CN107328996A - Robust electric transmission line positive sequence parameter identification method - Google Patents
Robust electric transmission line positive sequence parameter identification method Download PDFInfo
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
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Abstract
The invention discloses a kind of robust electric transmission line positive sequence parameter identification method, including：The phasor measurement unit measurement installed by single back transmission line two ends obtains the three-phase current and voltage phasor at circuit two ends；According to single back transmission line three-phase Equivalent Model and the three-phase current and voltage phasor at combined circuit two ends, the accounting equation of line impedance parameter and admittance parameter is set up；The object function that the Huber estimation objective functions with robustness are recognized as line impedance parameter and admittance parameter is built, line impedance matrix and admittance matrix parameters are obtained so as to solve；Line impedance matrix and admittance matrix are decoupled using symmetrical component method, positive sequence impedance and positive sequence admittance parameter is obtained.This method is workable, it is easy to implement, and the positive sequence impedance parameters precision that identification is obtained is high, and with good robustness, identification result is more credible.
Description
Technical field
Distinguished the present invention relates to technical field of power system operation control, more particularly to a kind of robust electric transmission line positive sequence parameter
Knowledge method.
Background technology
With continuing to develop for power system, transmission line of electricity is also more and more, and what system also just became becomes increasingly complex, therefore
The requirement of our the parameter degrees of accuracy to transmission line of electricity is also just relatively higher.Accurate line parameter circuit value is correct progress Load flow calculation,
Accident analysis, relay protection setting, the basis of the various power system computations such as line losses management.When line parameter circuit value is inaccurate, to short
The calculating of road electric current, stability Calculation, the correctness influence of Load flow calculation is very big.So the accuracy of transmission line parameter is also
Affect the safety of power system, stable and reliability service.
Transmission line of electricity can be divided into overhead transmission line and cable run, be the carrier of power Transmission, and its voltage class is remote
Higher than power distribution network, and most of parameter of major network is known, is very different with power distribution network.
Line parameter circuit value measuring method has a lot, there is theoretical calculation, offline have a power failure measurement, online live line measurement.Traditional circuit
Theoretical calculation utilizes circuit geometric mean distance, the physical parameter such as material structure, with reference to temperature, geographical position based on Carson
Reactance is calculated Deng according to formula, resistance, susceptance.Or according to handbook formula, directly calculate circuit power frequency parameter, this side
Method have ignored the influence of aerial earth wire.And theoretical calculation only considered full symmetric situation, real-time temperature is not accounted for
Spend, the practical problem such as sag, therefore there is very big difference in the result and actual parameter of this method.Offline power failure measurement be by
Test line has a power failure, and departs from power network, using additional power source, utilizes the various meter measurement circuitry numbers such as voltmeter, ammeter
According to through manually reading tabular value and calculating parameters with reference to corresponding formula.This method, which exists, to be needed to stop test line
Electricity, backhauls the problems such as capable parallel circuit can not measure mutual inductance more.
The content of the invention
It is an object of the invention to provide a kind of robust electric transmission line positive sequence parameter identification method, calculate simple, and not by outer
Boundary's environment, payload influence, can be with accurate recognition line parameter circuit value, and practicality is good, with good robustness.
The purpose of the present invention is achieved through the following technical solutions：
A kind of robust electric transmission line positive sequence parameter identification method, including：
The phasor measurement unit measurement installed by single back transmission line two ends obtains the three-phase current and electricity at circuit two ends
Press phasor；
According to single back transmission line three-phase Equivalent Model and the three-phase current and voltage phasor at combined circuit two ends, line is set up
The accounting equation of road impedance parameter and admittance parameter；
Build the mesh that the Huber estimation objective functions with robustness are recognized as line impedance parameter and admittance parameter
Scalar functions, line impedance matrix and admittance matrix parameters are obtained so as to solve；
Line impedance matrix and admittance matrix are decoupled using symmetrical component method, positive sequence resistance, reactance is obtained and leads over the ground
Receive parameter.
