CN104133156A - Hybrid line single-ended traveling wave fault distance measuring method based on fault distance interval - Google Patents

Abstract

The invention discloses a hybrid line single-ended traveling wave fault distance measuring method based on a fault distance interval. A fault distance interval is preliminarily determined based on single-ended power frequency, the focus is on the scope of research of traveling wave, and the law of traveling wave is analyzed in a targeted mode, thereby realizing accurate fault location. The method is high in distance measuring precision, ranging dead zones do not exist for connection point neighborhood faults, and a connection point fault can be correctly identified or a fault section can be correctly distinguished. The method only uses single-ended data, is easy to implement technologically, has high economical efficiency, is convenient for device installation and popularization, and has high practical application value.

Description

A kind of series-parallel connection line one-end Method of Traveling Wave Fault Ranging based on fault distance interval

Technical field

The present invention relates to a kind of series-parallel connection line one-end Method of Traveling Wave Fault Ranging based on fault distance interval.

Background technology

Current power transmission circuit is transformed to pole line-cable series-parallel connection circuit power transmission mode gradually.Accurately rational reclosing strategy, to alleviating line walking burden, is formulated in the trouble spot of location series-parallel connection circuit, realizes the fast quick-recovery of power supply significant.

Existing series-parallel connection circuit distance-finding method, taking both-end amount method as main, comprises both-end power frequency amount method and both-end traveling wave method.Both-end power frequency amount method is mainly carried out trouble spot reckoning or search based on circuit sequence voltage after fault or order current amplitude relation, there is the problem such as pseudo-root, connection point near fault section error in judgement in the method, and fault section error in judgement will affect the correct enforcement of reclosing, may cause delayed recovery power supply or electrical network to suffer secondary pulse; Both-end traveling wave method catches the capable ripple of primary fault of arrival two ends bus and finds range, and theoretical precision is high, but too strong to GPS synchronous clock dependence in actual use, reliability is on the low side, and dual ended device cost is higher, is unfavorable for the popularization of distance-finding method.

The range finding of single-ended amount method is not restricted by the factors such as communication condition, economic condition, administration authority, low compared with both-end method cost, reliability is high, is easy to realize; If can ensure the precision of single-ended algorithm, single-ended amount method more has superiority than both-end amount method.But at present less to the research of single-ended amount method.Trace it to its cause, the information deficiency that single-ended power frequency amount Guttae Phacosylini is used, range finding result is undesirable; Single-ended traveling wave method is because complicated folding, reflection can occur row ripple in joint line, and wave head is difficult to identification, and application is restricted.Single Terminal Traveling Wave Fault Location method in existing power distribution network joint line does not have multianalysis row wave propagation behavior, and practicality is lower.In addition, by intelligent algorithm Judging fault section, in definite section, utilize row ripple to calculate fault distance, need a large amount of physical fault data, be difficult to realize from practical standpoint.Therefore, proposing a kind of single-ended amount distance-finding method that simultaneously meets precision and practicality requirement is the important directions of studying at present.

Summary of the invention

The present invention is in order to address the above problem, a kind of series-parallel connection line one-end Method of Traveling Wave Fault Ranging based on fault distance interval has been proposed, the method is utilized the fault distance Operations of Interva Constraint row ripple identification scope based on power frequency amount, promotes the dependable with function of Single Terminal Traveling Wave Fault Location; By analyzing pointedly focal zone expert ripple propagation law, build fault point positioning method, the failure criterion of section tie point and fault section criterion, and reject and ensure distance accuracy by interference wave.

