CN108445354B - Fault location method, device, equipment and medium based on traveling wave differential current - Google Patents

Fault location method, device, equipment and medium based on traveling wave differential current Download PDF

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CN108445354B
CN108445354B CN201810501420.6A CN201810501420A CN108445354B CN 108445354 B CN108445354 B CN 108445354B CN 201810501420 A CN201810501420 A CN 201810501420A CN 108445354 B CN108445354 B CN 108445354B
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current
traveling wave
differential current
fault
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CN108445354A (en
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洪潮
张野
张帆
杨健
李俊杰
孙鹏伟
李斌
张纪航
李博通
李霞林
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China South Power Grid International Co ltd
Tianjin University
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China South Power Grid International Co ltd
Tianjin University
Power Grid Technology Research Center of China Southern Power Grid Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
    • G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/088—Aspects of digital computing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
    • Y04S10/52—Outage or fault management, e.g. fault detection or location

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Abstract

The invention discloses a fault location method based on traveling wave differential current, which comprises the following steps: obtaining 1-mode voltage u of starting end J of direct current lineJ1And 1 mode current iJ1And 1-mode voltage u of DC line terminal Kk1And 1 mode current iK1(ii) a Obtaining 1-mode wave impedance Zc1And 1-mode propagation delay τ1(ii) a Obtain the traveling wave differential current of the 1 mode forward direction
Figure DDA0002313243740000011
Travelling wave difference current in reverse direction to 1 mode
Figure DDA0002313243740000012
Traveling wave differential current in the 1-mode forward direction
Figure DDA0002313243740000013
A traveling wave difference current in the direction opposite to the 1-mode
Figure DDA0002313243740000014
Taking the forward or backward traveling wave differential current as a reference standard, translating the traveling wave differential current in the other direction on a time axis to obtain the 1-mode forward traveling wave differential current
Figure DDA0002313243740000015
And the 1-mode reverse traveling wave differential current
Figure DDA0002313243740000016
The time difference Δ t at the maximum value of the Pearson correlation coefficient of (a); wherein, Delta t is epsilon (-tau)1,τ1) (ii) a Wherein, the-tau is1The propagation delay when the fault occurs at the starting end J is shown; wherein, the value of τ is1Propagation delay when a fault occurs at the terminal K; and calculating the fault position according to the time difference delta t. Can be simple and convenientThe method can reliably judge the position of the fault without being influenced by the fault type and has stronger anti-transition resistance capability.

Description

Fault location method, device, equipment and medium based on traveling wave differential current
Technical Field
The invention relates to the field of power system protection control, in particular to a fault location method, a fault location device, fault location equipment and a fault location medium based on traveling wave differential current.
Background
The high-voltage direct-current transmission technology is increasingly becoming an important transmission mode in China long-distance and large-capacity transmission and asynchronous networking due to the advantages of large transmission power, low investment cost, good control performance and the like. The high-voltage direct-current power grid is used as a tie line of a large-area power grid and is closely related to the stable operation of a power system connected with the high-voltage direct-current power grid. Because the transmission distance of the high-voltage direct-current transmission line is long, the fault probability is high, and it becomes very important to ensure the high-voltage direct-current transmission line to stably operate and timely search and clear faults. Therefore, the development of the fault location technology of the direct current transmission line has very important significance.
At present, fault location methods for direct current lines are mainly divided into traveling wave methods and fault analysis methods, wherein the traveling wave methods are widely applied, and the traveling wave method is used for locating a fault point according to the reflection characteristics of wave impedance discontinuous nodes on a transmission line. The traveling wave method can be classified into A, B, C, D, E and F-type 6 methods according to its principle. The position collected according to the method is an initial traveling wave generated by detecting faults at both ends of a line. And calculating to obtain the fault distance by using the time difference of the traveling wave reaching the double ends and the wave speed.
The inventor finds that the prior art has the following defects when implementing the embodiment of the invention: the traveling wave method has inherent problems of ultrahigh sampling rate, identification and calibration of an initial wave head and a reflected traveling wave, and the like, and provides great challenges for the research and development of the distance measuring device.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a fault location method based on traveling wave differential current, which can simply and reliably determine the position of a fault, is not affected by the type of the fault, and has strong anti-transition resistance capability.
In a first aspect, the present invention provides a fault location method based on traveling wave differential current, including:
obtaining 1-mode voltage u of starting end J of direct current lineJ1And 1 mode current iJ1And 1-mode voltage u of DC line terminal Kk1And 1 mode current iK1；
Obtaining 1-mode wave impedance Zc1And 1-mode propagation delay τ1；
According to the 1 modeWave impedance Zc1-mode propagation delay τ11-mode voltage u of starting end J of the direct current lineJ1And 1 mode current iJ1And 1-mode voltage u of the end K of the direct current linek1And 1 mode current iK1Obtain the traveling wave differential current of the 1 mode forward direction
Figure GDA0002313243730000021
Travelling wave difference current in reverse direction to 1 mode
Figure GDA0002313243730000022
Traveling wave differential current in the 1-mode forward direction
Figure GDA0002313243730000023
A traveling wave difference current in the direction opposite to the 1-mode
Figure GDA0002313243730000024
Taking the forward or backward traveling wave differential current as a reference standard, translating the traveling wave differential current in the other direction on a time axis to obtain the 1-mode forward traveling wave differential current
Figure GDA0002313243730000025
And the 1-mode reverse traveling wave differential current
Figure GDA0002313243730000026
The time difference Δ t at the maximum value of the Pearson correlation coefficient of (a); wherein, Delta t is epsilon (-tau)1,τ1) (ii) a Wherein, the-tau is1The propagation delay when the fault occurs at the starting end J is shown; wherein, the value of τ is1Propagation delay when a fault occurs at the terminal K;
and calculating the fault position according to the time difference delta t.
In a first possible implementation manner of the first aspect, the traveling-wave differential current in the 1-mode forward direction
Figure GDA0002313243730000027
A traveling wave difference current in the direction opposite to the 1-mode
Figure GDA0002313243730000028
Taking the forward or backward traveling wave differential current as a reference standard, translating the traveling wave differential current in the other direction on a time axis to obtain the 1-mode forward traveling wave differential current
Figure GDA0002313243730000029
And the 1-mode reverse traveling wave differential current
Figure GDA00023132437300000210
The time difference Δ t at the maximum value of the Pearson correlation coefficient includes:
selecting the time window after the fault as tst,tst+tw]The 1-mode reverse traveling wave differential current
Figure GDA00023132437300000211
As a reference standard; wherein, t isw≥2·τ1(ii) a Wherein, t isst≥tfault+τ1(ii) a Wherein, t isfaultThe time when the fault occurs; wherein, t isstSelecting a starting time for the redundancy window;
for a total time window of [ tst-τ1,tst+τ1+tw]The 1-mode forward traveling wave differential current
Figure GDA00023132437300000212
Translating backward by Δ t on the time axis; wherein, Delta t is epsilon (-tau)1,τ1)；
Obtaining the 1-mode forward traveling wave differential current according to a fault location function
Figure GDA0002313243730000031
And the 1-mode reverse traveling wave differential current
Figure GDA0002313243730000032
The time difference Δ t at the maximum value of the Pearson correlation coefficient of (a); wherein the fault range is a functionThe method comprises the following steps:
Figure GDA0002313243730000033
wherein, Delta t is epsilon (-tau)1,τ1)；
Then said calculating a fault location from said time difference Δ t comprises:
according to the 1-mode forward traveling wave differential current
Figure GDA0002313243730000034
Equal to the 1-mode reverse traveling wave difference current
Figure GDA0002313243730000035
And calculating the fault position by the time difference delta t.
