Fault positioning method based on impedance abrupt change point detection and related equipment

Abstract

The invention discloses a fault positioning method based on impedance abrupt change point detection and related equipment, relates to the technical field of power transmission line fault positioning, and solves the problem that an impedance abrupt change point of a power transmission line is easily misjudged as a fault point. According to the invention, the fault point reflection wave and the impedance abrupt change point reflection wave of the fault traveling wave model are identified through the instantaneous frequency of the fault traveling wave signal, so that the misjudgment rate of the fault point can be reduced; by dividing the first line section near the impedance abrupt change point and the second line section farther from the impedance abrupt change point, respectively calculating the corresponding first wave velocity and second wave velocity, and then calculating the fault point distance based on the first wave velocity and the second wave velocity, the positioning precision can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of transmission line fault location, and particularly to a fault location method and related equipment based on impedance mutation point detection. Background Art

[0002] Accurate fault ranging of transmission lines in the power system can quickly narrow down the fault location range, reduce the burden of line patrol, and shorten the fault elimination time, which is of great significance for improving the power supply reliability of the power system and reducing power outage losses.

[0003] The traveling wave location method is widely used as one of the most effective methods for fault location. According to different traveling wave location principles, the traveling wave location method is divided into the single - end traveling wave method and the double - end traveling wave method. Among them, the single - end traveling wave method uses the time when the initial fault traveling wave arrives at one end of the line and the time when the reflected traveling wave from the fault point arrives at this end, and combines the transmission speed of the fault traveling wave to calculate the fault point location; the double - end traveling wave method uses the time when the initial fault traveling wave arrives at both ends of the line, and combines the transmission speed of the fault traveling wave to calculate the fault point location.

[0004] Traditional traveling wave location methods default uniform line parameters. However, in actual lines, impedance mutation points such as branch points and transposition towers will cause mutations in the traveling wave reflection coefficient. The mutation of the reflection coefficient will cause changes in the amplitude and phase of the reflected wave, thereby changing the shape and amplitude of the synthesized wave near the mutation point, and thus misjudging the fault point. Therefore, traditional methods are prone to misjudge the reflected wave of the impedance mutation point as the reflected wave of the fault point.

[0005] In view of this, a fault location method and related equipment based on impedance mutation point detection are needed. Summary of the Invention

[0006] Aiming at the problem of easy misjudgment of fault points in the existing fault location methods, the present invention provides a fault location method and related equipment based on impedance mutation point detection, which can reduce the misjudgment rate of fault points. The specific technical solutions are as follows:

[0007] In a first aspect, an embodiment of the present application provides a fault location method based on impedance mutation point detection, including:

[0008] Obtain the fault traveling wave signal received at the first end of the transmission line; based on the instantaneous frequency of the fault traveling wave signal and a preset impedance mutation point feature database, identify the fault point reflected wave and the impedance mutation point reflected wave in the fault traveling wave signal; calculate the first time from the fault point to the first end of the fault traveling wave signal based on the fault point reflected wave; divide the transmission line into a first line segment and a second line segment based on the impedance mutation point corresponding to the impedance mutation point reflected wave; calculate the first wave velocity of the fault traveling wave signal in the first line segment and the second wave velocity of the fault traveling wave signal in the second line segment respectively; calculate the fault point distance based on the first wave velocity, the second wave velocity and the first time; output the fault location result based on the fault point distance.

[0009] Among them, the first line segment is a line segment formed by extending a first preset length to both sides with the impedance mutation point as the center, and the second line segment is the other line segment of the transmission line except the first line segment, and the length of the first line segment is less than the length of the second line segment.

[0010] Preferably, the impedance mutation point feature database is used to store impedance mutation point features, and the impedance mutation point features include the instantaneous frequency spectrum and reflection energy of the impedance mutation point reflected wave; the identifying the fault point reflected wave and the impedance mutation point reflected wave in the fault traveling wave signal based on the instantaneous frequency of the fault traveling wave signal and a preset impedance mutation point feature database includes: calculating the similarity between the characteristics of the reflected wave in the fault traveling wave signal and the impedance mutation point features based on the instantaneous frequency of the fault traveling wave signal; determining the impedance mutation point reflected wave in the fault traveling wave signal based on the similarity; determining the fault point reflected wave in the fault traveling wave signal based on the instantaneous frequency of the fault traveling wave signal and the impedance mutation point reflected wave.

