CN109725236A - A kind of bus-bar fault area determination method based on power frequency quantity Polarity comparision - Google Patents
A kind of bus-bar fault area determination method based on power frequency quantity Polarity comparision Download PDFInfo
- Publication number
- CN109725236A CN109725236A CN201910142248.4A CN201910142248A CN109725236A CN 109725236 A CN109725236 A CN 109725236A CN 201910142248 A CN201910142248 A CN 201910142248A CN 109725236 A CN109725236 A CN 109725236A
- Authority
- CN
- China
- Prior art keywords
- current
- bus
- fault
- virtual
- power frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
The invention discloses a kind of bus-bar fault area determination method based on power frequency quantity Polarity comparision, method and step includes: the fault component electric current of each relative branch after obtaining failure；Reference current and virtual current are calculated using the fault component electric current of each relative branch；Reference current reconstruction coefficients and virtual current reconstruction coefficients comprising power frequency component are calculated separately according to reference current and virtual current；Angle theta between calculating benchmark electric current reconstructing coefficient and virtual current reconstruction coefficients；Set threshold value θsetIf θ < θset, then it is determined as bus internal fault, is otherwise bus external fault.The bus-bar fault area determination method is using the angle of reference current reconstruction coefficients and virtual current reconstruction coefficients to characterize polar relationship between the two; it does not need additionally to be filtered and phasor calculation; substantially increase movement speed; it only selects fault current amount to participate in calculating simultaneously, avoids influence of the CVT transient characterisitics to protection element rapidity and reliability.
Description
Technical field
The present invention relates to a kind of bus-bar fault area determination method, especially a kind of bus based on power frequency quantity Polarity comparision
Fault zone determines method.
Background technique
After bus breaks down, accurate Judging fault region, it will help quickly cut off failure, improve electric system fortune
Capable stability.It is divided according to protection philosophy, bus protection has power frequency quantity protection and transient based protection two major classes.Power frequency quantity
Bus protection mainly by Polarity comparision and amplitude com parison combine in the way of carry out fault zone differentiation, wherein polar relationship
It is mainly related to the phase relation of electric current or each relative branch current sampling data of bus by comparing power frequency fault component voltage
Degree is to indicate.But stringent filtering measures are needed in order to accurately obtain power frequency phasor, filtering delay-time greatly reduces protection
Movement speed.Since traditional power frequency quantity bus protection has that anti-CT saturability is weak, one is had also been proposed in the prior art
Digital differential bus protection scheme of the kind based on broad sense α planar process, the algorithm map the CT secondary current signal of a cycle
Fault zone identification is carried out to α plane, can effectively avoid the problem of the anti-CT saturability deficiency of conventional differential formula bus.
But in order to meet the reliability of protection, filtering is increased, the time of protection act is longer.
Traveling wave principle bus protection is not influenced because it is swift in motion by CT saturation and capacitance current
And become research hotspot.Compared with power frequency quantity direction protection, traditional traveling wave direction protection is primarily present two problems.On the one hand
It is constrained to the defect (such as failing in voltage zero-cross point failure) of traveling wave direction protection principle itself；On the other hand, high pressure is defeated
The capacitance type potential transformer (capacitor voltage transformer, CVT) that electric system generallys use is by transient state mistake
Journey influences greatly, cannot effective progress of disease high-frequency voltage signal.
Summary of the invention
It is an object of the invention to: a kind of bus-bar fault area determination method based on power frequency quantity Polarity comparision, energy are provided
Enough improve the reliability and sensitivity of bus protection.
In order to achieve the above-mentioned object of the invention, the present invention provides a kind of bus-bar fault regions based on power frequency quantity Polarity comparision
It determines method, includes the following steps:
Step 1, obtain failure after each relative branch fault component electric current；
Step 2, reference current and virtual current are calculated using the fault component electric current of each relative branch；
Step 3, according to reference current and virtual current calculate separately the reference current reconstruction coefficients comprising power frequency component and
Virtual current reconstruction coefficients；
Step 4, the angle theta between calculating benchmark electric current reconstructing coefficient and virtual current reconstruction coefficients；
Step 5, threshold value θ is setsetIf θ < θset, then it is determined as bus internal fault, is otherwise bus external fault.
Further, in step 1, the acquisition time of fault component electric current is in the 1ms time window after failure occurs.
Further, in step 2, reference current and virtual current are calculated using the fault component electric current of each relative branch
When, the fault component electric current that need to define a relative branch is benchmark electric current, then virtual current is remaining each relative branch
The sum of fault component electric current.
Further, in rapid 3, the reference current weight comprising power frequency component is calculated separately according to reference current and virtual current
The specific steps of structure coefficient and virtual current reconstruction coefficients are as follows:
Step 3.1, converter technique being touched using Clake phase, decoupling processing is carried out to reference current and virtual current respectively；
Step 3.2, using combination modulus method respectively to after decoupling reference current and virtual current be combined modulus meter
It calculates, obtains reference current combination modulus and virtual current combination modulus；
Step 3.3, then reference current combination modulus and virtual current combination modulus carry out the multiresolution analysis of wavelet transformation,
Decomposed to the band space containing power frequency component；
Step 3.4, the frequency band containing power frequency component is reconstructed to obtain reference current reconstruction coefficients and virtual current reconstructs
Coefficient.
