Method, device and equipment for positioning single-phase earth fault point of current collection line and medium

Abstract

The invention provides a method, a device and equipment for positioning a single-phase earth fault point of a current collector, and a medium. The method comprises the following steps: acquiring a topological structure of a target current collection line and transient traveling wave signals of each monitoring area after a single-phase earth fault occurs; determining the arrival time of the transient traveling wave signal of each monitoring point according to the transient traveling wave signal of each monitoring point; determining a fault distance between any two regions according to the arrival time of the transient traveling wave signal of each monitoring point, and determining the actual length of each region according to the topological structure; constructing a fault area discrimination matrix based on the fault distance of any two areas, the actual length of each area and the topological structure; and according to the fault area discrimination matrix, positioning a single-phase earth fault point of the target current collection line. According to the method, the fault area discrimination matrix can be constructed through the actual length of each area, and fault point positioning is performed based on the fault area discrimination matrix, so that the error of fault point positioning is reduced, and the fault positioning precision requirement of the wind power plant current collection line is met.

Description

Technical Field

[0001] The present invention relates to the technical field of line detection, and in particular to a method, device, equipment and medium for locating a single-phase grounding fault point of a collector line. Background Art

[0002] As an important component of renewable energy, wind energy plays an important role in sustainable energy transformation. However, most of my country's wind farms are located in barren mountainous grasslands with harsh environments, and short-circuit faults of collector lines occur frequently. If the faults cannot be located in time, the wind power will be abandoned.

[0003] The collector line is connected to a large number of wind turbines and is used to collect the power of each unit. Its head end is connected to the busbar of the wind farm booster station so that the wind power can be sent to the power grid after boosting. The special features of its structure and fault location are: 1) The length of a single collector line in a wind farm is generally about 10km and a large number of wind turbines are connected. The distance between these wind turbines is small, usually only a few hundred meters. Therefore, the phenomenon of wave refraction and reflection between the wind turbine branches and the collector line branches is serious; 2) Most collector lines are located in hilly areas, and it is difficult to install and maintain monitoring devices; 3) The wind farm collector line is short, and the fault location accuracy requirements are higher than those of the transmission and distribution lines; 4) For the convenience of installation and maintenance, the wind farm collector line monitoring device should generally be installed in the box transformer, and the surrounding three-phase voltage and current electromagnetic signals are strong, that is, the noise interference is large, which affects the signal quality. Especially when a single-phase grounding occurs in the line, the short-circuit current is small and the signal-to-noise ratio is low.

[0004] In view of the particularity of wind farm collector lines, in terms of theoretical research, the existing wind farm collector line fault location methods can be roughly divided into three categories according to the implementation principles: fault analysis method, artificial intelligence method and traveling wave method.

[0005] The fault analysis method is simple to implement and requires little investment, but the ranging accuracy is easily affected by the transition resistance. In addition, there are many wind turbines densely connected on the collector line. If the complex wind turbine fault characteristics cannot be accurately described, it will also have an adverse effect on the ranging effect. Related literature has studied the wind turbine current output characteristics and fault location after a single-phase grounding fault. The research and analysis are based on the assumption that the output current of each wind turbine is equal after the fault. However, this assumption does not hold true in most mountainous wind power lines, because the wind speed at each wind turbine is quite different, and the ranging error will also increase when the transition resistance is large.

[0006] The artificial intelligence method can achieve fault location with a small number of measurement points, but it requires a large amount of historical fault data for model training, and once the wind farm increases or decreases wind turbines and causes the topology structure to change, the model is no longer applicable. Although relevant literature uses XGBoost and LSTM to establish a regression model, fault location can be achieved only with the measurement points on the system side, it still requires a large amount of historical fault data for model training.

[0007] Compared with the above two methods, the traveling wave method uses transient traveling wave information for fault distance measurement. Since the size and transmission process of the traveling wave signal are unrelated to the fault characteristics of the wind turbine, the traveling wave method can avoid complex analysis of wind turbine fault characteristics and achieve fault location. However, there are also some difficulties in the application of the traveling wave method in the fault location problem of the wind farm collector line. First, since the wind farm collector line is short and there are many wind turbines densely connected, the traveling wave refraction and reflection between many wind turbines and line branches are serious, and the current traveling wave signal of the single-phase grounding fault is weak (especially when the grounding resistance is large and the initial phase angle of the fault is small), and the wave head calibration is difficult. In addition, considering that the three-phase voltage and current electromagnetic signals around the wind farm traveling wave acquisition device are strong and the noise interference is serious, the collected transient traveling waves may contain a lot of noise, which further increases the difficulty of wave arrival time calibration, so that the traditional wave head calibration method may not be able to obtain the accurate traveling wave arrival time. Secondly, the accuracy of traveling wave ranging will also be affected by the traveling wave velocity. Usually, the traveling wave velocity is calculated through line parameters. However, the geographical environment of wind farms is complex and diverse, and the presence of a large number of jumpers on the side of tension towers and corner towers leads to dynamic changes in the electrical parameters of the collector lines, which determines the uncertainty of the traveling wave velocity. However, in the formula method, the parameters are constant, and the corresponding traveling wave velocity is a fixed value. The calculated traveling wave velocity has a large error, which will further increase the ranging error when used for fault location.

[0008] It can be seen that there is still a lack of effective and simple method for locating single-phase grounding faults of wind farm collector lines. Summary of the invention

[0009] The embodiments of the present invention provide a method, device, equipment and medium for locating a single-phase grounding fault point of a collector line, so as to solve the problem that there is currently a lack of an effective and simple method for locating a single-phase grounding fault of a collector line in a wind farm.

