CN104377669B - A kind of wide area protection algorithm for comparing impedance principle based on cross measure - Google Patents
A kind of wide area protection algorithm for comparing impedance principle based on cross measure Download PDFInfo
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- CN104377669B CN104377669B CN201410674772.3A CN201410674772A CN104377669B CN 104377669 B CN104377669 B CN 104377669B CN 201410674772 A CN201410674772 A CN 201410674772A CN 104377669 B CN104377669 B CN 104377669B
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Abstract
A kind of wide area protection algorithm for comparing impedance principle based on cross measure; each branch road cross measure impedance is calculated respectively using the protection terminal device IED installed at node bus the spill currents for gathering busbar voltage and all connected circuits of node in real time; when the different short dots of system break down, there is obvious otherness in its cross measure imaginary impedance size and impedance angle.This patent compares impedance protection criterion using this feature difference as cross measure, and the impedance value of wide-area communication is converted into protection direction amount of logic by IED by each branch protection criterion.The direction amount of logic for obtaining all nodes in region is built the one-dimensional row vector matrix of 1 × n ranks by wide area protection decision center; and a failure judgement region is compared according to determinant of a matrix; and the IED in region is sent to by wide-area communication, the IED for obtaining information realizes secondary failure judgement circuit with reference to each branch road transverse impedance criterion the result of the action.Constraint of the wide area protection to the traffic can be greatly reduced in the present invention.
Description
Technical field
It is a kind of wide area for comparing impedance principle based on cross measure the invention belongs to relay protection field in power system
Protection algorism.
Background technology
Wide area protection based on wide area multi-source information can quickly and accurately recognize fault element and realize fault element
Quickly isolate the study hotspot as new relay protection, its outstanding feature be to can solve the problem that traditional back-up protection delay it is long,
The problems such as setting value order difficulty, while improving the adaptivity of protection.The feature also embody Fault Identification element algorithm and its
Implementation method is the research emphasis and core of wide area protection.
The current existing wide area protection algorithm that can quickly recognize fault element is mainly used in current differential principle
Wide area protection algorithm.Wide area current differential principle is simple, and action is quick and with split-phase function, but it is to power network multiple point measuring number
According to synchronism require it is higher, it is larger by area distribution formula capacitive effect, while protection domain can not have load current stream
Go out, the measurement accumulated error of multiple spot electric current may also produce larger out-of-balance current in power network, then influence its sensitivity and
Reliability (D.Novosel, G.Bartok, G.Henneberg, P.Mysore, D.Tziouvaras, and S.Ward.IEEE
PSRC report on performance of relaying during wide-area stressed conditions
[J].IEEE Transactions on Power Delivery,2010,25(1):3-16.).To overcome wide area current differential
Part problem is protected, wide area comprehensive impedance protection algorism proposes to pass in and out the ratio of electric current sum using many terminal voltages in region and with region
Comprehensive impedance algorithm is constructed, the method overcome Wide-area current differential protection is influenceed by distributed capacitor, maintains similar difference
The higher sensitivity of dynamic protection, but the similar Wide-area current differential protection of the protection scheme, protection zone can not have load electricity
Stream, otherwise protection domain is incorrect with Current calculation, while the protection needs also exist for the strict synchronism (Li Zhen of Wide-area Measurement Information
It is emerging, Yin Xianggen, Zhang Zhe, wide area relay protection criterion research [J] the electrotechnics of what will duty based on comprehensive impedance comparison principle
Journal, 2012,27 (8):179-186.).
The content of the invention
The present invention with solve wide area differential protection Dependency Specification stringent synchronization, claimed scope be not present load current with
And area distribution electric capacity influence the problems such as the purpose of, propose it is a kind of based on cross measure compare impedance principle wide area protection calculate
Method, the algorithm is based only upon the synchronism of conventional line current comparison pilot protection, utilizes busbar voltage and the ratio of circuit spill current
Value directly constitutes transverse impedance calculating, and structure is horizontal on the basis of many point impedance judged results of wide area are converted to direction amount of logic
Compare the wide area protection algorithm of impedance principle to measurement, this thinking is the advantage for remaining Wide-area current differential protection, simultaneously
Overcome the influence of the strict synchronism of wide area and load current and distributed capacitor.The ability of anti-transition resistance is improved,
There is higher sensitivity compared with wide area differential is protected.