[0011] Preferably, the calculating the first wave velocity of the fault traveling wave signal in the first line segment and the second wave velocity of the fault traveling wave signal in the second line segment respectively includes: obtaining an environmental correction coefficient and a theoretical wave velocity; calculating the second wave velocity based on the environmental correction coefficient and the theoretical wave velocity; calculating the first wave velocity based on the environmental correction coefficient, the theoretical wave velocity and the reflection coefficient of the impedance mutation point.

[0012] Preferably, the first line segment includes a sub-line segment with a second preset length, and the second line segment includes a sub-line segment with a third preset length, and the second preset length is less than the third preset length.

[0013] Preferably, the calculating the fault point distance based on the first wave velocity, the second wave velocity and the first time includes: establishing an objective function, and the expression of the objective function includes:

[0014]

[0015] Wherein, N is the serial number of the sub-line segment where the fault point is located, i is the serial number of the sub-line segment, and Δx i is the length of the sub-line segment i, and v i is the wave velocity corresponding to the sub-line segment i, and t meas is the first time; solve the objective function to obtain the sub-line segment where the fault point is located; based on the sub-line segment where the fault point is located, determine the distance of the fault point.

[0016] Preferably, the first preset length is 50 meters, the second preset length is 10 meters, and the third preset length is 100 meters.

[0017] Preferably, outputting the fault location result based on the fault point distance includes: obtaining the longitude and latitude of the first end and the topological structure of the transmission line; calculating the longitude and latitude of the fault point based on the longitude and latitude of the first end, the topological structure, and the fault point distance as the geographical coordinates of the fault point; outputting the geographical coordinates as the fault location result.

[0018] In a second aspect, an embodiment of the present application provides a fault location system based on impedance mutation point detection, which is applied to the method described in the first aspect. The system includes:

[0019] An acquisition module, configured to acquire a fault traveling wave signal received at the first end of the transmission line;

[0020] An identification module, configured to identify a fault point reflected wave and an impedance mutation point reflected wave in the fault traveling wave signal based on the instantaneous frequency of the fault traveling wave signal and a preset impedance mutation point feature database;

[0021] A calculation module, configured to calculate a first time from the fault point to the first end of the fault traveling wave signal based on the fault point reflected wave;

[0022] A division module, configured to divide the transmission line into a first line segment and a second line segment based on the impedance mutation point corresponding to the impedance mutation point reflected wave; wherein, the first line segment is a line segment formed by extending a first preset length to both sides with the impedance mutation point as the center, and the second line segment is the other line segment of the transmission line except the first line segment, and the length of the first line segment is less than the length of the second line segment;

[0023] The calculation module is further configured to calculate a first wave velocity of the fault traveling wave signal in the first line segment and a second wave velocity of the fault traveling wave signal in the second line segment respectively;

[0024] The calculation module is further configured to calculate the fault point distance based on the first wave velocity, the second wave velocity, and the first time;

[0025] A positioning module, configured to output a fault location result based on the distance to the fault point.

[0026] In a third aspect, an embodiment of the present application provides a computing device, including: a memory for storing a program; a processor for loading the program to execute the method described in the first aspect.

[0027] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, where the computer-readable storage medium includes a stored program, and when the program runs, it controls the device where the computer-readable storage medium is located to execute the method described in the first aspect.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: By identifying the fault point reflection wave and the impedance mutation point reflection wave of the fault traveling wave signal through the instantaneous frequency of the fault traveling wave signal, the misjudgment rate of the fault point can be reduced; By dividing the first line segment near the impedance mutation point and the second line segment far from the impedance mutation point, and respectively calculating the corresponding first wave velocity and second wave velocity, and then calculating the distance to the fault point based on the first wave velocity and the second wave velocity, the positioning accuracy can be improved. Description of the Drawings

[0029] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to actual scale.

