Traveling wave-based single-ended data transmission line fault positioning method, medium and equipment

Abstract

The invention provides a traveling wave-based single-end data transmission line fault positioning method, a medium and equipment, and relates to the technical field of data transmission line fault identification and localization, and the method comprises the steps: measuring a current signal at a first bus end, carrying out the filtering and mode decomposition of the current signal, and extracting a traveling wave; calculating the wave-front arrival time of the traveling wave; calculating a first fault distance and a second fault distance; if the first fault distance and the second fault distance are close to the midpoint of the transmission line, determining that the fault distance is an average value of the first fault distance and the second fault distance; otherwise, comparing which one of the wave-front arrival time of the third traveling wave when the fault is in the first half section of the line and the wave-front arrival time of the third traveling wave when the fault is in the second half section of the line is closer to the actually recorded wave-front arrival time of the third traveling wave, and determining the fault distance as the first fault distance if the former is closer to the actually recorded wave-front arrival time of the third traveling wave; and if the first fault distance is closer, determining the fault distance as a second fault distance. According to the method, the fault of the data transmission line can be simply, conveniently and accurately positioned.

Description

Technical Field

[0001] The present invention relates to the technical field of data transmission line fault identification and positioning, and in particular to a single-ended data transmission line fault positioning method, medium and equipment based on traveling waves. Background Art

[0002] Transmission line faults are caused by severe weather conditions such as hurricanes, heavy snow, insulator failure, natural insulation breakdown, and fallen trees on overhead lines. While transient faults can be cleared by themselves, permanent faults require service teams to identify and replace damaged components before power can be restored. Transmission line fault location identification and rapid restoration are important tasks for transmission system operators and maintenance personnel. To this end, accurate fault locations must be determined, otherwise the inspection of high-voltage long transmission lines will become tedious and time-consuming. Traveling wave-based fault location methods are becoming increasingly important to alleviate the shortcomings of power frequency-based methods. The performance of traveling wave-based fault location methods depends only on the accurate detection of wavefront arrival time, sampling frequency, and time synchronization. With new developments in signal processing and data acquisition systems, traveling wave-based fault location methods are potential alternatives when higher fault location accuracy is required. As an alternative to communication-based traveling wave methods, transmission system operators prefer single-ended methods and basic phasor techniques. These methods all use single-ended traveling wave information for fault location, without any communication and GPS signals. Although these algorithms are relatively economical and easy to deploy, they all have the problem of identifying the second traveling wave front source, that is, whether it is reflected from the fault location or from the remote impedance discontinuity of the line. To overcome these problems, combined impedance and traveling wave based methods are proposed, in which the fault half section identification uses a single-ended impedance based method and therefore has the same limitations. For AI-based methods to identify the fault half section, although AI / ML (Artificial Intelligence / Machine Learning) has made great progress in recent research work and practical applications, they face some problems when applied to power system protection and fault location problems. The lack of rich real data and the reliance on simulated data lead to non-coverage issues. Summary of the invention

[0003] The purpose of the present invention is to provide a single-ended data transmission line fault location method, medium and device based on traveling waves, aiming to simply and accurately locate the fault of the data transmission line. The specific technical solution is as follows:

[0004] A single-ended data transmission line fault location method based on traveling waves, the method comprising the following steps:

[0005] S100, when a fault occurs in a transmission line between the first bus and the second bus, measuring a current signal at an end of the first bus, filtering and pattern decomposing the current signal, and extracting a traveling wave;

[0006] S200, calculating the arrival time of the traveling wave front;

[0007] S300, calculating, according to the first and second traveling wave front arrival times measured by the fault locator on the first bus, a first fault distance when the fault is located on the transmission line in the first half from the first bus, and a second fault distance when the fault is located on the transmission line in the second half from the first bus;

[0008] S400. If the first fault distance and the second fault distance are close to the midpoint of the transmission line, the fault distance is determined to be the average of the first fault distance and the second fault distance; otherwise, the third line wave front arrival time when the fault is in the first half of the line and the third line wave front arrival time when the fault is in the second half of the line are compared to see which one is closer to the actually recorded third line wave front arrival time. If the former is closer, the fault distance is determined to be the first fault distance, and if the latter is closer, the fault distance is determined to be the second fault distance.

[0009] Furthermore, in step S100, a bandpass filter is used to filter out the traveling wave, and then Clarke transformation is used to decompose the phase current into a ground mode of phase a and two air modes α and β to extract the traveling wave.