Further, in step 3.1, when carrying out decoupling processing to reference current and virtual current, the Clake phase utilized is touched
The CLARK transformation matrix of converter technique are as follows:
In formula (16), ia、ibAnd icCurrent value under respectively three phase coordinates.
Further, in step 3.2, to after decoupling reference current and virtual current be combined modulus calculate when, benefit
The calculation formula of combination modulus method are as follows:
Δizh=4 Δ iα+Δiβ (17)
In formula (17), iαAnd iβCurrent value under respectively two phase coordinates.
Further, in step 4, the angle theta between reference current reconstruction coefficients and virtual current reconstruction coefficients calculates public
Formula are as follows:
In formula (14), CjrFor benchmark electric current reconstructing coefficient, CjvFor virtual current reconstruction coefficients, Cjr·CjvIndicate CjrAnd Cjv
Dot product, | Cjr| and | Cjv| it is respectively CjrAnd Cjv2- norm.
Further, in step 5, the threshold value θ of settingsetFor
The beneficial effects of the present invention are: reference current is decomposed into different frequencies from virtual current using wavelet transformation
Band is reconstructed the frequency band containing power frequency component to obtain corresponding reconstruction coefficients, seeks reference current reconstruction coefficients and virtual electricity
The angle of reconstruction coefficients is flowed to characterize polar relationship between the two, does not need additionally to be filtered and phasor calculation, significantly
Movement speed is improved, in addition fault current amount is only selected to participate in calculating, effectively prevents CVT transient characterisitics to protection element
The influence of rapidity and reliability.
Detailed description of the invention
Fig. 1 is flow chart of the method for the present invention；
Fig. 2 is the 500kV bus-bar system illustraton of model of the embodiment of the present invention；
Fig. 3 is the 500kV bus-bar system internal fault complementary network figure of the embodiment of the present invention；
Fig. 4 is the 500kV bus-bar system external fault complementary network figure of the embodiment of the present invention；
Fig. 5 is virtual current original waveform after internal fault of the invention；
Fig. 6 is reference current original waveform after internal fault of the invention；
Fig. 7 is waveform after virtual current wavelet transformation after internal fault of the invention；
Fig. 8 is waveform after reference current wavelet transformation after internal fault of the invention；
Fig. 9 is waveform after virtual current wavelet transformation in 1ms after internal fault of the invention；
Figure 10 is waveform after reference current wavelet transformation in 1ms after internal fault of the invention；
Figure 11 is virtual current original waveform after external fault of the invention；
Figure 12 is reference current original waveform after external fault of the invention；
Figure 13 is waveform after virtual current wavelet transformation after external fault of the invention；
Figure 14 is waveform after reference current wavelet transformation after external fault of the invention；
Figure 15 is waveform after virtual current wavelet transformation in 1ms after external fault of the invention；
Figure 16 is waveform after reference current wavelet transformation in 1ms after external fault of the invention；
Figure 17 is the value of present invention angle theta in different initial angle angle Down Highway internal fault external faults；
Figure 18 is the value of present invention angle theta in different transition resistance Down Highway internal fault external faults；
Virtual current original waveform when Figure 19 is bus internal fault of the invention under 10dB noise conditions；
Reference current original waveform when Figure 20 is bus internal fault of the invention under 10dB noise conditions；
Waveform after virtual current wavelet transformation when Figure 21 is bus internal fault of the invention under 10dB noise conditions；
Waveform after reference current wavelet transformation when Figure 22 is bus internal fault of the invention under 10dB noise conditions；
Virtual current original waveform when Figure 23 is bus external fault of the invention under 10dB noise conditions；
Reference current original waveform when Figure 24 is bus external fault of the invention under 10dB noise conditions；
Waveform after virtual current wavelet transformation when Figure 25 is bus external fault of the invention under 10dB noise conditions；
Waveform after reference current wavelet transformation when Figure 26 is bus external fault of the invention under 10dB noise conditions.
Specific embodiment
To known to the analysis result of traditional polarity of traveling wave comparison expression bus protection principle: when failure occurs outside area, therefore
Hinder the initial traveling wave of line voltage distribution and the initial polarity of traveling wave of electric current on the contrary, the initial traveling wave of non-fault line voltage and electric current initial row
Wave polarity is identical；And when troubles inside the sample space, each initial traveling wave of associated circuitry voltage of bus is identical as the initial polarity of traveling wave of electric current, table 1
Made a concrete analysis of bus and route respectively failure when route on the voltage and current traveling wave fault feature that detects.Wherein own
The Δ u and Δ i of route are the initial traveling wave of voltage and the initial traveling wave of electric current, if Δ S=Δ u × Δ i.
