CN104977502B - A kind of extra high voltage direct current transmission line internal fault external fault recognition methods - Google Patents

A kind of extra high voltage direct current transmission line internal fault external fault recognition methods Download PDF

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CN104977502B
CN104977502B CN201510316846.0A CN201510316846A CN104977502B CN 104977502 B CN104977502 B CN 104977502B CN 201510316846 A CN201510316846 A CN 201510316846A CN 104977502 B CN104977502 B CN 104977502B
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fault
current
lateral areas
morphology
outside
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CN201510316846.0A
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CN104977502A (en
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陈仕龙
曹蕊蕊
毕贵红
杨具瑞
李兴旺
荣俊香
谢佳伟
王彦武
罗璐
李建平
黄钰淇
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昆明理工大学
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Abstract

The present invention relates to a kind of extra high voltage direct current transmission line internal fault external fault recognition methods, belong to HVDC transmission system technical field of relay protection.The present invention gathers fault current data first, by comparing polarity of the fault current at waveform catastrophe point, Cutoff current traveling wave direction, and then failure judgement signal is outside rectification lateral areas, or in area or outside inversion lateral areas, when judging that signal is in area or outside inversion lateral areas, it is in area or outside inversion lateral areas to carry out failure judgement to the attenuation of failure high-frequency signal further according to circuit and border.The present invention can solve the problems, such as the interaction of both-end existence information using one-terminal current transient protection method, realize and completely protect, for distinguishing rectification side external area error, troubles inside the sample space and inverter side external area error.

Description

A kind of extra high voltage direct current transmission line internal fault external fault recognition methods
Technical field
The present invention relates to a kind of extra high voltage direct current transmission line internal fault external fault recognition methods, belong to D.C. high voltage transmission system System technical field of relay protection.
Background technology
At present using traveling-wave protection as main protection in DC line protection, using differential under-voltage protection, differential protection as standby Protection.Traveling-wave protection and differential the under-voltage protection easy tripping in high resistance earthing fault, current differential protection sensitivity is not high, protects Shield action is slower.It is the development side of extra high voltage direct current transmission line protection to the transient protection of high frequency content attenuation characteristic using border To what scholars studied in recent years usually not considers extra-high voltage using border to the transient protection method of high frequency content attenuation characteristic The attenuation characteristic of direct current overlength transmission line of electricity, thus all fronts protection truly can not be realized, and both-end transient protection side Although method can be realized and completely protected, existence information interaction problem.It is therefore desirable to study with higher reliability and can realize The completely extra-high voltage direct-current transmission line guard method of protection.
The content of the invention
The invention provides a kind of extra high voltage direct current transmission line internal fault external fault recognition methods, for distinguishing rectification side External area error, troubles inside the sample space and inverter side external area error, completely guarantor can not be realized by solving the method that current electric power scholar proposes Shield can realize completely protection and the insecure problem of criterion.
What extra high voltage direct current transmission line internal fault external fault recognition methods of the present invention was realized in:Methods described it is specific Step is as follows:
After Step1, extra-high voltage DC transmission system break down, rectification side data acquisition device collection fault current traveling wave Fault current data after Mintrop wave head reaches during 5ms in window;
Step2, by comparing rectification side polarity of the fault current that detects of installation place at waveform catastrophe point is protected, sentenced Determine current traveling wave direction, and then failure judgement signal is come from outside rectification lateral areas, or in area or outside inversion lateral areas;
The fault-current signal detected is first subjected to morphology MMG conversion, chooses wherein one layer of MMG conversion coefficient point Analysis;
When current waveform is when the polarity of catastrophe point is negative, failure occurs outside rectification lateral areas;
When current waveform in the polarity of catastrophe point is timing, failure occurs outside troubles inside the sample space or inversion lateral areas;
Step3, when judging signal in the area or when outside inversion lateral areas, further according to circuit and border to failure high-frequency signal Attenuation come failure judgement be in the area or inversion lateral areas outside;
Step3.1, the fault message first detected to rectification side protection installation place carry out multi-scale analysis, obtain failure letter The transient current morphology spectrum of breath;
Step3.2, first whole transient current morphology spectrum is normalized, for eliminating sensitivity of the morphology spectrum to yardstick Property, it is then that the morphology spectrum yardstick of the transient current morphology spectrum after normalization is corresponding with the frequency domain relation of wavelet scale, shape State spectrum partition of the scale is 5 sections, i.e.,:Yardstick 1-8,8-16,16-32,32-64,64-128, then to 1-8,8-16,16-32,32- 64th, 64-128 yardsticks are summed respectively, obtain five values;
Step3.3, morphology spectrum yardstick 1-8,8-16,16-32,32-64,64-128 after segmentation are summed respectively again To five values be normalized, obtain the characteristic quantity P of failure judgement1、P2、P3、P4、P5
Step3.4, by fault message high band characteristic quantity P1Value amplify 10 respectively3Multiple, i.e. T=P1×103, According to the size of T values come failure judgement be occur in area or outside inversion lateral areas;
Work as T>It is troubles inside the sample space when 10;
When 0<It is inverter side external area error during T≤10.