[0010] Further, the step S200 specifically includes the following steps: squaring the traveling wave signal and detecting the positive and negative traveling wave fronts; using a smoother to reduce waveform distortion; using a parabola best fit interpolation method, selecting three adjacent data points with large changes from the frontier interval of the signal, and using these three data points to fit a quadratic parabola model by the least squares method, the fitting function is: y(t)=at 2 +bt+c, where a, b, c are fitting parameters, t is time, y(t) is signal amplitude, and the frontier moment of the traveling wave is calculated by the vertex position of the parabola. The vertex coordinate formula is where tvertex is the arrival time of the traveling wave front.

[0011] Furthermore, in step S300, the calculation formula of the first fault distance is as follows:

[0012]

[0013] The calculation formula of the second fault distance is as follows:

[0014]

[0015] Among them, d 1 is the first fault distance, d2 is the second fault distance, t A1 and t A2 are the first and second traveling wave front arrival times measured by the fault locator at the first bus, l is the total length of the transmission line, and V is the propagation speed of the traveling wave on the line.

[0016] Furthermore, in step S400, if the absolute difference between the first fault distance and the second fault distance is less than 600 m, it is determined that the first fault distance and the second fault distance are close to the midpoint of the transmission line, and the fault distance is an average value of the first fault distance and the second fault distance.

[0017] Furthermore, in step S400, when the fault is in the first half of the line, the calculation formula for the arrival time of the third wave front is as follows:

[0018]

[0019] When the fault is in the second half of the line, the calculation formula for the arrival time of the third wave front is as follows:

[0020]

[0021] in, is the arrival time of the third wavefront when the fault is in the first half of the line, d_3rdwavefront_first is the distance corresponding to the arrival time of the third wavefront when the fault is in the first half of the line, is the arrival time of the third wavefront when the fault is in the second half of the line, and d_3rdwavefront_seond is the distance corresponding to the arrival time of the third wavefront when the fault is in the second half of the line.

[0022] Furthermore, if Then d = d 1 ,like Then d = d 2 , if none of them are satisfied, there is no fault; among them, is the arrival time of the third wave front actually recorded by the fault locator at the first busbar, ∈ is the comparison threshold, d is the fault distance, d 1 is the first fault distance, d 2 is the second fault distance.

[0023] Furthermore, the current signal sampling frequency is 1 MHz, and the comparison threshold ∈ is 2 μs.

[0024] The present invention also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the single-ended data transmission line fault location method based on traveling waves as described above are implemented.

[0025] The present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the single-ended data transmission line fault location method based on traveling waves as described above are implemented.

[0026] The present invention provides a single-ended data transmission line fault location method, medium and device based on traveling waves, which have the following beneficial effects:

[0027] (1) The present invention provides a single-ended data transmission line fault location method, medium and device based on traveling waves. When a fault occurs in a transmission line between a first bus and a second bus, a current signal is measured at the first bus end, and the current signal is filtered and pattern-decomposed to extract the traveling wave; the traveling wave front arrival time is calculated; based on the first and second traveling wave front arrival times measured by the fault locator at the first bus, a first fault distance when the fault is located in the front half of the transmission line from the first bus and a second fault distance when the fault is located in the rear half of the transmission line from the first bus are calculated respectively; if the first fault distance and the second fault distance are If the distance is close to the midpoint of the transmission line, the fault distance is determined to be the average of the first fault distance and the second fault distance; otherwise, the third traveling wave front arrival time when the fault is in the first half of the line and the third traveling wave front arrival time when the fault is in the second half of the line are compared to see which one is closer to the actually recorded third traveling wave front arrival time. If the former is closer, the fault distance is determined to be the first fault distance, and if the latter is closer, the fault distance is determined to be the second fault distance. Single-ended fault location based purely on traveling waves can be achieved without the need for phasor and impedance calculations. It only needs to use the measured time-domain current signal for simple algebraic calculations to obtain accurate fault location.

[0028] (2) This method has good accuracy for different fault intensities, fault types, fault resistances and fault starting angles.

[0029] (3) This technology can be implemented in intelligent electronic devices with a minimum sampling rate of 1 MHz to achieve fault location accuracy over the span of two towers.