[0030] Figure 1 It is a schematic flow chart of a fault location method based on impedance mutation point detection provided by an embodiment of the present application;

[0031] Figure 2 It is a schematic structural diagram of a fault location system based on impedance mutation point detection provided by an embodiment of the present application;

[0032] Figure 3 It is a schematic structural diagram of a computing device provided by an embodiment of the present application. Detailed Embodiments

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0034] It should be understood that when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their combinations.

[0035] It should also be understood that the terms used in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0036] It should be further understood that the term "and / or" used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0037] To solve the problem that the impedance mutation point is easily misjudged as the fault point in the traditional fault location method, the present invention provides a fault location method and related equipment based on impedance mutation point detection, which can reduce the misjudgment rate of the fault point.

[0038] Please refer to Figure 1 , Figure 1 This application provides a fault location method based on impedance mutation point detection for an embodiment of the present application. This method is applied to a computing device; as Figure 1 shown, this method includes:

[0039] Step 101, the computing device acquires the fault traveling wave signal received at the first end of the transmission line.

[0040] Among them, the computing device can be a computing module, a control module or a monitoring and acquisition module arranged on the transmission line, which can directly acquire the traveling wave signal on the transmission line; it can also be a server, or an intelligent terminal such as a personal computer or a tablet directly operated by power system management personnel or maintenance personnel, which is communicatively connected to the first end by wire or wirelessly, and acquires the fault traveling wave signal received at the first end from the first end.

[0041] Among them, the first end can be the head or the tail of the transmission line.

[0042] Preferably, the fault traveling wave signal can be the traveling wave signal received at the first end within 10 ms after the fault occurs.

[0043] Step 102, the computing device identifies the fault point reflected wave and the impedance mutation point reflected wave in the fault traveling wave signal based on the instantaneous frequency of the fault traveling wave signal and a preset impedance mutation point feature database.

[0044] Among them, after a fault occurs, a large number of waveforms are received at the first end. The computing device needs to identify the fault point reflected wave from these waveforms to locate the fault point, and at the same time, it also needs to identify the impedance mutation point reflected wave to eliminate the interference of the impedance mutation point.

[0045] Specifically, the impedance mutation points include known impedance mutation points and temporary impedance mutation points. The known impedance mutation points are impedance mutation points that already existed and were detected before calculating the fault point position, and data such as their corresponding characteristics and impedance mutation types have been stored in a preset impedance mutation point feature database; the temporary impedance mutation points are impedance mutation points that were not detected or temporarily generated before calculating the fault point position.

[0046] Exemplarily, the known impedance mutation points can include the branch points of transmission lines, the connection points of transmission lines and cables, the connection points of lightning conductors and cross arms of transmission towers, etc.; the temporary impedance mutation points can include bird nests, ice-covered line segments, etc.

[0047] Preferably, the impedance mutation point feature database is used to store impedance mutation point features, and the impedance mutation point features include the instantaneous frequency spectrum and reflection energy of the reflected wave of the impedance mutation point; the computing device can calculate the similarity between the features of the reflected wave in the fault traveling wave signal and the impedance mutation point features based on the instantaneous frequency of the fault traveling wave signal; determine the impedance mutation point reflected wave in the fault traveling wave signal based on the similarity; and determine the fault point reflected wave in the fault traveling wave signal based on the instantaneous frequency of the fault traveling wave signal and the impedance mutation point reflected wave.

[0048] Among them, the computing device can perform Hilbert transform on the fault traveling wave signal S(t) to generate an analytic signal Z(t) = S(t) + jH[S(t)]; where t is time, j is the imaginary unit, and H[S(t)] represents the Hilbert transform of the fault traveling wave signal S(t).

[0049] Then, the computing device can calculate the instantaneous frequency of the analytic signal. The calculation formula for the instantaneous frequency is:

[0050]

[0051] Among them, f(t) represents the instantaneous frequency of the signal, d / dt is the operator for taking the derivative with respect to time t, and arg[Z(t)] is the phase function of the analytic signal Z(t).

[0052] Then, the computing device can calculate the corresponding reflected energy based on the instantaneous frequency, and then use the instantaneous frequency and the reflected energy as the characteristics of the reflected wave to calculate the similarity between the characteristics of each reflected wave and the characteristics of the impedance mutation point. When the calculated similarity is greater than the preset similarity threshold, the computing device can determine that the corresponding reflected wave is the reflected wave of the impedance mutation point.

