence of outer failure.
The non-detection load branch of table 1 emulates tables of data
By 1 data of table it can be concluded that, when shunting when protecting section downstream, on non-detection branches load occurs for fault point
Smaller, the amplitude of both ends electric current positive sequence fault component is almost the same, and phase difference is approximately equal to 182 °, and action current is much smaller than braking
Electric current, protection are reliably failure to actuate；When failure occurs when protecting section upstream, the shunting of non-detection branches load current is larger,
But protection still can reliably be failure to actuate.
(2) non-detection branches power supply influences external area error
Protection section is MN section, and MN section includes and do not detect power supply branch, and the following table 2 is for verifying external area error (event
Barrier occurs in f2Point and f3Point) when, above-mentioned self-adaptive current differential protecting method action situation and non-detection load branch are to area
The influence of outer failure.DG in simulation model is adjusted into MN protection section, access point is away from bus 4km.According to number before failure
According to it can be concluded that source current amplitude is about 117A, then start-up criterion starting current threshold I is protectedset2About 140A, braking system
Number Krel2Take 0.4.
Table 2 does not detect power supply branch emulation tables of data
By 2 data of table it can be concluded that the similar conclusion of result corresponding with table 1, non-detection branches power supply protect external area error
The Reliability of Microprocessor of shield does not influence, and protection is reliably failure to actuate.
(3) influence of the normal duty switching to protection
Protection section is MN section, and MN section includes and do not detect power supply branch.Table 3 for verify normal duty switching with
And when motor self-starting, self-adaptive current differential protection scheme action situation.The rated current of switching load is by feedback in section
The 10% of line rated current considers, it is assumed that rated current 60A, protection start-up criterion starting current threshold are 72A.Load is thrown
The emulation data cut are as shown in table 3.
3 load switching of table emulates tables of data
It can be by load switching mistake using the operating criterion of self-adaptive current differential protection scheme it can be seen from 3 data of table
Journey is identified as troubles inside the sample space, but for RL load, the phasor of both ends electric current positive sequence fault component and is less than starting current threshold,
Therefore protection does not start reliably；For motor self-starting process, start-up criterion is protected voltage can be needed to believe with effectively start
Number auxiliary, otherwise may malfunction.
In conclusion self-adaptive current differential protection scheme is capable of the operating condition of join protection section itself, (whether there is or not
Detection branches, the introducing whether there is or not voltage) the adaptive reasonable setting program of selection, it is adapted to distribution protection section
Situations such as feeder line structure variation and power swing.
It should be understood by those skilled in the art that, embodiments herein can provide as method, system or computer program
Product.Therefore, complete hardware embodiment, complete software embodiment or reality combining software and hardware aspects can be used in the application
Apply the form of example.Moreover, it wherein includes the computer of computer usable program code that the application, which can be used in one or more,
The computer program implemented in usable storage medium (including but not limited to magnetic disk storage, CD-ROM, optical memory etc.) produces
The form of product.
The application is referring to method, the process of equipment (system) and computer program product according to the embodiment of the present application
Figure and/or block diagram describe.It should be understood that can be realized by computer program instructions each in flowchart and/or the block diagram
The combination of process and/or box in process and/or box and flowchart and/or the block diagram.It can provide these computers
Processor of the program instruction to general purpose computer, special purpose computer, Embedded Processor or other programmable data processing devices
To generate a machine, so that being generated by the instruction that computer or the processor of other programmable data processing devices execute
For realizing the function of being specified in one or more flows of the flowchart and/or one or more blocks of the block diagram
Device.
These computer program instructions, which may also be stored in, is able to guide computer or other programmable data processing devices with spy
Determine in the computer-readable memory that mode works, so that instruction stored in the computer readable memory generation includes
The manufacture of command device, the command device are realized in one box of one or more flows of the flowchart and/or block diagram
Or the function of being specified in multiple boxes.
These computer program instructions also can be loaded onto a computer or other programmable data processing device, so that counting
Series of operation steps are executed on calculation machine or other programmable devices to generate computer implemented processing, thus in computer
Or the instruction executed on other programmable devices is provided for realizing in one or more flows of the flowchart and/or box
The step of function of being specified in figure one box or multiple boxes.
Finally it should be noted that: the above embodiments are merely illustrative of the technical scheme of the present invention and are not intended to be limiting thereof, to the greatest extent
Invention is explained in detail referring to above-described embodiment for pipe, it should be understood by those ordinary skilled in the art that: still
Can with modifications or equivalent substitutions are made to specific embodiments of the invention, and without departing from spirit and scope of the invention appoint
What modification or equivalent replacement, should all cover within the scope of the claims of the present invention.
Claims (7)
1. a kind of active power distribution network current differential protection method, which is characterized in that the described method includes:
The failure front and back protection section is determined according to the positive-sequence component of protection section both ends electric current before and after active power distribution network failure
Attribute-bit；
Differential protection is carried out to the protection section according to the attribute-bit of protection section described before and after the failure.