The technical scheme that the present invention takes is：
A kind of wide area protection algorithm for comparing impedance principle based on cross measure,
Step one：The IED that each node (referring generally to bus) place is installed in protected area obtains node and showed in real time respectively
There is the existing busbar voltage U of protection devicea、Ub, Uc and be connected all circuits spill current Icda-j、Icdb-j、Icdc-j, its
Middle j is j-th strip branch road.
Step 2：Calculate the cross measure impedance Z of all circuits respectively using busbar voltage and spill currentci-j,WhereinFor node bus x phases (A, B, C phase, other statements of this patent are similar) voltage,For j-th strip
Circuit x phase spill currents.Measurement impedance Z is further calculated respectivelyci-jImaginary part and phase.
Step 3：Position based on system short-circuit point is different, and its cross measure imaginary impedance and phase angle are present significantly
Difference, composition cross measure compares impedance protection criterion and is：|Imag(Zci-j)|<Xset∩-ε<Arg(Zci-j)<180+ ε, wherein
XsetTo compare protection definite value, Xset=krelimag(ZC//(RF+(mZL-j+Zm)//((1-m)ZL-j+Zn))ejδ)max, wherein Zm、
Zn、ZL-j、ZcRespectively the impedance of circuit m, n end systems, line impedance, circuit distribution capacitive reactance, m be trouble point apart from the position at m ends,
0<m<1, δ is both end voltage phase difference, krelFor safety factor.
Step 4：Impedance protection criterion is compared based on cross measure, circuit cross measure is defined and compares impedance protection direction
For：Meet criterion Rj=1 (positive direction, bus point to circuit), otherwise Rj=0, wherein j are circuit branch road.
Step 5：IEDjThe impedance protection direction of all branch roads of node is counted, if any j bar branch roads, R1、…Rj, definition node
Direction amount of logic FBjRepresent node direction, FBj=R1∪R2∪…∪Rj(it is positive direction to be equal to 1, shows that event occurs for the region
Barrier).
Step 6：Based on Graph Theory, all node directions in the region of acquisition constitute 1 by wide area protection decision center ×
The one-dimensional row vector matrix of n ranks.
Step 7：Whether judgment matrix determinant meets | FB| >=2, condition is such as met, is tentatively judged as in protection zone
Break down, fault zone is the connected circuit of correspondence column vector node.Wide area protection takes fault tolerance judgment：Calculate intermediary matrix D
=FB* C, wherein C are network adjacent matrix, intermediary matrix logically D ', calculate fault-tolerant matrix W=D ′ ＆FB, arrange in searching matrix W
Vector is that 1 corresponding node is malfunctioning node；Condition is such as unsatisfactory for, is system failure.
Step 8：IED is obtained after wide area protection fault section detection result, and according to node, circuit branch road situation is carried out in succession
It is secondary to judge, meet R simultaneously if there is multiple branch roadsj=1, then this node failure select branch road wait feelings are judged to side gusset
Condition, directly judges this circuit for fault element if certain circuit offside fault message is obtained；If there is no multiple branch roads
Meet R simultaneouslyj=1, this node directly judges to meet Rj=1 circuit is faulty line, and sends information to offside (information one
As have the forwarding of wide area protection decision center, special circumstances can select other passages to directly transmit).
The present invention utilizes the synchronism of conventional line current comparison pilot protection, direct calculate node busbar voltage and circuit
The ratio of spill current constitutes cross measure impedance, is compared based on wide area multiple spot transverse impedance and realizes wide area protection algorithm.The algorithm
Principle is succinct, while overcoming wide scope stringent synchronization and there is the influence of load current；The present invention will be counted on the spot simultaneously
The cross measure of calculation compares impedance conversion for logical message, and only upload logic amount is in wide area protection, and information content is small, substantially reduces wide
Domain system communicating requirement；First order matrix dimension calculates the Project Realization for being conducive to wide area protection with wide area protection fault-tolerant processing.
Brief description of the drawings
Fig. 1 is present system scheme total figure.
Type Equivalent Circuit Model figure when Fig. 2 is present system troubles inside the sample space.
