CN114397531A - Single-phase earth fault area positioning method and system, storage medium and feeder terminal - Google Patents
Single-phase earth fault area positioning method and system, storage medium and feeder terminal Download PDFInfo
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Abstract
The invention discloses a single-phase earth fault section positioning method, a single-phase earth fault section positioning system, a storage medium and a feeder terminal, wherein the method comprises the following steps: starting zero-sequence voltage and zero-sequence current recording when the zero-sequence voltage amplitude of the distribution line is detected to exceed a preset voltage threshold value, and obtaining a first zero-sequence voltage waveform and a first zero-sequence current waveform; broadcasting a wave recording instruction and a wave recording starting time to a surrounding area, so that a transient wave recording type fault indicator linked with a feeder line terminal in the surrounding area sends a three-phase current wave recording waveform of a first preset time period after the wave recording starting time to the feeder line terminal when receiving the wave recording instruction; and when the duration time after the recording is started exceeds a preset time limit value, determining a single-phase earth fault section according to the first zero-sequence voltage waveform, the first zero-sequence current waveform and the received all three-phase current recording waveforms. The method can avoid environmental interference, reduce the communication burden of the power distribution main station and improve the accuracy of fault location.
Description
Technical Field
The invention relates to the technical field of power grids, in particular to a method and a system for positioning a single-phase earth fault area, a storage medium and a feeder terminal.
Background
With the rapid development of distribution automation and distributed power supplies, the positioning of the single-phase earth fault of the active power distribution network is more and more emphasized. In order to realize the positioning of a single-phase earth fault section of a power grid, a centralized feeder automation scheme and a state recording type fault indicator centralized positioning scheme are provided in the related art. However, the following problems exist in the related art:
(1) the investment of the centralized feeder automation scheme is large, the feeder terminal and the switch are installed together as complete equipment, the cost of the complete equipment is high, and power failure is needed in the installation process.
(2) Transient state record wave type fault indicator centralized positioning scheme, because transient state record wave type fault indicator judges rising and the decline of single-phase voltage through detecting the earth electric field, judge that the degree of accuracy is not high, easily receive environmental disturbance, record wave start threshold sets up the difficulty, and the threshold sets up lowly, will frequently record the wave, and the threshold sets up high, and sensitivity will worsen, and high resistance earth fault is difficult to start.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. To this end, a first object of the invention is to propose a single-phase earth fault section location method. The method can avoid environmental interference, reduce the communication burden of the automatic power distribution master station, improve the positioning accuracy of the single-phase earth fault and save the cost.
A second object of the invention is to propose a computer-readable storage medium.
A third object of the present invention is to provide a feeder terminal.
A fourth object of the present invention is to provide a single-phase earth fault section positioning system.
In order to achieve the above object, an embodiment of a first aspect of the present invention provides a method for positioning a single-phase ground fault section, including the following steps: starting zero-sequence voltage and zero-sequence current recording when the zero-sequence voltage amplitude of the distribution line is detected to exceed a preset voltage threshold value, and obtaining a first zero-sequence voltage waveform and a first zero-sequence current waveform; broadcasting a wave recording instruction and a wave recording starting time to a surrounding area, so that a transient wave recording type fault indicator linked with the feeder line terminal in the surrounding area sends a three-phase current wave recording waveform of a first preset time period after the wave recording starting time to the feeder line terminal when receiving the wave recording instruction; and when the duration time after the recording is started exceeds a preset time limit value, determining a single-phase earth fault section according to the first zero-sequence voltage waveform, the first zero-sequence current waveform and the received all three-phase current recording waveforms, wherein the time period corresponding to the preset time limit value is the first time period.
In addition, the single-phase earth fault section positioning method of the embodiment of the invention can also have the following additional technical characteristics:
according to an embodiment of the present invention, the determining a single-phase ground fault section according to the first zero-sequence voltage waveform, the first zero-sequence current waveform and the received all three-phase current recording waveforms includes: obtaining a plurality of corresponding second zero sequence current waveforms according to the three-phase current waveform of each transient recording type fault indicator; judging whether a first zero-sequence current amplitude corresponding to the first zero-sequence current waveform and second zero-sequence current amplitudes corresponding to the plurality of second zero-sequence current waveforms both exceed a preset current threshold value; and if the first zero-sequence current amplitude and the second zero-sequence current amplitude corresponding to the kth transient recording type fault indicator both exceed the preset current threshold, determining that the single-phase ground fault occurs in the area where the feeder terminal and the kth transient recording type fault indicator are located.
According to an embodiment of the present invention, after determining that a single-phase ground fault occurs in the area where the feeder terminal and the kth transient logging type fault indicator are located, the method further includes: carrying out differential filtering on the first zero-sequence voltage waveform by adopting a preset differential filter to obtain a first zero-sequence voltage differential filtering value; performing band-pass filtering on the first zero-sequence current waveform by using a preset band-pass filter to obtain a first zero-sequence current band-pass filtering value; calculating a first correlation coefficient between the first zero-sequence current band-pass filter value and the first zero-sequence voltage differential filter value; and if the first correlation coefficient is smaller than a first preset threshold value, judging that the single-phase earth fault occurs in a section behind the feeder line terminal.