The three-phase current and voltage phasor according to single back transmission line three-phase Equivalent Model and combined circuit two ends, builds
The accounting equation of vertical line impedance parameter and admittance parameter includes：
The three-phase current at single back transmission line two ends meets equation below with voltage：
Wherein,Respectively a, b, c three-phase electricity at M ends and N-terminal
Flow phasor；Respectively a, b, c three-phase at M ends and N-terminal
Voltage phasor；Z、YcLine impedance parameter respectively to be identified, admittance parameter；
Above-mentioned equation is converted into following forms：
In above formula,
Then current time, parameter x to be identified is：
X=[x11 x12 ... x19 x21 x22 ... x29]T；
Meet following linear equation：
Ax=B+v；
Wherein, A is the coefficient matrix that current time three-phase voltage is constituted with electric current phasor, and B is current time both end voltage
The constant term of phasor composition drops, and v is equation residual error phasor；
Comprising 18 unknown quantitys in the parameter x of identification, then the number of equation is greater than equal to 18, take it is multigroup not in the same time
Data solve, wherein, A dimension is that 6n × 18, n >=3, B dimension is 6n × 1, and objectives equation is as follows：
It is described to build the Huber estimation objective functions with robustness as line impedance parameter and admittance parameter identification
Object function, include so as to solve and obtain line impedance matrix and admittance matrix：
Huber robust estimation theories assume that actual observation data obey Huber distributions, and Huber distributions are pollution distributions
One kind, its main body is normal distribution, and interference sections obey Laplace distributions；
Huber distribution probability density be：
Wherein, ε is pollution rate, and it represents ratio of the data of pollution part shared by whole data；λ is observation；
For standardized normal distribution density, in interval-c≤λ≤c, observation is obeyed just
State is distributed；In λ ＞ c, observation obeys Laplace distributions；C value is between 1.0~2.0；
The Maximum-likelihood estimation of Huber distributions estimates that its object function is for Huber：
Wherein, k is robust threshold adjustment coefficient, relevant with pollution rate ε；viFor measurement residuals, vi=(yci-ymi)/s, yci
And ymiThe calculated value and measured value of output vector are represented respectively；S exists | vi|≤k is interval, takes the standard deviation sigma of error in measurementi, s exists
|vi| ＞ k are interval, take Kmad, Kmad=med | yci-ymi|；According to object function, when | vi| during ＞ k, reduction large deviation measures shadow
Ring；
The Huber estimation objective functions to be set up are the functions of equation residual error, be may be defined as：
PiFor the weight of i-th of measurement, weights are 1/ σi 2, ρ (vi) it is the corresponding object function of Huber methods, viTo measure
Residual error；
Consider that PMU errors in measurement are consistent, setting up Huber estimation objective functions is：
Specifically, according to linear equation Ax=B+v, this estimation objective function can be further represented as：
Wherein, Aixi-BiResidual error when sampling instant is i is represented, is finally to ask for meeting this object function for minimum
When phasor x；N is sampling sum；The Huber estimation objective functions are least square when observation error is less than threshold value
The object function of method, when observation error is more than threshold value, can weaken its adverse effect to object function, automatic rejection master
Bad data in net phasor measurement unit data；
Optimization Method is recycled to obtain line impedance matrix and admittance matrix.