[0030] (4) This technology does not require any communication infrastructure and field experiments to compensate for the processing delays introduced by various components of the IED and measurement systems, and is suitable for actual deployment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic flow chart of a single-ended data transmission line fault location method based on traveling waves provided by the present invention;

[0032] Figure 2 is an overall flow chart of an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the transmission line when the fault is in the first half of the line;

[0034] Figure 4 This is a schematic diagram of the transmission line when the fault is in the second half of the line;

[0035] Figure 5 4 is a structural block diagram of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the accompanying drawings provided by the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. According to the following description, the advantages and features of the present invention will be more clear. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0037] Example 1

[0038] This embodiment provides a single-ended data transmission line fault location method based on traveling waves, see Figure 1 , 2 As shown, the method comprises the following steps:

[0039] S100: When a transmission line between a first bus and a second bus fails, a current signal is measured at an end of the first bus, and the current signal is filtered and pattern-decomposed to extract a traveling wave.

[0040] See also Figure 3 , 4 As shown, considering a transmission line connected between a first busbar A and a second busbar B, when a fault occurs, a current signal is measured at the first busbar end and used as an input of an IED (intelligent electronic device) arranged at the first busbar A end.

[0041] In a preferred embodiment, a bandpass filter is used to filter out the traveling wave, and then Clarke transformation is used to decompose the phase current into a ground mode of phase a and two air modes α and β to extract the traveling wave.

[0042] Specifically, a bandpass filter is designed according to the frequency range of the traveling wave signal, and the correct design parameters of the bandpass filter are selected, that is, a center frequency close to the frequency of the traveling wave signal and an appropriate bandwidth are selected to ensure that the traveling wave signal can be effectively filtered out, and the collected current signal is input into the bandpass filter. The filter will filter out the low-frequency and high-frequency parts according to the designed center frequency and bandwidth, leaving only the frequency components of the traveling wave signal.

[0043] The attenuation of the ground mode signal (zero sequence component) is greater than that of the air mode, and it usually stands out in the signal after Clarke transformation. Therefore, the ground mode signal (zero sequence component) can be used to identify the occurrence of ground faults. α and β signals, further traveling wave analysis, by analyzing the signals on the α and β axes, determine whether the traveling wave propagates toward the fault source (forward) or away from the fault source (reverse), and the fault location can be calculated based on the propagation time difference of the traveling wave signal.

[0044] S200, calculating the arrival time of the traveling wave front.

[0045] In a preferred embodiment, the following steps are specifically included: (1) Squaring the traveling wave signal and detecting the positive and negative traveling wave fronts. The amplitude contrast of the traveling wave is improved by squaring the traveling wave signal, so that the arrival time of the traveling wave is more easily identified in signal processing. In order to achieve precise positioning, the positive traveling wave and the negative traveling wave are detected. The positive traveling wave and the negative traveling wave propagate from the fault point to both ends respectively. By detecting the propagation time of these two traveling waves, the position of the fault point can be calculated according to the known propagation speed (propagation speed of the transmission line). (2) A smoother is used to reduce waveform distortion, thereby avoiding any false zero crossings caused by noise. (3) The parabola best fit interpolation method is used to select three adjacent data points with large changes from the leading edge interval of the signal, and these three data points are used to fit a quadratic parabola model by the least squares method. The fitting function is: y(t) = at 2 +bt+c, where a, b, c are fitting parameters, t is time, y(t) is signal amplitude, and the frontier moment of the traveling wave is calculated by the vertex position of the parabola. The vertex coordinate formula is where t vertex The arrival time of the traveling wave front is improved, and the calculation accuracy of the traveling wave front arrival time is improved. After obtaining the accurate arrival time of the traveling wave front, the time difference between different measurement points is calculated using the known traveling wave propagation speed, so as to infer the fault location.

[0046] S300, based on the first and second traveling wave front arrival times measured by the fault locator on the first bus, respectively calculate a first fault distance when the fault is located on the transmission line in the front half from the first bus, and a second fault distance when the fault is located on the transmission line in the rear half from the first bus.

[0047] Specifically, the calculation formula of the first fault distance is as follows:

[0048]

[0049] The calculation formula of the second fault distance is as follows:

[0050]

[0051] Among them, d 1is the first fault distance, d 2 is the second fault distance, t A1 and t A2 are the first and second traveling wave front arrival times measured by the fault locator at the first bus, l is the total length of the transmission line, and V is the propagation speed of the traveling wave on the line.

[0052] S400. If the first fault distance and the second fault distance are close to the midpoint of the transmission line, the fault distance is determined to be the average of the first fault distance and the second fault distance; otherwise, the third line wave front arrival time when the fault is in the first half of the line and the third line wave front arrival time when the fault is in the second half of the line are compared to see which one is closer to the actually recorded third line wave front arrival time. If the former is closer, the fault distance is determined to be the first fault distance, and if the latter is closer, the fault distance is determined to be the second fault distance.