[0010] In a first aspect, an embodiment of the present invention provides a method for locating a collector single-phase grounding fault point, comprising: Acquire the topological structure of the target collector line and the transient traveling wave signals of each monitoring area after a single-phase grounding fault occurs; wherein the topological structure includes multiple areas, and each area corresponds to at least one monitoring point; Determine the arrival time of the transient traveling wave signal of each monitoring point according to the transient traveling wave signal of each monitoring point; Determine the fault distance between any two areas based on the arrival time of the transient traveling wave signal at each monitoring point, and determine the actual length of each area based on the topological structure; Based on the fault distance between any two regions, the actual length and topological structure of each region, a fault region discrimination matrix is ​​constructed; According to the fault area discrimination matrix, the single-phase grounding fault point of the target collector line is located.

[0011] In a possible implementation, a fault region discrimination matrix is ​​constructed based on the fault distance between any two regions, the actual length and topological structure of each region, including: For any two areas, the difference between the fault distance and the actual length of the first area is used as the matrix element corresponding to the two areas; wherein the first area is used to represent the area where the head-end monitoring point in the two areas is located; Based on the matrix elements and topological structures corresponding to any two regions, a fault region discrimination matrix is ​​constructed.

[0012] In a possible implementation, locating a single-phase grounding fault point of a target collector line according to a fault area discrimination matrix includes: According to the fault area discrimination matrix, the fault area where the single-phase grounding fault point of the target collector line is located is determined; Based on the fault area, locate the single-phase grounding fault point of the target collector.

[0013] In a possible implementation, determining the fault area where the single-phase grounding fault point of the target collector line is located according to the fault area discrimination matrix includes: In the fault area discrimination matrix, if k The row matrix elements are all less than 0, and the k If all the elements of the column matrix are greater than 0, it is determined that the single-phase grounding fault point of the target collector is located in the topological structure. k In the region, k is an integer not less than 1; In the fault area discrimination matrix, for any column, if the column m The row matrix elements are m +1 row matrix elements is 0, it is determined that the single-phase grounding fault point of the target collector line is located in the trunk area of ​​the topological structure; m An integer not less than 2.

[0014] In a possible implementation, an end monitoring point is provided in the head end region of the target collector line, and a tail end monitoring point is provided in the tail end region; Based on the fault area, locate the single-phase grounding fault point of the target collector line, including: Based on the fault area where the single-phase grounding fault point of the target collector line is located, determining the monitoring point corresponding to the fault area; Based on the arrival time of the transient traveling wave signal of the monitoring point corresponding to the fault area, the arrival time of the transient traveling wave signal of the monitoring point at the head end of the target collector line, and the matrix elements between the fault area and the head end area, a first fault distance calculation algebraic formula is obtained; Based on the arrival time of the transient traveling wave signal of the monitoring point corresponding to the fault area, the arrival time of the transient traveling wave signal of the monitoring point at the tail end of the target collector line, and the matrix elements between the fault area and the head end area, a second fault distance calculation algebraic formula is obtained; Based on the first fault distance calculation algebraic formula and the second fault distance calculation algebraic formula, the wave velocity is eliminated to locate the single-phase grounding fault point of the target collector line.

[0015] In a possible implementation, the actual length of each region is determined according to the following formula:

[0016] in, For Region i The actual length of is the monitoring point corresponding to the headend area; It is the second node in the backbone area; For Region i Corresponding monitoring points; For the main area i nodes; is the monitoring point corresponding to the tail end area; For the main area n -1 node; is the actual length of area 1; For Region i The actual length of For Region n The actual length of

[0017] In a possible implementation, determining the arrival time of the transient traveling wave signal of each monitoring point according to the transient traveling wave signal of each monitoring point includes: Performing noise reduction processing on the transient traveling wave signal of each monitoring point to obtain the transient traveling wave signal after noise reduction of each monitoring point; Reconstruct the transient traveling wave signal after noise reduction at each monitoring point to obtain the reconstructed transient traveling wave signal at each monitoring point; The reconstructed transient traveling wave signal of each monitoring point is demodulated, and the traveling wave head of the reconstructed transient traveling wave signal of each monitoring point is calibrated to determine the arrival time of the transient traveling wave signal of each monitoring point.

[0018] In a second aspect, an embodiment of the present invention provides a device for locating a collector single-phase grounding fault point, comprising: The acquisition module is used to obtain the topological structure of the target collector and the transient traveling wave signals of each monitoring area after a single-phase grounding fault occurs; the topological structure includes multiple areas, each area corresponds to at least one monitoring point; A calibration module, used to determine the arrival time of the transient traveling wave signal of each monitoring point according to the transient traveling wave signal of each monitoring point; A determination module is used to determine the fault distance between any two areas according to the arrival time of the transient traveling wave signal of each monitoring point, and to determine the actual length of each area according to the topological structure; A construction module, used to construct a fault region discrimination matrix based on the fault distance between any two regions, the actual length and topological structure of each region; The discrimination module is used to locate the single-phase grounding fault point of the target collector line according to the fault area discrimination matrix.

[0019] In a third aspect, an embodiment of the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the processor implements the steps of the method described in the first aspect or any possible implementation manner of the first aspect.

[0020] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method described in the first aspect or any possible implementation method of the first aspect are implemented.