Line impedance matrix and admittance matrix are decoupled using symmetrical component method, positive sequence resistance, reactance is obtained and leads over the ground
Parameter of receiving includes：
Structural matrix T：
The matrix T constructed herein is a kind of symmetrical component transformation, and its effect is that, a, b, the phase component of c three-phases is converted into just
Sequence, negative phase-sequence and zero-sequence component；Wherein, a is twiddle factor,
The matrix equation of three-phase electricity pressure drop and three-phase current relation is set up using circuit phase component model：
In above formula,Three-phase electricity pressure drop is represented,Represent three-phase current；
Three-phase electricity pressure drop and three-phase current are replaced with into order components, obtained：
Represent each order components of voltage drop, i.e., positive and negative, residual voltage drop；Represent each sequence point of electric current
Amount, i.e., positive and negative, zero-sequence current；；
It is further represented as：
ZpThe as impedance matrix of order components, i.e.,：
Z therein(1)For circuit positive sequence impedance, Z(2)Represent circuit negative sequence impedance, Z(0)Represent circuit zero sequence impedance；
Similarly, it is same to release for admittance matrix：
Y thereinc(1)For the admittance over the ground of circuit positive sequence, Yc(2)Represent the admittance over the ground of circuit negative phase-sequence, Yc(0)Represent circuit zero sequence
Admittance over the ground.
As seen from the above technical solution provided by the invention, it is only necessary to gather three-phase current, the voltage phase at circuit two ends
Information is measured, it is workable, it is easy to implement, and the positive sequence impedance parameters precision that identification is obtained is high, with good robust energy
Power, identification result is more credible.
Brief description of the drawings
In order to illustrate the technical solution of the embodiments of the present invention more clearly, being used required in being described below to embodiment
Accompanying drawing be briefly described, it should be apparent that, drawings in the following description are only some embodiments of the present invention, for
For one of ordinary skill in the art, on the premise of not paying creative work, it can also be obtained according to these accompanying drawings
His accompanying drawing.
Fig. 1 is a kind of flow chart of robust electric transmission line positive sequence parameter identification method provided in an embodiment of the present invention；
Fig. 2 is the triphase flow schematic diagram of single back transmission line provided in an embodiment of the present invention；
Fig. 3 is 500kV analogue systems schematic diagram provided in an embodiment of the present invention.
Embodiment
With reference to the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete
Ground is described, it is clear that described embodiment is only a part of embodiment of the invention, rather than whole embodiments.It is based on
Embodiments of the invention, it is every other that those of ordinary skill in the art are obtained under the premise of creative work is not made
Embodiment, belongs to protection scope of the present invention.
The embodiment of the present invention provides a kind of robust electric transmission line positive sequence parameter identification method, and this method belongs to on-line identification side
Method.On-line identification method, can be without having a power failure to measurement circuitry, you can to two end datas, such as voltage, electric current, and phase angle etc. is carried out
Synchronous acquisition, so that the identification of online line parameter circuit value is realized, and its precision, it is more efficient.As shown in figure 1, real for the present invention
A kind of flow chart of robust electric transmission line positive sequence parameter identification method of example offer is applied, it mainly comprises the following steps：
Step 11, the phasor measurement unit measurement installed by single back transmission line two ends obtain the three-phase electricity at circuit two ends
Stream and voltage phasor.
In the embodiment of the present invention, transmission line of electricity Phasor Measurements are installed at single back transmission line two ends of required measurement in advance
Device, three-phase voltage, the electric current phasor at the single back transmission line two ends of measurement.
Exemplary, the implication that the triphase flow of single back transmission line may refer to parameters in Fig. 2, Fig. 2 will be rear
Text is illustrated one by one.
Step 12, three-phase current and voltage phase according to single back transmission line three-phase Equivalent Model and combined circuit two ends
Amount, sets up the accounting equation of line impedance parameter and admittance parameter.