2. the method as described in claim 1, which is characterized in that according to protection section both ends electric current before active power distribution network failure
Positive-sequence component determines that the process of the attribute-bit of the failure front and back protection section includes:
If protecting the sum of the positive-sequence component of section both ends electric current I before active power distribution network failureun.mLess than or equal to non-detection branch attribute
Adjust threshold Iset.un, then the attribute-bit of the protection section is that there is no non-detection branch before failure, otherwise, institute before failure
The attribute-bit for stating protection section is to exist for detection branch.
3. the method as described in claim 1, which is characterized in that according to protection section both ends electric current after active power distribution network failure
Positive-sequence component determines that the process of the attribute-bit of the failure front and back protection section includes:
If protecting the sum of the positive-sequence component of section both ends electric current to be not zero after active power distribution network failure, the protection zone after failure
The attribute-bit of section is troubles inside the sample space, and otherwise, the attribute-bit of the protection section is external area error after failure；
Wherein, Iun.m=| Im.pre+In.pre|, Im.preFor the positive-sequence component for protecting section head end electric current before failure, In.preFor failure
The positive-sequence component of preceding protection section end current, Iset.unThreshold is adjusted for non-detection branch attribute.
4. the method as described in claim 1, which is characterized in that the attribute according to protection section described before and after the failure
Mark carries out differential protection to the protection section, comprising:
If protecting the attribute-bit of section after failure is troubles inside the sample space, it is that there is no do not examine that the attribute-bit of section is protected before failure
Branch is surveyed, then when the positive-sequence component of the protection section both ends electric current meets following formula after failure, protection section carries out differential protection:
If protecting the attribute-bit of section after failure is troubles inside the sample space, it is to exist not detect that the attribute-bit of section is protected before failure
Branch, and meet and voltage signal is not present in the non-detection branch, then after failure the protection section both ends electric current positive sequence
When component meets following formula, protection section carries out differential protection:
If protecting the attribute-bit of section after failure is troubles inside the sample space, it is to exist not detect that the attribute-bit of section is protected before failure
Branch, and there are voltage signals in the satisfaction non-detection branch, then the positive sequence of the protection section both ends electric current is divided after failure
When amount meets following formula, protection section carries out differential protection:
If the attribute-bit for protecting section before failure is external area error, the protection section is without differential protection；
Wherein, Iset1=0.1KmIN, Krel1∈ [0.275,0.45], Iset2=max (KunIun.m,0.1KmIN), Krel3=Krel2∈
[0.35,0.45], Δ Im1For the positive-sequence component for protecting section head end electric current after failure, Δ In1To protect segment ends after failure
The positive-sequence component of electric current, Iset1It is that there is no the corresponding starting currents of protection section of non-detection branch for attribute tags before failure
Threshold, KmIt is that there is no the corresponding safety factor of protection section of non-detection branch, I for attribute tags before failureNIt is specified for feeder line
Electric current, Krel1It is that there is no the corresponding restraint coefficient of protection section of non-detection branch, I for attribute tags before failureset2For failure
Preceding attribute tags are in the presence of non-detection branch and the corresponding starting current of protection section of voltage signal is not present in non-detection branch
Threshold, Krel2For attribute tags before failure be in the presence of non-detection branch and the protection section of voltage signal is not present in non-detection branch
Corresponding restraint coefficient, KunFor the corresponding safety factor of protection section that attribute tags before failure are in the presence of non-detection branch,
Iun.mFor the sum of the positive-sequence component for protecting section both ends electric current before failure, Iset3It is in the presence of not detecting branch for attribute tags before failure
Road and there are the corresponding starting current threshold of the protection section of voltage signal, K for non-detection branchrel3It is for attribute tags before failure
In the presence of non-detection branch and non-detection branch there are the corresponding restraint coefficient of protection section of voltage signal, UφφFor three-phase voltage
In appoint two-phase voltage it is poor, UsetThreshold is adjusted for the voltage of active power distribution network after failure.
5. a kind of active power distribution network current differential protection device, which is characterized in that described device includes:
Determining module, for determining failure front and back according to the positive-sequence component of protection section both ends electric current before and after active power distribution network failure
The attribute-bit of the protection section；
Protective module, it is differential for being carried out according to the attribute-bit of protection section described before and after the failure to the protection section
Protection.
6. device as claimed in claim 5, which is characterized in that the determining module, comprising:
First determination unit, if for the sum of positive-sequence component of protection section both ends electric current I before active power distribution network failureun.mIt is less than
Threshold I is adjusted equal to non-detection branch attributeset.un, then the attribute-bit of the protection section is that there is no do not detect before failure
Branch, otherwise, the attribute-bit of the protection section is to exist for detection branch before failure；
Second determination unit, if for protecting the sum of the positive-sequence component of section both ends electric current to be not zero after active power distribution network failure,
Then the attribute-bit of the protection section is troubles inside the sample space, and otherwise, the attribute-bit of the protection section is external area error；
Wherein, Iun.m=| Im.pre+In.pre|, Im.preFor the positive-sequence component for protecting section head end electric current before failure, In.preFor failure
The positive-sequence component of preceding protection section end current, Iset.unThreshold is adjusted for non-detection branch attribute.
