CN109188206A - A kind of guard method with branched line based on petal type power grid - Google Patents
A kind of guard method with branched line based on petal type power grid Download PDFInfo
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- CN109188206A CN109188206A CN201811054721.5A CN201811054721A CN109188206A CN 109188206 A CN109188206 A CN 109188206A CN 201811054721 A CN201811054721 A CN 201811054721A CN 109188206 A CN109188206 A CN 109188206A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
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- Locating Faults (AREA)
Abstract
本发明属于电网线路板线路保护技术领域，尤其涉及一种基于花瓣式电网的带分支线路的保护方法。本发明基于对称分量法的思想，提出了利用自由振荡频率表进行判断依据以快速进行故障判断和相线定位的保护方法，该方法不受故障时刻、负荷电流以及震荡等暂态量的影响，提高了电网故障判断以及故障相定位的效率以及准确性。
The invention belongs to the technical field of line protection of power grid circuit boards, and in particular relates to a protection method for branch lines based on a petal-type power grid. Based on the idea of the symmetrical component method, the present invention proposes a protection method that uses the free oscillation frequency table as the basis for judgment to quickly perform fault judgment and phase line location. The efficiency and accuracy of power grid fault judgment and fault phase location are improved.
Description
Technical field
The invention belongs to grid line line circuit protection technique field more particularly to a kind of bands point based on petal type power grid
The guard method of branch line.
Background technique
The petal mode of connection of power distribution network is as a kind of propagable method of operation and technical solution, to carry out the world comprehensively
First-class distribution network construction provides new thinking and supporting method.Petal power grid is led to by every two feedback line of the same substation
Guo Zhongya switching station pulls bracelet and is connected into pressure ring net in one " petal-shaped "；" petal " shape looped network of different substation is tangent to each other
It is connected with each other, multiple " petal-shaped " looped networks constitute " flower " shape centered on substation.When normal operation, petal-shaped annular
The not transregional power supply of power distribution network, the interconnection switch between petal disconnect, and the interconnection switch closure in substation is only led in failure
It crosses the bus contact in substation or between substation and carries out large-scale load transfer between petal, and important load is due to setting
Liaison office between petal realizes more the spare power supplies, therefore greatly improves the flexibility and reliability of power supply.Distribution
Formula power supply device refers to that power is thousands of watts of independent current sources to 50MW small modules formula, with environmental compatible.These power supplys by
Power department, power consumer or the 3rd side are all, specifically require to meet electric system and user.Such as peak regulation is outlying use
Family or the power supply of shopping centre and residential block, save power transmission and transformation investment, improve power supply reliability etc..
In power transmission line circuit network, especially in the petal electric network composition containing numerous branched lines, in order to guarantee its electricity
The efficient self-healing and rapid recovery capability of net, need quickly quickly to cut off faulty line, this not only needs to configure movement
Quick relay protection device, more to the quick judgement of faulty line and positioning to ensure its accuracy acted, traditional guarantor
Maintaining method needs long time window to be filtered in calculating and influence when locating bad lines due to receiving transient state component
The time is eliminated in the influences such as wave, isolation, is worth the delay of protection act, the speed of entire protection act and accurately by larger
Influence, this brings adverse effect to the popularization and application of petal power grid.
Summary of the invention
The purpose of the invention is that provide a kind of can be avoided is influenced by route transient state component, utilizes free vibration
Frequency is swung to the method for faulty section/route/mutually carry out quick analyzing and positioning, and data needed for this method are few, and processing routine is simply fast
Victory, and can easily realize computer disposal, it is capable of the realization protection of high efficient and flexible.
To achieve the above object, the invention adopts the following technical scheme that.