[0053] In a preferred embodiment, if the absolute difference between the first fault distance and the second fault distance is less than 600 m, it is determined that the first fault distance and the second fault distance are close to the midpoint of the transmission line, and the fault distance is the average of the first fault distance and the second fault distance.

[0054] In one embodiment, when the fault is in the first half of the line, the calculation formula for the arrival time of the third wave front is as follows:

[0055]

[0056] When the fault is in the second half of the line, the calculation formula for the arrival time of the third wave front is as follows:

[0057]

[0058] in, is the arrival time of the third wavefront when the fault is in the first half of the line, d_3rdwavefront_first is the distance corresponding to the arrival time of the third wavefront when the fault is in the first half of the line, is the arrival time of the third wavefront when the fault is in the second half of the line, and d_3rdwavefront_seond is the distance corresponding to the arrival time of the third wavefront when the fault is in the second half of the line.

[0059] In one embodiment, if Then d = d 1 ,like Then d = d 2 , if none of them are satisfied, there is no fault; among them, is the arrival time of the third wave front actually recorded by the fault locator at the first busbar, ∈ is the comparison threshold, d is the fault distance, d 1 is the first fault distance, d2 is the second fault distance.

[0060] In a preferred embodiment, the current signal sampling frequency is 1 MHz, and the comparison threshold ∈ is 2 μs.

[0061] The single-ended data transmission line fault location method based on traveling waves provided by the present invention measures a current signal at the first bus end when a fault occurs in the transmission line between the first bus and the second bus, and performs filtering and mode decomposition on the current signal to extract the traveling wave; calculates the traveling wavefront arrival time; and calculates the first fault distance when the fault is located in the front half of the transmission line from the first bus, and the second fault distance when the fault is located in the rear half of the transmission line from the first bus, respectively, according to the first and second traveling wavefront arrival times measured by the fault locator at the first bus. If the first fault distance and the second fault distance are close to the transmission line, the fault locator can determine the fault location of the transmission line. If the fault is at the midpoint of the line, the fault distance is determined to be the average of the first fault distance and the second fault distance; otherwise, the third line wave front arrival time when the fault is in the first half of the line and the third line wave front arrival time when the fault is in the second half of the line are compared to see which one is closer to the actually recorded third line wave front arrival time. If the former is closer, the fault distance is determined to be the first fault distance, and if the latter is closer, the fault distance is determined to be the second fault distance. Single-ended fault location based purely on traveling waves can be achieved without the need for phasor and impedance calculations. It only needs to use the measured time-domain current signal for simple algebraic calculations to obtain accurate fault location.

[0062] Example 2

[0063] This embodiment provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the single-ended data transmission line fault location method based on traveling waves described above are implemented.

[0064] The storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), a random access memory (RAM), a flash memory, a hard disk (HDD) or a solid-state drive (SSD), etc.; the storage medium may also include a combination of the above-mentioned types of memory.

[0065] Example 3

[0066] This embodiment provides a computer device, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the single-ended data transmission line fault location method based on traveling waves as described above when executing the program.

[0067] like Figure 5 As shown, the computer device may include: at least one processor 71, such as a CPU (Central Processing Unit), at least one communication interface 73, a memory 74, and at least one communication bus 72. The communication bus 72 is used to realize the connection and communication between these components. The communication interface 73 may include a display screen (Display) and a keyboard (Keyboard), and the optional communication interface 73 may also include a standard wired interface and a wireless interface. The memory 74 may be a high-speed RAM memory (Random Access Memory, volatile random access memory) or a non-volatile memory (non-volatile memory), such as at least one disk storage. The memory 74 may optionally be at least one storage device located away from the aforementioned processor 71. The memory 74 stores application programs, and the processor 71 calls the program code stored in the memory 74 to execute any of the above method steps.

[0068] The communication bus 72 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus. The communication bus 72 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 5 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0069] Among them, the memory 74 may include a volatile memory (English: volatile memory), such as a random access memory (English: random-access memory, abbreviated: RAM); the memory may also include a non-volatile memory (English: non-volatile memory), such as a flash memory (English: flash memory), a hard disk (English: hard disk drive, abbreviated: HDD) or a solid-state drive (English: solid-state drive, abbreviated: SSD); the memory 74 may also include a combination of the above types of memory.

[0070] The processor 71 may be a central processing unit (CPU), a network processor (NP), or a combination of a CPU and a NP.

[0071] The processor 71 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0072] Optionally, the memory 74 is also used to store program instructions. The processor 71 can call the program instructions to implement the single-ended data transmission line fault location method based on traveling waves of the present invention.