According to an embodiment of the present invention, after determining that a single-phase ground fault occurs in the area where the feeder terminal and the kth transient logging type fault indicator are located, the method further includes: performing band-pass filtering on the second zero-sequence current waveform by using the preset band-pass filter to obtain a second zero-sequence current band-pass filtering value; calculating a second correlation coefficient between the second zero-sequence current band-pass filter value and the first zero-sequence voltage differential filter value; and if the second correlation number is smaller than a second preset threshold value, determining that the single-phase ground fault occurs in a section behind a kth transient recording type fault indicator, wherein k is a positive integer.
According to an embodiment of the invention, the second zero sequence current waveform is obtained by:
wherein, I0(n) is the zero sequence current value at the nth sampling instant, IA(n)、IB(n)、IC(n) are A, B, C three-phase current values at the nth sampling timing, respectively.
According to an embodiment of the invention, the first zero sequence voltage differential value is obtained by:
wherein h isD1For the predetermined differential filter, [ U ]0 FTU]D1(N) is the first zero sequence voltage differential value of the nth sampling moment, N is a positive integer, U0 FTUAnd (n) is the first zero sequence voltage value at the nth sampling moment.
According to an embodiment of the present invention, the first zero-sequence current band-pass filtered value is obtained by the following formula:
wherein h isBPFor the preset band pass filter, [ I ]0 FTU]BP(n) is a first zero-sequence current band-pass filter value at the nth sampling moment, I0 FTU(n) is a first zero sequence current value at the nth sampling moment; obtaining the second zero-sequence current band-pass filter value by the following formula:
wherein h isBPFor the preset band pass filter, [ I ]0 FI,k]BP(n) is a second zero-sequence current band-pass filter value at the nth sampling moment, I0 FI,kAnd (n) is the second zero sequence current value at the nth sampling moment.
According to an embodiment of the present invention, the first correlation coefficient is obtained by the following formula
Obtaining the second phase relation number by the following formula
Wherein [ U ]0 FTU]D1(n) is the first zero sequence voltage differential value at the nth sampling moment, [ I ]0 FTU]BP(n) is a first zero sequence current band-pass filter value at the nth sampling moment, [ I0 FI,k]BPAnd (N) is a second zero-sequence current band-pass filtering value at the nth sampling moment, and N is a positive integer.
According to an embodiment of the invention, the method further comprises: and sending the single-phase earth fault section to a distribution automation main station of the distribution line.
In order to achieve the above object, a second embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored, where the computer program is executed by a processor to implement the above-mentioned single-phase ground fault section locating method of the present invention.
In order to achieve the above object, a feeder terminal according to a third embodiment of the present invention includes a memory, a processor, and a computer program stored in the memory, where the computer program is executed by the processor to implement the above-mentioned single-phase ground fault section locating method.
In order to achieve the above object, a fourth aspect of the present invention provides a single-phase ground fault section positioning system, including: the feeder line terminal is used for starting zero sequence voltage and zero sequence current wave recording when the zero sequence voltage amplitude of the distribution line is detected to exceed a preset voltage threshold value, obtaining a first zero sequence voltage waveform and a first zero sequence current waveform, and broadcasting a wave recording instruction and a wave recording starting time to a surrounding area; the transient recording type fault indicator is linked with the feeder line terminal and is used for sending a three-phase current recording waveform of a first preset time period after the recording starting time to the feeder line terminal when the recording instruction is received; the feeder line terminal is further configured to determine a single-phase ground fault section according to the first zero-sequence voltage waveform, the first zero-sequence current waveform and the received all three-phase current wave-recording waveforms when the duration time after the recording is started exceeds a preset time limit, where a time period corresponding to the preset time limit is the first time period.
In addition, the single-phase earth fault section positioning system of the embodiment of the invention also has the following additional technical characteristics:
according to an embodiment of the present invention, when determining a single-phase ground fault section according to the first zero-sequence voltage waveform, the first zero-sequence current waveform and the received all three-phase current waveform, the feeder terminal is specifically configured to: obtaining a plurality of corresponding second zero sequence current waveforms according to the three-phase current waveform of each transient recording type fault indicator; judging whether a first zero-sequence current amplitude corresponding to the first zero-sequence current waveform and second zero-sequence current amplitudes corresponding to the plurality of second zero-sequence current waveforms both exceed a preset current threshold value; and if the first zero-sequence current amplitude and the second zero-sequence current amplitude corresponding to the kth transient recording type fault indicator both exceed the preset current threshold, determining that the single-phase ground fault occurs in the area where the feeder terminal and the kth transient recording type fault indicator are located, wherein k is a positive integer.