A kind of guard method with branched line based on petal type power grid, includes the following steps:
Step 1. measures the three-phase current that front and back occurs for failure, and three-phase current is converted, alternate spill current, zero are obtained
Sequence electric current；To each phase current, each alternate spill current, zero-sequence current carries out FFT transform；To obtain zero-sequence current and alternate difference electricity
The spectrogram of stream；
Step 2. constructs zero-sequence current basic frequency criterion according to the distribution characteristics of zero-sequence current frequency spectrum；max{FN.ABC}≥
ε1；Wherein ε1For threshold value, according to running data setting；If meeting criterion, it can determine that fault type is two-phase
Ground fault or singlephase earth fault；It is three phase short circuit fault or two-phase short-circuit fault if being unsatisfactory for；
Step 3. is on the basis of step 2 is determined as ungrounded failure, according to three phase short circuit fault and two-phase short-circuit fault
Amplitude Characteristics difference constructs Amplitude Ration criterion:Wherein ε2For safety factor, wherein X, Y, Z are three-phase
In any one phase；f0For power frequency, fkFor k-th of basic free oscillation frequency；If meeting criterion, it can determine that fault type is
Two-phase short-circuit fault, and X, Y phase are failure phase, Z is non-faulting phase；It is on the contrary then be three phase short circuit fault；
Step 4. is short according to single-phase grounding fault and two phase ground on the basis of step 2 is determined as ground fault
Road failure spill current spectrum distribution feature difference constructs spill current basic frequency criterion: max { FN.XY}≤ε3；Wherein ε3For thresholding
Value,；According to running data setting；If meeting criterion, fault type can be identified as single-phase grounding fault, and
X, Y phase is non-faulting phase；It is on the contrary then be two-phase short circuit and ground fault；
Step 5. is on the basis of step 4 is determined as double earthfault, according to the skin quality of two-phase short circuit and ground fault, structure
Build Amplitude Ration frequency criterion:Wherein ε4For threshold value,；According to running data setting；It is mostly full
Sufficient criterion, then X, Y are failure phase, and Z is non-faulting phase.
Further improvement or refinement to the above method further include ε1=10；ε2=10；ε3=50；ε4=10.
Further improvement or refinement to the above method further include, and in the step 1, obtain zero-sequence current and alternate
The spectrogram of spill current specifically refers to: in grid collapses, constructing the pull-type expression formula of faulty circuit parameter, obtains failure
The fundamental resonance equation of additivity solves the a-c cycle solution of fundamental resonance equation, using frequency values as abscissa, respectively with each
Phase short-circuit current value is that ordinate draws spectrogram.
The beneficial effect is that: the present invention is based on the thought of symmetrical component method, propose using free oscillation frequency table into
Row judgment basis with quickly carry out breakdown judge and phase line positioning guard method, this method is not by fault moment, load current
And the influence of the transients such as concussion, improve the efficiency and accuracy of electric network fault judgement and faulty phase locating.
Detailed description of the invention
Fig. 1 is the transmission line malfunction illustraton of model based on distributed parameter model building；
Fig. 2 is transmission line malfunction additivity figure；
Fig. 3 is the barrier simplified circuit of model decomposition figure
Fig. 4 is the flow chart of the guard method with branched line based on petal type power grid；
Fig. 5 is alternate spill current spectrogram in embodiment.
Specific embodiment
It elaborates below in conjunction with specific embodiment to the invention.
It is as shown in Figure 1 using distributed parameter model building transmission line malfunction illustraton of model；According to principle of stacking, entire petal
The state of shape power grid in the event of a failure is considered as the state that the petal power grid of normal state is superimposed with the petal power grid of fault case；
Wherein the petal power grid of fault case can be regarded as again is made of electric system and faulty circuit, failure additivity figure such as Fig. 2
It is shown, it is assumed that each phase voltage in fault point is(X=A, B, C)；It then can be convenient according to failure
Adjust the parameters for determining faulty circuit；
When three phase short circuit fault occurs for power transmission line route, faulty circuit parameter can be obtained according to the boundary condition at failure
Pull-type expression formula are as follows:
Faulty circuit still three-phase symmetrical after three phase short circuit fault occurs for system, therefore can simplify and divided to be single-phase
Analysis, simplified circuit are as shown in Figure 3；
It enablesThen by uniform
Equation for transmission line is available:
WhereinHave for N side systemBased on above-mentioned basis；?