To achieve these goals, the present invention adopts following technical scheme:

A series-parallel connection line one-end Method of Traveling Wave Fault Ranging based on fault distance interval, comprises the following steps:

(1) based on circuit distributed parameter model, utilize the pure resistive of transition resistance, build localization of fault equation, first assumed fault occurs in certain point on certain section circuit, localization of fault equation is searched for to be converted to zero point this section of corresponding mapping function solved to bare minimum point;

(2) to every section of circuit searching for extreme point in length range separately, comprehensive each section result obtains the interval at place, trouble spot, the relation of failure judgement point and tie point neighborhood, if be positioned at neighborhood, performs step 3); Beyond neighborhood, perform step 5);

(3) determine whether tie point place fault by tie point failure criterion: be that the interior tie point of this neighborhood is trouble spot, range finding finishes; Otherwise determine time interval T, by fault section criterion Judging fault section;

(4) determine the polar relationship of each current traveling wave in fault section; Reject interference wave with reference to series-parallel connection line construction; Reflect reflection wave once through section head end and trouble spot according to polar relationship identification, through section end reflection reflection wave once, the corresponding moment of record; Calculate fault distance, range finding finishes;

(5) fault distance interval is converted to time interval; According to the polar relationship of determining in fault section, reject interference wave with reference to series-parallel connection line construction; Reflect reflection wave once through section head end and trouble spot according to polar relationship identification, through section end reflection reflection wave once, the corresponding moment of record; Calculate fault distance, range finding finishes.

In described step (1), series-parallel connection circuit is the alternatively distributed structure of pole line, cable, thereby pole line and cable are divided into circuit different sections naturally, and what each section herein referred to is exactly each built on stilts line segment and each cut cable.

In described step (2), the interval method of each section result localization of faults is specially:

1) if only have the point in a section in all results, all the other are each section tie point, get this interior some position;

2) if there is the point in two sections in all results, all the other are section tie point, get the section tie point position between 2 interior points;

3), if all results are section tie point, get the tie point position of repeating.

In described step (3), the criterion of tie point fault is: when tie point place fault, row ripple is constant through even reflection polarity in (afterwards) two sections before tie point, that is:

$\left\{\begin{array}{c}\mathrm{sgn}\left[M(t_0+\frac{{2L}_{j-1}}{v_{j-1}})\right]\·\mathrm{sgn}\left[M(t_0+\frac{{4L}_{j-1}}{v_{j-1}})\right]=1\\ \mathrm{sgn}\left[M(t_0+\frac{{2L}_j}{v_j})\right]\·\mathrm{sgn}\left[M(t_0+\frac{{4L}_j}{v_j})\right]=1\end{array}\right.$

Wherein, t ₀for the primary fault current traveling wave that measuring junction detects, L _j, L _j-1be respectively j section and j-1 section line length, v _j, v _j-1be respectively the row wave-wave speed on j section and j-1 section circuit, the Wavelet Modulus Maxima (WMM) in corresponding moment in the bracket after wavelet transformation is carried out in M representative to electric current line line ripple, and sgn function represents polarity.When two formulas are set up simultaneously in formula, judge that trouble spot is T _j.

In described step (3), fault section criterion is: row ripple reflects the type that once depends on guilty culprit section with the polar relationship that reflects twice through between trouble spot and tie point, polarity is identical, illustrate that fault occurs in built on stilts line segment, polarity is contrary, illustrate that fault occurs in cut cable, that is:

Wherein, t ' is in time interval, the moment of reflecting wave head arrival measuring junction once through tie point, trouble spot picking out according to polar relationship.

The concrete grammar of described step (4) is: determining after fault section, determine the polar relationship of three current traveling waves according to the structure of series-parallel connection circuit, then, in the time interval of delimiting, detect respectively the wave head that meets polarity condition, in the moment corresponding according to wave head, calculate fault distance.

In described step (4), the moment of reflection wave is to calculate the direct conditions of fault distance, and this moment is unknown, need to be according to polar relationship detecting in time interval separately.

In described step (4), (5), proposing the method for interference wave with reference to series-parallel connection line construction is: from the viewpoint of polarity of traveling wave and section length two, will may cause the wavelet modulus maxima zero setting of wave head of interference to wave head to be identified.