In the step Step1, data acquisition device sample frequency is 40kHz.
Fault current uses 1 mold component in the step Step2.
In the step Step2, morphology MMG becomes MMG conversion coefficients when exchanging α=2 for, i.e. when morphology MMG is converted, What is taken is the waveform of the second layer.
The method of the invention principle is:
When DC transmission system breaks down, line boundary (right side label 4,5,6) and circuit (label 8) are to fault transient The attenuation of information high fdrequency component, extra-high voltage direct-current transmission bipolar DC system with reference to shown in Fig. 1 illustrate.f1、f2、f3 Respectively outside rectification lateral areas (between left side reference numerals 3 and 4), in area outside (label 8) and inversion lateral areas (between right side label 3 and 4) Trouble point.F outside rectification lateral areas1When (between left side reference numerals 3 and 4) point breaks down, under the independent role of trouble power, electric currentRectification side protection device (label 7) is flowed to by earthing pole, with defined electric current i1Positive direction is on the contrary, mutation current is negative sense Mutation;As circuit f in area2F outside point or inversion lateral areas3When point breaks down, equally under the independent role of trouble power, electric currentRectification side protection device (label 7) is flowed to by earthing pole, can be produced and defined electric current i1Direction identical mutation Electric current, mutation current are forward mutation assay.Therefore can be come failure judgement as criterion according to the polarity of electric current at failure catastrophe point Occur outside rectification lateral areas (between left side reference numerals 3 and 4) or in area outside (label 8) or inversion lateral areas (right side label 3 and 4 it Between).And during Multi-resolution morphological gradient MMG technical finesse transient signals, it can not only extract rising edge and the decline of signal waveform Edge, and the polarity information of signal is can be seen that, therefore morphology MMG can be utilized to become and bring this side external area error (left side of differentiation Between label 3 and 4) and troubles inside the sample space (label 8) or inverter side external area error (between right side label 3 and 4).
Because DC transmission system is usually bipolar DC system, coupling be present between two-stage, transient state is protected to eliminate circuit coupling The influence of shield, to rectification side external area error (between left side reference numerals 3 and 4), troubles inside the sample space (label 8) and inverter side external area error (between right side label 3 and 4) transient current carries out phase-model transformation, takes 1 mold component, then it is entered using formula (1), (2), (3) Row MMG is converted, and chooses the analysis of wherein one layer of MMG conversion coefficient, and MMG conversion coefficients when choosing α=2 here draw oscillogram, Polarity in failure catastrophe point can be seen that by this waveform, as shown in figure 3, in Fig. 3 oscillogram, there are three waveforms, Each waveform has an apparent mutation between sampled point 50-100, and first is that negative sense is mutated, second and the 3rd Individual is all forward mutation assay, so will can just be separated by this waveform outside outside rectification lateral areas and inversion lateral areas;
Multi-resolution morphological gradient (MMG) is defined as:
Wherein, the symbol ⊕ in (1), (2) formula represents dilation operation, and symbol Θ represents erosion operation.
