CN108693444B - A kind of failure point of power transmission line localization method based on electromagnetic signal time reversal - Google Patents
A kind of failure point of power transmission line localization method based on electromagnetic signal time reversal Download PDFInfo
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- CN108693444B CN108693444B CN201810498192.1A CN201810498192A CN108693444B CN 108693444 B CN108693444 B CN 108693444B CN 201810498192 A CN201810498192 A CN 201810498192A CN 108693444 B CN108693444 B CN 108693444B
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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
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
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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
- G01R31/088—Aspects of digital computing
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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
- G01R31/11—Locating faults in cables, transmission lines, or networks using pulse reflection methods
Abstract
The present invention is a kind of failure point of power transmission line localization method based on electromagnetic signal time reversal, this method is based on electromagnetism time reversal principle, single observation point is arranged in any one terminal in distribution network, measures and records one section of fault high frequency transient signal having in limit；Measuring signal is subjected to time backward, is injected into distribution network Simulation Calculation by observation point, the norm value in power distribution network at different conjecture positions is calculated, judges abort situation by finding peak value maximum and energy root maximum.This method is different from traditional judgement traveling wave method and impedance method, the distribution network of a complex topology structure can be covered by an observation point, it is not influenced by fault impedance size, while there is stronger anti-noise ability, there is stronger practical value in transmission open acess.
Description
Technical field
The invention belongs to relay protection of power system and distribution network fault location, are based on failure more particularly to one kind
High frequency transient signal analyzes fault diagnosis and localization method.
Background technique
Transmission line of electricity is the element of power grid, and due to having a very wide distribution, and ultra-high-tension power transmission line is exposed to for a long time
In the severe natural environment such as wind, rain, thunder, electricity, inevitably break down.These failures directly affect transmission line of electricity peace
Full reliability service even will cause large area blackout when serious.Therefore, failure should check abort situation after occurring as early as possible,
Processing accident, fast recovery of power supply, to improving, safe operation of power system is horizontal, operational reliability is particularly significant for this.Route hair
Trouble-shooting point is a key technology for guaranteeing power network safety operation after raw failure, and the positioning failure of precise and high efficiency can
Mitigate line walking burden, save a large amount of manpower and material resources, and restoring electricity for route can be accelerated, reduces because of warp comprehensive caused by having a power failure
Ji loss, therefore have important practical significance to transmission line of electricity accurate fault location.
Traditional transmission line fault location technology is broadly divided into impedance method and traveling wave method two types at present, the former algorithm
Simply, it is easy to accomplish, disadvantage is that positioning result is affected by fault resstance, can not be suitable for multiple terminals Distributed power
Net.The main stream approach that traveling wave method is positioned as current power transmission line fault needs to estimate the spread speed of traveling wave in the line, benefit
Abort situation is analyzed and estimated with the transient state travelling wave signal that transmission line malfunction generates.Traveling wave method in recent years at home and abroad from
It is theoretical all to have obtained faster development to application, but there is also some still unsolved technical problems, such as high resistance earthing fault
When transient state travelling wave weak output signal lead to not extract pulse characteristics, the arrival time of main bang and catadioptric signal is difficult to know
Not etc..Localization method can be divided into single-ended mensuration, double-end measurement method and multiple-end measurement method again from observation point quantity.For more
Terminal distribution power network, there are multi-load, the complex topology structure of more bifurcateds, distributed power generation, single-ended mensuration is difficult to
It is applicable in, double-end measurement method (or multiple-end measurement method) needs to carry out high-precision time synchronization and data to the measurement data of each terminal
Telecommunication, this undoubtedly increases the complexity and cost of monitoring system.The above method improves traveling wave method to a certain extent
Reliability, but the validity of fault location still depends critically upon the extraction effect of wavefront.
Summary of the invention
The purpose of this invention is to provide a kind of electrical power distribution network fault location method based on single-ended measurement, is not necessarily to time synchronization
Communication apparatus is adaptable to more bifurcateds, the fault diagnosis of multiple terminals distribution power network and quickly positioning.