Beneficial effect of the present invention is:

1. belong to single-ended amount distance-finding method, series-parallel connection circuit distance-finding method majority is both-end amount method at present, and existing single-ended amount distance-finding method lacks practicality; Single-ended amount method of the present invention is practical, compared with both-end amount method good economy performance, reliability high, be easy to realize at device;

2. there is not range finding dead band in total track length; For the tie point place fault between pole line, cable, can provide tie point failure criterion; For tie point near fault, can provide fault section criterion;

3. highly versatile, can be used for multistage pole line-cable series-parallel connection circuit.

Brief description of the drawings

Fig. 1 is order component schematic diagram in fault section;

Fig. 2 is the catadioptric schematic diagram of fault traveling wave;

Fig. 3 is Type B joint line schematic diagram;

Fig. 4 a is section tie point neighborhood fault schematic diagram;

Fig. 4 b is section tie point near fault schematic diagram;

Fig. 5 is for disturbing row ripple schematic diagram.

Embodiment:

Below in conjunction with accompanying drawing and embodiment, the invention will be further described.

1 fault distance interval

Series-parallel connection track section parameter is inconsistent, and wave impedance point of discontinuity is more, causes its row wave propagation behavior more more complicated than single type circuit, relies on single-ended traveling wave cannot complete fault localization accurately.But in the time that fault coverage is known, traveling wave has specific rule.Therefore, utilize single-ended power frequency amount tentatively to determine abort situation neighborhood, analyze targetedly the dissemination of single-ended traveling wave in focal zone, be conducive to accurately determine abort situation.

Consider the segmentation feature of joint line parameter, adopt the preliminary localization of faults neighborhood of method of deducing piecemeal fault section.Take into account cable line distributed capacitance larger, adopt distributed parameter transmission line model.

Based on circuit distributed parameter model, utilize the pure resistive of transition resistance, build localization of fault equation.Taking singlephase earth fault as example, formula (1) has provided single type line fault positioning equation.

$\mathrm{Im}({\stackrel{\·}{U}}_{F1}+{\stackrel{\·}{U}}_{F2}+{\stackrel{\·}{U}}_{F0}/{\stackrel{\·}{I}}_{F2})=0---\left(1\right)$

In formula: be respectively trouble spot place sequence voltage, for fault branch negative-sequence current.

Joint line cannot be determined fault section in advance, therefore not directly apply trouble spot, formula (1) location.Adopt the mode processing of deducing piecemeal trouble spot herein, first assumed fault occurs on j section circuit apart from section head end x _jthe F point at place, as shown in Figure 1:

To search for and be converted to the mapping function search bare minimum point corresponding to this section zero point equation (1):

$\min \left|\right|\mathrm{Im}({\stackrel{\·}{U}}_{\mathrm{jF}1}+{\stackrel{\·}{U}}_{\mathrm{jF}2}+{\stackrel{\·}{U}}_{\mathrm{jF}0}/{\stackrel{\·}{I}}_{\mathrm{jF}2})\left|\right|---\left(2\right)$

