Breakpoint positioning method and system for non-in-operation cable

Abstract

The invention discloses a breakpoint positioning method and system for a non-in-operation cable, and belongs to the field of cable monitoring and fault detection. The method comprises the following steps: injecting a high-frequency pulse signal into a non-in-operation cable in a normal state, and obtaining a pulse signal of the non-in-operation cable in the normal state; injecting a high-frequency pulse signal into a non-in-operation cable according to a preset time interval, and obtaining a pulse signal of the non-in-operation cable; carrying out differential processing on the pulse signal of the non-in-operation cable acquired each time and the pulse signal in the normal state, judging the differential signal, and taking the differential signal as a fault signal under the condition that a fault exists; decomposing the fault signal to obtain an SGC component containing cable breakpoint information; and calibrating the SGC component to obtain the arrival time of two wave heads of the fault signal in the component so as to calculate the position and time of the cable breakpoint. According to the method, the relative position and time information between the non-in-operation cable breakpoint and the transformer substation can be provided.

Description

Technical Field

[0001] The invention relates to a method and system for locating the breakpoint of a non-operating cable, and belongs to the field of cable monitoring and fault detection. Background Art

[0002] As the power infrastructure continues to expand, cables are laid for backup power transmission, and these cables are either in a non-operating state or waiting to be activated. However, these non-operating cables are easy targets for theft because they have no actual load and current flow, lack effective monitoring and detection methods, and are easy targets for theft. Traditional cable theft prevention monitoring methods usually rely on a simple judgment of whether the cable is physically damaged or broken, but often cannot provide accurate breakpoint location information, and cannot monitor abnormal events in real time when the cable is not online or not transmitting current.

[0003] In addition, most of the existing breakpoint detection methods focus on judging faults by changes in current or voltage when the cable is in normal operation; however, these methods are not applicable to the case of non-operating cables, because in the non-operating state, there is no current flowing in the cable, and it is impossible to judge whether the cable is damaged or stolen through conventional current and voltage monitoring methods; manual inspections also have problems such as poor timeliness and limited coverage, especially at night or when there is no one on duty, it is difficult to detect whether the cable has a breakpoint in time; due to the inability to obtain cable status data in real time, traditional methods have a large blind spot in the anti-theft monitoring of non-operating cables.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The present invention provides a method and system for locating the breakpoint of a non-operating cable, which can monitor the cable status in real time when the cable is in a non-operating state, and effectively locate the position and time of the cable breakpoint (that is, provide the relative position and time information between the cable breakpoint and the substation), thereby improving the anti-theft / fault monitoring capability of the cable in the power system and reducing the economic losses and project delays caused by cable failures.

[0006] The technical solution of the present invention is:

[0007] According to a first aspect of the present invention, a method for locating a breakpoint of a non-operating cable is provided, comprising the following steps:

[0008] Step 1: inject a high-frequency pulse signal into a non-operating cable in a normal state to obtain a pulse signal of the non-operating cable in a normal state;

[0009] Step 2: injecting a high-frequency pulse signal into the non-operating cable at a preset time interval to obtain a pulse signal of the non-operating cable;

[0010] Step 3: Perform differential processing on the pulse signal of the non-operating cable obtained each time and the pulse signal in the normal state, judge the differential signal, and use the differential signal as a fault signal if a fault exists;

[0011] Step 4: Decompose the fault signal to obtain the cable breakpoint information Quantity;

[0012] Step 5: Right The component is calibrated to obtain the arrival times of two wave heads of the fault signal in the component;

[0013] Step 6: Calculate the location and time of the cable breakpoint based on the calibrated wave head arrival time.

[0014] Furthermore, the acquisition of the signals in steps 1 and 2 is specifically as follows: a low-voltage high-frequency signal generating module and a high-frequency reflected wave detection module are installed at the incoming line of the substation; a high-frequency pulse signal is injected into the non-operating cable according to a preset time interval through the low-voltage high-frequency signal generating module; and the pulse signal of the cable is acquired in real time through the high-frequency reflected wave detection module.

[0015] Further, the judging of the differential signal adopts one of the following methods: obtaining an extreme value point of the differential signal, judging the amplitude of the differential signal.

[0016] Furthermore, the step of obtaining extreme value points for the differential signal is as follows: if the number of extreme value points is greater than a first preset value, it is considered that the pulse signal of the non-operating cable currently obtained has a fault.