7. device as claimed in claim 5, which is characterized in that the protective module is used for:
If protecting the attribute-bit of section after failure is troubles inside the sample space, it is that there is no do not examine that the attribute-bit of section is protected before failure
Branch is surveyed, then when the positive-sequence component of the protection section both ends electric current meets following formula after failure, protection section carries out differential protection:
If protecting the attribute-bit of section after failure is troubles inside the sample space, it is to exist not detect that the attribute-bit of section is protected before failure
Branch, and meet and voltage signal is not present in the non-detection branch, then after failure the protection section both ends electric current positive sequence
When component meets following formula, protection section carries out differential protection:
If protecting the attribute-bit of section after failure is troubles inside the sample space, it is to exist not detect that the attribute-bit of section is protected before failure
Branch, and there are voltage signals in the satisfaction non-detection branch, then the positive sequence of the protection section both ends electric current is divided after failure
When amount meets following formula, protection section carries out differential protection:
If the attribute-bit for protecting section before failure is external area error, the protection section is without differential protection；
Wherein, Iset1=0.1KmIN, Krel1∈ [0.275,0.45], Iset2=max (KunIun.m,0.1KmIN), Krel3=Krel2∈
[0.35,0.45], Δ Im1For the positive-sequence component for protecting section head end electric current after failure, Δ In1To protect segment ends after failure
The positive-sequence component of electric current, Iset1It is that there is no the corresponding starting currents of protection section of non-detection branch for attribute tags before failure
Threshold, KmIt is that there is no the corresponding safety factor of protection section of non-detection branch, I for attribute tags before failureNIt is specified for feeder line
Electric current, Krel1It is that there is no the corresponding restraint coefficient of protection section of non-detection branch, I for attribute tags before failureset2For failure
Preceding attribute tags are in the presence of non-detection branch and the corresponding starting current of protection section of voltage signal is not present in non-detection branch
Threshold, Krel2For attribute tags before failure be in the presence of non-detection branch and the protection section of voltage signal is not present in non-detection branch
Corresponding restraint coefficient, KunFor the corresponding safety factor of protection section that attribute tags before failure are in the presence of non-detection branch,
Iun.mFor the sum of the positive-sequence component for protecting section both ends electric current before failure, Iset3It is in the presence of not detecting branch for attribute tags before failure
Road and there are the corresponding starting current threshold of the protection section of voltage signal, K for non-detection branchrel3It is for attribute tags before failure
In the presence of non-detection branch and non-detection branch there are the corresponding restraint coefficient of protection section of voltage signal, UφφFor three-phase voltage
In appoint two-phase voltage it is poor, UsetThreshold is adjusted for the voltage of active power distribution network after failure.
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| CN110098600A (en) * | 2019-05-08 | 2019-08-06 | 天津大学 | A kind of cable monopolar grounding fault guard method based on line capacitance transfer charge |
| CN111509678A (en) * | 2020-04-08 | 2020-08-07 | 广东电网有限责任公司 | Anti-synchronization error self-adaptive distribution network differential protection method |
| CN111693818A (en) * | 2019-03-15 | 2020-09-22 | 中国电力科学研究院有限公司 | Distribution line protection method and device |
| CN112531657A (en) * | 2020-12-04 | 2021-03-19 | 东莞理工学院 | Braking coefficient self-adaptive distribution network differential protection method based on transient direction |
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| CN111693818A (en) * | 2019-03-15 | 2020-09-22 | 中国电力科学研究院有限公司 | Distribution line protection method and device |
| CN111693818B (en) * | 2019-03-15 | 2024-05-14 | 中国电力科学研究院有限公司 | Distribution line protection method and device |
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| CN111509678A (en) * | 2020-04-08 | 2020-08-07 | 广东电网有限责任公司 | Anti-synchronization error self-adaptive distribution network differential protection method |
| CN112531657A (en) * | 2020-12-04 | 2021-03-19 | 东莞理工学院 | Braking coefficient self-adaptive distribution network differential protection method based on transient direction |
| CN112531657B (en) * | 2020-12-04 | 2023-08-08 | 东莞理工学院 | Brake coefficient self-adaptive distribution network differential protection method based on transient direction |
| CN113708352A (en) * | 2021-08-23 | 2021-11-26 | 广东电网有限责任公司 | Relay protection method and device |
| CN114221307A (en) * | 2021-12-09 | 2022-03-22 | 南京南瑞继保电气有限公司 | Line differential protection braking coefficient adjusting method and device and electronic equipment |
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