Fig. 3 is the node system figure of 10 machines of IEEE 39 of the present invention.
Impedance simulation result is compared in system cross measure when Fig. 4 is K1 point failures of the present invention.
Embodiment
As Figure 1-Figure 4, one kind compares impedance wide area relay protection criterion based on cross measure, comprises the following steps：
The IED installed at step 1. node bus obtains three-phase voltage amount U at node bus in real timea、Ub、UcAnd be connected
All circuit spill current I connectcda-j、Icdb-j、Icdc-j, wherein j is j-th strip branch road.
Step 2. calculates the cross measure impedance of all circuits using busbar voltage and circuit spill current respectively, with j-th strip
Exemplified by circuit, cross measure impedanceWhereinFor node bus x phase voltages,For x phase spill currents.
Step 3. cross measure impedance comparison criterion is with Zci-jFeature difference is attached most importance to, and the step is to Zci-jFeature carry out
Analysis.Following examples are descriptive, are not limited, it is impossible to limit analysis result of the present invention with this.
With reference to the concrete analysis of the circuit equivalent model of accompanying drawing 2：
During system normal operating condition, circuit flows mainly through the load current of passing through property, and the spill current at circuit two ends is main
It is the electric current for flowing through line-to-ground distribution capacity, cross measure impedance value is equal to line equivalent capacitive reactance Zc, its capacitor value is very big, and one
As all more than kilohm rank, simultaneously because Zci-jIn capacitive, imaginary values are larger, and its impedance angle is at -90 ° or so.
On circuit occur external area error when, flowing through the electric current of circuit may increase, but circuit two ends spill current still
It is line-to-ground capacitance current, the same normal operation of cross measure impedance value characteristic.
System occurs in troubles inside the sample space, show that the cross measure impedance of circuit two ends has following relation by accompanying drawing 2
Zcim-j+Zcin-j=ZC//(RF+(mZL-j+Zm)//((1-m)ZL-j+Zn))=Zth-j (1)
U in formulam、UnRespectively circuit both end voltage virtual value, δ is circuit both end voltage phase angle difference.
It can be obtained by formula (1) (2)：
Similar analysis can also obtain the same result of N-terminal measurement impedance.It therefore, it can obtain laterally to survey during troubles inside the sample space
Measure impedance ranges：
When knowing that troubles inside the sample space occurs for circuit according to analysis, two ends cross measure impedance is respectively less than a definite value, the definite value and electricity
Source impedance, line impedance, transition point position and transition resistance are relevant with circuit both end voltage difference δ, from systematic parameter and operation
Feature understands that the definite value is substantially in perception, and imaginary part is smaller, it is contemplated that the influence of transition resistance and calculation error, cross measure
Compare impedance and be possible to be in capacitive, but the absolute value of its imaginary part is much smaller than the actual capacitive reactance Z of circuitC/ 2, its phase angle 0 °~
180°。
This patent is by taking accompanying drawing 3 as an example, and circuit L17 is away from (the K of bus B16 sides total track length 0% for setting1) place occur it is various short
Road failure and earth fault (transition resistance takes 0~300 Ω), system 1s moment after steady-state operation break down, and calculate nearly event
Hinder each circuit cross measure impedance results of point as shown in Figure 4.
Step 4. is analyzed according to step 3, and it is as follows to compare impedance protection criterion based on cross measure：
In formula, XsetIt is to compare definite value, can be determined by formula (1), (4)
Xset=krelimag(Zth-jejδ)max
=krelimag(ZC//(RF+(mZL-j+Zm)//((1-m)ZL-j+Zn))ejδ)max
(6)
In formula, krelFor safety factor, recommendation is set as 1.2~1.5；Wherein Zm、Zn、ZL-j、ZcRespectively circuit m, n ends
System impedance, line impedance, equivalent line capacitive reactance；M is trouble point apart from the position at m ends, 0<m<1, after systematic parameter is determined,
According to different m values, it is easy to calculate maximum according to Circuit theory；Consider measurement error, calculation error and the influence at δ angles, ε
Typically take 15 °~30 °；RFFor trouble point grounding resistance；δ is circuit both sides phase difference of voltage；" // ", represents that impedance parallel connection is calculated.