According to an embodiment of the present invention, after determining that a single-phase ground fault occurs in the area where the feeder terminal and the kth transient logging-type fault indicator are located, the feeder terminal is further configured to: carrying out differential filtering on the first zero-sequence voltage waveform by adopting a preset differential filter to obtain a first zero-sequence voltage differential filtering value; performing band-pass filtering on the first zero-sequence current waveform by using a preset band-pass filter to obtain a first zero-sequence current band-pass filtering value; calculating a first correlation coefficient between the first zero-sequence current band-pass filter value and the first zero-sequence voltage differential filter value; and if the first correlation coefficient is smaller than a first preset threshold value, judging that the single-phase earth fault occurs in a section behind the feeder line terminal.
According to an embodiment of the present invention, after determining that a single-phase ground fault occurs in the area where the feeder terminal and the kth transient logging-type fault indicator are located, the feeder terminal is further configured to: performing band-pass filtering on the second zero-sequence current waveform by using the preset band-pass filter to obtain a second zero-sequence current band-pass filtering value; calculating a second correlation coefficient between the second zero-sequence current band-pass filter value and the first zero-sequence voltage differential filter value; and if the second correlation number is smaller than a second preset threshold value, determining that the single-phase earth fault occurs in a section behind the kth transient recording type fault indicator.
According to an embodiment of the invention, the system further comprises a distribution automation master station, the feeder terminal is further configured to send the single-phase ground fault section to the distribution automation master station of the distribution line.
According to the single-phase earth fault area positioning method and system, the storage medium and the feeder terminal, the more accurate single-phase earth fault starting is realized through the zero-sequence voltage super-threshold value so as to avoid environmental interference, meanwhile, the transient recording type fault indicator only needs to upload three-phase current waveforms at a specified time to the nearby feeder terminal, the communication burden of the power distribution automation main station is reduced, and the single-phase earth fault positioning accuracy is improved through the linkage of the feeder terminal and the transient recording type fault indicator. In addition, the scheme can realize the positioning of the single-phase earth fault section without installing a switch and feeder terminal complete equipment, thereby saving the cost.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
Fig. 1 is a flow chart of a single-phase ground fault zone location method of an embodiment of the present invention;
FIG. 2 is a flowchart of step S103 of one embodiment of the present invention;
FIG. 3 is a flowchart of step S103 of another embodiment of the present invention;
figure 4 is a schematic diagram of a distribution line configuration according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a fault location of a particular embodiment of the present invention;
FIG. 6 is a schematic illustration of a fault location of another embodiment of the present invention;
FIG. 7 is a schematic diagram of a fault location of yet another embodiment of the present invention
Fig. 8 is a block diagram of a single-phase ground fault zone location system according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The following describes a single-phase ground fault area locating method, a single-phase ground fault area locating system, a single-phase ground fault area storage medium and a feeder terminal according to an embodiment of the present invention with reference to fig. 1 to 8 and a specific embodiment.
Fig. 1 is a flowchart of a single-phase ground fault area locating method according to an embodiment of the present invention.
In this embodiment, the main body of execution of the single-phase ground fault zone location method may be a feeder terminal. As shown in fig. 1, the method for locating a single-phase ground fault area specifically comprises the following steps:
s101, starting zero sequence voltage and zero sequence current recording to obtain a first zero sequence voltage waveform and a first zero sequence current waveform when detecting that the zero sequence voltage amplitude of the distribution line exceeds a preset voltage threshold.
The zero sequence voltage amplitude can be detected by a voltage transformer on a distribution line, the feeder line terminal can communicate with the voltage transformer to obtain the zero sequence voltage amplitude, and then whether the zero sequence voltage amplitude exceeds a preset voltage threshold value or not is judged, and the preset voltage threshold value can be calibrated as required.
And S102, broadcasting a wave recording instruction and a wave recording starting time to a surrounding area, so that when a transient wave recording type fault indicator linked with the feeder line terminal in the surrounding area receives the wave recording instruction, a three-phase current wave recording waveform of a first preset time period after the wave recording starting time is sent to the feeder line terminal.
Specifically, one or more transient recording type fault indicators linked with the feeder terminal can be arranged on a distribution line in the area around the feeder terminal in advance, and the feeder terminal can broadcast a recording instruction and a recording starting time to the surrounding area in a wireless broadcasting mode. And when the corresponding transient recording type fault indicator receives a recording instruction, the three-phase current recording waveform of a first preset time period after the recording starting moment is sent to the feeder line terminal. Wherein the first preset time period may be a shorter one time period, whereby transmission of unnecessary waveforms may be avoided.
S103, when the duration time after the recording is started exceeds a preset time limit value, determining a single-phase earth fault section according to the first zero-sequence voltage waveform, the first zero-sequence current waveform and the received all three-phase current recording waveforms, wherein the time period corresponding to the preset time limit value is the first time period.
According to the single-phase earth fault section positioning method, more accurate single-phase earth fault starting can be realized according to the condition that the zero sequence voltage amplitude exceeds the preset voltage threshold, environmental interference is avoided, and the wave recording starting accuracy of the transient wave recording type fault indicator is improved; the single-phase earth fault location is carried out through the linkage of the feeder terminal and the transient recording type fault indicator, the location accuracy can be improved, a large number of switches and feeder terminal complete equipment do not need to be installed, and the cost is low.