[0021] The embodiment of the present invention provides a method, device, equipment and medium for locating a single-phase grounding fault point of a collector line. Compared with the traditional method, the embodiment of the present invention can complete the distance measurement and determine the arrival time of the transient traveling wave signal through the transient traveling wave signal corresponding to each monitoring point of the target collector line and the topological structure. Only one monitoring point can be set for each area, and the required monitoring points are few, which is highly convenient and economical. In addition, the embodiment of the present invention takes into account the deviation between the actual length and the calculated length of each area, constructs the corresponding fault area discrimination matrix through its actual length, and locates the fault point based on the fault area discrimination matrix, which can reduce the error of fault point positioning to meet the accuracy requirements of wind farm collector line fault positioning. Finally, the method provided by the embodiment of the present invention can automatically, quickly and effectively calculate the fault distance, is convenient for engineering application, does not require manual line inspection and on-site experiments, and maximizes the convenience of positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 It is a schematic diagram of wind farm collector line topology and monitoring point configuration; Figure 2 It is a flow chart of the implementation of the method for locating the single-phase grounding fault point of a collector line provided by an embodiment of the present invention; Figure 3 It is the flow chart of the signal decomposition process implemented by MRSVD; Figure 4 is a flow chart of an implementation of a method for locating a collector single-phase grounding fault point provided by another embodiment of the present invention; Figure 5 It is a structural schematic diagram of a device for locating a collector single-phase grounding fault point provided by an embodiment of the present invention; Figure 6 is a schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific embodiments will be described below in conjunction with the accompanying drawings.

[0026] Figure 1 It is a schematic diagram of wind farm collector topology and monitoring point configuration, such as Figure 1 As shown, in Figure 1 In the topological structure of the wind farm collector line, multiple areas can be included, and these areas can be divided into trunk areas and other areas according to the topological distribution. Among them, the first monitoring point on the system side trunk area can be defined as the head end monitoring point of the collector line, and the last monitoring point can be defined as the tail end monitoring point of the collector line. The straight line between the head end monitoring point and the tail end monitoring point is the trunk line, and the trunk line is divided into multiple trunk areas through the connection points of any two adjacent trunk lines and the collector line branches. Correspondingly, the monitoring points at the end of each collector line branch and the connection points between the branch and the trunk line form other areas.

[0027] Below Figure 1 Taking the provided wind farm collector line topology and monitoring point configuration schematic diagram as an example, the method provided in this embodiment is described in combination with other related drawings.

[0028] See also Figure 2 , Figure 2: is a flow chart of a method for locating a collector single-phase grounding fault point provided by an embodiment of the present invention, the method comprising: Step 110: Acquire the topological structure of the target collector line and the transient traveling wave signals of each monitoring area after a single-phase grounding fault occurs; wherein the topological structure includes multiple areas, and each area corresponds to at least one monitoring point.

[0029] In this embodiment, according to the topological structure of the target collector line, the high-voltage side of the wind turbine box transformer corresponding to the head end of the target collector line and the end of each collector line branch can be used as monitoring points, and a traveling wave acquisition device can be installed at each monitoring point to extract the transient traveling wave signals obtained at each monitoring point after a single-phase grounding fault occurs.

[0030] Step 120: Determine the arrival time of the transient traveling wave signal at each monitoring point according to the transient traveling wave signal at each monitoring point.

[0031] In this embodiment, due to the particularity of the wind farm collector line, the fault distance measurement method commonly used in the transmission and distribution line does not have good portability on the collector line. In addition, the commonly used methods in engineering are manual line inspection, field tests, etc., which are time-consuming and labor-intensive. The traveling wave method used in the embodiment of the present invention is based on theoretical research, and uses transient traveling wave information for fault distance measurement. Considering the problems existing in the application of the traveling wave method in the fault location problem of the wind farm collector line, the embodiment of the present invention processes the transient traveling wave signal of each monitoring point as follows to deal with the problems existing in the traveling wave method.

[0032] Accordingly, in an optional embodiment, determining the arrival time of the transient traveling wave signal of each monitoring point according to the transient traveling wave signal of each monitoring point in step 120 may include: Step 121: performing noise reduction processing on the transient traveling wave signal of each monitoring point to obtain the transient traveling wave signal after noise reduction of each monitoring point.

[0033] Step 122: reconstruct the transient traveling wave signal after noise reduction at each monitoring point to obtain a reconstructed transient traveling wave signal at each monitoring point.

[0034] Step 123: demodulate the reconstructed transient traveling wave signal of each monitoring point, and perform traveling wave head calibration on the reconstructed transient traveling wave signal of each monitoring point to determine the arrival time of the transient traveling wave signal of each monitoring point.

[0035] In this embodiment, in step 121, multi-resolution singular value decomposition (MRSVD) may be used to perform noise reduction processing on the transient traveling wave signal of each monitoring point to obtain the transient traveling wave signal after noise reduction of each monitoring point to improve its signal-to-noise ratio.

[0036] Figure 3 This is the flow chart of the signal decomposition process implemented by MRSVD. Figure 3 Step 121 will be described in detail.

[0037] MRSVD decomposition is based on the Hankel matrix. After obtaining the Hankel matrix, the transient traveling wave signal of each monitoring point is decomposed into an approximate component similar to the original signal by binary recursive decomposition. and a detail component In the process of MRSVD decomposing the transient traveling wave signals of each monitoring point, each layer of decomposition can reduce the noise of the transient traveling wave signals of each monitoring point to a certain extent.