Technical scheme is as follows:
A kind of failure point of power transmission line localization method based on electromagnetic signal time reversal, includes the following steps:
[1] it according to the circuit types parameter of transmission line of electricity, wire topologies, transmission line conductive parameters, is calculated defeated
The characterisitic parameter of electric line；
[2] several failures conjecture position x is set in the model of power transmission system of foundationG；
[3] by electric current, the voltage transformer of relay protection system on transmission line of electricity, monitoring obtains faulty transmission circuit
The time domain Full wave shape of voltage u (t), electric current i (t), t ∈ [tf,tf+ T], wherein tfIt is measurement initial time, when T is signal sampling
Between length, and the waveform in finite time length is acquired record；
[4] inverting of time backward is carried out to the acquired electromagnetic data that step [3] obtain, obtains the time in acquisition duration T
Backward signal；
ur(t)=u (T-t), ir(t)=i (T-t)；
[5] characterisitic parameter of the transmission line of electricity based on step [1] establishes transmission line simulation model, and backward signal is input to
In transmission line simulation model, fault observation sites position x is calculatedGThe current or voltage at place responds, and according to norm theory meter
The peak value norm responded in duration 2T is calculated, fault observation sites position corresponding to the maximum of peak value norm is obtained
xp,realFault observation sites position x corresponding to maximum with energy norme,real, and judge to obtain the position where fault point
It sets；
The wherein mathematic(al) representation of peak value Number Norm Criterion are as follows:
The wherein mathematic(al) representation of energy norm criterion are as follows:
X in formulaGFor the position for guessing fault point；I(xG, t) and it is conjecture position xGT changes the short circuit current at place at any time；
Sup is xGLocate the peak value of short circuit current absolute value；Indicate the corresponding independent variable x when norm takes maximumGValue.
[6] fault point determines:
[6.1] according to distance between adjacent fault point in step [2] be d when x is calculatedp,realWith xe,real, realize just
Walk fault location:
[6.2] work as xp,realWith xe,realAs a result unanimously or close in situation, in xp,realOr xe,realNear zone takes step
[2] the distance between adjacent fault point is d/5~d/20 in, repeats step [1]~[5], obtains the exact position of fault point
Realize that fault point is accurately positioned；
[6.3] work as xp,realWith xe,realWhen result difference is larger, in xe,realNear zone takes adjacent failure in step [2]
The distance between point is d/5~d/20, repeats step [1]~[5], is accurately positioned, obtains the exact position of fault point
Realize that fault point is accurately positioned.
Further, in step [1] transmission line of electricity characterisitic parameter calculation formula are as follows:
In formula: Z (ω) ' indicates unit length transmission line impedance matrix；Y (ω) ' indicates unit length transmission-line admittance square
Battle array；L' indicates unit length transmission line inductance matrix；Z'wIndicate unit length transmission line resistor matrix；Z'gIndicate unit length
Transmission line the earth impedance matrix；C' indicates unit length transmission line capacitor matrix；Y'gWith indicating unit length transmission line area mobility
Matrix.
Further, in step [5] transmission line simulation model analytic equation are as follows:
Wherein, V, I are node voltage, current phasor, Y respectivelyCIt is transmission line character admittance matrix, S is cable network
Scattering parameter hypermatrix, T are pipeline incidence matrix, and Γ is to propagate hypermatrix, W(s)Be synthesis driving source super vector, [1] indicate with
The consistent unit matrix of S and Γ matrix dimensionality.
Further, x in step [6.2]p,realNear zone refers to x on transmission line of electricityp,real- d~xp,realThe position of+d
Place；xe,realNear zone refers to x on transmission line of electricitye,real- d~xe,realAt the position of+d.
Compared with prior art, the advantageous effects that the present invention has are as follows:
1., without carrying out multiple observation station data communications and time synchronization, contracting the present invention is based on the data of single observation station
While small hardware cost, the position error introduced due to time synchronization error can be eliminated, while in application by failure
The influence of noise introduced when impedance and measurement is smaller, improves positional accuracy.