As shown in Table 1:
1. when bus external fault:
Faulty line: Δ u × Δ i < 0 (1)
Non-fault line: Δ u × Δ i > 0 (2)
2. when bus internal fault:
Δu×Δi>0 (3)
As shown in Figure 1, the bus-bar fault area determination method provided by the invention based on power frequency quantity Polarity comparision, including such as
Lower step:
Step 1, the fault component electric current for obtaining each relative branch after failure, due to method of the invention be not required to extract it is high
Frequency transient state component, therefore it is not required to excessively high sample rate, therefore sample frequency is set as 20kHz；
Step 2, reference current and virtual current are calculated using the fault component electric current of each relative branch；
Step 3, according to reference current and virtual current calculate separately the reference current reconstruction coefficients comprising power frequency component and
Virtual current reconstruction coefficients；
Step 4, the angle theta between calculating benchmark electric current reconstructing coefficient and virtual current reconstruction coefficients；
Step 5, threshold value θ is setsetIf θ < θset, then it is determined as bus internal fault, is otherwise bus external fault.
Further, in step 1, the acquisition time of fault component electric current is in the 1ms time window after failure occurs.
Further, in step 2, reference current and virtual current are calculated using the fault component electric current of each relative branch
When, the fault component electric current that need to define a relative branch is benchmark electric current, then virtual current is remaining each relative branch
The sum of fault component electric current.
Further, in rapid 3, the reference current weight comprising power frequency component is calculated separately according to reference current and virtual current
The specific steps of structure coefficient and virtual current reconstruction coefficients are as follows:
Step 3.1, for three-phase power transmission system, there is coupling between each phase voltage and each phase current, to avoid alternate coupling
The influence of conjunction carries out decoupling processing by phase-model transformation, the present invention using Clake phase touch converter technique respectively to reference current and
Virtual current carries out decoupling processing；
Step 3.2, it because using a kind of Modulus Analysis, may cause under certain failures almost without transient state travelling wave component,
This can make protection failure in any case, this does not allow in high-voltage fence, examine to improve protection failure as far as possible
Disconnected sensitivity, using combination modulus method respectively to after decoupling reference current and virtual current be combined modulus calculate, obtain
Obtain reference current combination modulus and virtual current combination modulus；
Step 3.3, then reference current combination modulus and virtual current combination modulus carry out the multiresolution analysis of wavelet transformation,
The band space containing power frequency component is decomposed to, when sample frequency is 20kHz, the 7th layer of approximation coefficient includes power frequency component (0
~78.125Hz), the approximation coefficient of this layer is reconstructed, the signal component of corresponding power frequency component, present invention selection are obtained
Db4 small echo is as wavelet basis；
Step 3.4, the frequency band containing power frequency component is reconstructed to obtain reference current reconstruction coefficients and virtual current reconstructs
Coefficient.
Further, in step 3.1, when carrying out decoupling processing to reference current and virtual current, the Clake phase utilized is touched
The CLARK transformation matrix of converter technique are as follows:
In formula (16), ia、ibAnd icCurrent value under respectively three phase coordinates.
Further, in step 3.2, to after decoupling reference current and virtual current be combined modulus calculate when, benefit
The calculation formula of combination modulus method are as follows:
Δizh=4 Δ iα+Δiβ (17)
In formula (17), iαAnd iβCurrent value under respectively two phase coordinates.
Further, in step 4, the angle theta between reference current reconstruction coefficients and virtual current reconstruction coefficients calculates public
Formula are as follows:
In formula (14), CjrFor the reference current reconstruction coefficients on jth scale, CjvFor the virtual current reconstruct on jth scale
Coefficient, Cjr·CjvIndicate CjrAnd CjvDot product, | Cjr| and | Cjv| it is respectively CjrAnd Cjv2- norm.
Further, in step 5, the threshold value θ of settingsetFor
As shown in Fig. 2, the present invention, by taking 500kV substation bus bar as an example, 5 associations that L1~L5 is connected by bus M are propped up
Road, R1~R5 are the protection location of the respective lines end nearly bus M installation.Wherein im(m=1,2,3,4,5) it is surveyed for each route of bus
The electric current measured, stray capacitance equivalent impedance is C to bus M over the groundS.Defining electric current positive direction is that bus flows to route, works as bus
On when breaking down at F1, super-imposed networks as shown in figure 3,For the auxiliary voltage at the F1 of fault point, Δ im(m=
It 1,2,3,4,5) is to flow through each protection location RmFault component electric current.
It is identical with each relative branch current polarity of bus known to formula (3) by table 1 when bus internal fault, that is, have:
By formula (4) it is found that (Δ i1+Δi2+Δi3+Δi4) and Δ i5Polarity is identical, that is, has:
(Δi1+Δi2+Δi3+Δi4)×Δi5>0 (5)
By taking L2 line fault as an example, super-imposed networks as shown in figure 4,For the auxiliary voltage at the F2 of fault point.By
Table 1 and formula (1), each relative branch current polarity relationship of 4 median generatrix of (2) analysis chart can obtain:
If ignoring Δ icInfluence, can be obtained according to Kirchhoff's current law (KCL) and formula (6):
Know Δ i5It is opposite with the sum of other branch trouble current weights polarity, it may be assumed that
(Δi1+Δi2+Δi3+Δi4)×Δi5< 0 (9)
In summary known to bus-bar fault signature analysis:
It is important to note that the condition that above-mentioned current polarity relationship is set up is to set fault current to be directed toward route by bus
It is positive.If setting reference current Δ irFor route L5 fault component electric current；Virtual current Δ ivFor the fault component of route L1~L4
The sum of electric current.Then reference current Δ ir, virtual current Δ ivMeet:
By reference current Δ irWith virtual current Δ ivBetween polar relationship can accurate judgement fault zone.Traditional traveling wave
Bus protection principle mostly characterizes polarity of traveling wave using Wavelet Modulus Maxima, and in the case where wavefront is more gentle, it is small
Wave modulus maximum is smaller, the influence vulnerable to noise jamming.The present invention utilizes reference current and virtual electricity after short period internal fault
Angle between stream realizes Polarity comparision.By the two of current signal x (t) into wavelet transform is defined as:
dj(k)=< x (t), ψj,k(t)>,j,k∈Z (12)
In formula (12), ψj,k(t)=2j/2ψ(2jT-k) the discrete wavelet family of functions for being morther wavelet ψ (t), j is scale coefficient.