[0053] Exemplarily, the computing device can calculate the similarity between the characteristics of the reflected wave and the characteristics of the impedance mutation point based on the dynamic time warping (DTW) algorithm.

[0054] After determining the reflected wave of the impedance mutation point, the computing device can identify the reflected wave of the fault point from the remaining reflected waves in the fault traveling wave signal.

[0055] Preferably, the computing device can detect the primary reflected wave through the wavelet transform energy threshold, screen the subsequent reflected waves by combining polarity judgment, and eliminate the invalid reflection points with amplitudes lower than 3 times the noise level.

[0056] Among them, the computing device can decompose the reflected wave into 5 layers using the Db4 wavelet and extract the high-frequency components (20 - 100 kHz) in the decomposition result; then mark the peak points with reflected energy higher than 3 times the noise level; and then extract the reflected wave of the fault point from these peak points based on the characteristic that the polarity of the fault reflected wave is opposite to that of the initial wave head.

[0057] It can be understood that when the reflected wave of the fault point indicates that there are multiple fault points at the same time, the computing device can sequentially or parallelly execute the steps below to determine the position of the fault point; then based on the drone or the image acquisition device at the corresponding position, first confirm whether there is an impedance mutation caused by an accidental situation, and then notify the maintenance personnel to go to handle the accidental situation or perform fault repair.

[0058] In some other possible implementations, the characteristics of the impedance mutation point may include one or more of the current characteristics, voltage characteristics, and electric field characteristics of the traveling wave signal.

[0059] Step 103: The computing device calculates a first time from the fault point to the first end of the fault traveling wave signal based on the reflected wave of the fault point.

[0060] Among them, the computing device can extract the arrival time of the wave head of the reflected wave of the fault point through methods such as threshold detection method, slope detection method, and wavelet transform method; and then calculate the first time based on the head wave arrival time and the tail wave arrival time in multiple consecutive reflected waves of the fault point.

[0061] It can be understood that calculating the first time through the arrival times of the wave heads of the first and second reflected waves in multiple reflected waves of the fault point has a longer time interval and stronger anti-interference ability.

[0062] Preferably, the computing device can perform continuous wavelet transform on the reflected wave at the fault point to obtain wavelet coefficients; then determine the arrival time of the wavefront of the reflected wave at the fault point based on the modulus maxima of the wavelet coefficients. By suppressing noise interference through time-frequency joint analysis, the accuracy of the wavefront detection time can be improved.

[0063] Among them, the computing device can use wavelet basis functions such as Morlet wavelet, Daubechies wavelet, Haar wavelet, Symlets wavelet, etc.

[0064] Step 104: The computing device divides the transmission line into a first line segment and a second line segment based on the impedance mutation point corresponding to the reflected wave at the impedance mutation point.

[0065] Among them, after obtaining the reflected wave at the impedance mutation point, the computing device can determine whether the corresponding impedance mutation point of the reflected wave at the impedance mutation point is an impedance mutation point that already existed on the transmission line before the fault based on the characteristics of the reflected wave at the impedance mutation point. If so, then the computing device can obtain the reflection coefficient and geographical coordinates of the impedance mutation point from the impedance mutation point feature database or other preset databases.

[0066] If not, then the computing device can first obtain the reflection coefficient of the corresponding impedance mutation point based on the characteristics of the reflected wave at the impedance mutation point, and then estimate the position of the impedance mutation point on the transmission line based on the reflected wave at the impedance mutation point. It can be understood that the computing device can also regard the impedance mutation point as a fault point, locate the impedance mutation point based on the method of the embodiment of the present application, then obtain an image of the corresponding position based on the image acquisition device, and then confirm the type of the impedance mutation point based on the image, and finally update the characteristics, type, and geographical location of the impedance mutation point to the impedance mutation point feature database.

[0067] Then, the computing device can divide the transmission line into a first line segment and a second line segment based on the positions of these impedance mutation points.

[0068] Among them, the first line segment is a line segment formed by extending a first preset length to both sides with the impedance mutation point as the center, the second line segment is the other line segment of the transmission line except the first line segment, and the length of the first line segment is less than the length of the second line segment.