Fig. 2 is a flowchart of step S103 according to an embodiment of the present invention.
Referring to fig. 2, determining a single-phase ground fault section according to the first zero-sequence voltage waveform, the first zero-sequence current waveform and the received all three-phase current recording waveforms may include the following steps:
and S201, obtaining a plurality of corresponding second zero sequence current waveforms according to the three-phase current recording waveforms of the transient recording type fault indicators.
Specifically, the second zero-sequence current waveform can be obtained by the following formula:
wherein, I0(n) is the zero sequence current value at the nth sampling instant, IA(n)、IB(n)、IC(n) are A, B, C three-phase current values at the nth sampling timing, respectively.
S202, whether a first zero-sequence current amplitude corresponding to the first zero-sequence current waveform and second zero-sequence current amplitudes corresponding to the plurality of second zero-sequence current waveforms exceed a preset current threshold value is judged.
And S203, if the first zero-sequence current amplitude and the second zero-sequence current amplitude corresponding to the kth transient recording type fault indicator both exceed a preset current threshold, determining that the single-phase ground fault occurs in the area where the feeder terminal and the kth transient recording type fault indicator are located, wherein k is a positive integer.
Fig. 3 is a flowchart of step S103 according to another embodiment of the present invention.
Specifically, referring to fig. 3, after it is determined that the single-phase ground fault occurs in the feeder terminal and the area where the kth transient recording type fault indicator is located, the centralized analysis of the area where the single-phase ground fault is located includes the following steps:
s301, differential filtering is carried out on the first zero-sequence voltage waveform by adopting a preset differential filter, and a first zero-sequence voltage differential filtering value is obtained.
Specifically, the first zero sequence voltage differential value may be obtained by:
wherein h isD1For presetting a differential filter, [ U ]0 FTU]D1(N) is the first zero sequence voltage differential value of the nth sampling moment, N is a positive integer, U0 FTUAnd (n) is the first zero sequence voltage value at the nth sampling moment.
And S302, respectively carrying out band-pass filtering on the first zero-sequence current waveform and the second zero-sequence current waveform by adopting a preset band-pass filter to obtain a first zero-sequence current band-pass filtering value and a second zero-sequence current band-pass filtering value.
Specifically, the first zero-sequence current band-pass filter value may be obtained by the following formula:
wherein h isBPFor presetting the band pass filter, [ I ]0 FTU]BP(n) is a first zero-sequence current band-pass filter value at the nth sampling moment, I0 FTUAnd (n) is the first zero sequence current value at the nth sampling moment.
The second zero-sequence current band-pass filter value can be obtained by the following formula:
wherein [ I ]0 FI,k]BP(n) is a second zero-sequence current band-pass filter value at the nth sampling moment, I0 FI,kAnd (n) is the second zero sequence current value at the nth sampling moment.
S303, respectively calculating a first correlation coefficient between the first zero-sequence current band-pass filter value and the first zero-sequence voltage differential filter value and a second correlation coefficient between the second zero-sequence current band-pass filter value and the first zero-sequence voltage differential filter value.
Specifically, the first correlation coefficient may be obtained by the following formula
The second phase relation number can be obtained by the following formula
S304, if the first correlation coefficient is smaller than a first preset threshold value, determining that the single-phase earth fault occurs in a section behind the feeder line terminal; and if the second correlation number is smaller than a second preset threshold value, determining that the single-phase earth fault occurs in a section behind the kth transient recording type fault indicator.
The first preset threshold may be equal to the second preset threshold, such as 0.
In some embodiments of the invention, after determining a single-phase ground fault section, the single-phase ground fault section may be sent to a distribution automation master station. Therefore, the segment positioning result is only required to be uploaded to the distribution automation main station, a large number of waveforms are not required to be uploaded, and unnecessary data transmission is avoided.
For ease of understanding, the single-phase ground fault section locating method of the present invention is described below with reference to fig. 4-7 by a specific embodiment:
referring to fig. 4, the line structure of the distribution line includes 1 feeder terminal 400 and 6 transient recording type fault indicators 401 and 406.
Current flows in from the position of the transient recording type fault indicator 401, and is divided into two branches at the position of the feeder terminal 400, one branch flows through the positions of the transient recording type fault indicators 402 and 403 and flows out from the position of the transient recording type fault indicator 403, the other branch flows through the position of the transient recording type fault indicator 404 and is divided into two branches again at the position, one branch flows through the position of the transient recording type fault indicator 405 and flows out from the position, and the other branch flows through the position of the transient recording type fault indicator 406 and flows out from the position. The specific steps of the fault section are as follows:
(1) when the feeder terminal 400 detects that the zero sequence voltage exceeds the threshold value, the zero sequence voltage and the zero sequence current of the feeder terminal are recorded, and a wave recording starting command and a wave recording starting moment are issued to the transient wave recording type fault indicator 401 in a wireless broadcasting mode to supplement 406;
(2) after receiving the wave recording instruction, the transient wave recording type fault indicator 401 and 406 sends the three-phase current waveform of the specified time period (i.e. the first preset time period after the wave recording starting time) to the feeder terminal 400;
(3) the feeder terminal 400 starts timing after starting wave recording, and determines a wave recording waveform to be subjected to centralized analysis in a self wave recording waveform and a collected transient wave recording type fault indicator 401 and 406 wave recording waveform after the time exceeds a limit value (namely the time corresponding to a first preset time period);
it should be noted that, if the wave recording time of the feeder terminal exceeds the limit value, redundancy exists in the wave recording waveform of the feeder terminal itself and/or the wave recording waveform of the received transient wave recording type fault indicator, the feeder terminal may screen out a waveform of a certain time period after the start of the wave recording from the wave recording waveform of the feeder terminal itself and the received wave recording waveform, and perform centralized analysis, where the certain time period may be less than or equal to a first preset time period.