With reference to the second possible implementation manner of the first aspect, the traveling-wave differential current in the 1-mode forward direction
Figure GDA0002313243730000036
A traveling wave difference current in the direction opposite to the 1-mode
Figure GDA0002313243730000037
Taking the forward or backward traveling wave differential current as a reference standard, translating the traveling wave differential current in the other direction on a time axis to obtain the 1-mode forward traveling wave differential current
Figure GDA0002313243730000038
And the 1-mode reverse traveling wave differential current
Figure GDA0002313243730000039
The time difference Δ t at the maximum value of the Pearson correlation coefficient includes:
selecting the time window after the fault as tst,tst+tw]The 1-mode forward traveling wave differential current
Figure GDA00023132437300000310
As a reference standard; wherein, t isw≥2·τ1(ii) a Wherein, t isst≥tfault+τ1(ii) a Wherein, t isfaultThe time when the fault occurs; wherein, t isstSelecting a starting time for the redundancy window;
for a total time window of [ tst-τ1,tst+τ1+tw]The 1-mode reverse traveling wave differential current
Figure GDA00023132437300000311
Forward shifting on the time axis by Δ t; wherein, Delta t is epsilon (-tau)1,τ1)；
Obtaining the 1-mode reverse traveling wave differential current according to a fault location two function
Figure GDA00023132437300000312
And the 1-mode forward traveling wave differential current
Figure GDA00023132437300000313
The time difference Δ t at the maximum value of the Pearson correlation coefficient of (a); wherein the fault-ranging two-function comprises:
Figure GDA00023132437300000314
wherein, Delta t is epsilon (-tau)1,τ1)；
Then said calculating a fault location from said time difference Δ t comprises:
according to the 1-mode reverse traveling wave differential current
Figure GDA0002313243730000041
Equal to the 1-mode forward traveling wave difference current
Figure GDA0002313243730000042
And calculating the fault position by the time difference delta t.
In a third possible implementation manner of the first aspect, the obtaining of the 1-mode voltage u of the starting end J of the dc line is performedJ1And 1 mode current iJiAnd terminal K1 modePress uk1And 1 mode current iK1The method comprises the following steps:
obtaining the positive voltage u of the starting end J of the direct current lineJPNegative electrode voltage uJN；
Obtaining the positive current i of the starting end J of the direct current lineJPNegative electrode current iJN；
Obtaining the positive voltage u of the starting end K of the direct current lineKPNegative electrode voltage uKN；
Obtaining the positive current i of the starting end K of the direct current lineKPNegative electrode current iKN；
According to the decoupling matrix, the positive voltage u is alignedJPThe negative electrode voltage uJNThe positive electrode current iJPThe negative electrode current iJNThe positive electrode voltage uKPThe negative electrode voltage uKNThe positive electrode current iKPAnd the negative electrode current iKNDecoupling to obtain the 1-mode voltage uJ1The current iJ1The 1-mode voltage uk1And the 1-mode current iK1。
In a fourth possible implementation manner of the first aspect, the obtaining 1-mode wave impedance Zc1And 1-mode propagation delay τ1The method comprises the following steps:
obtaining wave impedance Z according to the capacitance and the inductance of the direct current linecAnd a traveling wave propagation velocity v;
impedance Z of the wave according to a decoupling matrixcDecoupling to obtain the 1-mode wave impedance Zc1；
Decoupling the traveling wave propagation velocity v according to a decoupling matrix to obtain the 1-mode wave velocity v1；
According to the 1-mode wave velocity v1And the length of the direct current line is used for obtaining the 1 mode propagation delay tau1。
In a fifth possible implementation manner of the first aspect, the impedance Z according to the 1-mode wave isc1-mode propagation delay τ11-mode voltage U of starting end J of direct-current lineJ1And 1 mode current IJ1And 1-mode voltage of the terminal K of the direct current lineUk1And 1 mode current IK1Obtaining 1-mode forward traveling wave differential current
Figure GDA0002313243730000043
And 1-mode reverse traveling wave differential current
Figure GDA0002313243730000051
The method comprises the following steps:
according to the 1-mode wave impedance Zc1 mode voltage UJ1And the 1-mode current IJ1Obtaining 1-mode forward current traveling wave of the starting end J of the direct current line
Figure GDA0002313243730000052
And 1-mode reverse current traveling wave
Figure GDA0002313243730000053
According to the 1-mode wave impedance Zc1 mode voltage Uk1And the 1-mode current IK1Obtaining 1 mode forward current traveling wave of the K at the tail end of the current line
Figure GDA0002313243730000054
And 1-mode reverse current traveling wave
Figure GDA0002313243730000055
According to the 1 mode propagation delay tau11-mode forward current traveling wave
Figure GDA0002313243730000056
And the 1-mode forward current traveling wave
Figure GDA0002313243730000057
Obtaining the 1-mode forward traveling wave differential current
Figure GDA0002313243730000058
And according to said 1-mode propagation delay tau11-mode forward current traveling wave
Figure GDA0002313243730000059
And the 1-mode forward current traveling wave
Figure GDA00023132437300000510
Obtaining the 1-mode reverse traveling wave differential current
Figure GDA00023132437300000511
With reference to the fifth possible implementation manner of the first aspect, in a sixth possible implementation manner of the first aspect, the delay τ is propagated according to the 1-mode11-mode forward current traveling wave
Figure GDA00023132437300000512
And the 1-mode forward current traveling wave
Figure GDA00023132437300000513
Obtaining the 1-mode forward traveling wave differential current
Figure GDA00023132437300000514
And according to said 1-mode propagation delay tau11-mode forward current traveling wave
Figure GDA00023132437300000515
And the 1-mode forward current traveling wave
Figure GDA00023132437300000516
Obtaining the 1-mode reverse traveling wave differential current
Figure GDA00023132437300000517
The method comprises the following steps:
Figure GDA00023132437300000518
in a second aspect, the present invention further provides a fault location apparatus based on traveling wave differential current, including:
a voltage and current acquisition module for acquiring 1-mode voltage of the starting end J of the DC linePress UJ1And 1 mode current IJ1And 1-mode voltage U of terminal K of direct current linek1And 1 mode current IK1；
An impedance delay obtaining module for obtaining 1-mode wave impedance Zc1And 1-mode propagation delay τ1；
A traveling wave differential current acquisition module for acquiring the 1-mode wave impedance Zc1-mode propagation delay τ11-mode voltage U of starting end J of direct-current lineJ1And 1 mode current IJ1And 1-mode voltage U of the tail end K of the direct current linek1And 1 mode current IK1Obtain the traveling wave differential current of the 1 mode forward direction
Figure GDA00023132437300000519
Travelling wave difference current in reverse direction to 1 mode
Figure GDA00023132437300000520
A time difference acquisition module for obtaining the forward traveling wave difference current of the 1 mode
Figure GDA0002313243730000061
A traveling wave difference current in the direction opposite to the 1-mode
Figure GDA0002313243730000062
Taking the forward or backward traveling wave differential current as a reference standard, translating the traveling wave differential current in the other direction on a time axis to obtain the 1-mode forward traveling wave differential current
Figure GDA0002313243730000063
And the 1-mode reverse traveling wave differential current
Figure GDA0002313243730000064
The time difference Δ t at the maximum value of the Pearson correlation coefficient of (a); wherein, Delta t is epsilon (-tau)1,τ1)；
And the fault position calculation module is used for calculating the fault position according to the time difference delta t.
In a third aspect, an embodiment of the present invention further provides a fault location apparatus based on a traveling wave differential current, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, where the processor, when executing the computer program, implements the fault location method based on a traveling wave differential current as described in any one of the above.
In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, where the computer-readable storage medium includes a stored computer program, where, when the computer program runs, the apparatus where the computer-readable storage medium is located is controlled to execute any one of the above-mentioned fault location methods based on traveling wave differential current.
One of the above technical solutions has the following advantages: based on the waveform similarity and time shift relationship of the forward traveling wave differential current and the reverse traveling wave differential current of the line, the fault position is obtained by translating the forward traveling wave differential current and the reverse traveling wave differential current on a time axis, calculating the correlation of two sections of waveforms, finding out time shift data corresponding to fault position information through the highest point of the waveform similarity of the forward traveling wave differential current and the reverse traveling wave differential current, and substituting the time shift data into a formula when the forward traveling wave differential current and the reverse traveling wave differential current are equal. The fault occurrence position can be simply, conveniently and reliably found without ultrahigh sampling rate and identification and calibration of the initial wave head and the reflected traveling wave, is not influenced by fault types, and has strong anti-transition resistance capability.