[0038] The following takes the transient traveling wave signal of a monitoring point as an example to illustrate the MRSVD decomposition: Step 121.1 For a one-dimensional transient traveling wave signal , we can get the following second-order Hankel matrix H :

[0039] Step 121.2: Perform MRSVD decomposition on the obtained Hankel matrix to obtain multi-level approximate components and detail weight The overall structure diagram is as follows Figure 3 When the external noise is too strong, the wave arrival time information in the detail component may be affected by the noise, which may lead to deviations in the wave head calibration, or even the inability to perform the wave head calibration. Considering that the external noise mainly exists in the detail component Therefore, the embodiment of the present invention discards detail components containing a lot of noise layer by layer. Realize signal denoising.

[0040] Step 121.3: Select the optimal decomposition layer number for MRSVD denoising based on the preset threshold J . Decomposition level J When it is too large, the high-frequency components of the transient traveling wave signal about the wave arrival time information may be removed together with the noise, thus affecting the calibration of the wave arrival time; the number of decomposition layers J If the number of decomposition layers is too small, a large amount of noise in the signal is still not cleared, which still has a huge impact on the accuracy of wave arrival time calibration. J Layer and J The singular value difference of the -1 layer is used as the constraint condition for terminating the decomposition, namely:

[0041] When the singular value difference is less than the preset threshold When , the signal stops decomposing, and the corresponding number of decomposition layers is the optimal number of decomposition layers. J Among them, the preset threshold The approximate component energy of the same layer obtained by MRSVD decomposition and detail component energy The signal energy is measured by the 2-norm:

[0042] That is, the preset threshold corresponding to each layer is different.

[0043] Step 121.4: Decomposition by MRSVD J Layer Approximation Component Reconstruct the signal, and the resulting signal is the transient traveling wave signal after noise reduction at the monitoring point y ( n ).

[0044] After the noisy signal (the transient traveling wave signal of each monitoring point) is decomposed by MRSVD, the noise in the approximate component is effectively suppressed, but there are still multiple frequency components in the signal, and the wave arrival time cannot be directly calibrated. In order to further extract the wave arrival time information and reduce the possibility of residual noise, in step 122 of the embodiment of the present invention, the Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) method can be used to decompose and reduce noise, and then a new signal can be obtained by reconstructing some components. x ( n ), that is, the reconstructed transient traveling wave signal of each monitoring point. Compared with the general signal decomposition method, this method introduces an adaptive noise set, which can further reduce the interference of noise on the decomposition result and improve the reliability and stability of the decomposition.

[0045] Accordingly, for the transient traveling wave signal after noise reduction at any monitoring point, step 122 can be specifically implemented by the following steps: Step 122.1: Transform the de-noised transient traveling wave signal y ( n ) as the original signal N Add random noise ,get N A new signal (i∈[1,n]).

[0046]

[0047] Step 122.2:N The new signals are decomposed by EMD to obtain N indivual Components and average to get the first IMF 1 component, and then the original signal is combined with the first IMF Subtracting 1 component can get the residual signal r 1. Complete the first iteration:

[0048] Step 122.3: Calculate the residual signal r 1 is used as the original signal, and the above steps 122.1 and 122.2 are repeated until the residual signal obtained is a monotonic function and cannot be further decomposed. k Iterations. At this point, the denoised transient traveling wave signal is decomposed into:

[0049] in, k is the number of iterations.

[0050] Step 122.4: Considering that noise mainly interferes with the high-frequency components, while the impact on the middle-frequency components and low-frequency components is relatively small. To further avoid the impact of noise on the wave arrival time calibration, the embodiment of the present invention does not use the highest frequency component IMF 1Reconstruct the signal, but select the intrinsic mode components in the mid-high frequency band IMF 2 to reconstruct the signal and obtain the reconstructed transient traveling wave signal of each monitoring point x ( n ).

[0051] To further enhance the wave head feature in the signal, the embodiment of the present invention uses a high-order frequency-weighted energy operator (HFWEO) in step 123 to reconstruct the transient traveling wave signal of each monitoring point. x ( n ) to demodulate and accurately track the instantaneous mutation of the traveling wave signal energy, thereby calibrating the traveling wave head. HFWEO comes from the frequency-weighted energy operator (FWEO). Compared with FWEO, HFWEO further increases the weight of the instantaneous frequency, is more sensitive to the instantaneous energy impact in the signal, and improves the robustness of FWEO under interference. For discrete time signals x ( n ), that is, the reconstructed transient traveling wave signal of each monitoring point, the definition of HFWEO is as follows:

[0052] Where: x m ( n )for x ( n )of m Derivatives; for x ( n )of m Order frequency weighted energy operator, when the order m When increasing, the instantaneous frequency ω The weight will grow exponentially, which is more conducive to extracting high-frequency fault feature information. The embodiment of the present invention uses a third-order frequency-weighted energy operator, that is, m=3; Hilport transform is used to calibrate the traveling wave head of the reconstructed transient traveling wave signal of each monitoring point, and then determine the arrival time of the transient traveling wave signal of each monitoring point.

[0053] It can be seen that the weak fault feature extraction design using MRSVD-CEEMDAN and HFWEO in the embodiment of the present invention effectively overcomes the problem of weak traveling wave signal of single-phase grounding fault current of wind farm collector line (especially when the grounding resistance is large and the initial phase angle of the fault is small) and failure of traditional wave head calibration method.

[0054] Step 130: Determine the fault distance between any two areas according to the arrival time of the transient traveling wave signal at each monitoring point, and determine the actual length of each area according to the topological structure.

[0055] In this embodiment, in order to construct a fault region discrimination matrix, the embodiment of the present invention calculates and determines the fault distance between any two regions according to the principle of double-terminal traveling wave ranging. i Endpoints D i For the head end, area j Endpoints D j For the end, area i and Region j Fault distance between for:

[0056] in, For monitoring point D i and monitoring points D j The distance between is the transmission speed of the traveling wave signal; For monitoring point D i The arrival time of the corresponding transient traveling wave signal; For monitoring point D j The corresponding arrival time of the transient traveling wave signal.