(4) The specific process of the centralized analysis is as follows:
(a) the feeder terminal 400 calculates the zero-sequence current of the transient recording type fault indicator 401 and 406, and judges whether the zero-sequence current of the transient recording type fault indicator 401 and 406 and the zero-sequence current of the feeder terminal 400 exceed a preset current threshold value, if so, the situation that the single-phase ground fault possibly occurs in the area where the feeder terminal 400 and the transient recording type fault indicator 401 and 406 linked with the feeder terminal are located is described;
(b) calculating a zero sequence voltage differential of the feeder terminal 400;
(c) calculating the band-pass filtering values of the zero-sequence currents of the feeder terminal 400 and the transient recording type fault indicator 401 and 406;
(d) calculating a correlation coefficient between the zero sequence voltage differential of the feeder terminal 400 and the band-pass filtering result of the zero sequence current of the feeder terminal 400 and the transient recording type fault indicator 401 and 406;
(e) a correlation coefficient less than a preset threshold, e.g., 0, indicates that the fault point is downstream of the device, and a correlation coefficient greater than a preset threshold, e.g., 0, indicates that the fault point is upstream of the device.
As a possible implementation manner, if the correlation coefficients between the zero-sequence voltage differentials of the feeder terminal 400 and the transient waveform-recording type fault indicators 401 and 406 are all greater than the preset threshold value as a result of band-pass filtering of the zero-sequence currents of the feeder terminal 400 and the transient waveform-recording type fault indicators 406, it indicates that the single-phase ground fault is on the upstream line of the location where the transient waveform-recording type fault indicator 401 is located, as shown in fig. 5.
As a possible implementation, if only the band-pass filtering results of the zero-sequence currents of the feeder terminal 400 and the transient waveform-recording type fault indicators 401, 402, and 403 have correlation coefficients with the zero-sequence voltage differential of the feeder terminal 400 smaller than a threshold, it indicates that the single-phase ground fault is on the line behind the transient waveform-recording type fault indicator 403, as shown in fig. 6.
As a possible implementation, if only the band-pass filtering results of the zero-sequence currents of the feeder terminal 400 and the transient waveform-recording type fault indicator 401 are all smaller than the threshold value, it indicates that the single-phase ground fault exists in two possible fault sections behind the feeder terminal 400, one fault section is a line between the feeder terminal 400 and the transient waveform-recording type fault indicator 402, and the other fault section is a line between the feeder terminal 400 and the transient waveform-recording type fault indicator 404, as shown in fig. 7.
To sum up, according to the single-phase ground fault area positioning method of the embodiment of the present invention, the feeder terminal starts the wave recording of the zero sequence voltage and the zero sequence current of the feeder terminal according to the zero sequence voltage overrun, and simultaneously issues a wave recording instruction to the linked transient wave recording type fault indicator, the transient wave recording type fault indicator sends the A, B, C three-phase current wave recording waveform at a specified time to the linked feeder terminal, the feeder terminal performs centralized analysis on the wave recording waveforms to determine whether the single-phase ground fault is in the area of the feeder terminal and the linked transient wave recording type fault indicator, and if so, the feeder terminal reports the fault section to the power distribution automation main station. The technical scheme not only exerts the characteristics that the single-phase earth fault recording can be accurately started by the feeder line terminal according to the zero sequence voltage, but also exerts the characteristics that the transient recording type fault indicator is low in cost and convenient to install, can fully exert the respective advantages of the feeder line terminal and the transient recording type fault indicator, can further reduce a single-phase earth fault positioning section, and realizes more accurate single-phase earth fault section positioning.
Further, the present invention proposes a computer-readable storage medium.
In the embodiment of the present invention, a computer program is stored on a computer readable storage medium, and when the computer program is executed by a processor, the method for locating a single-phase earth fault section is implemented.
The invention also provides a feeder terminal, which comprises a memory, a processor and a computer program stored on the computer readable storage medium, wherein when the computer program is executed by the processor, the single-phase earth fault section positioning method is realized.
Fig. 8 is a block diagram of a single-phase ground fault section positioning system according to an embodiment of the present invention.
As shown in fig. 8, the single-phase ground fault section positioning system 800 includes: feeder terminal 810 and feeder terminal linkage's transient state record wave type fault indicator 820, the quantity of transient state record wave type fault indicator 820 can be one or more.