(1)-(3) the structural element g in formula+And g-Respectively:
g+={ g1,g2,…,gl-1,gl } (4)
g-=g1 ,g2,…,gl-1,gl}
Wherein, structural element g+And g-It is respectively used to extract the upper and lower edge of waveform to be analyzed, the g with underscore represents former Point position.In formula (1), (2),WithIts symbol corresponds to rising edge and the decline of transient-wave Edge, in formula (3)Represent the polarity of signal intensity.As α=1, f0=f is initial signal, when α ≠ 1 (α=2, 3 ...) when,
From the figure 3, it may be seen that the mold component waveform of electric current 1 that installation place (label 8) detects is protected in catastrophe point from rectification side Polarity finds (in Fig. 3 oscillogram, there is three waveforms, each waveform has individual apparent between sampled point 50-100 Mutation, first be negative sense mutation, second and the 3rd is all forward mutation assay), rectification side external area error (left side reference numerals 3 And between 4) when, current waveform is negative in the polarity of catastrophe point;It is and (right outside (label 8) or inversion lateral areas in failure generating region Between side label 3 and 4) when, current waveform is just in the polarity of catastrophe point.Therefore can be with the polarity of catastrophe point according to current waveform Failure judgement direction, when current waveform is when the polarity of catastrophe point is negative, (the left side reference numerals 3 and 4 outside rectification lateral areas occur for failure Between);When current waveform in the polarity of catastrophe point is timing, (the right side troubles inside the sample space (label 8) or inversion lateral areas outside occurs for failure Between side label 3 and 4).
When judging that failure occurs in area outside (label 8) or inversion lateral areas (between right side label 3 and 4), it is also necessary to enter One step failure judgement signal is outside circuit (label 8) or inversion lateral areas (between right side label 3 and 4).In the wide extra-high voltage of cloud In DC transmission system, when DC power transmission line internal fault (label 8), fault traveling wave signal via line (label 8) declines The protection installation place (label 7) of rectification side is reached after subtracting.When bus-bar fault outside inverter side generating region (between right side label 3 and 4) When, fault traveling wave signal will get to whole by the dual decay of line boundary (right side label 4,5,6) and circuit (label 8) Flow side protection installation place (label 7).Therefore it can be become according to fault transient signals in the amplitude of high band and be turned to event inside and outside offside area Hinder criterion.
In order to extract the characteristic vector of current signal exactly, in signal acquisition, it is desirable to which the signal length of sampling to the greatest extent may be used All transient informations can be included.Wavelet transformation amount of calculation when analyzing prolonged high-frequency signal is bigger, and the letter sampled Last result of calculation can be interfered comprising many non-faulting components in number, influence the validity of criterion.Morphology is being adopted When extracting current signal with morphology spectrum, above mentioned problem can not only be avoided well, and morphology is simply done in calculating process Simple plus-minus and comparison operation, when analyze prolonged high-frequency signal, can be quickly obtain result of calculation, meanwhile, it is several The stabilization signal of transient state component can be effective filtered out by learning morphologic opening and closing operation, transient characteristic is more obviously highlighted Come, facilitate the extraction of signal characteristic and calculate analysis.Meanwhile the size of form spectrum can be with faults signal high fdrequency component After via line and border attenuation, the degree of amplitude attenuation.Thus, herein from mathematical morphology morphology spectrum in area (label 8) and offside external area error (between right side label 3 and 4) transient signal is analyzed.Morphology spectrum in above-mentioned Step3 steps Extraction comprise the following steps that:
A3.1, the fault message first detected to rectification side protection installation place carry out multi-scale analysis, obtain fault message Transient current morphology spectrum;If f (x) is signal, g (x) is a convex structure function, and f (x) morphology spectrum passes through formula (5), (6) Extracted;
Because morphology spectrum is divided into negative scale morphology spectrum and positive scale morphology spectrum on reference axis is done centered on 0, left side is negative Morphology spectrum on scale, tried to achieve by formula (5), PSf(+r, g) represents opening operation morphology spectrum, and right side is the morphology spectrum on positive scale, Tried to achieve by formula (6), PSf(- r, g) represents closed operation morphology spectrum.Wherein, the symbol ο in (5), (6) formula represents opening operation, symbol Number represent closed operation.
R in formula (5), (6) is the radius of structural element,Represent the area in domain.
Flat-structure element is used herein, and the range scale selection of structural element is 1~150.