Drawings
Fig. 1 is a schematic flow chart of a fault location method based on traveling wave differential current according to a first embodiment of the present invention;
fig. 2 is a schematic diagram of a bipolar hvdc transmission system;
fig. 3 is a schematic diagram of forward and reverse traveling wave difference currents of the power transmission line according to the first embodiment of the present invention;
fig. 4 is a schematic diagram of the forward and reverse traveling wave difference currents of the transmission line in the presence of a fault according to the first embodiment of the present invention;
fig. 5 is a schematic flow chart of another fault location method based on traveling wave differential current according to a second embodiment of the present invention;
fig. 6 is a schematic flow chart of another fault location method based on traveling wave differential current according to a third embodiment of the present invention;
fig. 7 is a schematic structural diagram of a fault location apparatus based on traveling wave differential current according to a fourth embodiment of the present invention;
fig. 8 is a schematic diagram of a fault location apparatus based on traveling wave differential current according to a fifth embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the invention provides a fault location method based on traveling wave differential current, which is used for ensuring that a high-voltage direct-current transmission line stably operates and timely searching and clearing faults and is respectively explained in detail below.
Example one
Referring to fig. 1, a schematic flow chart of a fault location method based on traveling wave differential current according to a first embodiment of the present invention;
s11, obtaining the 1 mode voltage u of the starting end J of the direct current lineJ1And 1 mode current iJ1And 1-mode voltage u of DC line terminal Kk1And 1 mode current iK1；
Preferably, the 1-mode voltage u of the starting end J of the direct current line is obtainedJ1And 1 mode current iJ1And 1-mode voltage u of DC line terminal Kk1And 1 mode current iK1The method comprises the following steps:
obtaining the positive voltage u of the starting end J of the direct current lineJPNegative electrode voltage uJN；
Obtaining the positive current i of the starting end J of the direct current lineJPNegative electrode current iJN；
Obtaining direct currentPositive voltage u of line starting end KKPNegative electrode voltage uKN；
Obtaining the positive current i of the starting end K of the direct current lineKPNegative electrode current iKN；
According to the decoupling matrix, the positive voltage u is alignedJPThe negative electrode voltage uJNThe positive electrode current iJPThe negative electrode current iJNThe positive electrode voltage uKPThe negative electrode voltage uKNThe positive electrode current iKPAnd the negative electrode current iKNDecoupling to obtain the 1-mode voltage uJ1The current iJ1The 1-mode voltage uk1And the 1-mode current iK1。
Specifically, for a high-voltage direct-current transmission system, a transmission line of the high-voltage direct-current transmission system is generally composed of two transmission lines, namely a positive transmission line and a negative transmission line, as shown in fig. 2. There is electrical coupling between the two transmission lines. A real number decoupling matrix can be utilized
Figure GDA0002313243730000081
Decoupling the voltage and current of two poles, and the obtained voltage and current 0 mode (earth mode) component and 1 mode (line mode) component no longer have electrical coupling, taking the J end as an example:
Figure GDA0002313243730000082
wherein, the U J00 mode voltage of J terminal, UJ11 mode voltage of J terminal, the I J00 mode current of J terminal, IJ11 mode current of J terminal, UJPA positive voltage of J terminal, the UJNThe voltage of the negative electrode at the J terminal, the IJPCurrent of positive electrode of J terminal, IJNIs the negative current of the J terminal. In the same way, the voltage and current modulus of the K terminal can be obtained, and details are not repeated here.
It should be noted that, after the dc transmission line fails: (1) when an interelectrode (symmetrical) fault of a direct-current transmission line occurs, a fault current cannot flow through a ground loop, and theoretically, a 0-mode component does not exist, so that the 0-mode component cannot be used for fault location of the interelectrode fault; (2) the direct current transmission line parameters have frequency-variable characteristics, the traveling waves are spread on the direct current transmission line and have dispersion phenomena, the influence of the dispersion phenomena on the 0-mode traveling waves is more obvious, and the two factors are integrated, and the 1-mode component is utilized to realize the fault location algorithm.
S12, obtaining 1 mode wave impedance Zc1And 1-mode propagation delay τ1；
Preferably, the obtaining 1-mode wave impedance Zc1And 1-mode propagation delay τ1The method comprises the following steps:
obtaining wave impedance Z according to the capacitance and the inductance of the direct current linecAnd a traveling wave propagation velocity v;
impedance Z of the wave according to a decoupling matrixcDecoupling to obtain the 1-mode wave impedance Zc1；
Decoupling the traveling wave propagation velocity v according to a decoupling matrix to obtain the 1-mode wave velocity v1；
According to the 1-mode wave velocity v1And the length of the direct current line is used for obtaining the 1 mode propagation delay tau1。
The method comprises the following steps that JK represents a single lossless uniform transmission line with the length of L, and L and C are respectively an inductor and a capacitor of the transmission line with the unit length; wave impedance of the transmission line
Figure GDA0002313243730000091
Propagation velocity of traveling wave
Figure GDA0002313243730000092
And tau is the propagation delay of the traveling wave from one end of the line to the other end.
Specifically, the inductance L per unit length of the DC line is obtained1And a capacitor C1Decoupling the electric parameters of the transmission line according to the wave impedance
Figure GDA0002313243730000093
Obtaining the 1-mode wave impedance
Figure GDA0002313243730000094
According to the propagation velocity of the travelling wave
Figure GDA0002313243730000095
And the propagation delay tau is l/v, and the 1-mode propagation delay tau is obtained1＝l/v1。
S13, impedance Z of the 1 mode wavec1-mode propagation delay τ11-mode voltage U of starting end J of direct-current lineJ1And 1 mode current IJ1And 1-mode voltage u of the end K of the direct current linek1And 1 mode current iK1Obtain the traveling wave differential current of the 1 mode forward direction
Figure GDA0002313243730000096
Travelling wave difference current in reverse direction to 1 mode
Figure GDA0002313243730000097
Preferably, the impedance Z according to the 1-mode wavec1-mode propagation delay τ11-mode voltage U of starting end J of direct-current lineJ1And 1 mode current IJ1And 1-mode voltage U of the tail end K of the direct current linek1And 1 mode current IK1Obtaining 1-mode forward traveling wave differential current
Figure GDA0002313243730000098
And 1-mode reverse traveling wave differential current
Figure GDA0002313243730000099
The method comprises the following steps:
according to the 1-mode wave impedance ZcThe 1-mode voltage uJ1And the 1-mode current iJ1Obtaining 1-mode forward current traveling wave of the starting end J of the direct current line
Figure GDA00023132437300000910
And 1-mode reverse current traveling wave
Figure GDA00023132437300000911
According to the 1-mode wave impedance ZcThe 1-mode voltage uk1And the 1-mode current iK1Obtaining 1 mode forward current traveling wave of the K at the tail end of the current line
Figure GDA00023132437300000912
And 1-mode reverse current traveling wave
Figure GDA00023132437300000913
According to the 1 mode propagation delay tau11-mode forward current traveling wave
Figure GDA00023132437300000914
And the 1-mode forward current traveling wave
Figure GDA00023132437300000915
Obtaining the 1-mode forward traveling wave differential current
Figure GDA00023132437300000916
And according to said 1-mode propagation delay tau11-mode forward current traveling wave
Figure GDA00023132437300000917
And the 1-mode forward current traveling wave
Figure GDA00023132437300000918
Obtaining the 1-mode reverse traveling wave differential current
Figure GDA0002313243730000101
Preferably, said propagation delay τ according to said 1 mode11-mode forward current traveling wave
Figure GDA0002313243730000102
And the 1-mode forward current traveling wave
Figure GDA0002313243730000103
Obtaining the 1-mode forward traveling wave differential current
Figure GDA0002313243730000104
And according to said 1-mode propagation delay tau11-mode forward current traveling wave
Figure GDA0002313243730000105
And the 1-mode forward current traveling wave
Figure GDA0002313243730000106
Obtaining the 1-mode reverse traveling wave differential current
Figure GDA0002313243730000107
The method comprises the following steps:
Figure GDA0002313243730000108
specifically, the positive direction of defining circuit both ends electric current is the generating line and flows to the circuit, and the positive direction of travelling wave is that the J end points to the K end, and then both ends electric current travelling wave does:
Figure GDA0002313243730000109
wherein the
Figure GDA00023132437300001010
Forward current traveling wave being J terminal, said
Figure GDA00023132437300001011
A traveling wave of reverse current at J terminal, the
Figure GDA00023132437300001012
Is a forward current traveling wave of a K terminal, the
Figure GDA00023132437300001013
Is a reverse current traveling wave of K terminal, iJ1(t) is the positive direction current of the J terminal, iK1And (t) is the positive direction current of the K terminal. Defining the forward traveling wave difference current and the reverse traveling wave difference current of the power transmission line as follows:
Figure GDA00023132437300001014
when the line has no fault, the forward current traveling wave at the J end reaches the K end through the propagation delay tau, and
Figure GDA00023132437300001015
similarly, the reverse traveling wave is also
Figure GDA00023132437300001016
S14, forward traveling wave differential current in the 1 mode
Figure GDA00023132437300001017
A traveling wave difference current in the direction opposite to the 1-mode
Figure GDA00023132437300001018
Taking the forward or backward traveling wave differential current as a reference standard, translating the traveling wave differential current in the other direction on a time axis to obtain the 1-mode forward traveling wave differential current
Figure GDA00023132437300001019
And the 1-mode reverse traveling wave differential current
Figure GDA00023132437300001020
The time difference Δ t at the maximum value of the Pearson correlation coefficient of (a); wherein, Delta t is epsilon (-tau)1,τ1) (ii) a Wherein, the-tau is1The propagation delay when the fault occurs at the starting end J is shown; wherein, the value of τ is1Propagation delay when a fault occurs at the terminal K;
the inventors found that, when carrying out the examples of the present invention, the 1-mode forward traveling differential current
Figure GDA0002313243730000111
Backward (right) shift by Δ τ along the time axis1Is obtained
Figure GDA0002313243730000112
Then there are:
Figure GDA0002313243730000113
description is shifted backward
Figure GDA0002313243730000114
Obtained
Figure GDA0002313243730000115
And
Figure GDA00023132437300001118
will be completely coincident and shifted back for a time duration of Δ τ1The propagation time difference of the 1 mode traveling wave at two ends of the fault point is obtained; similarly, if the 1 mode reverse traveling wave difference current is to be used
Figure GDA0002313243730000116
Forward (left) shift by Δ τ along time axis1Is obtained
Figure GDA0002313243730000117
Then there are:
Figure GDA0002313243730000118
to explain the passing through
Figure GDA0002313243730000119
Obtained
Figure GDA00023132437300001117
And
Figure GDA00023132437300001110
will be completely coincident with a preceding time length of Δ τ1The propagation time difference of the 1-mode traveling wave at both ends of the fault point.
The specific derivation process is as follows:
referring to fig. 3, taking JK as an example of a single lossless uniform transmission line with length of l, the forward and reverse traveling wave differential currents of the transmission line are defined as follows:
Figure GDA00023132437300001111
when the line has no fault, the forward current traveling wave at the J end reaches the K end through the propagation delay tau, and
Figure GDA00023132437300001112
similarly, the reverse traveling wave is also
Figure GDA00023132437300001113
As shown in fig. 4, when a fault occurs in the F point inside the power transmission line, the propagation law of the traveling wave at the two ends of the power transmission line is destroyed. However, for the lines from the fault point F to the two sides of the line, the propagation law of the traveling wave still applies, taking the forward current traveling wave as an example:
Figure GDA00023132437300001114
in the formula (6), the value τJ＝lJFV is the propagation time delay of current travelling wave from fault point F to line J end, and tau isK＝lKFV is the propagation time delay of current travelling wave from fault point F to line K end, and lJFDistance from fault point F to line J, iKFThe distance from the fault point F to the end of the line K is τ ═ τJ+τK. The above-mentioned
Figure GDA00023132437300001115
And said
Figure GDA00023132437300001116
The current forward traveling waves on the left side and the right side of the fault point are respectively, and the difference between the current forward traveling waves and the current forward traveling waves is as follows:
Figure GDA0002313243730000121
in the formula iJF(t) and iKF(t) fault currents flowing to J and K terminals of the line at the fault point, iFAnd (t) is a fault current.
T of the first equation of equation (6) is represented by t- τKInstead, the following results are obtained:
Figure GDA0002313243730000122
substituting equations (6), (7) and (8) for the first equation of equation (5) to obtain the relationship between the forward traveling wave difference current and the fault current after the fault:
di+(t)＝iF(t-τK) (9)
similarly, the relation between the reverse traveling wave differential current after the fault and the fault current can be obtained:
di-(t)＝iF(t-τJ) (10)
it can be easily found by comparing the formulas (9) and (10): after line fault, the forward traveling differential current di+(t) and reverse traveling wave differential current di-(t) is equal to the fault current component at different times. If di is equal to+(t) backward (right) shift by Δ τ along time axis1Length of time of (d) to obtain di+(t-Δτ1) Then, there are:
di+(t-Δτ1)＝di-(t) (11)
wherein, Δ τ1＝τJ-τK。
In the embodiment of the invention, the propagation time difference of the 1-mode traveling wave at two ends of the fault point is defined as delta tau1＝τJ1-τK1Considering two extreme cases of fault location, when a fault occurs at the J-port exit:
Δτ1＝τJ1-τK1＝0-τ1＝-τ1
when a fault occurs at the K-terminal outlet:
Δτ1＝τJ1-τK1＝τ1-0＝τ1
referring to fig. 3 and the above analysis, one can see that:
Figure GDA0002313243730000131
formula (11) shows that di is retroverted+(t) obtained
Figure GDA0002313243730000132
And
Figure GDA0002313243730000133
will be completely coincident and shifted back for a time duration of Δ τ1。
If di is equal to+(t) forward (left) shift by Δ τ along time axis1Is obtained
Figure GDA00023132437300001311
Then there are:
Figure GDA0002313243730000134
formula (12) shows the process of advancing
Figure GDA0002313243730000135
Obtained
Figure GDA0002313243730000136
And
Figure GDA0002313243730000137
will be completely coincident and shifted back for a time duration of Δ τ1。
Equations (11) and (12) are derived based on lossless transmission lines. Due to the fact that distributed resistance exists in an actual power transmission line, unbalanced differential current exists in the 1-mode traveling wave differential current obtained through actual calculation under the influence of the resistance. In addition, the resistance also enables the waveform to be attenuated to a certain degree when the current traveling waves at two ends of the fault point are propagated on the line. Thus, di+(t-Δτ1) And di-The (t) waveforms do not completely coincide. But both reflect the fault current after the fault occurs, the variation trend of the fault current and the fault currentThe change trends of the flows are consistent, and high similarity is shown on the waveforms.
The Pearson correlation coefficient is a mathematical means for analyzing the linear correlation of the distance variable, and the specific method is to centralize two groups of data, namely, to obtain the average value of the two groups of data, to subtract the average value of the data elements of the two groups of data, and to calculate the correlation of the two groups of data after centralization by using cosine similarity. The expression is shown below:
Figure GDA0002313243730000138
and evaluating the similarity of the variation trends of the two sections of waveforms by using the Pearson correlation coefficient. Traveling wave differential current in the 1-mode forward direction
Figure GDA0002313243730000139
A traveling wave difference current in the direction opposite to the 1-mode
Figure GDA00023132437300001310
The forward or reverse traveling wave differential current in (1) is used as a reference standard, and the traveling wave differential current in the other direction is translated by delta t on a time axis to obtain
Figure GDA0002313243730000141
Or
Figure GDA0002313243730000142
And continuously calculate
Figure GDA00023132437300001416
And
Figure GDA0002313243730000143
pearson correlation coefficient of, or continuously calculating
Figure GDA0002313243730000144
And
Figure GDA0002313243730000145
when Δ t is Δ τ, the Pearson correlation coefficient of (1)1The Pearson correlation coefficient of both will take a maximum value and approach 1.