Wherein,

$\left\{\begin{array}{c}{\stackrel{,}{U}}_{\mathrm{jFs}}={\stackrel{,}{U}}_{\mathrm{js}}\mathrm{ch}{\mathrm{\γ}}_{\mathrm{js}}{x}_j-Z_{\mathrm{jcs}}{\stackrel{,}{I}}_{\mathrm{js}}\mathrm{sh}{\mathrm{\γ}}_{\mathrm{js}}{x}_j\\ {\stackrel{,}{U}}_{\mathrm{jFs}}={\stackrel{,}{U}}_{(j+1)s}\mathrm{ch}{\mathrm{\γ}}_{\mathrm{js}}(L_j-x_j)+Z_{\mathrm{jcs}}{\stackrel{,}{I}}_{(j+1)s}\mathrm{sh}{\mathrm{\γ}}_{\mathrm{js}}(L_j-x_j)\\ {\stackrel{,}{I}}_{\mathrm{jMFs}}=-(\frac{{\stackrel{,}{U}}_{\mathrm{js}}}{Z_{\mathrm{jcs}}}\mathrm{sh}{\mathrm{\γ}}_{\mathrm{js}}{x}_j-{\stackrel{,}{I}}_{\mathrm{js}}\mathrm{ch}{\mathrm{\γ}}_{\mathrm{js}}{x}_j)\\ {\stackrel{,}{I}}_{\mathrm{jNFs}}=-[\frac{{\stackrel{,}{U}}_{(j+1)s}}{Z_{\mathrm{jcs}}}\mathrm{sh}{\mathrm{\γ}}_{\mathrm{js}}(L_j-x_j)+{\stackrel{,}{I}}_{(j+1)s}\mathrm{ch}{\mathrm{\γ}}_{\mathrm{js}}(L_j-x_j)]\\ {\stackrel{,}{U}}_{(j+1)s}={\stackrel{,}{I}}_{(j+1)s}{Z}_{\mathrm{jNs}}\\ {\stackrel{,}{I}}_{\mathrm{jFs}}={\stackrel{,}{I}}_{\mathrm{jMFs}}+{\stackrel{,}{I}}_{\mathrm{jNFs}}\end{array}\right.---\left(3\right)$

In formula (2), (3): s represents order component, s=1,2,0, subscript j represents j section circuit, L _jbe j section line length, Z _jcsbe j section circuit order wave impedance, γ _jsbe j section circuit order propagation coefficient, for the assumed fault point place sequence voltage of j section, be respectively j section and injected the order electric current of assumed fault point by head end and end, be the order electric current on the assumed fault branch road of j section, Z _jNsequivalent peer-to-peer system impedance used when supposing j segment fault.Z _jN1can be expressed as:

$Z_{\mathrm{jN}1}=Z_{N1}+\underset{k=j+1}{\overset{n}{\mathrm{\Σ}}}{z}_{k1}{L}_k---\left(4\right)$

In formula, Z _n1for positive-sequence impedance of opposite side system, z _k1be the positive sequence impedance of k section circuit unit length, L _kit is k section line length.

For certain section of circuit, mapping function only comprises variable of fault distance, if the hypothesis breaking down in this section is set up, the minimum point of mapping function within the scope of this segment length is trouble spot.Being false if suppose, there is not zero crossing in mapping function, but will reach minimum value at nearly fault end points place, can judge accordingly the position relationship of this section and true fault section.

To the extreme point of every section of circuit search type (2) in length range separately, comprehensive each section result obtains the Primary Location result of trouble spot, and method is:

1) if only have the point in a section in all results, all the other are each section tie point, get this interior some position;

2) if there is the point in two sections in all results, all the other are section tie point, get the section tie point position between 2 interior points;

3), if all results are section tie point, get the tie point position of repeating.

Neighborhood that can localization of faults place by Primary Location result, this is for realizing the identification of row ripple feasibility is provided from single-ended targetedly.The interval D of fault distance can be expressed as:

D＝[d-εL,d+εL] (5)

In formula: d is the Primary Location result based on single-ended power frequency amount, and L is total line length, and ε is length percent, and ε is according to real system situation value.

Accurately locate 2 trouble spots

Under the given prerequisite of fault section, the identification of row ripple is limited in less specific region, thereby can in focal zone, hold row ripple propagation law, realizes trouble spot and accurately locates.

2.1 row setback reflective analysis

Series-parallel connection circuit as shown in Figure 2, the F point between j section B C is in t _fmoment breaks down.I ₀(t), i ₁(t), i ₂(t) be respectively primary fault current traveling wave that measuring junction A detects, reflect reflection wave once through section head end B and trouble spot, reflect reflection wave once through segment ends C, three is respectively t in the corresponding moment ₀, t ₁, t ₂.Three current traveling waves can be expressed as:

$\left\{\begin{array}{c}{i}_0\left(t\right)=(1+{\mathrm{\ρ}}_A){\mathrm{ri}}_b(t-t_f-{\mathrm{\τ}}_{\mathrm{AF}})\\ i_1\left(t\right)={\mathrm{\ρ}}_B{\mathrm{\ρ}}_{F}r(1+{\mathrm{\ρ}}_A)i_b(t-t_f-{\mathrm{\τ}}_{\mathrm{AF}}-{2\mathrm{\τ}}_{\mathrm{BF}})\\ i_2\left(t\right)={\mathrm{\ρ}}_C{r}_{F}r(1+{\mathrm{\ρ}}_A)i_f(t-t_f-{\mathrm{\τ}}_{\mathrm{AF}}-{2\mathrm{\τ}}_{\mathrm{CF}})\end{array}\right.---\left(6\right)$

In formula: ρ _a, ρ _b, ρ _c, ρ _fbe respectively the reflection coefficient of current traveling wave at bus A, section tie point B, tie point C, F place, trouble spot, r _ffor current traveling wave is at the refraction coefficient at F place, r is the refraction coefficient product at current traveling wave each tie point place between AF, τ _aF, τ _bF, τ _cFbe respectively the travel-time of current traveling wave on circuit AF, BF, CF, i _b, i _fbe respectively trouble spot produce along circuit with the capable ripple of fault current that direction is propagated.

Visible, i ₁(t), i ₂(t) respectively with i ₀(t) relative polarity depends on the polarity of section tie point place reflection coefficient.The framework that series-parallel connection circuit replaces based on pole line, cable, surge impedance of a line presents the distribution that size replaces, cause current traveling wave identical in same section two-end-point place reflection coefficient polarity, and being positive-negative polarity along different sections alternately changes, thereby the polarity of the particular row ripple in focal region has certain regularity, on this basis, realize the accurate Calculation of internal fault position between focal region.

Accurately locate 2.2 trouble spots

Using Type B joint line as analysis and simulation object, as shown in Figure 3.In fault appears at respectively three sections time, each reflection coefficient and i ₀(t), i ₁(t), i ₂(t) polarity is in table 1.

Table 1 current traveling wave polarity table

Thus, can utilize this polar relationship, at moment t ₁, t ₂the time neighborhood T at place separately ₁, T ₂interior identification i ₁(t), i ₂(t).Can calculate respectively fault distance x according to each self-corresponding moment of identified wave head ₁, x ₂, the two on average finally obtains position of failure point x:

$\left\{\begin{array}{c}{x}_1=\underset{k=1}{\overset{j-1}{\mathrm{\Σ}}}{L}_k+\frac{(t_1-t_0)v_j}{2}\\ x_2=\underset{k=1}{\overset{j}{\mathrm{\Σ}}}{L}_k-\frac{(t_2-t_0)v_j}{2}\\ x=\frac{(x_1+x_2)}{2}\end{array}\right.---\left(7\right)$

Wherein, v _jfor row wave-wave speed corresponding to fault section, time interval T ₁, T ₂interval D is corresponding with fault distance:

$\left\{\begin{array}{c}{T}_1=[t_0+2(d-\mathrm{\ϵL}])/v_j,t_0+2(d+\mathrm{\ϵL})/v_j]\\ T_2=[t_0+2(L_j-d-\mathrm{\ϵL})/v_j,t_0+2(L_j-d+\mathrm{\ϵL})/v_j]\end{array}\right.---\left(8\right)$

2.3 section tie point neighborhood localization of fault

When section tie point neighborhood fault across two sections, there is the problem of tie point place fault distinguishing and fault section identification in fault distance interval, and therefore section tie point neighborhood fault has singularity, needs analyzing in detail.Fig. 4 (a) and Fig. 4 (b) are respectively tie point T _jfault and T _jthe situation of near fault.Judge that the fault that meets formula (9) is tie point neighborhood fault:

||d-L _Tj||≤εL (9)

In formula: L _tjfor certain tie point is to the distance after the velocity of wave normalization of measuring junction.