Assuming that the discrete sample of current signal x (t) is c0(n), then the approximation coefficient c on jth scalej(n) and detail coefficients dj(n) may be used
Logical Mallat fast algorithm implementation.
In formula (13), h (n), g (n) are wavelet decomposition filter bank coefficients, are determined by selected morther wavelet ψ (t).
Wavelet transform is a kind of process of multiresolution analysis, and signal is broken down into different frequencies after wavelet transform
The component of band.Pairing approximation coefficient and detail coefficients carry out single branch reconstruct, letter of the available signal x (t) under different frequency bands
Breath.In view of transient state ingredient is mainly contained after failure in electric current, therefore first to reference current Δ i after failurerAnd virtual current
ΔivWavelet transform is carried out, the coefficient of wavelet decomposition containing power frequency component is reconstructed, obtaining includes work on jth scale
The reference current reconstruction coefficients C of frequency componentjrWith virtual current reconstruction coefficients Cjv, then CjrAnd CjvBetween angle theta can be by following formula
It finds out:
In formula (14), Cjr·CjvIndicate CjrAnd CjvDot product, | Cjr| and | Cjv| it is CjrAnd Cjv2- norm.
Under opposed polarity relationship, CjrAnd CjvBetween angle it is different.If CjrAnd CjvPolarity is identical, and whithin a period of time two
Person's waveform is similar, therefore the angle theta of the two is approximately 0；If CjrAnd CjvPolarity is on the contrary, both whithin a period of time waveform phase
Instead, then the angle of the two is approximately 180 °.Bus-bar fault region criterion is established according to angle theta.If fault current flows into bus
Just, if:
θ < θset (15)
It is judged as internal fault, is otherwise external fault.θ in formulasetFor threshold value, event when comprehensively considering inside and outside failure
Hinder feature and criterion sensitivity, takes θsetForThe selection of threshold value will affect the sensitivity of protection, to Protection criteria to Guan Chong
It wants.For Protection criteria of the present invention, threshold value choose it is excessive, it is and too small by the sensitivity of criterion when reducing external area error
By the sensitivity of criterion when reducing troubles inside the sample space.By aforementioned theory analysis it is found that in troubles inside the sample space, θ is close to 0 °, and outside area
When failure, θ is close to π.The case where there are sample point data loss in Practical Project measurement, analysis mode (14) is known:
1) when bus internal fault, C at this timejr·Cjv> 0, | Cjr||Cjv| > 0,If reference current Δ i5It adopts
Sampling point is lost, Cjr·CjvReduce, | Cjr||Cjv| reduce, after internal fault occurs known to formula (4), reference current and virtual electricity
It is identical to flow polarity, and reference current Δ i5The case where sampled point is all lost hardly occurs, therefore Cjr·CjvWith | Cjr
||Cjv| it is consistently greater than 0.Known to the above analysis:Similarly analysis internal fault is virtual
The case where current sample point is lost can equally obtain:
2) when external fault occurs for bus, there is Cjr·Cjv< 0, | Cjr||Cjv| > 0,If virtual current samples
Point is lost, Cjr·CjvIncrease, | Cjr|||Cjv| reduce, virtual current and reference current after external fault occurs known to formula (6)
Polarity is on the contrary, and all 20 sample point datas the case where all losing are not in therefore C substantiallyjr·CjvIt is consistently less than
0, | Cjr||Cjv| it is consistently greater than 0.From the analysis above, we can see thatSimilarly isolated-phase buses occurs external
Sampled point loss, which occurs, for reference current when failure to obtain:
Meet when bus internal fault known to the above analysisWhen bus external faultTherefore this hair
Bright selected threshold value
In order to verify the accuracy of the method for the present invention, establishes simulation model: utilizing PSCAD/EMTDC electromagnetic transient simulation
Software establishes 500kV bus-bar system simulation model as shown in Figure 2, and bus uses LGJQT-1400 type special type light steel-core-aluminium
Twisted wire, using the Pingwu Central China Power Grid 500kV cable architecture parameter, (conducting wire uses the conductors on quad bundled of LGJQ-300 × 4 to route, single
0.108 Ω of conductor resistance/km).The length of route L1~L5 is respectively 200,130,250,270,300km, and route is using frequency
Rate correlation model, line construction select 3H5 shaft tower.Bus direct-to-ground capacitance CSFor 0.01 μ F, data window selects 1ms, i.e., 20 are adopted
Sampling point data.