In the embodiment of the present invention, three-phase current and the voltage at single back transmission line two ends meet equation below：
Wherein,Respectively a, b, c three-phase electricity at M ends and N-terminal
Flow phasor；Respectively a, b, c three-phase at M ends and N-terminal
Voltage phasor；Z、YcLine impedance parameter respectively to be identified, admittance parameter；
Specifically：
In formula, Zkk=Rkk+jXkk, ZkkFor the circuit self-impedance of k (k=a, b, c) phase, accordingly, RkkRepresent the line of k phases
Road series resistance, XkkThe circuit series reactance of k phases is represented, j represents imaginary unit；Zmn=Rmn+jXmn, Zmn (Rmn, Xmn), it is m
Mutual impedance (mutual resistance, mutual reactance) (m ≠ n) between (m=a, b, c) and n (n=a, b, c) phase, accordingly, RmnRepresent m
Mutual resistance between phase and n phases, XmnRepresent the mutual reactance between m phases and n phases；YkkFor the line-to-ground of k (k=a, b, c) phase
Admittance, YmnFor the transadmittance between m (m=a, b, c) and n (n=a, b, c) phase.Zmm(Rmm, Xmm), it is m (m=a, b, c) phase
Self-impedance (self-resistance, from reactance).
Above-mentioned equation is converted into following forms：
In above formula,
Then current time, parameter x to be identified is：
X=[x11 x12 ... x19 x21 x22 ... x29]T (7)
Meet following linear equation：
Ax=B+v (8)；
Wherein, A is the coefficient matrix that current time three-phase voltage is constituted with electric current phasor, and B is current time both end voltage
The constant term of phasor composition drops, and v is equation residual error phasor；
Comprising 18 unknown quantitys in the parameter x of identification, then the number of equation is greater than equal to 18.Therefore, take it is multigroup not
Data in the same time are solved, wherein, A dimension is that 6n × 18, n >=3, B dimension is 6n × 1, and objectives equation is as follows：
Above-mentioned matrix equation (9) is measured by single back transmission line three-phase Equivalent Model of formula (4) according to circuit both sides are multigroup
What phasor was obtained.Each phase resistance of acquisition, reactance, susceptance, i.e. Z and Y can be calculated by formula (9)cUnknown parameter in two matrixes.
Two parameter matrixs (3 × 3) to be identified have been written as the form of a linear vector x (18 × 1) by formula (9), from
And conveniently solve.
Further, then by symmetrical component method, phase parameter is converted into order parameter, just obtained circuit positive sequence resistance,
Reactance and over the ground susceptance.Needed during carrying out robust identification with reference to the robust method formation object function that Huber estimates hereinafter
Above-mentioned matrix equation is used, and in instances, the Huber estimation robust identifications applied to reference to above-mentioned matrix equation are calculated
Method comes the positive sequence resistance of identification circuit, reactance and susceptance parameter.
The Huber estimation objective functions of step 13, structure with robustness are used as line impedance parameter and admittance parameter
The object function of identification, line impedance matrix and admittance matrix parameters are obtained so as to solve.
In traditional least square (LS) method, that waits power treats each group of data, when occur individual data deviation compared with
During big situation, final identification result will significantly deviate actual value so that the robustness of algorithm is poor.
To make identification result that there is robustness, the Huber estimation objective functions with robustness, Huber can be introduced
Robust estimation theory assumes that actual observation data obey Huber distributions, and Huber distributions are one kind of pollution distribution, its main body
It is normal distribution, interference sections obey Laplace distributions；
Huber distribution probability density be：
Wherein, ε is pollution rate, and it represents ratio of the data of pollution part shared by whole data；λ is observation.
For standardized normal distribution density, in interval-c≤λ≤c, observation is obeyed
Normal distribution；In λ ＞ c, observation obeys Laplace distributions；C value is exemplary between 1.0~2.0, can be by
C value is set to 1.5.
The Maximum-likelihood estimation of Huber distributions estimates that its object function is for Huber：
Wherein, k is robust threshold adjustment coefficient, relevant with pollution rate ε；viFor measurement residuals, vi=(yci-ymi)/s, yci
And ymiThe calculated value and measured value of output vector are represented respectively；S exists | vi|≤k is interval, takes the standard deviation sigma of error in measurementi, s
| vi| ＞ k are interval, take Kmad, Kmad=med | yci-ymi|；According to object function, when | vi| during ＞ k, reduction large deviation is measured
Influence.