Step 5. definition circuit cross measure compares impedance protection direction and is：Meet formula (5) criterion Rj=1 (regulation
For positive direction, bus points to circuit), otherwise Rj=0, wherein j are circuit branch road.
Step 6.IEDjBe connected all branch impedance direction (such as R in statistic procedure 5 with node1、Rj), definition node direction
FBjTo represent at node branch road and logical message, node direction FBj=R1∪R2∪…∪Rj(it is positive direction to be equal to 1, shows this
Break down in region).
Step 7. is based on Graph Theory, and all node directions in the region of acquisition are constituted 1 × n by wide area protection decision center
The one-dimensional row vector matrix of rank.It is example explanation that the lower protection zone of short circuit, which occurs, for circuit L16 in accompanying drawing 3 of the present invention, with node serial number
For matrix column vector sequence number, the one-dimensional row vector matrix F of 1 × 6 rank of correspondenceB=[FBB15FBB16FBB17FBB19FBB21FBB24]1×6=
[110000]。
Whether step 8. judgment matrix determinant meets | FB| >=2, condition is such as met, is tentatively judged as sending out in protection zone
Raw failure.There is distortion situation in view of direction in wide area calculating or communication process, wide area protection there must be fault tolerance, this
Patent fault-tolerance approach is as follows：Calculating network Topology connection Matrix C
Calculate intermediary matrix D=FB* C, further by intermediary matrix logically D '
Calculate fault-tolerant matrix W=D ′ ＆FB, column vector is that 1 corresponding node is malfunctioning node in searching matrix W.
Such as it is unsatisfactory for | FB| >=2, it is system failure.
Step 9：Based in step 8, IED is obtained after wide area protection fault section detection result, according to node circuit in succession
Branch case carries out secondary judgement, and R is met simultaneously if there is multiple branch roadsj=1, then this node failure select branch road wait offside
Node estimate of situation, directly judges this circuit for fault element if certain circuit offside fault message is obtained；If do not deposited
R is met in multiple branch roads simultaneouslyj=1, this node directly judges to meet Rj=1 circuit is faulty line, and is sent information to pair
Side (information typically has the forwarding of wide area protection decision center, and special circumstances can select other passages to directly transmit).
Described above is presently preferred embodiments of the present invention, but the present invention should not be limited to the embodiment and accompanying drawing institute
Disclosure.So every do not depart from the lower equivalent or modification completed of spirit disclosed in this invention, guarantor of the present invention is both fallen within
The scope of shield.
Claims (7)
1. a kind of wide area protection algorithm for comparing impedance principle based on cross measure, it is characterised in that comprise the following steps：
Step one：At node bus install IED obtain in real time busbar voltage and be connected all circuits spill current, using point
The ratio of phase busbar voltage and circuit spill current calculates the cross measure impedance Z of all circuits respectivelyci-j；
Step 2：Position based on protection zone short dot is different, and its cross measure imaginary impedance size and impedance angle are deposited
In obvious difference, constitute cross measure and compare impedance protection criterion, and define circuit cross measure impedance protection direction and be：It is full
Sufficient criterion Rj=1, otherwise Rj=0；
Step 3：IEDjThe cross measure impedance protection direction of all branch road circuits of node is counted, section is determined using with logical relation
Point direction FBj；
Step 4：Based on Graph Theory, all node directions in the region of acquisition are constituted 1 × n ranks by wide area protection decision center
One-dimensional row vector matrix FB, whether judgment matrix determinant meet | FB| >=2, tentatively judge that protection zone is with reference to network topology
It is no to break down；
Step 5：IED obtains wide area protection fault section detection result, and two are realized with reference to branch road cross measure impedance judged result
It is secondary to judge, further determine that faulty line.
2. a kind of wide area protection algorithm for being compared impedance principle based on cross measure according to claim 1, its feature is existed
In：Step one：Cross measure impedanceWhereinIt is node busbar voltage,For circuit spill current.