[0057] according to Figure 1 Given the topology, the actual length of each region can be defined as follows:

[0058] in, For Region i The actual length of is the monitoring point corresponding to the headend area; It is the second node in the backbone area; For Region i Corresponding monitoring points; For the main area i nodes; is the monitoring point corresponding to the tail end area; For the main area n -1 node; is the actual length of area 1; For Region i The actual length of For Region n The actual length of

[0059] Step 140: construct a fault region discrimination matrix based on the fault distance between any two regions, the actual length and topological structure of each region.

[0060] Among them, based on the fault distance between any two areas, the actual length and topological structure of each area, a fault area discrimination matrix is ​​constructed, which may include: For any two areas, the difference between the fault distance and the actual length of the first area is used as the matrix element corresponding to the two areas; wherein the first area is used to characterize the area where the head-end monitoring point in the two areas is located.

[0061] Based on the matrix elements and topological structures corresponding to any two regions, a fault region discrimination matrix is ​​constructed.

[0062] In this embodiment, the area i and Region j For example, the fault distances corresponding to these two areas are With area i Actual length Subtract as a matrix element, that is, the region i and Region j The corresponding matrix elements are:

[0063] Among them, the main diagonal matrix elements in the fault area discrimination matrix are all replaced by "0".

[0064] Accordingly, combined Figure 1 , the obtained fault area discrimination matrix can be expressed as: .

[0065] Step 150: Locate the single-phase grounding fault point of the target collector line according to the fault area discrimination matrix.

[0066] In this embodiment, in order to locate the single-phase grounding fault point of the target collector line, it is necessary to first determine the area where the fault point is located, and then determine the specific location of the fault point based on the area.

[0067] Accordingly, in an optional embodiment, locating the single-phase grounding fault point of the target collector line according to the fault area discrimination matrix may include: According to the fault area discrimination matrix, the fault area where the single-phase grounding fault point of the target collector line is located is determined.

[0068] Based on the fault area, locate the single-phase grounding fault point of the target collector.

[0069] In this embodiment, since there are backbone areas and other areas (1~ n ), accordingly, determining the fault area where the single-phase grounding fault point of the target collector line is located needs to be judged in two situations. The following describes these two situations through an optional embodiment.

[0070] In an optional embodiment, determining the fault area where the single-phase grounding fault point of the target collector line is located according to the fault area discrimination matrix may include: In the fault area discrimination matrix, if k The row matrix elements are all less than 0, and the k If all the elements of the column matrix are greater than 0, it is determined that the single-phase grounding fault point of the target collector is located in the topological structure. k In the region, k An integer not less than 1.

[0071] In the fault area discrimination matrix, for any column, if the column m The row matrix elements are m +1 row matrix elements is 0, it is determined that the single-phase grounding fault point of the target collector line is located in the trunk area of ​​the topological structure; m An integer not less than 2.

[0072] In this embodiment, the area k For example, when the areak When a fault occurs, the first k The row matrix elements are all less than 0, and the k The column matrix elements are all greater than 0, where k is an integer not less than 1, that is k [1, n ] is established, and accordingly, the discrimination principle can be expressed as:

[0073] Based on this discrimination principle, the principle can be applied in reverse to determine whether the fault point is between 1 and n other areas in .

[0074] For its backbone area, regardless of the fault T Type node or T There is always m Line and m The multiplication of the elements of the +1 row matrix is ​​0. m [2, n -1], that is

[0075] Based on this discrimination principle, by applying the principle in reverse, it can be determined whether the fault point is in the backbone area.

[0076] According to the above two identification principles, the specific area where the fault point is located, that is, the fault area, can be quickly located.

[0077] In addition, in another optional embodiment, considering that there are many factors in actual engineering that affect the fault distance measurement accuracy, it may cause the matrix elements in the fault area discrimination matrix that should be 0 to be not 0. Therefore, when applying the fault area discrimination matrix to determine the fault area, a certain margin μ should be left for the comparison between the matrix elements and 0, that is, for any matrix element in the fault area discrimination matrix, if the matrix element is within the preset margin interval, the matrix element is corrected to "0". Correspondingly, the preset margin interval can be expressed as: [- μ , μ ].

[0078] After determining the fault area where the fault point is located, correspondingly, based on the fault area, locating the single-phase grounding fault point of the target collector line may include: Based on the fault area where the single-phase grounding fault point of the target collector line is located, a monitoring point corresponding to the fault area is determined.

[0079] Based on the arrival time of the transient traveling wave signal of the monitoring point corresponding to the fault area, the arrival time of the transient traveling wave signal of the target collector head end monitoring point, and the matrix elements between the fault area and the head end area, a first fault distance calculation algebraic formula is obtained.

[0080] Based on the arrival time of the transient traveling wave signal of the monitoring point corresponding to the fault area, the arrival time of the transient traveling wave signal of the target collector tail end monitoring point, and the matrix elements between the fault area and the head end area, a second fault distance calculation algebraic formula is obtained.

[0081] Based on the first fault distance calculation algebraic formula and the second fault distance calculation algebraic formula, the wave velocity is eliminated to locate the single-phase grounding fault point of the target collector line.