The Huber estimation objective functions to be set up are the functions of equation residual error, be may be defined as：
PiFor the weight of i-th of measurement, weights are 1/ σi 2, ρ (vi) it is the corresponding object function of Huber methods, viTo measure
Residual error.
Consider that PMU errors in measurement are consistent, setting up Huber estimation objective functions is：
Specifically, according to linear equation Ax=B+v, this estimation objective function can be further represented as：
Aixi-BiResidual error when sampling instant is i is represented, when finally asking for meeting this object function for minimum
Phasor x.N is sampling sum；The Huber estimation objective functions are least square when observation error is less than threshold value
The object function of method, when observation error is more than threshold value, can weaken its adverse effect to object function, automatic rejection master
Bad data in net phasor measurement unit data；
Optimization Method is recycled to obtain line impedance matrix and admittance matrix, it is exemplary, heredity calculation can be passed through
Method obtains line impedance matrix and admittance matrix to calculate.
Step 14, using symmetrical component method line impedance matrix and admittance matrix are decoupled, obtain positive sequence resistance, reactance and
Admittance parameter over the ground.
After the impedance matrix and admittance matrix that are obtained by genetic algorithm, it can decouple and obtain positive-sequence component；Detailed process
It is as follows：
Structural matrix T：
The matrix T constructed herein is a kind of symmetrical component transformation, and its effect is that, a, b, the phase component of c three-phases is converted into just
Sequence, negative phase-sequence and zero-sequence component.Wherein, a is twiddle factor,
This formula is the matrix equation for the three-phase electricity pressure drop and three-phase current relation set up by circuit phase component model.In formula,Three-phase electricity pressure drop is represented,Represent three-phase current.
Three-phase electricity pressure drop and three-phase current are replaced with into order components, obtained：
Represent each order components of voltage drop, i.e., positive and negative, residual voltage drop；Represent each sequence point of electric current
Amount, i.e., positive and negative, zero-sequence current；Impedance matrix Z is exactly previously mentioned phase component impedance matrix.
It is further represented as：
ZpThe as impedance matrix of order components, i.e.,：
Z therein(1)For circuit positive sequence impedance (that is, positive sequence resistance, reactance), Z(2)Represent circuit negative sequence impedance, Z(0)Table
Timberline road zero sequence impedance.
Similarly, it is same to release for admittance matrix：
Y thereinc(1)For the admittance over the ground of circuit positive sequence, Yc(2)Represent the admittance over the ground of circuit negative phase-sequence, Yc(0)Represent circuit zero sequence
Admittance over the ground.
Robust electric transmission line positive sequence parameter identification method (the following letter provided below with specific example the present invention
Claim, the inventive method) proved：
This example builds 500kV analogue systems using PSCAD, as shown in figure 3, to single time distribution line L1 positive order parameter
Recognized.500kV circuits L1 is single loop line, and line length is 200km；Positive sequence parameter design value is：Resistance R1=3.1524
Ω, reactance XL1=55.2061 Ω, susceptance B1=7.0564 × 10-4S.In Fig. 3, mainly recognize be transmission line of electricity two ends (M,
N P+jQ represents the load power of line end in positive sequence resistance, reactance between) and over the ground susceptance parameter, figure, and P is load
Active, Q is idle for load.
Assuming that phasor measurement unit has been installed at circuit L1 two ends, when having measured normal operation, the three-phase at circuit L1 two ends is not
(three-phase voltage, electric current phasor herein can be asymmetric, therefore this method only needs to use for symmetrical voltage, electric current phasor
The metric data of the two ends asymmetrical three-phase at multiple stable state moment can pick out the positive sequence ginseng of the circuit when circuit is normally run
Number), the sampling interval is 10ms.Sampling time is 10s, takes 900 groups of data after stable state and according to embodiment identification circuit L1
Positive sequence impedance, and following experiment is set, to show the validity of the method for the invention.