[0017] Furthermore, the amplitude of the differential signal is judged as follows: if the maximum value of the amplitude of the differential signal is greater than a second preset value, it is considered that the pulse signal of the currently acquired non-operating cable has a fault.

[0018] Furthermore, the step 4 is specifically: using a clustering symplectic geometry algorithm to decompose the fault signal to obtain a Quantity.

[0019] Furthermore, the method of decomposing the fault signal by using the clustering symplectic geometry algorithm comprises the following steps:

[0020] Step 4.1: Reconstruct the fault signal to obtain the trajectory matrix;

[0021] Step 4.2: construct the first Hamiltonian matrix through the trajectory matrix; construct the second Hamiltonian matrix based on the first Hamiltonian matrix;

[0022] Step 4.3: The first Hamiltonian matrix and the second Hamiltonian matrix are both Hamiltonian matrices, so as to construct a symplectic orthogonal matrix to obtain the eigenvectors of the covariance symmetric matrix; the covariance symmetric matrix is ​​obtained by the autocorrelation analysis of the trajectory matrix;

[0023] Step 4.4: Based on the eigenvectors of the covariance symmetric matrix and the trajectory matrix, calculate the conversion coefficient matrix to construct a single set of trajectory matrices ;

[0024] Step 4.5: Transformed into a set of length The reconstructed signal of the output signal can be obtained by diagonally averaging the remaining single group trajectory matrices. Group reconstruction signal;

[0025] Step 4.6: Use the clustering algorithm to select the reconstructed signal corresponding to the normal value and perform linear superposition to obtain the hth , then Removed from the fault signal, the residual signal is recorded as ;

[0026] Step 4.7: Calculate the residual signal RMSE between the fault signal and

[0027] Step 4.8: Set the iteration threshold :like , then the residual signal Construct a new trajectory matrix and repeat steps 4.2 to 4.7 with the number of iterations h=h+1 until .

[0028] Furthermore, the clustering algorithm is a DBSCAN clustering algorithm.

[0029] Furthermore, the step 5 is specifically: The second-order transient extraction algorithm is used to calibrate the arrival times of the two wave heads of the fault signal in this component.

[0030] Furthermore, the step 6 is specifically as follows:

[0031] Step 6.1: Use the two wave head times obtained by STET and Substituting into the following formula we get:

[0032] ;

[0033] In the formula, is the distance between the cable breakpoint and the substation, is the wave velocity of the fault signal; and is the arrival time of the two wave heads of the fault signal;

[0034] Step 6.2: Using the obtained Bring in , calculate the cable break time .

[0035] According to a second aspect of the present invention, a breakpoint locating system for a non-operating cable is provided, comprising any one of the above-mentioned breakpoint locating methods for a non-operating cable.

[0036] According to a third aspect of the present invention, a processor is provided, wherein the processor is used to execute an operation, wherein the operation includes executing any one of the above-mentioned methods for locating a breakpoint of a non-operating cable.

[0037] The beneficial effects of the present invention are as follows: by adopting high-frequency pulse signal injection and reflected wave detection technology, the problem of fault location of non-operating cables is effectively solved. When the cable is not in operation, traditional current and voltage monitoring methods cannot play a role. The present invention, through the combination of differential processing and clustered symplectic geometry algorithm, can detect the state of the cable in real time and accurately locate the breakpoint position, avoiding the monitoring blind spot caused by the lack of current flow in the traditional method. Specifically, the present invention successfully calibrates the wave head arrival time of the fault signal through the clustered symplectic geometry algorithm and the second-order transient extraction algorithm, and calculates the fault position and time of the cable through the improved single-ended method, with high positioning accuracy. This method greatly improves the anti-theft and fault monitoring capabilities of non-operating cables in the power system, and provides a strong guarantee for the safe operation of power infrastructure. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a flow chart of the method for locating the breakpoint of a non-operating cable of the present invention;

[0039] Figure 2 This is a signal waveform diagram detected by the high-frequency reflected wave detection module under normal conditions;

[0040] Figure 3 This is the signal waveform diagram detected by the high-frequency reflected wave detection module when the breakpoint is 2 km away from the substation;

[0041] Figure 4 This is the fault signal waveform after time difference when the breakpoint is 2km away from the substation;

[0042] Figure 5 The clustering symplectic geometry algorithm is used to decompose the various modal diagrams of the fault signal when the breakpoint is 2 km away from the substation;

[0043] Figure 6 The clustering symplectic geometry algorithm is used when the breakpoint is 2 km away from the substation. Component diagram;