A. tie point place fault

The distributed architecture replacing based on pole line, cable, row ripple is identical in the polarity of same section two-end-point place reflection coefficient, therefore constant through even reflection polarity in same section.This polar relationship can be used as to judge whether this trouble spot is the criterion of tie point:

$\left\{\begin{array}{c}\mathrm{sgn}\left[M(t_0+\frac{{2L}_{j-1}}{v_{j-1}})\right]\·\mathrm{sgn}\left[M(t_0+\frac{{4L}_{j-1}}{v_{j-1}})\right]=1\\ \mathrm{sgn}\left[M(t_0+\frac{{2L}_j}{v_j})\right]\·\mathrm{sgn}\left[M(t_0+\frac{{4L}_j}{v_j})\right]=1\end{array}\right.---\left(10\right)$

In formula: the Wavelet Modulus Maxima (WMM) in corresponding moment in the bracket after wavelet transformation is carried out in M representative to electric current line line ripple, sgn function represents polarity.When two formulas are set up simultaneously in formula (10), judge that trouble spot is T _j.

B. tie point near fault

When tie point near zone fault, as shown in Fig. 4 (b), F is true fault point, T _jfor section tie point, F ⁰for the trouble spot by power frequency amount Primary Location, F ' is for F point is about T _jsymmetric points, i ₁(t), i ₂(t) be respectively the capable ripple of fault current from F and F '.

Now the interval conversion method of time domain is:

$T=(t_0,t_0+\frac{2}{v_F}(\mathrm{\ϵL}+|d-L_{\mathrm{Tj}}\left|\right))]---\left(11\right)$

In formula: v _ffor a velocity of wave corresponding to F place section.

In the time that F ' is positioned at interval D, because of T _jboth sides surge impedance of a line difference, i ₁(t), i ₂(t) at T _jthe reflection coefficient polarity at place is contrary, and the initial polarity of the two is contrary simultaneously, therefore i ₁(t), i ₂(t) polarity is identical.Now cannot failure judgement section according to polarity of traveling wave.

Analyze i ₁(t) i and in Fig. 4 (b) ₃(t), note i ₃(t) at T _jthe reflection coefficient at place is designated as ρ.If F point is positioned at pole line side, ρ >0, i ₃and i (t) ₁(t) polarity is identical; If F point is positioned at cable side, ρ <0, i ₃and i (t) ₁(t) polarity is contrary.This polar relationship and F, T _jthe relative position of the two is irrelevant, provides accordingly fault section criterion:

In formula, t' is in the interval T of time domain, the i that utilizes table one Semi-polarity relation recognition to go out ₁or i (t) ₂(t) moment of arrival measuring junction.

3. algorithm is realized

Aforementioned analysis is to carry out under the hypothesis of not considering interference, and in actual conditions, the reflection wave of some tie points there will be in time interval to be identified, if its polarity is identical with reflection wave to be identified, forms and disturbs, and may affect the accuracy of range finding result.Therefore rejecting interference wave is the key that this paper method realizes.Getting rid of on the basis of disturbing the series-parallel connection line fault location algorithm that preceding method can complete.

3.1 interference waves are rejected

As shown in Figure 5, j section internal fault, the current traveling wave that trouble spot produces is divided into the i of initial positive dirction according to initial motion direction _bwith initial reciprocal i _f.Initial positive dirction row ripple is in section k (k=1,2 ... j-1) in, through even reflection, its polarity remains unchanged, and what arrive measuring junction is that (same polarity, reversed polarity are herein with respect to i to same polarity ripple ₀(t) polarity).Initial reciprocal current traveling wave, at section k (k=j+1, j+2 ... n) in, after odd reflection, arrive measuring junction: if k section is overhead transmission line, section end points reflection coefficient be on the occasion of, polarity of traveling wave remains unchanged, and what arrive measuring junction is reversed polarity ripple; If k section is cable line, section end points reflection coefficient is negative value, and through the reversal of poles of odd reflected traveling wave, what arrive measuring junction is same polarity ripple.Due to row ripple, to propagate the decay of following more obvious at section tie point place, and therefore reject while interference and do not consider the multiple reflections in certain section, or reflection process in Multi sectional.