[0082] In this embodiment, considering that the wave speed of the traveling wave signal used in actual engineering is different, in order to eliminate the influence of the error on the ranging accuracy, the embodiment of the present invention adopts the redundant information method to eliminate the wave speed. k For example, according to Figure 2 The topological structure of this area is D k The first monitoring point is D 1. The tail monitoring point is D n According to the monitoring points corresponding to the area D k , Head end monitoring point D 1 and the tail monitoring point D n , eliminate the wave velocity, and recalculate the fault distance corresponding to the fault area, and use the recalculated fault distance as the final distance measurement result, that is, the position of the fault point relative to the head-end monitoring point.

[0083] Correspondingly, the first fault distance calculation algebraic formula can be expressed as:

[0084] in, For monitoring point D 1 and monitoring points D k The distance between For monitoring point k The arrival time of the transient traveling wave signal; Arrival time of the transient traveling wave signal at the head-end monitoring point.

[0085] The second fault distance calculation algebraic formula can be expressed as:

[0086] in, For monitoring point D k and monitoring points D n The distance between Arrival time of the transient traveling wave signal at the head-end monitoring point.

[0087] because ,have to:

[0088]

[0089] Monitoring Points D k The connection point with the backbone area is T k , can be obtained , and finally the wave velocity v The expression is:

[0090] The wave speed v Substitute the algebraic value of into the fault distance calculation formula corresponding to the fault area, and get the final distance measurement result, that is, the position of the fault point relative to the head-end monitoring point can be expressed as:

[0091] It can be seen that the method provided by the embodiment of the present invention first identifies the fault area through the fault area discrimination matrix, and then uses redundant information to eliminate the influence of the wave speed error on the ranging accuracy, further reducing the collector line fault location error, so as to meet the wind farm collector line fault location accuracy requirements.

[0092] Figure 4 FIG. 1 is a flow chart of a method for locating a collector single-phase grounding fault point provided by another embodiment of the present invention. Figure 4 As shown, the method provided in this embodiment can be described as: Step 1: Install a traveling wave acquisition device at the high-voltage side of the wind turbine box transformer at the head end of the wind farm collector line and at the end of each collector line branch. After a fault occurs, the traveling wave acquisition device is used to collect transient traveling wave signals corresponding to the monitoring points at each end.

[0093] Step 2: Use the multi-resolution singular value decomposition method to perform noise reduction processing on the transient traveling wave signal of each monitoring point to improve the signal-to-noise ratio of the transient traveling wave signal of each monitoring point.

[0094] Step 3: Use the adaptive noise-discriminating set empirical mode decomposition method to decompose and reconstruct the transient traveling wave signal after noise reduction at each monitoring point, so as to further highlight the prominent features of the traveling wave and obtain the reconstructed transient traveling wave signal of each monitoring point.

[0095] Step 4: Use a high-order frequency-weighted energy operator to detect signal singularity and calibrate the traveling wave head of the reconstructed transient traveling wave signal at each monitoring point to determine the arrival time of the transient traveling wave signal at each monitoring point.

[0096] Step 5: Use the double-terminal traveling wave method to calculate the distance corresponding to each monitoring area, and construct a fault interval discrimination matrix based on the calculated distance to discriminate the fault area through the fault interval discrimination matrix.

[0097] Step 6: Based on the topological structure of the target collector, it can be divided into other areas and trunk areas. If there is a fault area in the judgment matrix, k The row matrix elements are all less than 0, and the k If all column elements are greater than 0, the fault point is determined to be located in the region k In; if there is a fault area discrimination matrix k The row matrix elements are k+ If the multiplication of the matrix elements in a row is 0, the fault point is determined to be located in the backbone area. k middle.

[0098] Step 7: Based on the fault area, determine the first fault distance calculation algebraic formula and the second fault distance calculation algebraic formula, use redundant information elimination, the first fault distance calculation algebraic formula and the second fault distance calculation algebraic formula to eliminate the influence of wave speed on the ranging accuracy, and use the target collector head end monitoring point D 1 and the nearest measuring point passing the fault point D k The data obtained at both ends (monitoring points corresponding to the fault area) are used to recalculate the fault distance as the final distance measurement result.

[0099] It can be seen that the method provided by the embodiment of the present invention has the following beneficial effects compared with the traditional method: 1) First, the fault area is identified through the fault area discrimination matrix, and then the influence of the wave velocity error on the ranging accuracy is eliminated by using redundant information, further reducing the collector line fault location error, so that it meets the wind farm collector line fault location accuracy requirements; 2) It is only necessary to install measurement points at the head end of the collector line and the high-voltage side of the wind turbine box transformer at the end of each collector line branch to complete the ranging, requiring fewer measurement points and good economy; 3) The fault distance can be calculated automatically, quickly and effectively, which is convenient for engineering application and does not require manual line inspection and field experiments; 4) The weak fault feature extraction design using MRSVD-CEEMDAN and HFWEO effectively overcomes the problem of weak traveling wave signal of single-phase grounding fault current of wind farm collector lines (especially when the grounding resistance is large and the initial phase angle of the fault is small), and the failure of traditional wave head calibration methods.

[0100] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0101] The following is an embodiment of the device of the present invention. For details not described in detail therein, reference may be made to the corresponding method embodiment described above.