Experiment one：Directly using data are emulated, without processing；
Experiment two：Random Gaussian is superimposed in ideal emulation data, real transmission line of electricity Phasor Measurements dress is simulated
Put data；Wherein, the error in measurement standard deviation of voltage x current amplitude is 0.1%, and phase angle error is 0.1 °；
Experiment three：It is random by 5 groups of Current magnitude measurement zero setting on the basis of experiment one, with transmission line simulation phasor amount
Survey device and measure and bad data occur.
Under two kinds of experimental programs, the positive sequence parameter identification result that the inventive method is obtained is as shown in table 1
The positive sequence parameter identification result of table 1
Table 1 shows that identification result of the present invention is almost consistent with design load under ideal emulation data, shows of the present invention
Method is basic feasible solution；In actual motion, when the data that power transmission line phasor measurement unit is obtained are containing certain measurement noise,
Methods described is slightly better than least square method.If but when power transmission line phasor measurement unit metric data has bad data, the side
Method will be substantially better than least square method, identification result it is with a high credibility.
Contrast experiment strongly suggests that the inventive method is more suitable for containing the actual power transmission line for measuring noise or even bad data
The metric data of road phasor measurement unit, can effectively reduce the adverse effect that bad data is recognized to positive sequence impedance parameter, gained is just
Sequence impedance parameter value is more credible.
Through the above description of the embodiments, those skilled in the art can be understood that above-described embodiment can
To be realized by software, the mode of necessary general hardware platform can also be added to realize by software.Based on such reason
Solution, the technical scheme of above-described embodiment can be embodied in the form of software product, and the software product can be stored in one
Non-volatile memory medium (can be CD-ROM, USB flash disk, mobile hard disk etc.) in, including some instructions are to cause a calculating
Machine equipment (can be personal computer, server, or network equipment etc.) performs the side described in each embodiment of the invention
Method.
The foregoing is only a preferred embodiment of the present invention, but protection scope of the present invention be not limited thereto,
Any one skilled in the art is in the technical scope of present disclosure, the change or replacement that can be readily occurred in,
It should all be included within the scope of the present invention.Therefore, protection scope of the present invention should be with the protection model of claims
Enclose and be defined.
Claims (4)
1. a kind of robust electric transmission line positive sequence parameter identification method, it is characterised in that including：
The phasor measurement unit measurement installed by single back transmission line two ends obtains the three-phase current and voltage phase at circuit two ends
Amount；
According to single back transmission line three-phase Equivalent Model and the three-phase current and voltage phasor at combined circuit two ends, circuit resistance is set up
The accounting equation of anti-parameter and admittance parameter；
Build the target letter that the Huber estimation objective functions with robustness are recognized as line impedance parameter and admittance parameter
Number, line impedance matrix and admittance matrix parameters are obtained so as to solve；
Line impedance matrix and admittance matrix are decoupled using symmetrical component method, obtain positive sequence resistance, reactance and over the ground admittance join
Number.