It arrivesExpression formula be
For above formula, s=± j ω0It is its conjugate pole, represents iN(t) power frequency component in obtains its culminating paint equation:
ZN(s)cosh(γl)+ZC(s) sinh (γ l)=0----------------- formula is 1.；
A frequency component of its transient state noise component has been corresponded to formula each real root 1. or every a pair of of Conjugate complex roots,
The real root s of aperiodic component in current failure component is represented including one0And its basic free oscillation frequency component sk, (k=
1,2,3.....K)；Caused by failure motivate under, formula 1. i.e. represent in transmission line of electricity due to distribution capacity, system impedance with
And line impedance constitutes resonant relationship equation；Also referred to as fundamental resonance equation, serial a-c cycle solution are free oscillation frequency
Rate；For in actual track；Route can be reduced to lossless route to account for；On this basis 1. convertible obtains it
Exponential equation:
e2st=Γ ejθej2kπ--- --- --- --- --- -- formula is 2.；
Wherein
For sufficiently large basic free oscillation frequency k value, R can be ignoredC, then have θ=π；Basic free oscillation can be obtained
The approximation of frequency isIt is divided between each frequencyThat is, ought substantially freely
When frequency of oscillation is enough big, the interval between side frequency be it is equal and be placed in fault point to system end distance dependent；
Each pole that fundamental resonance equation is acquired according to pull-type inverse transformation expansion theorem can acquire protection using decomposition theorem
The amplitude of basic free oscillation frequency K component in the current temporary state component of installation place:
By above formula it can be found that working as false voltage initial phase angleWhen, the amplitude of basic free oscillation frequency reaches
Maximum, whenWhen, the amplitude of basic free oscillation frequency reaches minimum, no matter but failure occur in what moment, base
This free oscillation frequency component exists.This is because when potential is maximum value, voltage highest on capacitor, the energy of storage
Maximum, so the basic free oscillation frequency current weight that capacitor electric discharge generates is also maximum, when in potential zero passage when short circuit occurs
When instantaneous short circuit, although the voltage on capacitor is zero, energy is stored in inductance at this time, the energy releases after short circuit
To capacitor charging, basic free oscillation frequency current weight is formed, so basic free oscillation frequency current weight and being not zero.
Therefore, when short circuit occurs on the super-high voltage road for be distributed capacitor, no matter short circuit occurs in what moment, basic free oscillation
Frequency component electric current is to exist certainly；Likewise, to asymmetric short trouble, including line to line fault/ground fault, single-phase connect
Earth fault can summarize after being analyzed: only existing when three phase short circuit fault and two-phase short-circuit fault occurs and freely shake substantially
It swings frequency, only exist zero group of free oscillation frequency when singlephase earth fault occurs, when exposing ground short circuit, then simultaneously
There are basic free oscillation frequencies and zero group of free oscillation frequency；
That is, free oscillation frequency component, max { F is not present in zero-sequence current when ungrounded short troubleN.ABC}=0；
When ground short circuit failure, there are free oscillation frequency component, max { F for zero-sequence currentN.ABC> 0；
When singlephase earth fault, any free oscillation frequency component, max { F is not present in the alternate spill current of non-faultingN.XY}=
0；
When double earthfault, basic free oscillation frequency component, max { F in the alternate spill current of failureN.XY> 0；
When in view of practical calculating, serial compensation capacitance and shunt reactor in petal power grid etc. can be to the freedom of route
Frequency of oscillation has an impact；The basic structure setting threshold value of petal power grid complies with reality when can be according to actual motion
Calculated result；
Based on above-mentioned basis, the present invention is based on the basic procedures of the guard method with branched line of petal type power grid as schemed
Shown in 4, step includes:
Step 1. measures the three-phase current that front and back occurs for failure, and three-phase current is converted, alternate spill current, zero are obtained
Sequence electric current；
To each phase current, each alternate spill current, zero-sequence current carries out FFT transform；To obtain zero-sequence current and alternate difference
The spectrogram of electric current；
Step 2. judges whether it is ground fault according to zero-sequence current basic frequency criterion；
According to the distribution characteristics of zero-sequence current frequency spectrum, zero-sequence current basic frequency criterion is constructed；
max{FN.ABC}≥ε1；Wherein ε1For threshold value, according to running data setting；ε under normal circumstances1=
10；
If meeting criterion, it can determine that fault type is double earthfault or singlephase earth fault；If being unsatisfactory for
It is then three phase short circuit fault or two-phase short-circuit fault；
Step 3. is on the basis of step 2 is determined as ungrounded failure, according to three phase short circuit fault and two-phase short-circuit fault
Amplitude Characteristics difference constructs Amplitude Ration criterion:
Wherein ε2For safety factor, ε under normal circumstances2=10；, wherein X, Y, Z are in three-phase
Any one phase；f0For power frequency, fkFor k-th of basic free oscillation frequency；