According to above analysis, reject interference wave from the viewpoint of polarity and line length two, method is as follows:

1) to i ₂(t) interference that may be subject to only need be considered the section before fault section.If i ₂(t) be same polarity ripple, by the correspondence moment be the WMM zero setting of wave head (the corresponding moment is herein and i ₀(t) reach moment poor of measuring junction), calculate x with formula (7) afterwards ₂; If i ₂(t) be reversed polarity ripple, without rejecting interference wave, directly calculate x ₂;

2) if i ₁(t) be same polarity ripple, by the correspondence moment be and the WMM zero setting of the wave head of (j < k≤n and k section are cable); If i ₁(t) be reversed polarity ripple, by the correspondence moment be the WMM zero setting of (j < k≤n and k section are pole line) wave head.

Multistage joint line is compared to Type B joint line, the framework being interspersed based on pole line, cable equally, and therefore aforementioned polarity rule is applicable equally; The two is distinguished in two time intervals that are only multistage circuit and there will be more interference.Multistage series-parallel connection circuit, after rejecting interference wave, will be converted into the problem of the wave head of the corresponding polarity of identification in two time intervals, and this explanation this paper method has versatility to multistage series-parallel connection circuit.

3.2 algorithms are realized

The specific implementation step of algorithm is as follows:

1) based on single-ended power frequency amount preliminary localization of faults position d and the interval D of fault distance;

2) fault current line modulus is carried out wavelet transformation and calculated modulus maximum WMM;

3) relation with tie point neighborhood according to formula (9) failure judgement point: be positioned at neighborhood, perform step 4); Beyond neighborhood, perform step 6);

4) determine whether tie point place fault according to formula (10): be that the interior tie point of this neighborhood is trouble spot, range finding finishes; Otherwise determine time interval T according to formula (11), according to formula (12) Judging fault section;

5), according to the polar relationship of determining in fault section, reject interference wave with reference to series-parallel connection line construction; Calculate fault distance according to formula (7) afterwards, range finding finishes;

6) according to formula (8), interval fault distance D is converted to time interval T ₁and T ₂; According to the polar relationship of determining in fault section, reject interference wave with reference to series-parallel connection line construction; Realize trouble spot according to formula (7) and accurately locate, range finding finishes.

By reference to the accompanying drawings the specific embodiment of the present invention is described although above-mentioned; but not limiting the scope of the invention; one of ordinary skill in the art should be understood that; on the basis of technical scheme of the present invention, those skilled in the art do not need to pay various amendments that creative work can make or distortion still in protection scope of the present invention.

Claims (8)

1. the series-parallel connection line one-end Method of Traveling Wave Fault Ranging based on fault distance interval, is characterized in that: comprise the following steps:

(1) based on circuit distributed parameter model, utilize the pure resistive of transition resistance, build localization of fault equation, first assumed fault occurs in certain point on certain section circuit, localization of fault equation is searched for to be converted to zero point this section of corresponding mapping function solved to bare minimum point;

(2) to every section of circuit searching for extreme point in length range separately, comprehensive each section result obtains the interval at place, trouble spot, the relation of failure judgement point and tie point neighborhood, if be positioned at neighborhood, performs step 3); Beyond neighborhood, perform step 5);

(3) determine whether tie point place fault by tie point failure criterion: be that the interior tie point of this neighborhood is trouble spot, range finding finishes; Otherwise determine time interval T, by fault section criterion Judging fault section;

(4) determine the polar relationship of each current traveling wave in fault section, reject interference wave with reference to series-parallel connection line construction; Reflect reflection wave once through section head end and trouble spot according to polar relationship identification, through section end reflection reflection wave once, the corresponding moment of record; Calculate fault distance, range finding finishes;

(5) fault distance interval is converted to time interval, according to the polar relationship of determining in fault section, rejects interference wave with reference to series-parallel connection line construction; Reflect reflection wave once through section head end and trouble spot according to polar relationship identification, through section end reflection reflection wave once, the corresponding moment of record; Calculate fault distance, range finding finishes.