A3.2, morphology spectrum yardstick is corresponding with the frequency domain relation of wavelet scale, morphology spectrum partition of the scale is 5 sections, i.e.,:Chi Spend 1-8,8-16,16-32,32-64,64-128.To eliminate sensitiveness of the morphology spectrum to yardstick, morphology spectrum is normalized first, Then this 5 sections morphology spectrum is calculated respectively, as characteristic quantity P1、P2、P3、P4、P5.Wherein P1~P5Method for solving be (specific Can also be referring to above-mentioned steps Step3):
A3.2.1, by normalized morphology spectrum respectively to 1-8,8-16,16-32,32-64,64-128 yardstick sum, obtain 5 values;
A3.2.2,5 values in A3.2.1 are normalized again, obtain P1、P2、P3、P4、P5.Table 1 is morphology spectrum yardstick With the frequency domain corresponding relation of the wavelet decomposition number of plies.
The frequency domain corresponding relation of the morphology spectrum yardstick of table 1 and the wavelet decomposition number of plies
In the extra high voltage direct current transmission line non unit transient protection schematic diagram shown in Fig. 1, two-terminal direct current transmission system master To be made up of converting plant, DC power transmission line (label 8) and Inverter Station.
Direct-current transmission converter station is made up of basic convertor unit, mainly includes converter power transformer 2, transverter 3, flat ripple electricity Anti- device 4, DC filter 5 and PLC wave filters 6 and protection device 7, because being non unit transient protection schematic diagram, therefore only one end Current conversion station have protection device 7.It is the two-terminal DC transmission system engineering that can carry out anti-power delivery, if the AC system from left side 1 power transmission of AC system 1 to the right, then (two, the left side transverter 3, two of converter power transformer 2, two is flat for the current conversion station in left side Wave reactor 4, two DC filter 5, two PLC wave filters 6, protection device 7 form) it is converting plant, the current conversion station on right side (two, the right side DC filter 5, two of smoothing reactor 4, two of transverter 3, two of converter power transformer 2, two PLC is filtered Device 6 forms) it is Inverter Station;When anti-power delivery, then right side current conversion station (two, the right side transverter 3, two of converter power transformer 2, two The individual DC filter 5, two of smoothing reactor 4, two PLC wave filters 6 form) it is converting plant, left side current conversion station (two, left side The DC filter 5, two of smoothing reactor 4, two of transverter 3, two of converter power transformer 2, two PLC wave filters 6, protection dress Put 7 compositions) it is Inverter Station.I.e. the AC system 1 at both ends can be used as sending end or be used as receiving end, when power is just sent, They provide commutation voltage to rectifier (left side converter power transformer 2) and inverter (right side converter power transformer 2);Work as anti-power delivery When, they provide commutation voltage to rectifier (right side converter power transformer 2) and inverter (left side converter power transformer 2), create real The condition of the existing change of current.Power supply of the sending end power system as direct current transportation simultaneously, there is provided the power of transmission, and receiving-end system then phase When the power sent in load, receiving and consumption by direct current transportation.
Smoothing reactor 4, DC filter 5 and PLC wave filters 6 form the border of DC power transmission line;8 be direct current transportation Circuit, it is connected using positive and negative polarities wire with the positive and negative polarities of both ends current conversion station, forms the closed loop of DC side;Two-terminal-grounding The ground return circuit that electrode systems 9 are formed, can be as the standby wire of transmission system.
The beneficial effects of the invention are as follows:
1st, from determining fault direction, which kind of small echo the selection of its coefficient, selects as a kind of transient state edge detection method Wavelet basis, some specific parameter values determination and using small echo to sign mutation point carry out rim detection when, it is also past It is generally white noise, these factors can affect to final testing result toward with noise jamming; And Multi-resolution morphological gradient MMG converter techniques can not only carry out de-noising in processing procedure to signal, but also can extract The rising edge and trailing edge of signal, it will thus be seen that the polarity of signal.When MMG exponent number increase, the trickleer change of waveform Change can also be embodied well.
2nd, MMG is a kind of fast and effectively transient signal analysis method, and it is a kind of pure analysis side based on time domain Method, MMG converter techniques are more simple and quick than wavelet decomposition, and after MMG is converted, amplitude attenuation is very small, become without corresponding displacement Change, more conducively hardware detection.