2. it is temporary for failure that it is different from conventional method present invention utilizes the adapted local cosine transform principle of time reversal technology
The discriminatory analysis of state signal traveling wave details, is integrally injected, Inversion Calculation is sentenced by norm based on the sampled signal in finite time
According to realizing fault location.It avoids the erroneous judgement of traveling wave arrival time and wave head feature is difficult to the problems such as extracting.In multiple terminals point
Cloth distribution network, make somebody a mere figurehead-application backgrounds such as buried mixing distribution line (inhomogeneous medium) under with unique advantage.
3. the present invention realizes the accurate positionin to transmission line malfunction using energy norm and the double criterions of peak value norm, sufficiently
Consider the noise immunity of the stability of root criterion and peak value Number Norm Criterion in energy norm.Using first in abort situation calculating
It carries out that span d is larger, the lower coarse positioning of length resolution, obtains the approximate region of fault point, then to carry out span d smaller, long
The higher fine positioning of resolution ratio is spent, has greatly saved computing cost in this way, accelerates Inversion Calculation speed, and measurement result meets
Long transmission line, high-precision positioning requirements.The mean value of energy norm locator value and peak value norm locator value is used in calculating, so that
Positioning result combines stronger anti-noise ability, focusing and stability requirement.
Detailed description of the invention
Fig. 1 is technical solution of the present invention flow chart；
Fig. 2 is test club tower dimensional drawing of the present invention；
Fig. 3 experimental configuration schematic diagram of the present invention；
Fig. 4 is the faulted phase current waveform for not considering cross talk conditions；
Fig. 5 is the source-series injection transmission line model schematic diagram of inverting voltage；
Fig. 6 is that transmission line model schematic diagram is injected in the parallel connection of inverting current source；
Fig. 7 is not consider the norm value of cross talk conditions along route distribution map；
Fig. 8 is the three-phase current waveform for considering cross talk conditions；
Fig. 9 is to consider that the norm value of cross talk conditions is distributed along route.
Specific embodiment
In recent years, time reversal (Time Reversal, TR) is as a kind of new skill based on signal time domain backout
Art has the characteristics that time and space double focus, in acoustics, biomedicine, radar imagery, communication, electromagnetic radiation positioning
Etc. multiple fields be rapidly developed.Consider under lossless case, describing a two-conductor line, (or ideal big ground is singly led
Line route), the telegraph equation that we can be following describes the communication process of wave
Wherein v (x, t) and i (x, t) is the voltage and current on transmission line of electricity respectively, and L' and C' are transmission line unit lengths
Inductance and capacitor.
It is available to above-mentioned equation application time inversion (t →-t)
Wherein, since the direction of motion of charge changes, while t takes negative sign, reply electric current i (t) takes negative.It can be with
Find out, in lossless transmission line of electricity, telegraph equation meets time reversal invariance.In the case where the time taking inverse, electromagnetic field
Variation and communication process are referred to as electromagnetism time reversal (Electromagnetic Time Reversal, EMTR), and EMTR is from reason
It is positioned by upper it has been confirmed that can be used for transmission line fault localization, since EMTR has space-time focusing in non-uniform dielectric,
The technology has under multiple terminals distribution power network, the application backgrounds such as aerial-buried mixing distribution line (inhomogeneous medium)
There is unique advantage.It is different from conventional method for the discriminatory analysis of fault transient signals traveling wave details, avoids traveling wave arrival
Moment erroneous judgement and wave head feature are difficult to the problems such as extracting.
Norm is commonly used to the feature of quantitative description electromagnetic pulse waveform, such as peak value, energy, rectification integrated value, norm mention
A kind of unified mathematical form is supplied, to state the sensitive parameter of electromagnetic pulse.The present invention is based on electromagnetism time reversal technologies to mention
The novel fault localization method for fault high frequency transient signal out has been invented in conjunction with norm theory for based on 2- norm
Energy criterion and based on ∞-norm peak value criterion, can realize in the case where single observation point to Distributed power net
It is accurately positioned.In the method, we are only concerned about the 2- norm and ∞-norm of transient signal, expression formula and corresponding physics
Meaning is as shown in table 1.