If meeting criterion, it can determine that fault type is two-phase short-circuit fault, and X, Y phase are failure phase, Z is non-faulting
Phase；It is on the contrary then be three phase short circuit fault；
Step 4. is short according to single-phase grounding fault and two phase ground on the basis of step 2 is determined as ground fault
Road failure spill current spectrum distribution feature difference constructs spill current basic frequency criterion:
max{FN.XY}≤ε3；Wherein ε3For threshold value, ε under normal circumstances3=50；It is set according to running data
It is fixed；If meeting criterion, fault type can be identified as single-phase grounding fault, and X, Y phase are non-faulting phase；It is on the contrary then be two
Phase ground short circuit failure；
Step 5. is on the basis of step 4 is determined as double earthfault, according to the skin quality of two-phase short circuit and ground fault, structure
Build Amplitude Ration frequency criterion:Wherein ε4For threshold value, ε under normal circumstances4=10；；According to system reality
Operation data setting；Meet criterion, then X, Y are failure phase, and Z is non-faulting phase more；
Short-circuit test is carried out to certain petal power grid, obtains each phase current when three-phase shortcircuit, observes alternate spill current frequency
Spectrogram is as shown in Figure 5；
It is as shown in table 1 that three-phase shortcircuit phase selection decision table can be obtained by Fig. 5:
1 three-phase shortcircuit decision table of table
According to same method, other fault types of petal power grid can also quickly be judged；It is not superfluous herein
It states；
Finally it should be noted that above embodiments are only to illustrate the technical solution of the invention, rather than to this hair
It is bright create protection scope limitation, although being explained in detail referring to preferred embodiment to the invention, this field it is general
Lead to it will be appreciated by the skilled person that can be modified or replaced equivalently to the technical solution of the invention, without departing from this
The spirit and scope of innovation and creation technical solution.
Claims (3)
1. a kind of guard method with branched line based on petal type power grid, which comprises the steps of:
Step 1. measures the three-phase current that front and back occurs for failure, and three-phase current is converted, and obtains alternate spill current, zero sequence electricity
Stream；To each phase current, each alternate spill current, zero-sequence current carries out FFT transform；To obtain zero-sequence current and alternate spill current
Spectrogram；
Step 2. constructs zero-sequence current basic frequency criterion according to the distribution characteristics of zero-sequence current frequency spectrum；max{FN.ABC}≥ε1；Its
Middle ε1For threshold value, according to running data setting；If meeting criterion, it can determine that fault type is two phase ground
Failure or singlephase earth fault；It is three phase short circuit fault or two-phase short-circuit fault if being unsatisfactory for；
Step 3. is on the basis of step 2 is determined as ungrounded failure, according to three phase short circuit fault and two-phase short-circuit fault amplitude
Feature difference constructs Amplitude Ration criterion:Wherein ε2For safety factor, wherein X, Y, Z are in three-phase
Any one phase；f0For power frequency, fkFor k-th of basic free oscillation frequency；If meeting criterion, it can determine that fault type is two-phase
Short trouble, and X, Y phase are failure phase, Z is non-faulting phase；It is on the contrary then be three phase short circuit fault；
Step 4. is on the basis of step 2 is determined as ground fault, according to single-phase grounding fault and two-phase grounding fault event
Hinder spill current spectrum distribution feature difference, constructs spill current basic frequency criterion: max { FN.XY}≤ε3；Wherein ε3For threshold value,；Root
According to running data setting；If meeting criterion, fault type can be identified as single-phase grounding fault, and X, Y phase
For non-faulting phase；It is on the contrary then be two-phase short circuit and ground fault；
Step 5., according to the skin quality of two-phase short circuit and ground fault, constructs width on the basis of step 4 is determined as double earthfault
Value is than frequency criterion:Wherein ε4For threshold value,；According to running data setting；More satisfactions are sentenced
According to then X, Y are failure phase, and Z is non-faulting phase.
2. a kind of guard method with branched line based on petal type power grid according to claim 1, which is characterized in that ε1
=10；ε2=10；ε3=50；ε4=10.
3. a kind of guard method with branched line based on petal type power grid according to claim 1, which is characterized in that institute
It states in step 1, the spectrogram for obtaining zero-sequence current and alternate spill current specifically refers to: in grid collapses, building event
Hinder the pull-type expression formula of circuit parameter, obtain the fundamental resonance equation of failure additivity, solves the exchange of fundamental resonance equation
Frequency solution draws spectrogram by ordinate of each phase short-circuit current value respectively using frequency values as abscissa.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110988598A (en) * | 2019-12-17 | 2020-04-10 | 国网河北省电力有限公司 | Ground fault location method of petal-type urban power grid based on zero-sequence current correlation |
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| CN110988598B (en) * | 2019-12-17 | 2021-01-26 | 国网河北省电力有限公司 | Petal type urban power grid ground fault positioning method based on zero sequence current association |
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