[0069] It can be understood that the first line segment is the line segment closer to the impedance mutation point. Due to the existence of the impedance mutation point, the impedance mutation point (such as a branch point, a transposition tower, a lightning arrester, etc.) will cause significant changes in the inductance L per unit length and the capacitance C per unit length of the line. For example, the changes brought about by the structure and devices of the impedance mutation point itself (such as the bifurcation of the branch point line resulting in an increase in inductance and a decrease in capacitance), and the secondary changes caused by the structure of the impedance mutation point (such as water accumulation in the branch point structure), etc. The second line segment farther away from the impedance mutation point can be regarded as a line with uniform parameters.

[0070] Therefore, by dividing the transmission line into the first line segment and the second line segment, calculating the corresponding first wave velocity and the second wave velocity respectively, and then performing fault location based on the first wave velocity and the second wave velocity, the location accuracy can be improved.

[0071] Preferably, the first line segment includes a sub-line segment with a second preset length, the second line segment includes a sub-line segment with a third preset length, and the second preset length is less than the third preset length.

[0072] Preferably, the first preset length is 50 meters, the second preset length is 10 meters, and the third preset length is 100 meters.

[0073] By further dividing the first line segment and the second line segment into smaller sub-line segments, the accuracy of fault location can be further improved. At the same time, since the second line segment is much longer than the first line segment, fine-grained sub-line segment division in the first line segment will not cause excessive consumption of computing resources.

[0074] Exemplarily, the total length of the transmission circuit is 100 KM, the number of impedance mutation points is 3, the first preset length is 50 meters, the second preset length is 10 meters, and the third preset length is 100 meters. It can be calculated that the number of sub-line segments of the first line segment is 3 * 10 = 30, the number of sub-line segments of the second line segment is (100000 - 3 * 100) / 100 = 997, and the total number of sub-line segments is 1027. In the traditional method, dividing the grid with a step size of 100m results in a total of 1000 grid numbers. The method of this embodiment only increases the calculation amount by 3%, while improving the calculation accuracy.

[0075] Step 105, the computing device calculates the first wave velocity of the fault traveling wave signal in the first line segment and the second wave velocity of the fault traveling wave signal in the second line segment respectively.

[0076] Among them, as described above, the second line segment is farther away from the impedance mutation point and can be regarded as a line with uniform parameters. Therefore, the influence of the current environmental factors can be considered, and the second wave velocity can be calculated in combination with the theoretical wave velocity. The first line segment is closer to the impedance mutation point, and the influence of the impedance mutation point needs to be further considered.

[0077] Preferably, the computing device can obtain an environmental correction coefficient and a theoretical wave velocity; based on the environmental correction coefficient and the theoretical wave velocity, calculate the second wave velocity; based on the environmental correction coefficient, the theoretical wave velocity, and the reflection coefficient of the impedance mutation point, calculate the first wave velocity.

[0078] Wherein, the environmental correction coefficient can be a coefficient calculated by the computing device based on current environmental factors such as temperature and humidity, or a coefficient obtained by the computing device based on a preset environmental factor - coefficient mapping relationship and the current environmental factor values.

[0079] Wherein, the computing device can calculate the theoretical wave velocity based on the capacitance per unit length and the inductance per unit length of each sub - line segment. The specific formula is Where v 0,i is the theoretical wave velocity of sub - line segment i, C i is the capacitance per unit length of sub - line segment i, and L i is the inductance per unit length of sub - line segment i. Combining with the environmental correction coefficient, the second velocity can be obtained as v i2 = v 0,i ·α, where α is the environmental correction coefficient.

[0080] The expression for calculating the first velocity is:

[0081] v i ' = [v 0,i ·(1 + βΓ)]·α

[0082] Where v i ' is the first velocity, β is the compensation weight coefficient, and Γ is the reflection coefficient of the impedance mutation point.

[0083] Step 106, the computing device calculates the fault point distance based on the first wave velocity, the second wave velocity, and the first time.

[0084] Preferably, calculating the fault point distance based on the first wave velocity, the second wave velocity, and the first time includes: establishing an objective function, and the expression of the objective function includes:

[0085]

[0086] Where N is the serial number of the sub - line segment where the fault point is located, i is the sub - line segment serial number, Δx i is the length of sub - line segment i, v i is the wave velocity corresponding to sub - line segment i, and t meas is the first time; solving the objective function to obtain the sub - line segment where the fault point is located; determining the fault point distance based on the sub - line segment where the fault point is located.