The mathematic(al) representation and its physical significance of 1 p- norm of table
The mechanism for carrying out failure point of power transmission line positioning based on norm theory is as follows:
One, based on ∞-norm peak value criterion
By the radiation field propagated in strong scattering, reflecting medium due to multiple reflection and scattering effect, when passing through
Between after inverting, electromagnetic wave can be at the position that a certain particular moment converges in radiation source, i.e., when electromagnetism time reversal process has
Empty focusing, and the electromagnetic field converged can realize the maximum of amplitude at source position.This property is equally applicable to transmit
Lineation opinion, the communication process of electromagnetic wave on the transmission line are equivalent to external electromagnetic field and propagate in waveguiding structure in a tem mode, can
The propagation property of electromagnetic field three-dimensional space is applied in one-dimensional scene with regarding as.When short trouble has occurred in transmission line, therefore
The high frequency transient pulse signal that barrier generates can be by a step voltage source V over the groundFTo indicate.Consider one and makes somebody a mere figurehead lossless biography
Defeated line, reference ground are perfact conductor, and shorted to earth failure, the transient state electromagnetic pulse that fault overvoltage generates occur at position
It is propagated along cable to both ends, electromagnetic wave encounters at short fault location or cable terminations can reflect, transmission line head end electric current
Time domain analytic solutions are as follows:
Here, Z1Indicate the payload size of cable head end, ρ1Indicate the reflection coefficient of cable head end, TdtIndicate fault traveling wave
Travel to the time delay of cable head end.Transient current is made of the fault-current signal and subsequent reflection signal reached for the first time.
When transient signal is carried out time backward by us, and refill in telegram in reply road, then the short circuit electricity of short-circuit point
Flow expression formula are as follows:
Here TrtIndicate that traveling wave is propagated to the time delay for guessing abort situation by cable head end in refutation process.When conjecture position
When setting equal to true fault position, Trt=Tdt, head reaches signal and follow-up signal forms in-phase stacking, the expression formula of short circuit current
It is writeable are as follows:
It follows that when the position of conjecture is consistent with abort situation, short circuit current signal that Inversion Calculation obtains due to
The in-phase stacking of pulse forms the great effect of amplitude, this is that the space-time focussing property of time reversal technology is determined.
We can use this property by finding the maximum of peak value of short at different conjecture positions to judge
Abort situation obtains the peak value criterion (∞-norm) of the fault location based on time reversal technology are as follows:
In formula: xG--- the position of conjecture fault point；I(xG, t) --- conjecture position xGT becomes the short circuit current at place at any time
Change；Sup --- indicate xGLocate the peak value of short circuit current absolute value；--- it indicates when norm takes maximum, it is corresponding from change
Measure xGValue.
Two, the energy criterion based on 2- norm
For Lossless transport line model, it can be regarded as Two-port netwerk model, we use h (t) and hr(t) failure is indicated
With the system shock response during time reversal.Since Lossless transport line model meets reciprocity, it may be assumed that
H (t)=hr(t)
Assuming that from the two-port network input signal e (t) that one end constitutes transmission line, output signal isIts
InIndicate convolution.Output function is done into time reversal operation, and refills transmission back gauze network from output end, in input terminal
Obtained response are as follows:
Here, Rhh(t) cross-correlation function is indicated.The frequency-domain expression of g (t) can be written as:
G (f)=E*(f)·H*(f) H (f)=E*(f)·|H(f)|2
According to Holder inequality,
And if only if X (f)=KY*(f) when, equal sign is set up.
According to Pa Saiwaer (Parseval) theorem,
When guessing that abort situation is equal with physical fault position, Hr(f)=H (f), equal sign are set up.That is, when guessing
Location set place transmission function it is equal with the transmission function of physical fault position when, the output signal energy after time reversal
Reach maximum.We can come by comparing the 2- norm (energy root) of the short circuit current at different conjecture positions as a result,
Trouble-shooting position.Energy criterion (2- Number Norm Criterion) is written as:
X in formulaG--- the position of conjecture fault point；I(xG, t) --- conjecture position xGThe short circuit current at place t at any time
Variation；E(xG, t) --- conjecture position xGT changes the short circuit current energy at place at any time；--- it indicates to take most when norm
When big, corresponding independent variable xGValue.