The feeder terminal 810 is configured to start the recording of the zero-sequence voltage and the zero-sequence current when detecting that the zero-sequence voltage amplitude of the distribution line exceeds a preset voltage threshold, obtain a first zero-sequence voltage waveform and a first zero-sequence current waveform, and broadcast a recording instruction and a recording start time to a surrounding area. The transient recording type fault indicator 820 linked with the feeder line terminal is used for sending the three-phase current recording waveform of a first preset time period after the recording starting time to the feeder line terminal when receiving the recording instruction. The feeder line terminal 810 is further configured to determine a single-phase ground fault section according to the first zero-sequence voltage waveform, the first zero-sequence current waveform and the received all three-phase current recording waveforms when the duration after the recording is started exceeds a preset time limit, where a time period corresponding to the preset time limit is a first time period.
Specifically, the feeder terminal 810 may be specifically configured to, when determining the single-phase ground fault section according to the first zero-sequence voltage waveform, the first zero-sequence current waveform, and the received all three-phase current waveform,: obtaining a plurality of corresponding second zero-sequence current waveforms according to the three-phase current waveform of each transient waveform recording type fault indicator 820; judging whether a first zero-sequence current amplitude corresponding to the first zero-sequence current waveform and second zero-sequence current amplitudes corresponding to the plurality of second zero-sequence current waveforms all exceed a preset current threshold value; and if the first zero-sequence current amplitude and the second zero-sequence current amplitude corresponding to the kth transient state waveform recording type fault indicator both exceed a preset current threshold value, determining that the single-phase ground fault occurs in the area where the feeder line terminal and the kth transient state waveform recording type fault indicator 820 are located, wherein k is a positive integer.
In this embodiment, the second zero-sequence current waveform may be obtained by the following formula:
wherein, I0(n) is the zero sequence current value at the nth sampling instant, IA(n)、IB(n)、IC(n) are A, B, C three-phase current values at the nth sampling timing, respectively.
Further, after determining that the single-phase ground fault occurs in the area where the feeder terminal 810 and the kth transient recording type fault indicator 820 are located, the feeder terminal 810 is further configured to: carrying out differential filtering on the first zero-sequence voltage waveform by adopting a preset differential filter to obtain a first zero-sequence voltage differential filtering value; respectively carrying out band-pass filtering on the first zero-sequence current waveform and the second zero-sequence current waveform by adopting a preset band-pass filter to obtain a first zero-sequence current band-pass filtering value and a second zero-sequence current band-pass filtering value; respectively calculating a first correlation coefficient between the first zero-sequence current band-pass filter value and the first zero-sequence voltage differential filter value and a second correlation coefficient between the second zero-sequence current band-pass filter value and the first zero-sequence voltage differential filter value; and if the first correlation coefficient is smaller than a first preset threshold value, determining that the single-phase ground fault occurs in a section behind the feeder terminal 810, and if the second correlation coefficient is smaller than a second preset threshold value, determining that the single-phase ground fault occurs in a section behind the k-th transient recording type fault indicator 820.
Wherein the first zero sequence voltage differential value may be obtained by:
wherein h isD1For presetting a differential filter, [ U ]0 FTU]D1When (n) is the nth sampleFirst differential value of zero sequence voltage, N is positive integer, U0 FTUAnd (n) is the first zero sequence voltage value at the nth sampling moment.
The first zero-sequence current band-pass filter value can be obtained by the following formula:
wherein h isBPFor presetting the band pass filter, [ I ]0 FTU]BP(n) is a first zero-sequence current band-pass filter value at the nth sampling moment, I0 FTUAnd (n) is the first zero sequence current value at the nth sampling moment.
The second zero-sequence current band-pass filter value can be obtained by the following formula:
wherein [ I ]0 FI,k]BP(n) is a second zero-sequence current band-pass filter value at the nth sampling moment, I0 FI,kAnd (n) is the second zero sequence current value at the nth sampling moment.
The first correlation coefficient can be obtained by
The second phase relation number can be obtained by the following formula
The feeder terminal 810 may also be used to transmit single phase ground fault sections to a distribution automation master station.
It should be noted that, for other specific implementations of the single-phase ground fault section positioning system according to the embodiment of the present invention, reference may be made to the specific implementation of the single-phase ground fault section positioning method according to the above-mentioned embodiment of the present invention.
In summary, the single-phase ground fault section positioning system of the embodiment of the invention not only exerts the characteristics that the feeder terminal can realize accurate start of single-phase ground fault recording according to zero sequence voltage, but also exerts the characteristics that the transient recording type fault indicator is low in cost and convenient to install, can fully exert the respective advantages of the feeder terminal and the transient recording type fault indicator, can further reduce the single-phase ground fault positioning section, and realizes more accurate single-phase ground fault section positioning.
It should be noted that the logic and/or steps represented in the flowcharts or otherwise described herein, such as an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.