3. a kind of wide area protection algorithm for being compared impedance principle based on cross measure according to claim 1, its feature is existed
In：Step 2：Impedance protection criterion is compared in cross measure | Imag (Zci-j)|<Xset∩-ε<Arg(Zci-j)<180+ ε, wherein
XsetIt is to compare protection definite value Xset=krelimag(ZC//(RF+(mZL-j+Zm)//((1-m)ZL-j+Zn))ejδ)max, ε is calculating mistake
Difference；
In formula, krelFor safety factor；Wherein Zm、Zn、ZL-j、ZcRespectively the impedance of circuit m, n end systems, line impedance, circuit divide
Cloth capacitive reactance, equivalent line capacitive reactance；M is trouble point apart from the position at m ends, 0<m<1；After systematic parameter is determined, according to different m
Value, maximum is calculated according to Circuit theory；Consider measurement error, calculation error and the influence at δ angles, ε typically takes 15 °~30 °；
RFFor trouble point grounding resistance；δ is circuit both sides phase difference of voltage；" // ", represents that impedance parallel connection is calculated.
4. a kind of wide area protection algorithm for being compared impedance principle based on cross measure according to claim 1, its feature is existed
In：Step 3：IEDjCount the impedance protection direction R of all branch roads of node1、…、Rj, calculate node direction FBj=R1∪R2
∪…∪Rj。
5. a kind of wide area protection algorithm for being compared impedance principle based on cross measure according to claim 1, its feature is existed
In：Step 4：All node directions in the region of acquisition are constituted the one-dimensional row vector matrix of 1 × n ranks by wide area protection decision center,
Matrix column vector sequence number map network topological node is numbered.
6. a kind of wide area protection algorithm for being compared impedance principle based on cross measure according to claim 1, its feature is existed
In：Step 4：Whether calculating matrix determinant is more than 2, such as meets, is then tentatively judged as breaking down in protection zone, enters one
The column vector node that searching matrix determinant is equal to 1 is walked, with reference to the connectivity of network topology, is sentenced for two nodes being directly connected to
Break as fault zone, otherwise do this failure and judge, wait next time data start to recalculate matrix determinant.
7. a kind of wide area protection algorithm for being compared impedance principle based on cross measure according to claim 1, its feature is existed
In：Step 5：IED carries out secondary judgement, if the node has multiple branch roads while meeting Rj=1, then wait to side gusset
Judged result, directly judges this circuit for fault element if certain circuit offside fault message is obtained；If the node is not
There are multiple branch roads while meeting Rj=1, directly judge to meet Rj=1 circuit is faulty line, and sends information to offside.
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Citations (4)
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| CN102570426A (en) * | 2012-02-17 | 2012-07-11 | 黑龙江省电力有限公司 | Method for realizing back-up protection in wide area protection by using differential protection |
| CN102593797A (en) * | 2012-02-17 | 2012-07-18 | 黑龙江省电力有限公司 | Topological structure-based differential combination method |
| CN103354355A (en) * | 2013-05-09 | 2013-10-16 | 中国能源建设集团广东省电力设计研究院 | Method and device for networked protection of microgrid |
| CN103715669A (en) * | 2014-01-07 | 2014-04-09 | 华北电力大学 | Distributed wide-area self-adaptive inter-phase backup protection system and method |
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| US8405940B2 (en) * | 2009-10-13 | 2013-03-26 | Schweitzer Engineering Laboratories Inc | Systems and methods for generator ground fault protection |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102570426A (en) * | 2012-02-17 | 2012-07-11 | 黑龙江省电力有限公司 | Method for realizing back-up protection in wide area protection by using differential protection |
| CN102593797A (en) * | 2012-02-17 | 2012-07-18 | 黑龙江省电力有限公司 | Topological structure-based differential combination method |
| CN103354355A (en) * | 2013-05-09 | 2013-10-16 | 中国能源建设集团广东省电力设计研究院 | Method and device for networked protection of microgrid |
| CN103715669A (en) * | 2014-01-07 | 2014-04-09 | 华北电力大学 | Distributed wide-area self-adaptive inter-phase backup protection system and method |
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Application publication date: 20150225 Assignee: Yichang Yizhixing Technology Co.,Ltd. Assignor: CHINA THREE GORGES University Contract record no.: X2023980034895 Denomination of invention: A Wide Area Protection Algorithm Based on the Principle of Lateral Measurement and Comparison Impedance Granted publication date: 20170725 License type: Common License Record date: 20230426 |
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