[0087] Among them, the computing device can adjust the fault point distance based on the golden section method, that is, adjust the serial number N of the sub-line segment where the fault point is located, so that the objective function converges; the convergence condition of the objective function is that minf(N) is less than 0.1 microseconds.

[0088] Step 107, the computing device outputs a fault location result based on the fault point distance.

[0089] Among them, after obtaining the fault point distance, the computing device needs to further map the fault point distance to the actual geographical coordinates so that maintenance personnel can go to the fault point for maintenance and repair.

[0090] Preferably, outputting the fault location result based on the fault point distance includes: obtaining the longitude and latitude of the first end and the topological structure of the transmission line; calculating the longitude and latitude of the fault point as the geographical coordinates of the fault point based on the longitude and latitude of the first end, the topological structure and the fault point distance; outputting the geographical coordinates as the fault location result.

[0091] Among them, the computing device can obtain the longitude and latitude of the first end from the line tower coordinate database; perform linear interpolation along the transmission line topology with the fault distance as the path length, and combine with the geographic information system (GIS) to obtain the longitude and latitude of the fault point as the geographical coordinates; then the computing device can generate a fault location result based on the geographical coordinates.

[0092] In the embodiments of the present application, by identifying the fault point reflected wave and the impedance mutation point reflected wave of the fault traveling wave signal through the instantaneous frequency of the fault traveling wave signal, the misjudgment rate of the fault point can be reduced; by dividing the first line segment near the impedance mutation point and the second line segment far from the impedance mutation point, and calculating the corresponding first wave velocity and second wave velocity respectively, and then calculating the fault point distance based on the first wave velocity and the second wave velocity, the positioning accuracy can be improved.

[0093] The method part provided by the embodiments of the present application is described above, and the system part provided by the embodiments of the present application will be described below.

[0094] Please refer to Figure 2 , Figure 2 which is a schematic structural diagram of a fault location system based on impedance mutation point detection provided by the embodiments of the present application. As Figure 2 shown, the system 20 includes:

[0095] An acquisition module 201, configured to acquire the fault traveling wave signal received at the first end of the transmission line;

[0096] An identification module 202, configured to identify a fault point reflected wave and an impedance mutation point reflected wave in the fault traveling wave signal based on the instantaneous frequency of the fault traveling wave signal and a preset impedance mutation point feature database;

[0097] A calculation module 203, configured to calculate a first time from the fault point to the first end of the fault traveling wave signal based on the fault point reflected wave;

[0098] A division module 204, configured to divide the transmission line into a first line segment and a second line segment based on the impedance mutation point corresponding to the impedance mutation point reflected wave; wherein, the first line segment is a line segment formed by extending a first preset length to both sides with the impedance mutation point as the center, and the second line segment is other line segments in the transmission line except the first line segment, and the length of the first line segment is less than the length of the second line segment;

[0099] The calculation module 203 is further configured to calculate a first wave velocity of the fault traveling wave signal in the first line segment and a second wave velocity of the fault traveling wave signal in the second line segment respectively;

[0100] The calculation module 203 is further configured to calculate a fault point distance based on the first wave velocity, the second wave velocity and the first time;

[0101] A positioning module 205, configured to output a fault location result based on the fault point distance.

[0102] Preferably, the impedance mutation point feature database is used to store impedance mutation point features, and the impedance mutation point features include the instantaneous frequency spectrum and reflection energy of the impedance mutation point reflected wave; the identification module 202 is specifically configured to calculate the similarity between the features of the reflected wave in the fault traveling wave signal and the impedance mutation point features based on the instantaneous frequency of the fault traveling wave signal; determine the impedance mutation point reflected wave in the fault traveling wave signal based on the similarity; and determine the fault point reflected wave in the fault traveling wave signal based on the instantaneous frequency of the fault traveling wave signal and the impedance mutation point reflected wave.