And S15, calculating the fault position according to the time difference delta t.
In this embodiment, the traveling wave differential current in the 1-mode forward direction
Figure GDA0002313243730000146
A traveling wave difference current in the direction opposite to the 1-mode
Figure GDA0002313243730000147
Taking the forward or backward traveling wave differential current as a reference standard, translating the traveling wave differential current in the other direction on a time axis to obtain the 1-mode forward traveling wave differential current
Figure GDA0002313243730000148
And the 1-mode reverse traveling wave differential current
Figure GDA0002313243730000149
The time difference Δ t at the time of the maximum Pearson correlation coefficient of (a) is obtained by finding that, when the traveling wave difference current in the other direction is shifted by the time difference Δ t on the time axis, the traveling wave difference current as the reference standard becomes equal to the traveling wave difference current in the other direction. Assuming a reverse traveling wave differential current in the 1-mode
Figure GDA00023132437300001410
As a reference standard, the 1-mode forward traveling wave difference current
Figure GDA00023132437300001411
When the time axis is shifted to delta t, the forward traveling wave difference current according to the 1 mode exists
Figure GDA00023132437300001412
Equal to the 1-mode reverse traveling wave difference current
Figure GDA00023132437300001413
And calculating the fault position by the time difference delta t.
The embodiment has the following beneficial effects:
the fault position information can be obtained by analyzing the correlation between the forward traveling wave differential current and the reverse traveling wave differential current, the waveform similarity and the time shift relation based on the forward traveling wave differential current and the reverse traveling wave differential current of the line are obtained by deduction, the forward traveling wave differential current and the reverse traveling wave differential current are translated on a time axis, the correlation between two sections of waveforms is calculated, the time shift data corresponding to the fault position information is found out according to the highest point of the waveform similarity of the forward traveling wave differential current and the reverse traveling wave differential current, and the fault position is obtained by substituting the time shift data into a formula when the forward traveling wave differential current and the reverse traveling wave differential current are equal. The fault occurrence position can be simply, conveniently and reliably found without ultrahigh sampling rate and identification and calibration of the initial wave head and the reflected traveling wave, is not influenced by fault types, and has strong anti-transition resistance capability.
In a second embodiment, on the basis of the first embodiment, referring to fig. 5, a schematic flow chart of another fault location method based on traveling wave differential current according to a second embodiment of the present invention is provided; preferably, the traveling wave differential current in the 1-mode forward direction
Figure GDA00023132437300001414
A traveling wave difference current in the direction opposite to the 1-mode
Figure GDA00023132437300001415
Taking the forward or backward traveling wave differential current as a reference standard, translating the traveling wave differential current in the other direction on a time axis to obtain the 1-mode forward traveling wave differential current
Figure GDA0002313243730000151
And the 1-mode reverse traveling wave differential current
Figure GDA0002313243730000152
The time difference Δ t at the maximum value of the Pearson correlation coefficient includes:
s21, selecting the time window after the fault as tst,tst+tw]The 1-mode reverse traveling wave differential current
Figure GDA0002313243730000153
As a reference standard; wherein, t isw≥2·τ1(ii) a Wherein, t isst≥tfault+τ1(ii) a Wherein, t isfaultThe time when the fault occurs; wherein, t isstSelecting a starting time for the redundancy window;
note that, the t iswFor the intercepted waveform redundancy window, in order to better reflect the characteristics of the fault current, no matter where the line has a fault, the fault current traveling waves at two ends reach a fault point after being reflected by the line end point, and the condition t is metw≥2·τ1；tstSelecting a starting moment for the redundancy window, and ensuring that no matter where the line has a fault, fault traveling waves are transmitted to two ends of the line to meet tst≥tfault+τ1，tfaultTime of occurrence of a failure, tstThe guard activation time may be selected.
S22, total time window is [ tst-τ1,tst+τ1+tw]The 1-mode forward traveling wave differential current
Figure GDA0002313243730000154
Translating backward by Δ t on the time axis; wherein, Delta t is epsilon (-tau)1,τ1)；
In addition, Δ τ is expressed by equation (11)1Value range of (1) for comparing 1-mode forward traveling wave differential current
Figure GDA0002313243730000155
The total time window to be selected is tst-τ1,tst+τ1+tw]。
S23, obtaining the 1-mode forward traveling wave differential current according to a fault location function
Figure GDA0002313243730000156
And the 1-mode reverse traveling wave differential current
Figure GDA0002313243730000157
The time difference Δ t at the maximum value of the Pearson correlation coefficient of (a); wherein the fault ranging function comprises:
Figure GDA0002313243730000158
wherein, Delta t is epsilon (-tau)1,τ1)；
Then said calculating a fault location from said time difference Δ t comprises:
s24, forward traveling wave difference current according to the 1 mode
Figure GDA0002313243730000159
Equal to the 1-mode reverse traveling wave difference current
Figure GDA00023132437300001510
And calculating the fault position by the time difference delta t.
The embodiment has the following beneficial effects:
the waveform similarity and time shift relation based on the forward traveling wave differential current and the reverse traveling wave differential current of the line are obtained through derivation, and a time window after the fault is selected as [ t [ ]st,tst+tw]The 1-mode reverse traveling wave differential current
Figure GDA0002313243730000161
As a reference standard, by setting the total time window to [ t ]st-τ1,tst+τ1+tw]The 1-mode forward traveling wave differential current
Figure GDA0002313243730000162
Backward shifting by delta t on a time axis and calculating the 1-mode forward traveling wave difference current
Figure GDA0002313243730000163
And the 1-mode reverse traveling wave differential current
Figure GDA0002313243730000164
And (3) finding time shift data corresponding to fault position information according to the highest point of similarity of the two waveforms, and substituting the time shift data into a formula when the forward traveling wave differential current and the reverse traveling wave differential current are equal to obtain the fault position. The fault occurrence position can be simply, conveniently and reliably found without ultrahigh sampling rate and identification and calibration of the initial wave head and the reflected traveling wave, is not influenced by fault types, and has strong anti-transition resistance capability.
In a third embodiment, on the basis of the first embodiment, referring to fig. 6, a schematic flow chart of another fault location method based on traveling wave differential current according to a third embodiment of the present invention is provided;
preferably, the traveling wave differential current in the 1-mode forward direction
Figure GDA0002313243730000165
A traveling wave difference current in the direction opposite to the 1-mode
Figure GDA0002313243730000166
Taking the forward or backward traveling wave differential current as a reference standard, translating the traveling wave differential current in the other direction on a time axis to obtain the 1-mode forward traveling wave differential current
Figure GDA0002313243730000167
And the 1-mode reverse traveling wave differential current
Figure GDA0002313243730000168
The time difference Δ t at the maximum value of the Pearson correlation coefficient includes:
s31, selecting the time window after the fault as tst,tst+tw]The 1-mode forward traveling wave differential current
Figure GDA0002313243730000169
As a reference standard; wherein, t isw≥2·τ1(ii) a Wherein, t isst≥tfault+τ1(ii) a Wherein, t isfaultThe time when the fault occurs; wherein, t isstSelecting a starting time for the redundancy window;
note that, the t iswFor the intercepted waveform redundancy window, in order to better reflect the characteristics of the fault current, no matter where the line has a fault, the fault current traveling waves at two ends reach a fault point after being reflected by the line end point, and the condition t is metw≥2·τ1；tstSelecting a starting moment for the redundancy window, and ensuring that no matter where the line has a fault, fault traveling waves are transmitted to two ends of the line to meet tst≥tfault+τ1，tfaultTime of occurrence of a failure, tstThe guard activation time may be selected.