For the emulation testing under the conditions of different faults: when bus breaks down, by verifying, the present invention is mentioned algorithm not
The reliability of Protection criteria, 2~table of table 7 are done respectively under same fault initial angle, different transition resistances and different faults type
Corresponding simulating, verifying.
Bus troubles inside the sample space the simulation results: setting M bus generation A phase ground fault, 45 ° of fault initial angle, transition
200 Ω of resistance, waveform correlation is as shown in Fig. 5~Figure 10.According to reference current in 1ms data window after previous analysis calculating failure
It with virtual current angle, obtains: Cjr·Cjv=0.5783, | Cjr||Cjv|=0.5801, θ=0.0797rad.
The test result of difference initial angle protection algorism when table 2 is internal fault.From simulation result it is found that at the beginning of failure
The variation at beginning angle, angle theta can change therewith, but be stable in 0.5rad or less substantially.That is initial angle θ is much smaller than door
Threshold value θset, meet formula (15), be determined as internal fault.
Table 3 be internal fault when difference transition resistance under protection algorism test result, from analysis of simulation result it is found that folder
Angle θ is gradually increased with the increase of transition resistance, but stable within 0.1rad, respectively less than threshold value θset, meet formula
(15), it is determined as internal fault, i.e. algorithm is not influenced substantially by transition resistance.
Algorithm test result under different faults type when table 4 demonstrates internal fault is analyzed it is found that under different type
Angle theta will be different, but respectively less than threshold value θset, meet formula (15), be determined as internal fault.
In conclusion angle theta size base when bus internal fault under different faults between reference current and virtual current
This is within the scope of 0~1rad, respectively less than threshold value θset.I.e. mentioned algorithm being capable of reliable recognition bus troubles inside the sample space herein.
Bus external area error the simulation results: setting route L4 away from generation AB phase ground fault at M bus 50km, therefore
90 ° of initial angle of barrier, 150 Ω of transition resistance, correlated current waveform is as shown in Figure 11~16.After calculating failure according to previous analysis
Reference current and virtual current in 1ms data window, obtain: Cjr·Cjv=-1.3999, | Cjr||Cjv|=1.3999, θ=
3.1408rad。
Influence of the different faults initial angle to mentioned algorithm herein, table 5 have been done accordingly when in order to verify bus external fault
Simulating, verifying.Analyze the angle theta known to simulation result when failure occurs outside area, between reference current and virtual current
Substantially it is not influenced by fault initial angle, and θ ≈ 3.14, criterion (15) is not satisfied, are determined as external fault.
Simulation result of the algorithm under different transition resistances when table 6 demonstrates external area error, analysis is it is found that with transition electricity
The increase of resistance, angle theta are gradually reduced, but angle theta is approximately equal to 3.14, and criterion (15) are not satisfied, and are reliably determined as event outside area
Barrier.
Simulation result of the algorithm under different faults position and different faults type when table 7 demonstrates external area error, analysis
It is found that angle theta is held essentially constant under different faults type, it is all larger than threshold value θ0, criterion (15) are unsatisfactory for, are determined as outer
Portion's failure.
The value that Figure 17 show angle theta under bus internal fault external fault when initial angle changes within the scope of 5 °~120 ° is bent
Line.Wherein F1 is that B phase ground fault, 100 Ω of transition resistance occur for bus M；F2 is route L2 away from generation B phase at bus M 80km
Ground short circuit, 100 Ω of transition resistance；F3 is route L4 away from generation AB phase ground short circuit, transition resistance 150 at bus M50km
Ω.It is obvious from the angle theta difference known to Figure 17 curve between bus inside and outside fault reference electric current and virtual current.
The value of angle theta when Figure 18 show bus internal fault external fault when transition resistance changes within the scope of the Ω of 0 Ω~800
Curve.Wherein F1 be bus M occur A phase ground fault, 45 ° of fault initial angle.F2 is route L2 away from hair at bus M 100km
Raw BC phase short circuit, 45 ° of fault initial angle.F3 is route L4 away from ABC phase ground short circuit occurs at bus M 10km, and failure is initial
60 ° of angle.It can be seen that angle theta is almost nil when internal fault, when external fault angle theta be approximately equal to π, i.e. bus inside and outside therefore
It is obvious to hinder angle theta difference in size, Protection criteria high reliablity.
To sum up simulation result, can it is found that mentioned algorithm angle theta feature difference when internal fault external fault occurs is obvious herein
Reliable recognition fault zone, and do not influenced substantially by fault initial angle, transition resistance and fault type.
The beneficial effects of the present invention are:
(1) due to after CT saturation cannot correctly progress of disease primary side current, may result in the malfunction of protection.But
After failure in 1/4 power frequency period, CT basically will not produce saturated phenomenon.The mentioned criterion of the present invention utilizes 1/20 power frequency after failure
The fault traveling wave electric current of 1ms data window determines fault zone in period, therefore is not influenced by CT saturation theoretically.Table 8 is done
Corresponding emulation experiment carrys out the anti-TA saturability of testing algorithm.Wherein CT, which is saturated simulation model and uses, has preferable time-frequency special
The nonlinear time-domain equivalent-circuit model of property.