3rd, can solve the problems, such as the interaction of both-end existence information using one-terminal current transient protection method, realize and completely protect Shield.
Brief description of the drawings
Fig. 1 is extra high voltage direct current transmission line transient protection schematic diagram;
Fig. 2 is the flow chart of the method for the invention;
Fig. 3 is the mold component of fault transient state current 1 oscillogram after MMG is converted.
In Fig. 1:1- AC systems, 2- converter power transformers, 3- transverters, 4- smoothing reactors, 5- DC filters, 6- PLC wave filters, 7- protection devices, 8- DC power transmission lines, 9- ground electrode systems;
Embodiment
Embodiment 1:As Figure 1-3, a kind of extra high voltage direct current transmission line internal fault external fault recognition methods, methods described Comprise the following steps that:
After Step1, extra-high voltage DC transmission system break down, rectification side data acquisition device collection fault current traveling wave Fault current data after Mintrop wave head reaches during 5ms in window;
Step2, by comparing rectification side polarity of the fault current that detects of installation place at waveform catastrophe point is protected, sentenced Determine current traveling wave direction, and then failure judgement signal is come from outside rectification lateral areas, or in area or outside inversion lateral areas;
The fault-current signal detected is first subjected to morphology MMG conversion, chooses wherein one layer of MMG conversion coefficient point Analysis;
When current waveform is when the polarity of catastrophe point is negative, failure occurs outside rectification lateral areas;
When current waveform in the polarity of catastrophe point is timing, failure occurs outside troubles inside the sample space or inversion lateral areas;
Step3, when judging signal in the area or when outside inversion lateral areas, further according to circuit and border to failure high-frequency signal Attenuation come failure judgement be in the area or inversion lateral areas outside;
Step3.1, the fault message first detected to rectification side protection installation place carry out multi-scale analysis, obtain failure letter The transient current morphology spectrum of breath;
Step3.2, first whole transient current morphology spectrum is normalized, for eliminating sensitivity of the morphology spectrum to yardstick Property, it is then that the morphology spectrum yardstick of the transient current morphology spectrum after normalization is corresponding with the frequency domain relation of wavelet scale, shape State spectrum partition of the scale is 5 sections, i.e.,:Yardstick 1-8,8-16,16-32,32-64,64-128, then to 1-8,8-16,16-32,32- 64th, 64-128 yardsticks are summed respectively, obtain five values;
Step3.3, morphology spectrum yardstick 1-8,8-16,16-32,32-64,64-128 after segmentation are summed respectively again To five values be normalized, obtain the characteristic quantity P of failure judgement1、P2、P3、P4、P5
Step3.4, by fault message high band characteristic quantity P1Value amplify 10 respectively3Multiple, i.e. T=P1×103, According to the size of T values come failure judgement be occur in area or outside inversion lateral areas;
Work as T>It is troubles inside the sample space when 10;
When 0<It is inverter side external area error during T≤10.
Embodiment 2:As Figure 1-3, a kind of extra high voltage direct current transmission line internal fault external fault recognition methods, methods described Comprise the following steps that:
After Step1, extra-high voltage DC transmission system break down, rectification side data acquisition device collection fault current traveling wave Fault current data after Mintrop wave head reaches during 5ms in window;
Step2, by comparing rectification side polarity of the fault current that detects of installation place at waveform catastrophe point is protected, sentenced Determine current traveling wave direction, and then failure judgement signal is come from outside rectification lateral areas, or in area or outside inversion lateral areas;
The fault-current signal detected is first subjected to morphology MMG conversion, chooses wherein one layer of MMG conversion coefficient point Analysis;
When current waveform is when the polarity of catastrophe point is negative, failure occurs outside rectification lateral areas;
When current waveform in the polarity of catastrophe point is timing, failure occurs outside troubles inside the sample space or inversion lateral areas;
Step3, when judging signal in the area or when outside inversion lateral areas, further according to circuit and border to failure high-frequency signal Attenuation come failure judgement be in the area or inversion lateral areas outside;
Step3.1, the fault message first detected to rectification side protection installation place carry out multi-scale analysis, obtain failure letter The transient current morphology spectrum of breath;
Step3.2, first whole transient current morphology spectrum is normalized, for eliminating sensitivity of the morphology spectrum to yardstick Property, it is then that the morphology spectrum yardstick of the transient current morphology spectrum after normalization is corresponding with the frequency domain relation of wavelet scale, shape State spectrum partition of the scale is 5 sections, i.e.,:Yardstick 1-8,8-16,16-32,32-64,64-128, then to 1-8,8-16,16-32,32- 64th, 64-128 yardsticks are summed respectively, obtain five values;
Step3.3, morphology spectrum yardstick 1-8,8-16,16-32,32-64,64-128 after segmentation are summed respectively again To five values be normalized, obtain the characteristic quantity P of failure judgement1、P2、P3、P4、P5
Step3.4, by fault message high band characteristic quantity P1Value amplify 10 respectively3Multiple, i.e. T=P1×103, According to the size of T values come failure judgement be occur in area or outside inversion lateral areas;
Work as T>It is troubles inside the sample space when 10;
When 0<It is inverter side external area error during T≤10.