[0102] Figure 5 The structure diagram of the device for locating the single-phase grounding fault point of a collector provided by an embodiment of the present invention is shown. For the convenience of explanation, only the part related to the embodiment of the present invention is shown, which is described in detail as follows: like Figure 5 As shown, the positioning device 5 for the single-phase grounding fault point of the collector line includes: The acquisition module 51 is used to obtain the topological structure of the target collector and the transient traveling wave signals of each monitoring area after a single-phase grounding fault occurs; the topological structure includes multiple areas, each area corresponds to at least one monitoring point; The calibration module 52 is used to determine the arrival time of the transient traveling wave signal of each monitoring point according to the transient traveling wave signal of each monitoring point; A determination module 53, for determining the fault distance between any two areas according to the arrival time of the transient traveling wave signal of each monitoring point, and determining the actual length of each area according to the topological structure; A construction module 54 is used to construct a fault region discrimination matrix based on the fault distance between any two regions, the actual length and the topological structure of each region; The determination module 55 is used to locate the single-phase grounding fault point of the target collector line according to the fault area determination matrix.

[0103] In a possible implementation, the construction module 54 is specifically configured to: For any two areas, the difference between the fault distance and the actual length of the first area is used as the matrix element corresponding to the two areas; wherein the first area is used to represent the area where the head-end monitoring point in the two areas is located; Based on the matrix elements and topological structures corresponding to any two regions, a fault region discrimination matrix is ​​constructed.

[0104] In a possible implementation, the determination module 55 is specifically configured to: According to the fault area discrimination matrix, the fault area where the single-phase grounding fault point of the target collector line is located is determined; Based on the fault area, locate the single-phase grounding fault point of the target collector.

[0105] In a possible implementation, the determination module 55 is specifically configured to: In the fault area discrimination matrix, if k The row matrix elements are all less than 0, and the k If all the elements of the column matrix are greater than 0, it is determined that the single-phase grounding fault point of the target collector is located in the topological structure. k In the region, k is an integer not less than 1; In the fault area discrimination matrix, for any column, if the column m The row matrix elements are m +1 row matrix elements is 0, it is determined that the single-phase grounding fault point of the target collector line is located in the trunk area of ​​the topological structure; m An integer not less than 2.

[0106] In a possible implementation, an end monitoring point is provided in the head end region of the target collector line, and a tail end monitoring point is provided in the tail end region; The discrimination module 55 is specifically used for: Based on the fault area where the single-phase grounding fault point of the target collector line is located, determining the monitoring point corresponding to the fault area; Based on the arrival time of the transient traveling wave signal of the monitoring point corresponding to the fault area, the arrival time of the transient traveling wave signal of the monitoring point at the head end of the target collector line, and the matrix elements between the fault area and the head end area, a first fault distance calculation algebraic formula is obtained; Based on the arrival time of the transient traveling wave signal of the monitoring point corresponding to the fault area, the arrival time of the transient traveling wave signal of the monitoring point at the tail end of the target collector line, and the matrix elements between the fault area and the head end area, a second fault distance calculation algebraic formula is obtained; Based on the first fault distance calculation algebraic formula and the second fault distance calculation algebraic formula, the wave velocity is eliminated to locate the single-phase grounding fault point of the target collector line.

[0107] In a possible implementation, the actual length of each region is determined according to the following formula:

[0108] in, For Region i The actual length of is the monitoring point corresponding to the headend area; It is the second node in the backbone area; For Region i Corresponding monitoring points; For the main area i nodes; is the monitoring point corresponding to the tail end area; For the main area n -1 node; is the actual length of area 1; For Region i The actual length of For Region n The actual length of

[0109] In a possible implementation, the calibration module 52 is specifically configured to: Performing noise reduction processing on the transient traveling wave signal of each monitoring point to obtain the transient traveling wave signal after noise reduction of each monitoring point; Reconstruct the transient traveling wave signal after noise reduction at each monitoring point to obtain the reconstructed transient traveling wave signal at each monitoring point; The reconstructed transient traveling wave signal of each monitoring point is demodulated, and the traveling wave head of the reconstructed transient traveling wave signal of each monitoring point is calibrated to determine the arrival time of the transient traveling wave signal of each monitoring point.

[0110] Figure 6 Schematic diagram of an electronic device provided by an embodiment of the present invention. Figure 6 As shown, the electronic device 6 of this embodiment includes: a processor 60, a memory 61, and a computer program 62 stored in the memory 61 and executable on the processor 60. When the processor 60 executes the computer program 62, the steps in the above-mentioned embodiments of the method for locating a single-phase grounding fault point of a collector are implemented, for example Figure 2 Alternatively, when the processor 60 executes the computer program 62, the functions of each module / unit in the above-mentioned device embodiments are realized, for example Figure 5 The functions of each module / unit are shown.

[0111] Exemplarily, the computer program 62 may be divided into one or more modules / units, which are stored in the memory 61 and executed by the processor 60 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program 62 in the electronic device 6. For example, the computer program 62 may be divided into Figure 5 The modules / units shown.

[0112] The electronic device 6 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The electronic device 6 may include, but is not limited to, a processor 60 and a memory 61. Those skilled in the art will appreciate that Figure 6It is only an example of the electronic device 6 and does not constitute a limitation of the electronic device 6. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the electronic device may also include input and output devices, network access devices, buses, etc.

[0113] The processor 60 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0114] The memory 61 may be an internal storage unit of the electronic device 6, such as a hard disk or memory of the electronic device 6. The memory 61 may also be an external storage device of the electronic device 6, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electronic device 6. Further, the memory 61 may also include both an internal storage unit and an external storage device of the electronic device 6. The memory 61 is used to store the computer program and other programs and data required by the electronic device. The memory 61 may also be used to temporarily store data that has been output or is to be output.

[0115] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0116] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0117] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0118] In the embodiments provided by the present invention, it should be understood that the disclosed devices / electronic devices and methods can be implemented in other ways. For example, the device / electronic device embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as 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 mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0119] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0120] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0121] If the integrated module / unit 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 present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned embodiments of the method for locating the single-phase grounding fault point of each collector line can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device that can carry the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium.