The present invention is based on the failure point of power transmission line localization methods of electromagnetic signal time reversal, specifically comprise the following steps:
[1] it according to the circuit types parameter of transmission line of electricity, wire topologies, transmission line conductive parameters, is calculated defeated
The characterisitic parameter of electric line；Wherein circuit types parameter includes overhead transmission line or buried cable, phase line quantity, cable dimensions, leads
Body overhead height, conductor spacing etc.；Wire topologies include wiring path, prong numbers, bifurcation site, leg length；It passes
Defeated line conductive parameters include the electric parameter of conductor and the earth, the foundation for simulation model.
It says in general sense, the characterisitic parameter calculation formula of multi-conductor transmission lines are as follows:
In formula: Z (ω) ' indicates unit length transmission line impedance matrix；Y (ω) ' indicates unit length transmission-line admittance square
Battle array；L' --- unit length transmission line inductance matrix；Z'w--- unit length transmission line conductor impedance matrix；Z'g--- unit
Length transmission line the earth impedance matrix；C' --- unit length transmission line capacitor matrix；Y'g--- unit length transmission line ground
Admittance matrix.
For multi-conductor transmission lines, the inductance matrix of unit length includes the mutual inductance between the self-induction of conducting wire and conducting wire, is calculated
Formula are as follows:
In formula: μ0--- the magnetic capacity in free space；hi--- i-th transmission line height；ri--- i-th transmission
The radius of line；hj--- jth root transmission line height；dij--- the spacing of i-th transmission line and jth root transmission line.Lii' it is inductance
The diagonal entry of matrix represents the self-induction of conducting wire；Lij' be inductance matrix off diagonal element, represent the mutual inductance between conducting wire,
They together constitute inductance matrix.Impedance matrix is similar with its.
The capacitance matrix of unit length can be calculated from inductance matrix:
C'=μ0ε0L'-1
Unit length transmission line resistor matrix generally only considers conductor DC resistance, calculation formula are as follows:
In formula, σw--- it is transmission line conductors conductivity.
Consider that the earth is lost, the expression formula of the earth impedance are as follows:
In formula, γgFor the earth propagation constant, expression formula are as follows:
In formula, σg--- the conductivity of the earth, εg--- the earth relative dielectric constant.
The expression formula of the earth admittance are as follows:
Yg'=γg 2Zg'-1
Transmission line characteristic impedance expression formula are as follows:
Transmission line character admittance expression formula are as follows:
Yc=Zc'-1
[2] several failures conjecture position x is set in the model of power transmission system of foundationG, adjacent failure conjecture position it
Between distance be d；
[3] by electric current, the voltage transformer in relay protection system, voltage u (t), the electricity on faulty transmission road are monitored
Flow the time domain Full wave shape of i (t), t ∈ [tf,tf+ T], wherein tfIt is measurement initial time, T is signal sampling time span, and will
Waveform in finite time length is acquired record；
[4] inverting of time backward is carried out to the acquired electromagnetic data that step [3] obtain, obtains the backward in acquisition duration T
Signal ur(t)=u (T-t), ir(t)=i (T-t)；
[5] characterisitic parameter of the transmission line of electricity based on step [1] establishes transmission line simulation model, and inverting signal is input to
In transmission line simulation model, failure conjecture position x is calculatedGThe current or voltage at place responds, and according to norm theoretical calculation
The energy norm and peak value norm responded in duration 2T.
The mode of transmission line modeling can be time domain modeling and Modeling In Frequency Domain.Time domain modeling mainly utilizes EMTP-RV etc.
Business software calls software model to generate circuit model, the time-domain-simulation embedded by software by inputting transmission line parameter
Algorithm completes simulation calculation.Modeling In Frequency Domain is based on BLT frequency domain equation method (Baum-Liu-Tesche equation) and first establishes list
Bit length equivalence linear electrical parameter calculates voltage, current-responsive on transmission line by way of analytic equation under frequency domain.