It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (16)
1. A single-phase earth fault section location method, wherein the method is applied to a feeder terminal, and the method comprises the following steps:
starting zero-sequence voltage and zero-sequence current recording when the zero-sequence voltage amplitude of the distribution line is detected to exceed a preset voltage threshold value, and obtaining a first zero-sequence voltage waveform and a first zero-sequence current waveform;
broadcasting a wave recording instruction and a wave recording starting time to a surrounding area, so that a transient wave recording type fault indicator linked with the feeder line terminal in the surrounding area sends a three-phase current wave recording waveform of a first preset time period after the wave recording starting time to the feeder line terminal when receiving the wave recording instruction;
and when the duration time after the recording is started exceeds a preset time limit value, determining a single-phase earth fault section according to the first zero-sequence voltage waveform, the first zero-sequence current waveform and the received all three-phase current recording waveforms, wherein the time period corresponding to the preset time limit value is the first preset time period.
2. The method of claim 1, wherein the determining a single-phase ground fault section from the first zero-sequence voltage waveform, the first zero-sequence current waveform, and the received all three-phase current waveform records comprises:
obtaining a plurality of corresponding second zero sequence current waveforms according to the three-phase current waveform of each transient recording type fault indicator;
judging whether a first zero-sequence current amplitude corresponding to the first zero-sequence current waveform and second zero-sequence current amplitudes corresponding to the plurality of second zero-sequence current waveforms both exceed a preset current threshold value;
and if the first zero-sequence current amplitude and the second zero-sequence current amplitude corresponding to the kth transient recording type fault indicator both exceed the preset current threshold, determining that the single-phase ground fault occurs in the area where the feeder terminal and the kth transient recording type fault indicator are located, wherein k is a positive integer.
3. The single-phase ground fault section locating method of claim 2, wherein after determining that a single-phase ground fault occurs in the area where the feeder terminal and the kth transient logging-type fault indicator are located, further comprising:
carrying out differential filtering on the first zero-sequence voltage waveform by adopting a preset differential filter to obtain a first zero-sequence voltage differential filtering value;
performing band-pass filtering on the first zero-sequence current waveform by using a preset band-pass filter to obtain a first zero-sequence current band-pass filtering value;
calculating a first correlation coefficient between the first zero-sequence current band-pass filter value and the first zero-sequence voltage differential filter value;
and if the first correlation coefficient is smaller than a first preset threshold value, judging that the single-phase earth fault occurs in a section behind the feeder line terminal.
4. The single-phase ground fault section locating method of claim 3, wherein after determining that a single-phase ground fault occurs in the area where the feeder terminal and the kth transient logging-type fault indicator are located, further comprising:
performing band-pass filtering on the second zero-sequence current waveform by using the preset band-pass filter to obtain a second zero-sequence current band-pass filtering value;
calculating a second correlation coefficient between the second zero-sequence current band-pass filter value and the first zero-sequence voltage differential filter value;
and if the second correlation number is smaller than a second preset threshold value, determining that the single-phase earth fault occurs in a section behind the kth transient recording type fault indicator.
5. The single-phase ground fault section locating method according to claim 2, wherein the second zero-sequence current waveform is obtained by:
wherein, I0(n) is the zero sequence current value at the nth sampling instant, IA(n)、IB(n)、IC(n) are A, B, C three-phase current values at the nth sampling timing, respectively.
6. The single-phase ground fault section locating method according to claim 4, characterized in that the first zero sequence voltage differential value is obtained by:
wherein h isD1For the predetermined differential filter, [ U ]0 FTU]D1(N) is the first zero sequence voltage differential value of the nth sampling moment, N is a positive integer, U0 FTUAnd (n) is the first zero sequence voltage value at the nth sampling moment.
7. The single-phase ground fault section locating method of claim 4,
obtaining the first zero-sequence current band-pass filter value by the following formula:
wherein h isBPFor the preset band pass filter, [ I ]0 FTU]BP(n) is a first zero-sequence current band-pass filter value at the nth sampling moment, I0 FTU(n) is a first zero sequence current value at the nth sampling moment;
obtaining the second zero-sequence current band-pass filter value by the following formula:
wherein h isBPFor the preset band pass filter, [ I ]0 FI,k]BP(n) is a second zero-sequence current band-pass filter value at the nth sampling moment, I0 FI,kAnd (n) is the second zero sequence current value at the nth sampling moment.
8. The single-phase ground fault section locating method of claim 4,
obtaining the first correlation coefficient by the following formula
Obtaining the second phase relation number by the following formula
Wherein [ U ]0 FTU]D1(n) is the first zero sequence voltage differential value at the nth sampling moment, [ I ]0 FTU]BP(n) is a first zero sequence current band-pass filter value at the nth sampling moment, [ I0 FI,k]BPAnd (N) is a second zero-sequence current band-pass filtering value at the nth sampling moment, and N is a positive integer.
9. The single-phase ground fault section locating method according to any one of claims 1 to 8, characterized in that the method further comprises:
and sending the single-phase earth fault section to a distribution automation main station of the distribution line.
10. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out a single-phase earth-fault segment localization method according to any one of claims 1-9.