2. a kind of robust electric transmission line positive sequence parameter identification method according to claim 1, it is characterised in that the basis
The three-phase current and voltage phasor at single back transmission line three-phase Equivalent Model and combined circuit two ends, set up line impedance parameter and
The accounting equation of admittance parameter includes：
The three-phase current at single back transmission line two ends meets equation below with voltage：
Wherein,Respectively M ends and a, b, c three-phase current phase of N-terminal
Amount；Respectively M ends and a, b, c three-phase voltage phase of N-terminal
Amount；Z、YcLine impedance parameter respectively to be identified, admittance parameter；
Above-mentioned equation is converted into following forms：
In above formula,
Then current time, parameter x to be identified is：
X=[x11 x12 ...x19 x21 x22 ...x29]T；
Meet following linear equation：
Ax=B+v；
Wherein, A is the coefficient matrix that current time three-phase voltage is constituted with electric current phasor, and B is that phase drops in current time both end voltage
The constant term of composition is measured, v is equation residual error phasor；
Comprising 18 unknown quantitys in the parameter x of identification, then the number of equation is greater than equal to 18, takes multigroup number not in the same time
According to solution, wherein, A dimension is that 6n × 18, n >=3, B dimension is 6n × 1, and objectives equation is as follows：
3. a kind of robust electric transmission line positive sequence parameter identification method according to claim 2, it is characterised in that the structure
The object function that Huber estimation objective functions with robustness are recognized as line impedance parameter and admittance parameter, so that
Solution, which obtains line impedance matrix and admittance matrix, to be included：
Huber robust estimation theories assume that actual observation data obey Huber distributions, and Huber distributions are the one of pollution distribution
Kind, its main body is normal distribution, and interference sections obey Laplace distributions；
Huber distribution probability density be：
Wherein, ε is pollution rate, and it represents ratio of the data of pollution part shared by whole data；λ is observation；
For standardized normal distribution density, in interval-c≤λ≤c, observation obeys normal state point
Cloth；In λ ＞ c, observation obeys Laplace distributions；C value is between 1.0~2.0；
The Maximum-likelihood estimation of Huber distributions estimates that its object function is for Huber：
Wherein, k is robust threshold adjustment coefficient, relevant with pollution rate ε；viFor measurement residuals, vi=(yci-ymi)/s, yciAnd ymi
The calculated value and measured value of output vector are represented respectively；S exists | vi|≤k is interval, takes the standard deviation sigma of error in measurementi, s exists | vi| ＞
K is interval, takes Kmad, Kmad=med | yci-ymi|；According to object function, when | vi| during ＞ k, reduction large deviation measures influence；
The Huber estimation objective functions to be set up are the functions of equation residual error, be may be defined as：
PiFor the weight of i-th of measurement, weights are 1/ σi 2, ρ (vi) it is the corresponding object function of Huber methods, viIt is residual to measure
Difference；
Consider that PMU errors in measurement are consistent, setting up Huber estimation objective functions is：
Specifically, according to linear equation Ax=B+v, this estimation objective function can be further represented as：
Wherein, Aixi-BiResidual error when sampling instant is i is represented, when finally asking for meeting this object function for minimum
Phasor x；N is sampling sum；The Huber estimation objective functions are the mesh of least square method when observation error is less than threshold value
Scalar functions, when observation error is more than threshold value, can weaken its adverse effect to object function, automatic rejection major network phasor amount
The bad data surveyed in device data；
Optimization Method is recycled to obtain line impedance matrix and admittance matrix.
4. a kind of robust electric transmission line positive sequence parameter identification method according to claim 2, it is characterised in that using symmetrical
Component method decouples line impedance matrix and admittance matrix, obtains positive sequence resistance, reactance and admittance parameter includes over the ground：
Structural matrix T：
The matrix T constructed herein is a kind of symmetrical component transformation, and its effect is that, a, b, the phase component of c three-phases is converted into positive sequence,
Negative phase-sequence and zero-sequence component；Wherein, a is twiddle factor,
The matrix equation of three-phase electricity pressure drop and three-phase current relation is set up using circuit phase component model：
In above formula,Three-phase electricity pressure drop is represented,Represent three-phase current；
Three-phase electricity pressure drop and three-phase current are replaced with into order components, obtained：
Represent each order components of voltage drop, i.e., positive and negative, residual voltage drop；Each order components of electric current are represented, i.e.,
Positive and negative, zero-sequence current；；
It is further represented as：
ZpThe as impedance matrix of order components, i.e.,：
Z therein(1)For circuit positive sequence impedance, Z(2)Represent circuit negative sequence impedance, Z(0)Represent circuit zero sequence impedance；
Similarly, it is same to release for admittance matrix：
Y thereinc(1)For the admittance over the ground of circuit positive sequence, Yc(2)Represent the admittance over the ground of circuit negative phase-sequence, Yc(0)With representing line zero ordered pair
Admittance.
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