[0044] Figure 7 This is the wave head extraction diagram of the second-order transient extraction algorithm when the breakpoint is 2 km away from the substation;

[0045] Figure 8 This is the wave head extraction diagram of the second-order transient extraction algorithm when the breakpoint is 1 km away from the substation;

[0046] Fig. 9 This is the wave head extraction diagram of the second-order transient extraction algorithm when the breakpoint is 3 km away from the substation;

[0047] Fig.10 This is the wave head extraction diagram of the second-order transient extraction algorithm when the breakpoint is 4 km away from the substation;

[0048] Fig.11 This is the wave head extraction diagram of the second-order transient extraction algorithm when the breakpoint is 5 km away from the substation. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other arbitrarily without conflict.

[0050] like Figure 1-Figure 11 As shown, according to a first aspect of an embodiment of the present invention, a method for locating a breakpoint of a non-operating cable is provided, comprising the following steps:

[0051] Step 1: inject a high-frequency pulse signal into a non-operating cable in a normal state to obtain a pulse signal of the non-operating cable in a normal state;

[0052] Step 2: injecting a high-frequency pulse signal into the non-operating cable at a preset time interval to obtain a pulse signal of the non-operating cable;

[0053] In specific application, the operation can be as follows: install a low-voltage high-frequency signal generating module and a high-frequency reflected wave detection module at the incoming line of the substation; inject a high-frequency pulse signal into the non-operating cable according to a preset time interval through the low-voltage high-frequency signal generating module; obtain the pulse signal of the cable in real time through the high-frequency reflected wave detection module. Furthermore, the low-voltage high-frequency signal generating module can generate a high-frequency pulse signal, the frequency of the generated pulse signal can be adjusted within the range of 5000-16000Hz, the amplitude can be adjusted within the range of 12-48V, and the pulse signal emission interval of the pulse signal source is adjustable, and the interval time range is 0-10 minutes, so as to meet the detection needs of different types of cables;

[0054] Step 3: Perform differential processing on the pulse signal of the non-operating cable obtained each time and the pulse signal in the normal state, judge the differential signal, and use the differential signal as a fault signal if a fault exists;

[0055] The judging of the differential signal is specifically as follows:

[0056] Find extreme value points for the differential signal: if the number of extreme value points is greater than a first preset value, it is considered that the pulse signal of the non-operating cable currently obtained has a fault. Exemplarily, the first preset value is 10.

[0057] Alternatively, the amplitude of the differential signal is judged: if the maximum value of the differential signal amplitude is greater than a second preset value, it is considered that the pulse signal of the currently acquired non-operating cable has a fault. Exemplarily, the second preset value is 0.01 Vpu, where Vpu represents the amplitude of the high-frequency pulse signal emitted by the low-voltage high-frequency signal generating module.

[0058] Step 4: Decompose the fault signal using the clustering symplectic geometry algorithm to obtain the symplectic geometry component (SGC) containing the cable breakpoint information;

[0059] Decomposing the fault signal by using the clustering symplectic geometry algorithm comprises the following steps:

[0060] Step 4.1: Send the fault signal Reconstruct and obtain the trajectory matrix ;

[0061] X = [ x 1 x 1 + γ ⋯ x 1 + ( d − 1 ) γ x 2 x 2 + γ ⋯ x 2 + ( d − 1 ) γ ⋮ ⋮ ⋮ x m x m + γ ⋯ x m + ( d − 1 ) γ ]

[0062] Where n represents the length of the fault signal; ; is the embedding dimension; Delay time; delay time The value of is determined by the CC method, taking the delay time ; Embedding dimension The value of is determined by the power spectrum density of the fault signal: is the sampling frequency, Fault signal The frequency corresponding to the maximum peak of the power spectrum density; if the normalized frequency Less than a given threshold , then the embedding dimension , otherwise the embedding dimension ;

[0063] Step 4.2: Through the trajectory matrix Construct the first Hamiltonian matrix , the expression is as follows:

[0064] M = [ A 0 0 − A T ]

[0065] In the formula, is the symmetric covariance matrix, given by the trajectory matrix The results of autocorrelation analysis;

[0066] From the definition of Hamiltonian matrix, we can know that the squared Hamiltonian matrix still belongs to Hamiltonian matrix, so the second Hamiltonian matrix is ​​constructed ;

[0067] Step 4.3: , are all Hamiltonian matrices, thus constructing a symplectic orthogonal matrix , the expression is as follows:

[0068] Q T FQ = [ B R 0 B T ]

[0069] In the formula, is the sub-matrix after matrix transformation; is an upper triangular matrix with eigenvalues ; From the characteristics of the Hamiltonian matrix, we can see that the covariance symmetric matrix The characteristic values ​​of are: , eigenvalue The corresponding eigenvector is ;

[0070] Step 4.4: Based on the covariance symmetric matrix The eigenvector and trajectory matrix of , calculate the conversion coefficient matrix , thus constructing a single set of trajectory matrices ; Reconstruct trajectory matrix Depend on indivual Composition, which can be written as ;

[0071] because for The matrix of length needs to be converted into a matrix of length The reconstructed signal of The elements in are ,in , ,make ;

[0072] Step 4.5: According to the following formula Transformed into a set of length The reconstruction signal ; The remaining single group trajectory matrices are diagonally averaged in turn, so that the output signal decomposition can be obtained Group reconstruction signal;

[0073]

[0074] In the formula, , , ;

[0075] Step 4.6: Obtained by diagonal averaging Group reconstruction signal There is a periodic similarity between them, so the density-based spatial clustering algorithm (Density-Based Spatial Clustering of Applications with Noise, DBSCAN) is used to screen the reconstructed signals corresponding to the normal values ​​and perform linear superposition to obtain the hth , then From the fault signal The residual signal is denoted as ;

[0076]

[0077] In the formula, is the number of iterations (the initial value is 1);

[0078] The specific steps of the DBSCAN clustering algorithm are: first select the appropriate neighborhood value and density threshold As the input of the clustering algorithm, and The values ​​of are 0.05 and 4; then, the DBSCAN clustering algorithm is used to cluster the reconstructed signal, and the clustering results, core points, boundary points and outliers are output; finally, anomaly judgment is performed to take the largest class of reconstructed signals as normal values, and the others as abnormal values, and the reconstructed signal corresponding to the normal values ​​is obtained.

[0079] Step 4.7: Calculate the residual signal With fault signal The root mean square error (RMSE) between From the fault signal When it is removed, RMSE decreases accordingly, and as the number of iterations increases, RMSE gradually decreases; thus, RMSE can be used as the iteration termination condition to constrain the over-decomposition problem;

[0080]

[0081] Step 4.8: Set the iteration threshold :like , then the residual signal Construct a new trajectory matrix and repeat steps 4.2 to 4.7 with the number of iterations h=h+1 until , thus obtaining the final result.

[0082] Step 5: Right The second-order transient extraction transform (STET) algorithm is used to calibrate the arrival times of the two wave heads of the fault signal in the component. The specific steps are as follows:

[0083] Step 5.1: As a The function is short-time Fourier transform (STFT) to obtain , the calculation formula is:

[0084]

[0085] In the formula, is a sliding window, is the kernel function of Fourier transform, is the angular frequency, Represents the integrated variable in the short-time Fourier transform.

[0086] Step 5.2: The impact component is usually expressed in Dirac The function is expressed as:

[0087]

[0088] In the formula, is the amplitude of the impact component, For the moment of impact, combined , we can get:

[0089]

[0090] Ideally, the Dirac function The STFT transformation result should be concentrated at the time when the impact occurs , the time-frequency analysis algorithm usually uses the time-frequency energy of the two-dimensional group delay rearrangement divergence as , the calculation formula is as follows:

[0091]

[0092] Where: is the real part; for The derivative with respect to the frequency variable.

[0093] Combination of the above ,get:

[0094]

[0095] The above formula shows that the two-dimensional group delay of the STFT result of the impact component is focused on the occurrence time ;

[0096] Step 5.3: According to this characteristic, the second-order transient extraction transformation first constructs a second-order frequency change model, namely:

[0097]

[0098] In the formula, is the Fourier transform of the signal, and is the amplitude and phase of the signal in the frequency domain, and is the signal phase The first and second derivative functions of It is a symbol used to refer to frequency changes during frequency analysis. It is usually used with other frequency variables to help analyze and understand the characteristics of signals in the frequency domain.

[0099] Step 5.4: With the help of window function , the STFT transformation of the above formula is:

[0100]

[0101] In the formula, is the width of the window function.

[0102] Calculating 2D group delay paths , the calculation formula is:

[0103]

[0104] In the formula, for The derivative of a variable with respect to time.