11. A feeder terminal comprising a memory, a processor and a computer program stored on the memory, wherein the computer program, when executed by the processor, implements a single phase earth fault section location method as claimed in any one of claims 1 to 9.
12. A single-phase ground fault zone location system, the system comprising:
the feeder line terminal is used for starting zero sequence voltage and zero sequence current wave recording when the zero sequence voltage amplitude of the distribution line is detected to exceed a preset voltage threshold value, obtaining a first zero sequence voltage waveform and a first zero sequence current waveform, and broadcasting a wave recording instruction and a wave recording starting time to a surrounding area;
the transient recording type fault indicator is linked with the feeder line terminal and is used for sending a three-phase current recording waveform of a first preset time period after the recording starting time to the feeder line terminal when the recording instruction is received;
the feeder line terminal is further configured to determine a single-phase ground fault section according to the first zero-sequence voltage waveform, the first zero-sequence current waveform and the received all three-phase current wave-recording waveforms when the duration time after the recording is started exceeds a preset time limit, where a time period corresponding to the preset time limit is the first time period.
13. The single-phase ground fault section location system of claim 12, wherein the feeder terminal, when determining a single-phase ground fault section based on the first zero-sequence voltage waveform, the first zero-sequence current waveform, and the received all three-phase current waveform records, is specifically configured to:
obtaining a plurality of corresponding second zero sequence current waveforms according to the three-phase current waveform of each transient recording type fault indicator;
judging whether a first zero-sequence current amplitude corresponding to the first zero-sequence current waveform and second zero-sequence current amplitudes corresponding to the plurality of second zero-sequence current waveforms both exceed a preset current threshold value;
and if the first zero-sequence current amplitude and the second zero-sequence current amplitude corresponding to the kth transient recording type fault indicator both exceed the preset current threshold, determining that the single-phase ground fault occurs in the area where the feeder terminal and the kth transient recording type fault indicator are located, wherein k is a positive integer.
14. The single-phase ground fault section location system of claim 13, wherein the feeder terminal, after determining that a single-phase ground fault occurred in the area in which the feeder terminal and the kth transient fault-logging indicator are located, is further configured to:
carrying out differential filtering on the first zero-sequence voltage waveform by adopting a preset differential filter to obtain a first zero-sequence voltage differential filtering value;
performing band-pass filtering on the first zero-sequence current waveform by using a preset band-pass filter to obtain a first zero-sequence current band-pass filtering value;
calculating a first correlation coefficient between the first zero-sequence current band-pass filter value and the first zero-sequence voltage differential filter value;
and if the first correlation coefficient is smaller than a first preset threshold value, judging that the single-phase earth fault occurs in a section behind the feeder line terminal.
15. The single-phase ground fault section location system of claim 14, wherein the feeder terminal, after determining that a single-phase ground fault occurred in the area in which the feeder terminal and the kth transient fault-logging indicator are located, is further configured to:
performing band-pass filtering on the second zero-sequence current waveform by using the preset band-pass filter to obtain a second zero-sequence current band-pass filtering value;
calculating a second correlation coefficient between the second zero-sequence current band-pass filter value and the first zero-sequence voltage differential filter value;
and if the second correlation number is smaller than a second preset threshold value, determining that the single-phase earth fault occurs in a section behind the kth transient recording type fault indicator.
16. The single-phase ground fault section location system of any one of claims 12-15, further comprising a distribution automation master station,
and the feeder terminal is also used for sending the single-phase earth fault section to a distribution automation main station of the distribution line.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116008731A (en) * | 2023-02-15 | 2023-04-25 | 重庆大学 | Power distribution network high-resistance fault identification method and device and electronic equipment |
| CN117233542A (en) * | 2023-11-15 | 2023-12-15 | 武汉格蓝若智能技术股份有限公司 | Power distribution network single-phase earth fault section positioning method and system |
| CN117554753A (en) * | 2024-01-09 | 2024-02-13 | 山东大学 | Single-phase earth fault location method based on zero sequence voltage and current and terminal |
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2021
- 2021-12-07 CN CN202111484003.3A patent/CN114397531A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116008731A (en) * | 2023-02-15 | 2023-04-25 | 重庆大学 | Power distribution network high-resistance fault identification method and device and electronic equipment |
| CN116008731B (en) * | 2023-02-15 | 2023-08-25 | 重庆大学 | Power distribution network high-resistance fault identification method and device and electronic equipment |
| CN117233542A (en) * | 2023-11-15 | 2023-12-15 | 武汉格蓝若智能技术股份有限公司 | Power distribution network single-phase earth fault section positioning method and system |
| CN117233542B (en) * | 2023-11-15 | 2024-02-20 | 武汉格蓝若智能技术股份有限公司 | Power distribution network single-phase earth fault section positioning method and system |
| CN117554753A (en) * | 2024-01-09 | 2024-02-13 | 山东大学 | Single-phase earth fault location method based on zero sequence voltage and current and terminal |
| CN117554753B (en) * | 2024-01-09 | 2024-04-12 | 山东大学 | Single-phase earth fault location method based on zero sequence voltage and current and terminal |
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