Data analysis is emulated from table 8 it is found that either TA caused by troubles inside the sample space or external area error is saturated, protection is sentenced
According to the accurate Judging fault region of equal energy.
(2) the case where being lost in Practical Project measurement there are reference current and virtual current sampled value, be analysis area it is outer therefore
Hinder influence of the loss of data to algorithm, table 9~10 made respectively reference current data and virtual current in 20 sampled points with
Machine loses the emulation testing after several sampled points.
By 9~10 simulation result of table it is found that in the case where data random loss, troubles inside the sample space loss of data will cause folder
Angle θ becomes larger, and external area error loss of data causes angle theta to reduce.Even if in the case where losing 6 sample point datas, in area
Failure still meets criterion formula (15), and criterion is not satisfied in external area error.I.e. Protection criteria is not lost substantially by sample point data
Influence.
(3) emulation is established on the basis of ideal emulates signal, investigates the suitable of this method on the basis of noise below
Ying Xing.It is respectively set in bus internal fault external fault and sets making an uproar for different signal-to-noise ratio (signal-to-noise ratios SNRs)
Sound gives partial test result of algorithm under the influence of different noise intensities for table 11.Wherein Figure 19~Figure 26 is noise ratio
For 10dB situation Down Highway internal fault external fault correlated current waveform.
As shown in Table 11, in the case where considering noise jamming, which remains to correctly judge fault zone, there is one
The ability of fixed noise resistance interference, is consistent with theory analysis.
(4) bus protection being widely used in currently practical electric system is the current differential protection based on power frequency quantity, female
Line differential protection is mainly differentiated using kirchhoff electric current theorem to whether bus breaks down, and is operated normally and female
When line external area error, the sum of electric current for each outlet being connected with bus is 0；When bus-bar fault, what is connected on bus is all
The electric current of outlet and total current equal to fault point.Current differential protection carries out phasor using complete cycle or half cycle fourier algorithm
It calculates, arithmetic speed is long depending on the operand of algorithm and required data window.In terms of operand, every power frequency period
When sampling N point, a phasor is calculated using full-wave fourier algorithm and needs 2N multiplication and addition, and half cycle fourier algorithm needs N
Secondary multiplication and addition.When consideration sample rate is 1600Hz (32 point sampling), calculates a phasor full-wave fourier algorithm and need 64 times
Multiplication and addition, half cycle fourier algorithm need 32 multiplication algorithms.In data window long side, in order to guarantee the precision calculated, entirely
All fourier algorithms need the data window of 20ms, and half cycle fourier algorithm needs the data window of 10ms.Bus protection algorithm of the present invention
Calculation amount in process is mainly reflected in three aspect of Clarke phase-model transformation, wavelet function feedback and angle calcu-lation.Through thick
Slightly to estimate, phase-model transformation needs 18 multiplication, wavelet function feedbacks about to need 1264 multiplication, and angle calcu-lation needs 62 multiplication,
Entire calculation amount is about 1344 multiplication and a small amount of accumulating operation.Fast digital signal handles chip (digital signal
Processing, DSP) above-mentioned operation can be fast implemented.By taking the DS1003 based on TMS320C40 as an example, when realizing above-mentioned utilization
0.5ms is not exceeded, according to the dsp processor of more high primary frequency, arithmetic speed will faster.Actuation time is less than 5ms.Table 12
By conventional current differential protecting method compared with this paper mentions algorithm actuation time, wherein Ta is operating time of protection.
It to sum up analyzes, although mentioned method is larger on operand herein, operation can be completed in 0.5ms by DSP,
Long data window needed for simultaneously is only that 1ms substantially reduces data window length, therefore institute compared with traditional power frequency quantity protection algorism
The movement speed for mentioning algorithm will be much higher than power frequency quantity protection element.
The present invention when analyzing failure on the basis of each bus associated circuitry polar relationship, respectively define reference current with
Virtual current proposes a kind of mother based on power frequency quantity Polarity comparision by the corner dimension of both analyses come antipolarity relationship
It is slow, reliable in glitch initial angle and high resistive fault to solve traditional power frequency quantity bus protection movement speed for line protection algorism
The problem that property is low, is influenced by CVT transient characterisitics.It is available to draw a conclusion by theory deduction and simulation analysis:
1) when troubles inside the sample space, reference current is identical as virtual current polarity；When external area error, the two polarity is opposite.Therefore base
Polar relationship between quasi- electric current and virtual current can carry out Efficient Characterization with angle between the two.
2) algorithm constructs fault identification criterion using reference current and virtual current, and traditional traveling wave is avoided from principle
The problem of protection philosophy is by CVT Effect of Transient Component.
3) algorithm carries out fault zone differentiation, quick action, and theory analysis using the data window of 1ms and PSCAD is imitative
It is true the result shows that, mentioned algorithm can it is quick in all cases, accurately identify fault zone, substantially not by fault initial angle, mistake
Cross the influence of resistance, fault type, CVT Transfer characteristic.