In the step Step1, data acquisition device sample frequency is 40kHz.
Fault current uses 1 mold component in the step Step2.
In the step Step2, morphology MMG becomes MMG conversion coefficients when exchanging α=2 for, i.e. when morphology MMG is converted, What is taken is the waveform of the second layer.
Embodiment 3:As Figure 1-3, a kind of extra high voltage direct current transmission line internal fault external fault recognition methods, methods described Comprise the following steps that:
After Step1, extra-high voltage DC transmission system break down, rectification side data acquisition device collection fault current traveling wave Fault current data after Mintrop wave head reaches during 5ms in window;
Step2, by comparing rectification side polarity of the fault current that detects of installation place at waveform catastrophe point is protected, sentenced Determine current traveling wave direction, and then failure judgement signal is come from outside rectification lateral areas, or in area or outside inversion lateral areas;
The fault-current signal detected is first subjected to morphology MMG conversion, chooses wherein one layer of MMG conversion coefficient point Analysis;
When current waveform is when the polarity of catastrophe point is negative, failure occurs outside rectification lateral areas;
When current waveform in the polarity of catastrophe point is timing, failure occurs outside troubles inside the sample space or inversion lateral areas;
Step3, when judging signal in the area or when outside inversion lateral areas, further according to circuit and border to failure high-frequency signal Attenuation come failure judgement be in the area or inversion lateral areas outside;
Step3.1, the fault message first detected to rectification side protection installation place carry out multi-scale analysis, obtain failure letter The transient current morphology spectrum of breath;
Step3.2, first whole transient current morphology spectrum is normalized, for eliminating sensitivity of the morphology spectrum to yardstick Property, it is then that the morphology spectrum yardstick of the transient current morphology spectrum after normalization is corresponding with the frequency domain relation of wavelet scale, shape State spectrum partition of the scale is 5 sections, i.e.,:Yardstick 1-8,8-16,16-32,32-64,64-128, then to 1-8,8-16,16-32,32- 64th, 64-128 yardsticks are summed respectively, obtain five values;
Step3.3, morphology spectrum yardstick 1-8,8-16,16-32,32-64,64-128 after segmentation are summed respectively again To five values be normalized, obtain the characteristic quantity P of failure judgement1、P2、P3、P4、P5
Step3.4, by fault message high band characteristic quantity P1Value amplify 10 respectively3Multiple, i.e. T=P1×103, According to the size of T values come failure judgement be occur in area or outside inversion lateral areas;
Work as T>It is troubles inside the sample space when 10;
When 0<It is inverter side external area error during T≤10.
In the step Step1, data acquisition device sample frequency is 40kHz.
Fault current uses 1 mold component in the step Step2.
In the step Step2, morphology MMG becomes MMG conversion coefficients when exchanging α=2 for, i.e. when morphology MMG is converted, What is taken is the waveform of the second layer.
During troubles inside the sample space, change abort situation (abort situation refer to trouble point to rectification side protect mount point distance) and The size of transition resistance, during offside external area error (i.e. inverter side external area error), change the size of transition resistance.Simulation result is such as Shown in table 2.