S32, total time window is [ tst-τ1,tst+τ1+tw]The 1-mode reverse traveling wave differential current
Figure GDA00023132437300001610
Forward shifting on the time axis by Δ t; wherein, Delta t is epsilon (-tau)1,τ1)；
In addition, Δ τ is expressed by equation (11)1Value range of (1) for comparing 1-mode forward traveling wave differential current
Figure GDA0002313243730000171
The total time window to be selected is tst-τ1,tst+τ1+tw]。
S33, obtaining the 1-mode reverse traveling wave differential current according to the fault location two function
Figure GDA0002313243730000172
And the 1-mode forward traveling wave differential current
Figure GDA0002313243730000173
The time difference Δ t at the maximum value of the Pearson correlation coefficient of (a); wherein the fault-ranging two-function comprises:
Figure GDA0002313243730000174
wherein, Delta t is epsilon (-tau)1,τ1)；
Then said calculating a fault location from said time difference Δ t comprises:
s34, according to the 1 mode reverse traveling wave difference current
Figure GDA0002313243730000175
Equal to the 1-mode forward traveling wave difference current
Figure GDA0002313243730000176
And calculating the fault position by the time difference delta t.
The embodiment has the following beneficial effects:
the waveform similarity and time shift relation based on the forward traveling wave differential current and the reverse traveling wave differential current of the line are obtained through derivation, and a time window after the fault is selected as [ t [ ]st,tst+tw]The 1-mode forward traveling wave differential current
Figure GDA0002313243730000177
As a reference standard, by setting the total time window to [ t ]st-τ1,tst+τ1+tw]The 1-mode reverse traveling wave differential current
Figure GDA0002313243730000178
Translating forward by delta t on a time axis and calculating the 1-mode reverse traveling wave difference current
Figure GDA0002313243730000179
And the 1-mode forward traveling wave differential current
Figure GDA00023132437300001710
And (3) the correlation of the two sections of waveforms, finding out time shift data corresponding to fault position information through the highest point of similarity of the two waveforms, and substituting the time shift data into the forward and reverse traveling wave differential current phaseAnd obtaining the fault position in the equation of isochronous. The fault occurrence position can be simply, conveniently and reliably found without ultrahigh sampling rate and identification and calibration of the initial wave head and the reflected traveling wave, is not influenced by fault types, and has strong anti-transition resistance capability.
Referring to fig. 7, fig. 7 is a schematic structural diagram of a fault location apparatus based on a traveling wave differential current according to a fourth embodiment of the present invention, including:
a voltage/current obtaining module 71 for obtaining a 1-mode voltage u of the start end J of the dc lineJ1And 1 mode current iJ1And 1-mode voltage u of DC line terminal Kk1And 1 mode current iK1；
An impedance delay obtaining module 72 for obtaining 1-mode wave impedance Zc1And 1-mode propagation delay τ1；
A traveling wave difference current obtaining module 73 for obtaining the impedance Z of the 1-mode wave according toc1-mode propagation delay τ11-mode voltage u of starting end J of the direct current lineJ1And 1 mode current iJ1And 1-mode voltage u of the end K of the direct current linek1And 1 mode current iK1Obtain the traveling wave differential current of the 1 mode forward direction
Figure GDA0002313243730000181
Travelling wave difference current in reverse direction to 1 mode
Figure GDA0002313243730000182
A time difference obtaining module 74 for obtaining the traveling wave difference current in the 1-mode forward direction
Figure GDA0002313243730000183
A traveling wave difference current in the direction opposite to the 1-mode
Figure GDA0002313243730000184
Taking the forward or backward traveling wave differential current as a reference standard, translating the traveling wave differential current in the other direction on a time axis to obtain the 1-mode forward traveling wave differential current
Figure GDA0002313243730000185
And the 1-mode reverse traveling wave differential current
Figure GDA0002313243730000186
The time difference Δ t at the maximum value of the Pearson correlation coefficient of (a); wherein, Delta t is epsilon (-tau)1,τ1)；
And a fault location calculating module 75, configured to calculate a fault location according to the time difference Δ t.
Preferably, the time difference obtaining module 74 includes:
a reference standard selection unit for selecting a time window after a fault as [ t ]st,tst+tw]The 1-mode reverse traveling wave differential current
Figure GDA0002313243730000187
As a reference standard; wherein, t isw≥2·τ1(ii) a Wherein, t isst≥tfault+τ1(ii) a Wherein, t isfaultThe time when the fault occurs; wherein, t isstSelecting a starting time for the redundancy window;
a translation unit for a total time window of [ t ]st-τ1,tst+τ1+tw]The 1-mode forward traveling wave differential current
Figure GDA0002313243730000188
Translating backward by Δ t on the time axis; wherein, Delta t is epsilon (-tau)1,τ1)；
A time difference obtaining unit for obtaining the 1-mode forward traveling wave difference current according to a fault location function
Figure GDA0002313243730000189
And the 1-mode reverse traveling wave differential current
Figure GDA00023132437300001810
The time difference Δ t at the maximum value of the Pearson correlation coefficient of (a); wherein the fault ranging function comprises:
Figure GDA00023132437300001811
wherein, Delta t is epsilon (-tau)1,τ1)；
Then said calculating a fault location from said time difference Δ t comprises:
a fault calculation unit for calculating the differential current of the 1-mode forward traveling wave
Figure GDA0002313243730000191
Equal to the 1-mode reverse traveling wave difference current
Figure GDA0002313243730000192
And calculating the fault position by the time difference delta t.
Preferably, the time difference obtaining module 74 includes:
a reference standard selection unit for selecting a time window after a fault as [ t ]st,tst+tw]The 1-mode forward traveling wave differential current
Figure GDA0002313243730000193
As a reference standard; wherein, t isw≥2·τ1(ii) a Wherein, t isst≥tfault+τ1(ii) a Wherein, t isfaultThe time when the fault occurs; wherein, t isstSelecting a starting time for the redundancy window;
a translation unit for a total time window of [ t ]st-τ1,tst+τ1+tw]The 1-mode reverse traveling wave differential current di1- (t) forward shifting by Δ t on the time axis; wherein, Delta t is epsilon (-tau)1,τ1)；
A time difference obtaining unit for obtaining the 1-mode reverse traveling wave difference current according to a fault location two-function
Figure GDA0002313243730000194
And the 1-mode forward traveling wave differential current
Figure GDA0002313243730000195
The time difference Δ t at the maximum value of the Pearson correlation coefficient of (a); wherein the fault-ranging two-function comprises:
Figure GDA0002313243730000196
wherein, Delta t is epsilon (-tau)1,τ1)；
Then said calculating a fault location from said time difference Δ t comprises:
a fault calculation unit for calculating the differential current of the 1-mode reverse traveling wave
Figure GDA0002313243730000197
Equal to the 1-mode forward traveling wave difference current
Figure GDA0002313243730000198
And calculating the fault position by the time difference delta t.