Claims (8)
1. a kind of bus-bar fault area determination method based on power frequency quantity Polarity comparision, which comprises the steps of:
Step 1, obtain failure after each relative branch fault component electric current；
Step 2, reference current and virtual current are calculated using the fault component electric current of each relative branch；
Step 3, reference current reconstruction coefficients comprising power frequency component and virtual are calculated separately according to reference current and virtual current
Electric current reconstructing coefficient；
Step 4, the angle theta between calculating benchmark electric current reconstructing coefficient and virtual current reconstruction coefficients；
Step 5, threshold value θ is setsetIf θ < θset, then it is determined as bus internal fault, is otherwise bus external fault.
2. the bus-bar fault area determination method according to claim 1 based on power frequency quantity Polarity comparision, which is characterized in that
In step 1, the acquisition time of fault component electric current is in the 1ms time window after failure occurs.
3. the bus-bar fault area determination method according to claim 1 based on power frequency quantity Polarity comparision, which is characterized in that
In step 2, when calculating reference current and virtual current using the fault component electric current of each relative branch, an association need to be defined
The fault component electric current of branch is benchmark electric current, then virtual current is the sum of the fault component electric current of remaining each relative branch.
4. the bus-bar fault area determination method according to claim 1 based on power frequency quantity Polarity comparision, which is characterized in that
In rapid 3, reference current reconstruction coefficients and virtual current comprising power frequency component are calculated separately according to reference current and virtual current
The specific steps of reconstruction coefficients are as follows:
Step 3.1, converter technique being touched using Clake phase, decoupling processing is carried out to reference current and virtual current respectively；
Step 3.2, using combination modulus method respectively to after decoupling reference current and virtual current be combined modulus calculate, obtain
Obtain reference current combination modulus and virtual current combination modulus；
Step 3.3, then reference current combination modulus and virtual current combination modulus carry out the multiresolution analysis of wavelet transformation, by it
Decompose to the band space containing power frequency component；
Step 3.4, the frequency band containing power frequency component is reconstructed to obtain reference current reconstruction coefficients and virtual current reconstruction coefficients.
5. the bus-bar fault area determination method according to claim 4 based on power frequency quantity Polarity comparision, which is characterized in that
In step 3.1, when carrying out decoupling processing to reference current and virtual current, the Clake phase utilized touches the CLARK transformation of converter technique
Matrix are as follows:
In formula (16), ia、ibAnd icCurrent value under respectively three phase coordinates.
6. the bus-bar fault area determination method according to claim 5 based on power frequency quantity Polarity comparision, which is characterized in that
In step 3.2, to after decoupling reference current and virtual current be combined modulus calculate when, the meter of the combination modulus method utilized
Calculate formula are as follows:
Δizh=4 Δ iα+Δiβ (17)
In formula (17), iαAnd iβCurrent value under respectively two phase coordinates.
7. the bus-bar fault area determination method according to claim 1 based on power frequency quantity Polarity comparision, which is characterized in that
Angle theta calculation formula in step 4, between reference current reconstruction coefficients and virtual current reconstruction coefficients are as follows:
In formula (14), CjrFor benchmark electric current reconstructing coefficient, CjvFor virtual current reconstruction coefficients, Cjr·CjvIndicate CjrAnd CjvPoint
Multiply, | Cjr| and | Cjv| it is respectively CjrAnd Cjv2- norm.
8. the bus-bar fault area determination method according to claim 1 based on power frequency quantity Polarity comparision, which is characterized in that
In step 5, the threshold value θ of settingsetFor
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910142248.4A CN109725236A (en) | 2019-02-26 | 2019-02-26 | A kind of bus-bar fault area determination method based on power frequency quantity Polarity comparision |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910142248.4A CN109725236A (en) | 2019-02-26 | 2019-02-26 | A kind of bus-bar fault area determination method based on power frequency quantity Polarity comparision |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN109725236A true CN109725236A (en) | 2019-05-07 |
Family
ID=66301697
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910142248.4A Pending CN109725236A (en) | 2019-02-26 | 2019-02-26 | A kind of bus-bar fault area determination method based on power frequency quantity Polarity comparision |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109725236A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110133445A (en) * | 2019-06-10 | 2019-08-16 | 集美大学 | A kind of submarine cable fault distance-finding method, terminal device and storage medium |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101710164A (en) * | 2009-11-23 | 2010-05-19 | 清华大学 | Transmission line malfunction directional element |
| CN102122815A (en) * | 2011-02-28 | 2011-07-13 | 清华大学 | Ultra high-speed traveling wave direction pilot protection method, device and system for high voltage transmission line |