[0103] Preferably, the calculation module 203 is specifically configured to obtain an environmental correction coefficient and a theoretical wave velocity; calculate the second wave velocity based on the environmental correction coefficient and the theoretical wave velocity; and calculate the first wave velocity based on the environmental correction coefficient, the theoretical wave velocity and the reflection coefficient of the impedance mutation point.

[0104] Preferably, the first line segment includes a sub-line segment with a second preset length, and the second line segment includes a sub-line segment with a third preset length, and the second preset length is less than the third preset length.

[0105] Preferably, the calculation module 203 is specifically configured to establish an objective function, and the expression of the objective function includes:

[0106]

[0107] Wherein, N is the serial number of the sub-line segment where the fault point is located, i is the serial number of the sub-line segment, and Δx i is the length of the sub-line segment i, and v i is the wave velocity corresponding to the sub-line segment i, and t meas is the first time; solving this objective function to obtain the sub-line segment where the fault point is located; based on the sub-line segment where the fault point is located, determining the distance of the fault point.

[0108] Preferably, the first preset length is 50 meters, the second preset length is 10 meters, and the third preset length is 100 meters.

[0109] Preferably, the positioning module 205 is specifically configured to obtain the longitude and latitude of the first end, and the topological structure of the transmission line; based on the longitude and latitude of the first end, the topological structure and the fault point distance, calculate the longitude and latitude of the fault point as the geographical coordinate.

[0110] The fault location system based on impedance mutation point detection provided by the embodiments of the present application can be understood by referring to the corresponding content in the foregoing method embodiment part, and will not be repeated here.

[0111] As Figure 3 shown, Figure 3 is a possible logical structure diagram of a computing device provided by an embodiment of the present application. The computing device 300 includes: a processor 301, a communication interface 302, a memory 303, and a bus 304. The processor 301, the communication interface 302, and the memory 303 are interconnected through the bus 304. In the embodiments of the present application, the processor 301 is used to control and manage the actions of the computing device 300. For example, the processor 301 is used to execute Figure 1 the steps in the embodiments and / or other processes for the technologies described herein. The communication interface 302 is used to support the computing device 300 to communicate. The memory 303 is used to store the program code and data of the computing device 300.

[0112] Among them, the processor 301 can be a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field-programmable gate array, or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute various exemplary logical blocks, modules, and circuits described in connection with the disclosure of this application. The processor can also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a digital signal processor and a microprocessor, and so on. The bus 304 can be a peripheral component interconnect (PCI) bus, an extended industry standard architecture (EISA) bus, or the like. The bus can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, Figure 3 only a thick line is used to represent it in Figure 3 , but it does not mean that there is only one bus or one type of bus.

[0113] In another embodiment of the present application, a computer-readable storage medium is further provided. The computer-readable storage medium includes instructions that, when run on a computer, cause the computer to execute the above Figure 1 method described in the embodiment.

[0114] Those of ordinary skill in the art can realize that the units of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the components of each example have been generally described according to their functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0115] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the above-described systems, devices, and units can refer to the corresponding processes in the foregoing method embodiments and will not be repeated here.

[0116] In several embodiments provided by the embodiments of the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.

[0117] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0118] In addition, in each embodiment of the present invention, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0119] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present invention. The foregoing storage medium includes: USB flash drives, read-only memories (ROMs), random access memories (RAMs), mobile hard disks, magnetic disks, or optical discs, etc., which can store program codes.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A fault location method based on impedance mutation point detection, characterized in that, Including: Obtaining a fault traveling wave signal received at the first end of a transmission line; Identifying a fault point reflected wave and an impedance mutation point reflected wave in the fault traveling wave signal based on the instantaneous frequency of the fault traveling wave signal and a preset impedance mutation point feature database; Calculating a first time for the fault traveling wave signal to travel from the fault point to the first end based on the fault point reflected wave; Dividing the transmission line into a first line segment and a second line segment based on the impedance mutation point corresponding to the impedance mutation point reflected wave; wherein, the first line segment is a line segment formed by extending a first preset length to both sides centered on the impedance mutation point, the second line segment is the other line segment of the transmission line except the first line segment, and the length of the first line segment is less than the length of the second line segment; Calculating a first wave velocity of the fault traveling wave signal in the first line segment and a second wave velocity of the fault traveling wave signal in the second line segment respectively; Calculating a fault point distance based on the first wave velocity, the second wave velocity, and the first time; Outputting a fault location result based on the fault point distance.