Preferably, the voltage current obtaining module 71 includes:
obtaining the positive voltage u of the starting end J of the direct current lineJPNegative electrode voltage uJN；
Obtaining the positive current i of the starting end J of the direct current lineJPNegative electrode current iJN；
Obtaining the positive voltage u of the starting end K of the direct current lineKPNegative electrode voltage uKN；
Obtaining the positive current i of the starting end K of the direct current lineKPNegative electrode current iKN；
According to the decoupling matrix, the positive voltage u is alignedJPThe negative electrode voltage uJNThe positive electrode current iJPThe negative electrode current iJNThe positive electrode voltage uKPThe negative electrode voltage uKNThe positive electrode current iKPAnd the negative electrode current iKNDecoupling to obtain the 1-mode voltage uJ1The current iJ1The 1-mode voltage uk1And the 1-mode currentiK1。
Preferably, the impedance delay obtaining module 72 includes:
obtaining wave impedance Z according to the capacitance and the inductance of the direct current linecAnd a traveling wave propagation velocity v;
impedance Z of the wave according to a decoupling matrixcDecoupling to obtain the 1-mode wave impedance Zc1；
Decoupling the traveling wave propagation velocity v according to a decoupling matrix to obtain the 1-mode wave velocity v1；
According to the 1-mode wave velocity v1And the length of the direct current line is used for obtaining the 1 mode propagation delay tau1。
Preferably, the traveling wave difference current obtaining module 73 includes:
a J-end traveling wave current acquisition unit for acquiring the 1-mode wave impedance ZcThe 1-mode voltage uJ1And the 1-mode current iJ1Obtaining 1-mode forward current traveling wave of the starting end J of the direct current line
Figure GDA0002313243730000201
And 1-mode reverse current traveling wave
Figure GDA0002313243730000202
A K-terminal traveling wave current acquisition unit for acquiring the 1-mode wave impedance ZcThe 1-mode voltage uk1And the 1-mode current iK1Obtaining 1 mode forward current traveling wave of the K at the tail end of the current line
Figure GDA0002313243730000203
And 1-mode reverse current traveling wave
Figure GDA0002313243730000204
A traveling wave difference current acquisition unit for acquiring the 1-mode propagation delay tau11-mode forward current traveling wave
Figure GDA0002313243730000205
And the 1-mode forward current traveling wave
Figure GDA0002313243730000206
Obtaining the 1-mode forward traveling wave differential current
Figure GDA0002313243730000207
And according to said 1-mode propagation delay tau11-mode forward current traveling wave
Figure GDA0002313243730000208
And the 1-mode forward current traveling wave
Figure GDA0002313243730000209
Obtaining the 1-mode reverse traveling wave differential current
Figure GDA00023132437300002010
Preferably, the traveling wave difference current obtaining unit includes:
Figure GDA0002313243730000211
the embodiment has the following beneficial effects: based on the waveform similarity and time shift relationship of the forward traveling wave differential current and the reverse traveling wave differential current of the line, the fault position is obtained by translating the forward traveling wave differential current and the reverse traveling wave differential current on a time axis, calculating the correlation of two sections of waveforms, finding out time shift data corresponding to fault position information through the highest point of the waveform similarity of the forward traveling wave differential current and the reverse traveling wave differential current, and substituting the time shift data into a formula when the forward traveling wave differential current and the reverse traveling wave differential current are equal. The fault occurrence position can be simply, conveniently and reliably found without ultrahigh sampling rate and identification and calibration of the initial wave head and the reflected traveling wave, is not influenced by fault types, and has strong anti-transition resistance capability.
Referring to fig. 8, fig. 8 is a schematic diagram of a fault location apparatus based on a traveling wave differential current according to a fifth embodiment of the present invention, configured to execute the fault location method based on a traveling wave differential current according to the fifth embodiment of the present invention, and as shown in fig. 8, the terminal apparatus for fault location based on a traveling wave differential current includes: at least one processor 11, such as a CPU, at least one network interface 14 or other user interface 13, a memory 15, at least one communication bus 12, the communication bus 12 being used to enable connectivity communications between these components. The user interface 13 may optionally include a USB interface, and other standard interfaces, wired interfaces. The network interface 14 may optionally include a Wi-Fi interface as well as other wireless interfaces. The memory 15 may comprise a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory. The memory 15 may optionally comprise at least one memory device located remotely from the aforementioned processor 11.
In some embodiments, memory 15 stores the following elements, executable modules or data structures, or a subset thereof, or an expanded set thereof:
an operating system 151, which contains various system programs for implementing various basic services and for processing hardware-based tasks;
and (5) a procedure 152.
Specifically, the processor 11 is configured to call the program 152 stored in the memory 15 to execute the fault location method based on the traveling wave differential current according to the above embodiment.
The Processor may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. The general purpose processor may be a microprocessor or the processor may be any conventional processor or the like, and the processor is a control center of the fault location method based on traveling wave difference current, and various interfaces and lines are used to connect various parts of the whole fault location method based on traveling wave difference current.
The memory may be used to store the computer programs and/or modules, and the processor may implement various functions of the traveling wave differential current based fault ranging electronic device by operating or executing the computer programs and/or modules stored in the memory and calling up the data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required by at least one function (such as a sound playing function, a text conversion function, etc.), and the like; the storage data area may store data (such as audio data, text message data, etc.) created according to the use of the cellular phone, etc. In addition, the memory may include high speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), at least one magnetic disk storage device, a Flash memory device, or other volatile solid state storage device.
Wherein, the fault location integrated module based on the traveling wave differential current can be stored in a computer readable storage medium if the module is realized in the form of a software functional unit and sold or used as an independent product. Based on such understanding, all or part of the flow of the method according to the embodiments of the present invention may also be implemented by a computer program, which may be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the method embodiments may be implemented. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, etc. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals as is required by legislation and patent practice.
It should be noted that the above-described device embodiments are merely illustrative, where the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. In addition, in the drawings of the embodiment of the apparatus provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, and may be specifically implemented as one or more communication buses or signal lines. One of ordinary skill in the art can understand and implement it without inventive effort.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.
It should be noted that, in the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and in a part that is not described in detail in a certain embodiment, reference may be made to the related descriptions of other embodiments. Further, those skilled in the art will appreciate that the embodiments described in the specification are preferred and that acts and simulations are necessarily required in accordance with the invention.

Claims (10)

1. A fault location method based on traveling wave differential current is characterized by comprising the following steps:
obtaining 1-mode voltage u of starting end J of direct current lineJ1And 1 mode current iJ1And 1-mode voltage u of DC line terminal Kk1And 1 mode current iK1；
Obtaining 1-mode wave impedance Zc1And 1 mould transmissionPropagation delay tau1；
According to the 1-mode wave impedance Zc1-mode propagation delay τ11-mode voltage u of starting end J of the direct current lineJ1And 1 mode current iJ1And 1-mode voltage u of the end K of the direct current linek1And 1 mode current iK1Obtain the traveling wave differential current of the 1 mode forward direction
Figure FDA0002313243720000011
Travelling wave difference current in reverse direction to 1 mode
Figure FDA0002313243720000012
Traveling wave differential current in the 1-mode forward direction
Figure FDA0002313243720000013
A traveling wave difference current in the direction opposite to the 1-mode
Figure FDA0002313243720000014
Taking the forward or backward traveling wave differential current as a reference standard, translating the traveling wave differential current in the other direction on a time axis to obtain the 1-mode forward traveling wave differential current
Figure FDA0002313243720000015
And the 1-mode reverse traveling wave differential current
Figure FDA0002313243720000016
The time difference Δ t at the maximum value of the Pearson correlation coefficient; wherein, Delta t is epsilon (-tau)1,τ1) (ii) a Wherein, the-tau is1The propagation delay when the fault occurs at the starting end J is shown; wherein, the value of τ is1Propagation delay when a fault occurs at the terminal K;
and substituting the time difference delta t into a formula that the traveling wave difference current serving as the reference standard is equal to the traveling wave difference current after the translation on the time axis so as to calculate the fault position.
2. The traveling wave differential current-based fault location method according to claim 1, wherein the traveling wave differential current in the 1-mode forward direction
Figure FDA0002313243720000017
A traveling wave difference current in the direction opposite to the 1-mode
Figure FDA0002313243720000018
Taking the forward or backward traveling wave differential current as a reference standard, translating the traveling wave differential current in the other direction on a time axis to obtain the 1-mode forward traveling wave differential current
Figure FDA0002313243720000019
And the 1-mode reverse traveling wave differential current
Figure FDA00023132437200000110
The time difference Δ t at the maximum value of the Pearson correlation coefficient includes:
selecting the time window after the fault as tst,tst+tw]The 1-mode reverse traveling wave differential current
Figure FDA00023132437200000111
As a reference standard; wherein, t isw≥2·τ1(ii) a Wherein, t isst≥tfault+τ1(ii) a Wherein, t isfaultThe time when the fault occurs; wherein, t isstSelecting a starting time for the redundancy window;
for a total time window of [ tst-τ1,tst+τ1+tw]The 1-mode forward traveling wave differential current
Figure FDA0002313243720000021
Translating backward by Δ t on the time axis; wherein, Delta t is epsilon (-tau)1,τ1)；
According to fault distance measuring letterObtaining the 1-mode forward traveling wave differential current
Figure FDA0002313243720000022
And the 1-mode reverse traveling wave differential current
Figure FDA0002313243720000023
The time difference Δ t at the maximum value of the Pearson correlation coefficient of (a); wherein the fault ranging function comprises:
Figure FDA0002313243720000024
wherein, Delta t is epsilon (-tau)1,τ1)；
Then said calculating a fault location from said time difference Δ t comprises:
according to the 1-mode forward traveling wave differential current
Figure FDA0002313243720000025
Equal to the 1-mode reverse traveling wave difference current
Figure FDA0002313243720000026
And calculating the fault position by the time difference delta t.