The wherein expression formula of energy norm are as follows:
The expression formula of peak value norm are as follows:
[5.1] Building of Simulation Model
According to BLT Equation Theory, transmission circuit network can be abstractively with a series of pipeline (tube), node
(junction) etc. physical quantitys characterize, and the voltage, electric current on each node can write out its solution by BLT frequency domain equation
Analyse expression formula:
Wherein, V, I are node voltage, current phasor, Y respectivelyCIt is transmission line character admittance matrix, S is cable network
Scattering parameter hypermatrix, T are pipeline incidence matrix, and Γ is to propagate hypermatrix, W(s)It is synthesis driving source super vector.Wherein transmit
Line Characteristic mobility matrix YCIt is calculated and is obtained according to the unit length linear electrical parameter in step [1].
[5.2] scattering parameter hypermatrix is calculated
The connection of node both ends is all pipeline, cannot be indicated with reflection coefficient matrix, will scatter determining for hypermatrix at this time
Adopted formula solves the scattering hypermatrix of desired node in conjunction with the Kirchoff s voltage current law of node.According to voltage and current and conjunction
At the relational expression of voltage wave, in conjunction with Kirchoff s voltage current law, the reflection of wave is converted into voltage-current relationship, can be obtained
To the scattering hypermatrix expression formula of desired node:
CV, CIFor the coefficient matrix of the Kirchoff s voltage current law of node, YCIt is characteristic admittance matrix, ZCIt is characteristic
Impedance matrix.
[5.3] incidence matrix T is calculated
Wherein, Wu, WvIndicate the wave vector propagated in transmission network.
[5.4] it calculates and propagates hypermatrix Γ
Internet communication hypermatrix is made of propogator matrix of the wave in each pipeline, and the propogator matrix of each pipeline is by cable
Mode propagation constant γ and duct length l determine.It propagates hypermatrix and characterizes phase-amplitude in the propagation of the wave in whole network
Situation of change, expression formula are as follows:
[5.5] driving source super vector is calculated
The transient state pulse signal that transmission line failure generates is as lump driving source, expression formula are as follows:
The Internet communication hypermatrix being calculated, network scattering hypermatrix, driving source super vector are substituted into BLT hypermatrix
Equation acquires each resultant voltage wave.According to the relationship of resultant voltage wave and each node voltage current-responsive, parsed according to BLT frequency domain
Equation solution obtains the voltage and current response of each node of series transmission lines.
[5.6] mathematic(al) representation of energy norm criterion is calculated are as follows:
The expression formula of peak value criterion are as follows:
[6] fault point determines:
[6.1] according to distance between adjacent fault point in step [2] be d when x is calculatedp,realWith xe,real, realize just
Walk fault location:
[6.2] work as xp,realWith xe,realAs a result unanimously or close in situation, in xp,realOr xe,realNear zone takes step
[2] the distance between adjacent fault point is d/5~d/20 in, repeats step [1]~[5], obtains the exact position of fault point
Wherein xp,realNear zone refers to x on transmission line of electricityp,real- d~xp,realAt the position of+d；xe,realNear zone
Refer to x on transmission line of electricitye,real- d~xe,realAt the position of+d.
[6.3] work as xp,realWith xe,realWhen result difference is larger, in xe,realNear zone takes adjacent failure in step [2]
The distance between point is d/5~d/20, usually selects d/10, repeats step [1]~[5], is accurately positioned, obtains fault point
Exact position
This allows for the criterion that energy norm uses root, thus has stronger stability, therefore with energy norm
Fine positioning is carried out subject to Primary Location result and in its vicinity, to realize that fault point is accurately positioned.
Below with reference to field experiment practical measuring examples, the present invention is described in further detail.
(1) experimental configuration
This experiment is based on the double loop 10kV power distribution network, and overhead line parameter and shaft tower scene pictorial diagram are as shown in Figure 2,3, passes
Defeated line design parameter is as shown in table 2.