[0073] Those skilled in the art should understand that the present invention can be implemented in many other specific forms without departing from the spirit and scope of the present invention. Based on the embodiments of the present invention, any changes and modifications made by ordinary technicians in the field of the present invention according to the above disclosure are within the scope of protection of the claims.

Claims

1. A single-ended data transmission line fault location method based on traveling waves, characterized in that: The method comprises the following steps: S100, when a fault occurs in a transmission line between the first bus and the second bus, measuring a current signal at an end of the first bus, filtering and pattern decomposing the current signal, and extracting a traveling wave; S200, calculating the arrival time of the traveling wave front; S300, calculating, according to the first and second traveling wave front arrival times measured by the fault locator on the first bus, a first fault distance when the fault is located on the transmission line in the first half from the first bus, and a second fault distance when the fault is located on the transmission line in the second half from the first bus; S400. If the first fault distance and the second fault distance are close to the midpoint of the transmission line, the fault distance is determined to be the average of the first fault distance and the second fault distance; otherwise, the third line wave front arrival time when the fault is in the first half of the line and the third line wave front arrival time when the fault is in the second half of the line are compared to see which one is closer to the actually recorded third line wave front arrival time. If the former is closer, the fault distance is determined to be the first fault distance, and if the latter is closer, the fault distance is determined to be the second fault distance.

2. The single-ended data transmission line fault location method based on traveling waves according to claim 1, characterized in that: In step S100, a bandpass filter is used to filter out the traveling wave, and then the phase current is decomposed into a ground mode of phase a and two air modes α and β using Clarke transformation to extract the traveling wave.

3. The single-ended data transmission line fault location method based on traveling wave according to claim 1, characterized in that: The step S200 specifically includes the following steps: squaring the traveling wave signal and detecting the positive and negative traveling wave fronts; using a smoother to reduce waveform distortion; using the parabola best fit interpolation method, selecting three adjacent data points with large changes from the frontier interval of the signal, and using these three data points to fit a quadratic parabola model by the least squares method, the fitting function is: y(t)=at 2 +bt+c, where a, b, c are fitting parameters, t is time, y(t) is the signal amplitude, and the frontier moment of the traveling wave is calculated by the vertex position of the parabola. The vertex coordinate formula is where tvertex is the arrival time of the traveling wave front.

4. The single-ended data transmission line fault location method based on traveling wave according to claim 1, characterized in that: In step S300, the calculation formula of the first fault distance is as follows: The calculation formula of the second fault distance is as follows: Where d1 is the first fault distance, d2 is the second fault distance, t A1 and t A2 are the first and second traveling wave front arrival times measured by the fault locator at the first bus, l is the total length of the transmission line, and V is the propagation speed of the traveling wave on the line.

5. The single-ended data transmission line fault location method based on traveling wave according to claim 1, characterized in that: In step S400, if the absolute difference between the first fault distance and the second fault distance is less than 600 m, it is determined that the first fault distance and the second fault distance are close to the midpoint of the transmission line, and the fault distance is the average of the first fault distance and the second fault distance.

6. The method for locating faults in a single-ended data transmission line based on traveling waves according to claim 1, characterized in that: In step S400, when the fault is in the first half of the line, the calculation formula for the arrival time of the third wave front is as follows: When the fault is in the second half of the line, the calculation formula for the arrival time of the third wave front is as follows: in, is the arrival time of the third wavefront when the fault is in the first half of the line, d_3rdwavefront_first is the distance corresponding to the arrival time of the third wavefront when the fault is in the first half of the line, is the arrival time of the third wavefront when the fault is in the second half of the line, and d_3rdwavefront_seond is the distance corresponding to the arrival time of the third wavefront when the fault is in the second half of the line.

7. The method for locating faults in a single-ended data transmission line based on traveling waves according to claim 6, characterized in that: like Then d=d1, if Then d = d2. If none of them are satisfied, there is no fault. is the third traveling wave front arrival time actually recorded by the fault locator at the first bus, ∈ is the comparison threshold, d is the fault distance, d1 is the first fault distance, and d2 is the second fault distance.

8. The single-ended data transmission line fault location method based on traveling waves according to claim 7, characterized in that: The current signal sampling frequency is 1MHz and the comparison threshold ∈ is 2μs.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the single-ended data transmission line fault location method based on traveling waves as described in any one of claims 1 to 8 are implemented.

10. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the single-ended data transmission line fault location method based on traveling waves as described in any one of claims 1 to 8 are implemented.

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