3. The traveling wave differential current-based fault location method according to claim 1, wherein the traveling wave differential current in the 1-mode forward direction
Figure FDA0002313243720000027
A traveling wave difference current in the direction opposite to the 1-mode
Figure FDA0002313243720000028
Taking the forward or backward traveling wave differential current as a reference standard, translating the traveling wave differential current in the other direction on a time axis to obtain the 1-mode forward traveling wave differential current
Figure FDA0002313243720000029
And the 1-mode reverse traveling wave differential current
Figure FDA00023132437200000210
The time difference Δ t at the maximum value of the Pearson correlation coefficient includes:
selecting the time window after the fault as tst,tst+tw]The 1-mode forward traveling wave differential current
Figure FDA00023132437200000211
As a reference standard; wherein, t isw≥2·τ1(ii) a Wherein, t isst≥tfault+τ1(ii) a Wherein, t isfaultThe time when the fault occurs; wherein, t isstSelecting a starting time for the redundancy window;
for a total time window of [ tst-τ1,tst+τ1+tw]The 1-mode reverse traveling wave differential current
Figure FDA00023132437200000212
Forward shifting on the time axis by Δ t; wherein, Delta t is epsilon (-tau)1,τ1)；
Obtaining the 1-mode reverse traveling wave differential current according to a fault location two function
Figure FDA0002313243720000031
And the 1-mode forward traveling wave differential current
Figure FDA0002313243720000032
The time difference Δ t at the maximum value of the Pearson correlation coefficient of (a); wherein the fault-ranging two-function comprises:
Figure FDA0002313243720000033
wherein, Delta t is epsilon (-tau)1,τ1)；
Then said calculating a fault location from said time difference Δ t comprises:
according to the 1-mode reverse traveling wave differential current
Figure FDA0002313243720000034
Equal to the 1-mode forward traveling wave difference current
Figure FDA0002313243720000035
And calculating the fault position by the time difference delta t.
4. The traveling wave differential current-based fault location method according to claim 1, wherein the 1-mode voltage u of the starting end J of the direct current line is obtainedJ1And 1 mode current iJiAnd 1-mode voltage u of terminal Kk1And 1 mode current iK1The method comprises the following steps:
obtaining the positive voltage u of the starting end J of the direct current lineJPNegative electrode voltage uJN；
Obtaining the positive current i of the starting end J of the direct current lineJPNegative electrode current iJN；
Obtaining the positive voltage u of the starting end K of the direct current lineKPNegative electrode voltage uKN；
Obtaining the positive current i of the starting end K of the direct current lineKPNegative electrode current iKN；
According to the decoupling matrix, the positive voltage u is alignedJPThe negative electrode voltage uJNThe positive electrode current iJPThe negative electrode current iJNThe positive electrode voltage uKPThe negative electrode voltage uKNThe positive electrode current iKPAnd the negative electrode current iKNDecoupling to obtain the 1-mode voltage uJ1The current iJ1The 1-mode voltage uk1And the 1-mode current iK1。
5. The traveling wave differential current-based fault location method according to claim 1, wherein the 1-mode wave impedance Z is obtainedc1And 1-mode propagation delay τ1The method comprises the following steps:
obtaining wave impedance Z according to the capacitance and the inductance of the direct current linecAnd a traveling wave propagation velocity v;
impedance Z of the wave according to a decoupling matrixcDecoupling to obtain the 1-mode wave impedance Zc1；
Decoupling the traveling wave propagation velocity v according to a decoupling matrix to obtain the 1-mode wave velocity v1；
According to the 1-mode wave velocity v1And the length of the direct current line is used for obtaining the 1 mode propagation delay tau1。
6. The traveling wave differential current-based fault location method according to claim 1, wherein the fault location method is based on the 1-mode wave impedance Zc1-mode propagation delay τ11-mode voltage u of starting end J of the direct current lineJ1And 1 mode current iJ1And 1-mode voltage u of the end K of the direct current linek1And 1 mode current iK1Obtaining 1-mode forward traveling wave differential current
Figure FDA0002313243720000041
And 1-mode reverse traveling wave differential current
Figure FDA0002313243720000042
The method comprises the following steps:
according to the 1-mode wave impedance ZcThe 1-mode voltage uJ1And the 1-mode current iJ1Obtaining 1-mode forward current traveling wave of the starting end J of the direct current line
Figure FDA0002313243720000043
And 1-mode reverse current traveling wave
Figure FDA0002313243720000044
According to the 1-mode wave impedance ZcThe 1-mode voltage uk1And the 1-mode current iK1Obtaining said end K of the flow line1-mode forward current traveling wave
Figure FDA0002313243720000045
And 1-mode reverse current traveling wave
Figure FDA0002313243720000046
According to the 1 mode propagation delay tau11-mode forward current traveling wave
Figure FDA0002313243720000047
And the 1-mode forward current traveling wave
Figure FDA0002313243720000048
Obtaining the 1-mode forward traveling wave differential current
Figure FDA0002313243720000049
And according to said 1-mode propagation delay tau11-mode forward current traveling wave
Figure FDA00023132437200000410
And the 1-mode forward current traveling wave
Figure FDA00023132437200000411
Obtaining the 1-mode reverse traveling wave differential current
Figure FDA00023132437200000412
7. The traveling wave differential current-based fault location method according to claim 6, wherein said propagation delay τ is according to said 1-mode11-mode forward current traveling wave
Figure FDA00023132437200000413
And the 1-mode forward current traveling wave
Figure FDA00023132437200000414
Obtaining the 1-mode forward traveling wave differential current
Figure FDA00023132437200000415
And according to said 1-mode propagation delay tau11-mode forward current traveling wave
Figure FDA00023132437200000416
And the 1-mode forward current traveling wave
Figure FDA00023132437200000417
Obtaining the 1-mode reverse traveling wave differential current
Figure FDA0002313243720000051
The method comprises the following steps:
Figure FDA0002313243720000052
8. the utility model provides a fault location device based on travelling wave difference current which characterized in that includes:
a voltage and current acquisition module for acquiring 1-mode voltage u of the starting end J of the DC lineJ1And 1 mode current iJ1And 1-mode voltage u of DC line terminal Kk1And 1 mode current iK1；
An impedance delay obtaining module for obtaining 1-mode wave impedance Zc1And 1-mode propagation delay τ1；
A traveling wave differential current acquisition module for acquiring the 1-mode wave impedance Zc1-mode propagation delay τ11-mode voltage u of starting end J of the direct current lineJ1And 1 mode current iJ1And 1-mode voltage u of the end K of the direct current linek1And 1 mode current iK1Obtain the traveling wave differential current of the 1 mode forward direction
Figure FDA0002313243720000053
Travelling wave in reverse direction to 1 modeDifferential current
Figure FDA0002313243720000054
A time difference acquisition module for obtaining the forward traveling wave difference current of the 1 mode
Figure FDA0002313243720000055
A traveling wave difference current in the direction opposite to the 1-mode
Figure FDA0002313243720000056
Taking the forward or backward traveling wave differential current as a reference standard, translating the traveling wave differential current in the other direction on a time axis to obtain the 1-mode forward traveling wave differential current
Figure FDA0002313243720000057
And the 1-mode reverse traveling wave differential current
Figure FDA0002313243720000058
The time difference Δ t at the maximum value of the Pearson correlation coefficient; wherein, Delta t is epsilon (-tau)1,τ1)；
And the fault position calculation module is used for substituting the time difference delta t into a formula that the traveling wave difference current serving as the reference standard is equal to the traveling wave difference current after the traveling wave difference current is translated on the time axis so as to calculate the fault position.
9. A fault-ranging device based on a travelling wave differential current, comprising a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, the processor implementing the fault-ranging method based on a travelling wave differential current according to any one of claims 1 to 7 when executing the computer program.
10. A computer-readable storage medium, comprising a stored computer program, wherein the computer program, when executed, controls an apparatus in which the computer-readable storage medium is located to perform the fault location method based on traveling wave differential current according to any one of claims 1 to 7.
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