2 experimental line major parameter of table
Experimental line overall length 677m, totally 11 shaft towers, number are 22 to 32.Using the double exponential type high-tension pulses of a nanosecond
It rushes source and a pulse signal is injected for simulated failure overvoltage pulse signal, pulse source output terminal to route at No. 23 shaft towers
Failure phase is connect, ground terminal is connected with shaft tower the earth.The clock is only used to simulate to generate short trouble overvoltage in this experiment,
The not necessarily condition in the application of practical this method.Observation point is arranged on No. 22 shaft towers of route head end for we, end load
With 1500pF thin film capacitor come analogue transformer bus entrance capacitance, this is chosen according to the characterisitic parameter of real transformer
Alternative model, physical fault judgement in transmission line of electricity be directly accessed in transformer.Experimental configuration schematic diagram is as shown in Figure 3.With
Electric current loop measures the fault current on conductor, and measuring device and its major parameter are as shown in table 3.
3 measuring device of table and its major parameter
(2) fault transient waveform is measured
We consider two kinds of experiment measurement schemes, are respectively free of the single-phase measurement of crosstalk factor and include crosstalk factor
Three-phase measurement.
A) the single-phase measurement and its interpretation of result of crosstalk factor are not considered
For single-phase measurement, capacitive load only is connected in failure phase end, other non-faulting are mutually open circuit, in route head end
The electric current time domain waveform that place measures is as shown in Figure 4.In the larger situation of noise, denoising is carried out to waveform, utilizes formula
(1) time domain backward is carried out.
We are swashed the measuring signal after inverting with the parsing equation method modeling of BLT frequency domain at line port as lump
The source of encouraging is injected into circuit model, as shown in Figure 5.If measuring signal is voltage signal, according to Thevenin's theorem, desired voltage
Source should connect and access in transmission line circuit, wherein V1(T-t) voltage signal after backward, Z are indicated1, Z2Indicate the negative of first and last end
It carries, IF(t) short circuit current at conjecture position is indicated.
If measuring signal is that current signal as ideal current source and couples the electric current after backward according to Nortons theorem
Enter, then it is in parallel with fault impedance to inject source, as shown in Figure 6.Wherein, I1(T-t) current signal after backward, Z are indicated1, Z2It indicates
The load at first and last end, IF(t) short circuit current at conjecture position is indicated.
And the short circuit current norm value at different conjecture positions is calculated, distribution results are as shown in Figure 7 along the line.From result figure
In as can be seen that the energy and peak value of short circuit current at No. 23 shaft towers are maximum.
B) consider the three-phase measurement and its interpretation of result of crosstalk factor
For considering the three-phase measurement under cross talk conditions, it is all connected with capacitive load at the first and last end of three-phase line, in route
Head end measures the current signal in triple line simultaneously, and time domain waveform is as shown in Figure 8.By Inversion Calculation, obtained failure phase
On norm along be distributed it is as shown in Figure 9.It can be seen that energy and peak value maximum still match with abort situation.By
It is far smaller than norm value in failure phase in the short circuit current norm value in non-faulting phase, only depicts the norm of failure phase here
Distribution.It follows that we can also judge failure phase by this method by the statistics to norm value.
Studies have shown that ∞-Number Norm Criterion based on peak value has the stronger anti-noise of noise signal for introducing in measurement
Ability, and the amplitude at each moment of inverting signal is carried out due to introducing integral calculation based on the 2- norm of energy root
Cumulative summation, inverting output result more tend to stablize.A large amount of verification experimental verification shows that both methods judges to obtain the one of result
Cause property is fine.Two kinds of criterions should be used in combination in practical applications to estimate abort situation, be taken under higher distance resolution
The arithmetic mean of instantaneous value of the two positioning result, may make result both has stronger anti-noise ability, while also having stronger stabilization
Property.