2. a kind of series-parallel connection line one-end Method of Traveling Wave Fault Ranging based on fault distance interval as claimed in claim 1, it is characterized in that: in described step (1), series-parallel connection circuit is the alternatively distributed structure of pole line, cable, thereby pole line and cable are divided into circuit different sections naturally, what each section herein referred to is exactly each built on stilts line segment and each cut cable.

3. a kind of series-parallel connection line one-end Method of Traveling Wave Fault Ranging based on fault distance interval as claimed in claim 1, is characterized in that: in described step (2), the interval method of each section result localization of faults is specially:

1) if only have the point in a section in all results, all the other are each section tie point, get this interior some position;

2) if there is the point in two sections in all results, all the other are section tie point, get the section tie point position between 2 interior points;

3), if all results are section tie point, get the tie point position of repeating.

4. a kind of series-parallel connection line one-end Method of Traveling Wave Fault Ranging based on fault distance interval as claimed in claim 1, it is characterized in that: the concrete grammar of described step (4) is: determining after fault section, determine the polar relationship of three current traveling waves according to the structure of series-parallel connection circuit, then in the time interval of delimiting, detect respectively the wave head that meets polarity condition, in the moment corresponding according to wave head, calculate fault distance.

5. a kind of series-parallel connection line one-end Method of Traveling Wave Fault Ranging based on fault distance interval as claimed in claim 4, it is characterized in that: in described step (4), the moment of reflection wave is the direct conditions of calculating fault distance, this moment is unknown, need to be according to polar relationship detecting in time interval separately.

6. a kind of series-parallel connection line one-end Method of Traveling Wave Fault Ranging based on fault distance interval as claimed in claim 1, is characterized in that: in described step (3), the criterion of tie point fault is: tie point T _jwhile locating fault, row ripple is at tie point T _jconstant through even reflection polarity in front/rear two sections:

$\left\{\begin{array}{c}\mathrm{sgn}\left[M(t_0+\frac{{2L}_{j-1}}{v_{j-1}})\right]\&CenterDot;\mathrm{sgn}\left[M(t_0+\frac{{4L}_{j-1}}{v_{j-1}})\right]=1\\ \mathrm{sgn}\left[M(t_0+\frac{{2L}_j}{v_j})\right]\&CenterDot;\mathrm{sgn}\left[M(t_0+\frac{{4L}_j}{v_j})\right]=1\end{array}\right.$

Wherein, t ₀for the primary fault current traveling wave that measuring junction detects, L _j, L _j-1be respectively j section and j-1 section line length, v _j, v _j-1be respectively the row wave-wave speed on j section and j-1 section circuit, the Wavelet Modulus Maxima in corresponding moment in the bracket after wavelet transformation is carried out in M representative to electric current line line ripple, and unit is WMM, and sgn function represents polarity, when two formulas are set up simultaneously in formula, judges that trouble spot is T _j.

7. a kind of series-parallel connection line one-end Method of Traveling Wave Fault Ranging based on fault distance interval as claimed in claim 1, it is characterized in that: in described step (3), fault section criterion is: row ripple reflects the type that once depends on guilty culprit section with the polar relationship that reflects twice through between trouble spot and tie point, polarity is identical, illustrate that fault occurs in built on stilts line segment, polarity is contrary, illustrates that fault occurs in cut cable, that is:

Wherein, t ' is in time interval, the moment of reflecting wave head arrival measuring junction once through tie point, trouble spot picking out according to polar relationship.

8. a kind of series-parallel connection line one-end Method of Traveling Wave Fault Ranging based on fault distance interval as claimed in claim 1, it is characterized in that: in described step (4), (5), interference wave elimination method is: from the viewpoint of polarity of traveling wave and section length two, will may cause the wavelet modulus maxima zero setting of wave head of interference to wave head to be identified.