The simulation experiment result of table 2
T, MMG is calculated by above-mentioned steps to represent several groups of data selected when distinguishing outside in area and to lateral areas in table 2 Conversion obtains the polarity of failure catastrophe point also in table 2, is found from table 2, in order to more illustrate the reliability of such a method, During simulating, verifying, when circuit breaks down at the 800km and 1400km of inverter side in increase area and inversion lateral areas Grounding resistance during outer failure increases to 500 Ω, 1000 Ω.It was found that during troubles inside the sample space, with the increase of transition resistance, from guarantor It is more remote to protect the distance of installation place, though T value is reducing, but still meets T>10;During inverter side external area error, T value is increasingly It is small, still meet 0<T≤10.So such a method energy reliable recognition offside internal fault external fault, the size of transition resistance value do not influence The validity of criterion.
Above in conjunction with accompanying drawing to the present invention embodiment be explained in detail, but the present invention be not limited to it is above-mentioned Embodiment, can also be before present inventive concept not be departed from those of ordinary skill in the art's possessed knowledge Put that various changes can be made.

Claims (4)

  1. A kind of 1. extra high voltage direct current transmission line internal fault external fault recognition methods, it is characterised in that:The specific steps of methods described It is as follows:
    After Step1, extra-high voltage DC transmission system break down, rectification side data acquisition device collection fault current traveling wave Mintrop wave Fault current data after head reaches during 5ms in window;
    Step2, by comparing rectification side polarity of the fault current that detects of installation place at waveform catastrophe point is protected, judge electricity Popular ripple direction, and then failure judgement signal is come from outside rectification lateral areas, or in area or outside inversion lateral areas;
    The fault-current signal detected is first subjected to morphology MMG conversion, chooses wherein one layer of MMG conversion coefficients analysis;
    When current waveform is when the polarity of catastrophe point is negative, failure occurs outside rectification lateral areas;
    When current waveform in the polarity of catastrophe point is timing, failure occurs outside troubles inside the sample space or inversion lateral areas;
    Step3, when judging that signal in the area or when outside inversion lateral areas, declines further according to circuit and border to failure high-frequency signal It is in area or outside inversion lateral areas to subtract effect to carry out failure judgement;
    Step3.1, the fault message first detected to rectification side protection installation place carry out multi-scale analysis, obtain fault message Transient current morphology spectrum;
    Step3.2, first whole transient current morphology spectrum is normalized, for eliminating sensitiveness of the morphology spectrum to yardstick, so It is afterwards that the morphology spectrum yardstick of the transient current morphology spectrum after normalization is corresponding with the frequency domain relation of wavelet scale, morphology spectrum chi Degree is divided into 5 sections, i.e.,:Yardstick 1-8,8-16,16-32,32-64,64-128, then to morphology spectrum yardstick 1-8,8- after segmentation 16th, 16-32,32-64,64-128 sum respectively, obtain five values;
    Step3.3, what is obtained is summed respectively to morphology spectrum yardstick 1-8,8-16,16-32,32-64,64-128 after segmentation again Five values are normalized, and obtain the characteristic quantity P of failure judgement1、P2、P3、P4、P5
    Step3.4, by fault message high band characteristic quantity P1Value amplify 10 respectively3Multiple, i.e. T=P1×103, according to T The size of value, which carrys out failure judgement, to be occurred in area or outside inversion lateral areas;
    Work as T>It is troubles inside the sample space when 10;
    When 0<It is inverter side external area error during T≤10.
  2. 2. extra high voltage direct current transmission line internal fault external fault recognition methods according to claim 1, it is characterised in that:It is described In step Step1, data acquisition device sample frequency is 40kHz.
  3. 3. extra high voltage direct current transmission line internal fault external fault recognition methods according to claim 1, it is characterised in that:It is described Fault current uses 1 mold component in step Step2.
  4. 4. extra high voltage direct current transmission line internal fault external fault recognition methods according to claim 1, it is characterised in that:It is described In step Step2, morphology MMG becomes MMG conversion coefficients when exchanging α=2 for, i.e. when morphology MMG is converted, what is taken is the second layer Waveform.
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