Claims (5)
1. a kind of failure point of power transmission line localization method based on electromagnetic signal time reversal, which is characterized in that including walking as follows
It is rapid:
[1] according to the circuit types parameter of transmission line of electricity, wire topologies, transmission line conductive parameters, power transmission line is calculated
The characterisitic parameter on road；
[2] characterisitic parameter based on step [1] transmission line of electricity establishes transmission line simulation model, in the transmission line simulation model of foundation
Interior several failures of setting guess position xG, the distance between adjacent failure conjecture position is d；
[3] by electric current, the voltage transformer of relay protection system on transmission line of electricity, monitoring obtains the voltage of faulty transmission circuit
The time domain Full wave shape of u (t), electric current i (t), t ∈ [tf,tf+ T], wherein tfIt is measurement initial time, T is that the signal sampling time is long
Degree, and the waveform in finite time length is acquired record；
[4] inverting of time backward is carried out to the acquired electromagnetic data that step [3] obtain, obtains the time backward in acquisition duration T
Signal data；
ur(t)=u (T-t), ir(t)=i (T-t)
[5] inverting signal is input in the transmission line simulation model of step [2], failure conjecture position x is calculatedGThe electricity at place
Stream or voltage responsive, and the peak value norm responded in duration 2T according to norm theoretical calculation, obtain the pole of peak value norm
The corresponding fault observation sites position x of big valuep,realFault observation sites position x corresponding to maximum with energy norme,real,
And judge to obtain the position where fault point；
The wherein mathematic(al) representation of peak value Number Norm Criterion are as follows:
The wherein mathematic(al) representation of energy norm criterion are as follows:
X in formulaGFor the position for guessing fault point；I(xG, t) and it is conjecture position xGThe short circuit current at place；Sup indicates xGPlace's short circuit
The peak value of current absolute value；Indicate the corresponding independent variable x when norm takes maximumGValue；
[6] fault point determines:
[6.1] according to distance between adjacent fault point in step [2] be d when x is calculatedp,realWith xe,real, realize preliminary event
Barrier positioning；
[6.2] work as xp,realWith xe,realAs a result unanimously or close in situation, in xp,realOr xe,realNear zone takes step [2]
In the distance between adjacent fault point be d/5~d/20, repeat step [1]~[5], obtain the exact position of fault point
Realize that fault point is accurately positioned；
[6.3] work as xp,realWith xe,realWhen result difference is larger, in xe,realNear zone, take in step [2] adjacent fault point it
Between distance be d/5~d/20, repeat step [1]~[5], be accurately positioned, obtain the exact position of fault point
Realize that fault point is accurately positioned.
2. the failure point of power transmission line localization method according to claim 1 based on electromagnetic signal time reversal, step [1]
The characterisitic parameter calculation formula of middle transmission line of electricity are as follows:
In formula: Z (ω) ' indicates unit length transmission line impedance matrix；Y (ω) ' indicates unit length transmission-line admittance matrix；L'
Indicate unit length transmission line inductance matrix；Z'wIndicate unit length transmission line resistor matrix；Z'gIndicate unit length transmission line
The earth impedance matrix；C' indicates unit length transmission line capacitor matrix；Y'gIndicate unit length transmission line ground admittance matrix.
3. the failure point of power transmission line localization method according to claim 1 based on electromagnetic signal time reversal, feature
It is: the analytic equation of transmission line simulation model in step [5] are as follows:
Wherein, V, I are node voltage, current phasor, Y respectivelyCIt is transmission line character admittance matrix, S is the scattering ginseng of cable network
Number hypermatrix, T are pipeline incidence matrix, and Γ is to propagate hypermatrix, W(s)It is synthesis driving source super vector, [1] indicates and S and Γ
The consistent unit matrix of matrix dimensionality.
4. the failure point of power transmission line localization method according to claim 1 based on electromagnetic signal time reversal, feature
It is: x in step [6.2]p,realNear zone refers to x on transmission line of electricityp,real- d~xp,realAt the position of+d；xe,realNear
Region refers to x on transmission line of electricitye,real- d~xe,realAt the position of+d.
5. the failure point of power transmission line localization method according to claim 1 based on electromagnetic signal time reversal, feature
It is: x in step [6.3]e,realNear zone refers to x on transmission line of electricitye,real- d~xe,realAt the position of+d.
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