| CN103760461A (en) * | 2014-01-14 | 2014-04-30 | 昆明理工大学 | Bus protection method based on sudden-change direction of fault current containing power frequency bands |
| CN104090209A (en) * | 2014-07-02 | 2014-10-08 | 国家电网公司 | Bus protection method based on parameter identification |
| CN104242262A (en) * | 2014-08-28 | 2014-12-24 | 山东大学 | Rapid bus protection method based on fault component mean value product |
| CN105548806A (en) * | 2015-12-14 | 2016-05-04 | 山东理工大学 | Small current grounding fault line selection method based on transient traveling wave |
| CN108490312A (en) * | 2018-03-27 | 2018-09-04 | 中国矿业大学 | It is grounded section localization method based on the polar distribution of secondary transient state increment current amplitude |
| CN109301800A (en) * | 2018-10-23 | 2019-02-01 | 贵州电网有限责任公司 | Distribution line adaptive guard method and system based on traveling wave |
-
2019
- 2019-02-26 CN CN201910142248.4A patent/CN109725236A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101710164A (en) * | 2009-11-23 | 2010-05-19 | 清华大学 | Transmission line malfunction directional element |
| CN102122815A (en) * | 2011-02-28 | 2011-07-13 | 清华大学 | Ultra high-speed traveling wave direction pilot protection method, device and system for high voltage transmission line |
| CN103760461A (en) * | 2014-01-14 | 2014-04-30 | 昆明理工大学 | Bus protection method based on sudden-change direction of fault current containing power frequency bands |
| CN104090209A (en) * | 2014-07-02 | 2014-10-08 | 国家电网公司 | Bus protection method based on parameter identification |
| CN104242262A (en) * | 2014-08-28 | 2014-12-24 | 山东大学 | Rapid bus protection method based on fault component mean value product |
| CN105548806A (en) * | 2015-12-14 | 2016-05-04 | 山东理工大学 | Small current grounding fault line selection method based on transient traveling wave |
| CN108490312A (en) * | 2018-03-27 | 2018-09-04 | 中国矿业大学 | It is grounded section localization method based on the polar distribution of secondary transient state increment current amplitude |
| CN109301800A (en) * | 2018-10-23 | 2019-02-01 | 贵州电网有限责任公司 | Distribution line adaptive guard method and system based on traveling wave |
Non-Patent Citations (3)
| Title |
|---|
| 李小鹏等: ""基于工频量极性比较的高压输电线路超高速方向元件"", 《中国电机工程学报》 * |
| 李肖博等: ""基于虚拟电流波形特征的母线保护原理"", 《电力系统自动化》 * |
| 白嘉等: ""基于组合模量的行波电流极性比较式方向保护原理"", 《电网技术》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110133445A (en) * | 2019-06-10 | 2019-08-16 | 集美大学 | A kind of submarine cable fault distance-finding method, terminal device and storage medium |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Farshad et al. | Accurate single-phase fault-location method for transmission lines based on k-nearest neighbor algorithm using one-end voltage | |
| Yusuff et al. | Fault location in transmission lines based on stationary wavelet transform, determinant function feature and support vector regression | |
| CN101907437B (en) | Wavelet difference algorithm-based cable fault localization method | |
| CN103308804B (en) | Based on quick K-S converting electric power quality disturbance signal time and frequency parameter extracting method | |
| Adly et al. | A novel protection scheme for multi-terminal transmission lines based on wavelet transform | |
| CN103293449B (en) | Method for removing single-terminal traveling wave fault location dead area of high-voltage power grid in coal mine | |
| CN103018632B (en) | Small current grounding system single-phase ground fault line selection method based on fisher information | |
| CN109116186A (en) | A kind of one-end fault ranging method based on single-ended traveling wave method and intrinsic frequency method | |
| CN107543962A (en) | The computational methods of leading m-Acetyl chlorophosphonazo spectrum distribution | |
| CN110247420B (en) | Intelligent fault identification method for HVDC transmission line | |
| Chen et al. | A new approach to EHV transmission line fault classification and fault detection based on the wavelet transform and artificial intelligence | |
| CN109507534A (en) | One kind being based on the accident analysis of MMC-HVDC overhead transmission line and recognition methods | |
| CN105353269B (en) | A kind of online fault distance-finding method of high-tension cable | |
| Wang et al. | An edge computing method using a novel mode component for power transmission line fault diagnosis in distribution network | |
| CN109725236A (en) | A kind of bus-bar fault area determination method based on power frequency quantity Polarity comparision | |
| CN114636896A (en) | Single-phase grounding high-resistance fault traveling wave positioning method for power distribution network by utilizing kurtosis | |
| Tang et al. | A frequency sweep location method for soft faults of power cables based on MUSIC-pseudospectrum | |
| Deng et al. | A Single-Ended Fault Location Method for Transmission Line Based on Full Waveform Feature Extraction of Traveling Waves | |
| CN107153154B (en) | A kind of two sides earth cable insulation deterioration diagnosis method | |
| Fluty et al. | Electric transmission fault location techniques using traveling wave method and discrete wavelet transform | |
| Zhang et al. | Two terminals protection method for HVDC transmission lines based on maximal overlap discrete wavelet transform and cross-correlation coefficient of traveling wave | |
| Wang et al. | Fault location of flexible grounding distribution system based on multivariate modes and kurtosis calibration | |
| CN109188207B (en) | Bus fault positioning method based on initial traveling wave active power | |
| CN115494341A (en) | Power distribution network fault location method and system based on IELM-VMD algorithm | |
| CN102053213A (en) | Internal and external fault recognition method based on entropy of information for extra-high voltage (EHV) direct current electric transmission line |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20190507 |
|
| RJ01 | Rejection of invention patent application after publication |