[0122] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for locating a single-phase grounding fault point of a collector line, characterized in that: include: Acquire the topological structure of the target collector line and the transient traveling wave signals of each monitoring area after a single-phase grounding fault occurs; wherein the topological structure includes multiple areas, and each area corresponds to at least one monitoring point; Determine the arrival time of the transient traveling wave signal of each monitoring point according to the transient traveling wave signal of each monitoring point; Determine the fault distance between any two areas based on the arrival time of the transient traveling wave signal at each monitoring point, and determine the actual length of each area based on the topological structure; Based on the fault distance between any two regions, the actual length of each region and the topological structure, a fault region discrimination matrix is ​​constructed; The single-phase grounding fault point of the target collector line is located according to the fault area discrimination matrix.

2. The method for locating a collector line single-phase grounding fault point according to claim 1, characterized in that: The method of constructing a fault region discrimination matrix based on the fault distance between any two regions, the actual length of each region and the topological structure includes: For any two areas, the difference between the fault distance and the actual length of the first area is used as the matrix element corresponding to the two areas; wherein the first area is used to characterize the area where the head-end monitoring point in the two areas is located; Based on the matrix elements corresponding to any two regions and the topological structure, a fault region discrimination matrix is ​​constructed.

3. The method for locating a collector line single-phase grounding fault point according to claim 1, characterized in that: The locating the single-phase grounding fault point of the target collector line according to the fault area discrimination matrix comprises: Determine the fault area where the single-phase grounding fault point of the target collector line is located according to the fault area discrimination matrix; Based on the fault area, the single-phase grounding fault point of the target collector line is located.

4. The method for locating a collector line single-phase grounding fault point according to claim 3, characterized in that: The determining, according to the fault area discrimination matrix, the fault area where the single-phase grounding fault point of the target collector line is located comprises: In the fault area discrimination matrix, if k The row matrix elements are all less than 0, and the k If all the matrix elements in the columns are greater than 0, it is determined that the single-phase grounding fault point of the target collector line is located in the first k In the region, k is an integer not less than 1; In the fault area discrimination matrix, for any column, if the column m The row matrix elements are m +1 row matrix elements is 0, it is determined that the single-phase grounding fault point of the target collector line is located in the trunk area of ​​the topological structure; wherein, m An integer not less than 2.

5. The method for locating a collector line single-phase grounding fault point according to claim 3, characterized in that: The target collector line is provided with an end monitoring point in the head end region and a tail end monitoring point in the tail end region; The locating the single-phase grounding fault point of the target collector line based on the fault area includes: Based on the fault area where the single-phase grounding fault point of the target collector line is located, determining a monitoring point corresponding to the fault area; Based on the arrival time of the transient traveling wave signal of the monitoring point corresponding to the fault area, the arrival time of the transient traveling wave signal of the monitoring point at the head end of the target collector line, and the matrix elements between the fault area and the head end area, a first fault distance calculation algebraic formula is obtained; Based on the arrival time of the transient traveling wave signal of the monitoring point corresponding to the fault area, the arrival time of the transient traveling wave signal of the monitoring point at the tail end of the target collector line, and the matrix elements between the fault area and the head end area, a second fault distance calculation algebraic formula is obtained; Based on the first fault distance calculation algebraic formula and the second fault distance calculation algebraic formula, the wave velocity is eliminated to locate the single-phase grounding fault point of the target collector line.

6. The method for locating a collector line single-phase grounding fault point according to claim 1, characterized in that: The actual length of each area is determined according to the following formula: in, For Region i The actual length of is the monitoring point corresponding to the headend area; It is the second node in the backbone area; For Region i Corresponding monitoring points; For the main area i nodes; is the monitoring point corresponding to the tail end area; For the main area n -1 node; is the actual length of area 1; For Region i The actual length of For Region n The actual length of 7. The method for locating a collector line single-phase grounding fault point according to claim 1, characterized in that: Determining the arrival time of the transient traveling wave signal of each monitoring point according to the transient traveling wave signal of each monitoring point includes: Performing noise reduction processing on the transient traveling wave signal of each monitoring point to obtain the transient traveling wave signal after noise reduction of each monitoring point; Reconstruct the transient traveling wave signal after noise reduction at each monitoring point to obtain the reconstructed transient traveling wave signal at each monitoring point; The reconstructed transient traveling wave signal of each monitoring point is demodulated, and the traveling wave head of the reconstructed transient traveling wave signal of each monitoring point is calibrated to determine the arrival time of the transient traveling wave signal of each monitoring point.

8. A device for locating a single-phase grounding fault point of a collector line, characterized in that: include: The acquisition module is used to obtain the topological structure of the target collector and the transient traveling wave signals of each monitoring area after a single-phase grounding fault occurs; The topological structure includes a plurality of regions, each region corresponding to at least one monitoring point; A calibration module, used to determine the arrival time of the transient traveling wave signal of each monitoring point according to the transient traveling wave signal of each monitoring point; A determination module, used to determine the fault distance between any two areas according to the arrival time of the transient traveling wave signal of each monitoring point, and determine the actual length of each area according to the topological structure; A construction module, used for constructing a fault region discrimination matrix based on the fault distance between any two regions, the actual length of each region and the topological structure; A discrimination module is used to locate the single-phase grounding fault point of the target collector line according to the fault area discrimination matrix.

9. An electronic 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 computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method as claimed in any one of claims 1 to 7 are implemented.

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