2. The method according to claim 1, wherein The impedance mutation point feature database is used to store impedance mutation point features, and the impedance mutation point features include the instantaneous frequency spectrum and reflection energy of the impedance mutation point reflected wave; the identifying the fault point reflected wave and the impedance mutation point reflected wave in the fault traveling wave signal based on the instantaneous frequency of the fault traveling wave signal and the preset impedance mutation point feature database includes: Calculating the similarity between the characteristics of the reflected wave in the fault traveling wave signal and the impedance mutation point characteristics based on the instantaneous frequency of the fault traveling wave signal; Determining the impedance mutation point reflected wave in the fault traveling wave signal based on the similarity; Determining the fault point reflected wave in the fault traveling wave signal based on the instantaneous frequency of the fault traveling wave signal and the impedance mutation point reflected wave.

3. The method according to claim 1, wherein The calculating the first wave velocity of the fault traveling wave signal in the first line segment and the second wave velocity of the fault traveling wave signal in the second line segment respectively includes: Obtaining an environmental correction coefficient and a theoretical wave velocity; Calculating the second wave velocity based on the environmental correction coefficient and the theoretical wave velocity; Calculating the first wave velocity based on the environmental correction coefficient, the theoretical wave velocity, and the reflection coefficient of the impedance mutation point.

4. The method according to any one of claims 1 to 3, characterized in that, The first line segment includes a sub-line segment with a second preset length, the second line segment includes a sub-line segment with a third preset length, and the second preset length is less than the third preset length.

5. The method according to claim 4, characterized in that, The calculating the fault point distance based on the first wave velocity, the second wave velocity, and the first time includes: Establishing an objective function, and the expression of the objective function includes: Among them, N is the serial number of the sub-line segment where the fault point is located, i is the serial number of the sub-line segment, and Δx i is the length of the sub-line segment i, and v i is the wave velocity corresponding to the sub-line segment i, and t meas is the first time; Solving the objective function to obtain the sub-line segment where the fault point is located; Determining the fault point distance based on the sub-line segment where the fault point is located.

6. The method according to claim 4, characterized in that The first preset length is 50 meters, the second preset length is 10 meters, and the third preset length is 100 meters.

7. The method according to any one of claims 1-3, characterized in that, The outputting the fault location result based on the fault point distance includes: Obtaining the longitude and latitude of the first end, and the topological structure of the transmission line; Based on the longitude and latitude of the first end, the topological structure, and the fault point distance, calculate the longitude and latitude of the fault point as the geographical coordinates of the fault point; Output the geographical coordinates as the fault location result.

8. A fault location system based on impedance mutation point detection, characterized in that, Applied to the method according to any one of claims 1-7, the system includes: An acquisition module, configured to acquire the fault traveling wave signal received at the first end of the transmission line; An identification module, configured to identify the fault point reflected wave and the impedance mutation point reflected wave in the fault traveling wave signal based on the instantaneous frequency of the fault traveling wave signal and a preset impedance mutation point feature database; A calculation module, configured to calculate, based on the fault point reflected wave, the first time for the fault traveling wave signal to travel from the fault point to the first end; A division module, configured to divide the transmission line into a first line segment and a second line segment based on the impedance mutation point corresponding to the impedance mutation point reflected wave; wherein, the first line segment is a line segment formed by extending a first preset length to both sides with the impedance mutation point as the center, and the second line segment is the other line segment of the transmission line except the first line segment, and the length of the first line segment is less than the length of the second line segment; The calculation module is further configured to calculate, respectively, the first wave velocity of the fault traveling wave signal in the first line segment and the second wave velocity of the fault traveling wave signal in the second line segment; The calculation module is further configured to calculate the fault point distance based on the first wave velocity, the second wave velocity, and the first time; A positioning module, configured to output a fault location result based on the fault point distance.

9. A computing device, characterized in that, Comprising: A memory, configured to store a program; A processor, configured to load the program to execute the method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein when the program runs, it controls the device where the computer-readable storage medium is located to execute the method according to any one of claims 1-7.

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