[0105] Step 5.5: Based on the two-dimensional group delay calculation method defined in the above formula and taking into account the relevant constraints, the two-dimensional group delay of the second-order frequency variation model can be expressed as follows:

[0106]

[0107] In the formula, for The derivative with respect to the frequency variable, for The derivative of a variable with respect to time, for The derivative of a variable with respect to time, for The derivative with respect to the frequency variable.

[0108] Step 5.6: Using the above formula, we can get The second-order transient transformation of is:

[0109]

[0110] In the formula, Indicates the signal at time An instantaneous change occurs at is the Dirac function, which represents the impulse or instantaneous signal at a specific time point.

[0111] Step 5.7: Select the first two mutation value times after the second-order transient transformation as the two wave head arrival times of the fault signal and .

[0112] Step 6: Combined with the calibrated wave front arrival time, use the improved single-ended method to calculate the location and time of the cable breakpoint.

[0113] Step 6.1: Use the two wave head times obtained by STET and Substituting into the following formula we get:

[0114]

[0115] In the formula, is the distance between the cable breakpoint and the substation, is the wave velocity of the fault signal; , denote the positive sequence inductance and capacitance respectively;

[0116] Step 6.2: Using the obtained Bring in , calculate the cable break time .

[0117] By applying the above technical solution and introducing the clustering symplectic geometry algorithm, the present invention can efficiently decompose the fault signal and deeply explore its multiple features, especially in the complex reflection wave scenario generated by the cable breakpoint, which has significant advantages. The algorithm decomposes the signal into multiple sub-signals and classifies them based on geometric characteristics, thereby accurately extracting the high-frequency components of the fault signal. At the same time, the second-order transient extraction algorithm is used to accurately calibrate the wave head arrival time, which has higher sensitivity and timeliness than the traditional first-order method. By analyzing the second-order derivative characteristics of the signal, the algorithm can accurately identify the rapid change points in the waveform to ensure the accurate calibration of the arrival time of the reflected wave. The combination of the two technologies enables the present invention to have excellent positioning accuracy in cable fault location, thereby providing a strong guarantee for the safe operation of the power system.

[0118] The method of the present invention is now applied to a simulation environment for verification, and the simulation is carried out as follows:

[0119] The first set of simulations:

[0120] The frequency of the high-frequency pulse signal emitted by the low-voltage high-frequency signal generating module is set to 5000 Hz, and the amplitude is set to 48 V; the breakpoint position is set to 2 km, and the breakpoint time is set to 0.005 s. The cable line parameters are shown in Table 1.

[0121] Table 1

[0122]

[0123] Figure 2 This is the signal waveform diagram detected by the high-frequency reflected wave detection module when the cable is in normal condition. The figure shows that when the cable is in normal condition, the reflected wave waveform is stable and regular, and no abnormal waveform appears. This figure is used as a reference waveform for subsequent comparison with the abnormal signal waveform.

[0124] Figure 3 The signal waveform diagram of the high-frequency reflected wave detection module when the breakpoint is 2 km away from the substation. The figure shows that when the cable breaks, the waveform of the reflected wave changes significantly. The abnormal change of the waveform can promptly indicate the breakpoint fault caused by cable damage or theft.

[0125] Figure 4 The fault signal waveform after differential processing when the breakpoint is 2 km away from the substation. The figure shows the fault signal waveform after differential processing of the pulse signal at the breakpoint and the pulse signal in the normal state. Through this waveform, the system can identify the abnormal state of the cable and calculate the specific location of the fault.

[0126] Figure 5The figure shows the modal diagrams of the fault signal decomposed by the clustering symplectic geometry algorithm when the breakpoint is 2 km away from the substation. The figure shows the modal signals obtained by decomposing the fault signal by the clustering symplectic geometry algorithm. By analyzing the modal signals obtained, the system can identify the specific location of the cable breakpoint and provide accurate data for further positioning calculations.

[0127] Figure 6 The clustering symplectic geometry algorithm is used when the breakpoint is 2 km away from the substation. Component graph. This graph shows the components extracted in the clustering symplectic geometry algorithm. This component diagram reveals the abnormal signal characteristics generated when the cable is broken, which is used for subsequent wave head extraction and positioning calculation.

[0128] Figure 7 This is the wave head extraction diagram of the second-order transient extraction algorithm when the breakpoint is 2 km away from the substation. This figure shows how to accurately extract the wave head from the reflected signal through the second-order transient extraction algorithm. The extracted wave head information provides key data for subsequent positioning calculations, ensuring that the time and location of the cable breakpoint can be accurately determined. The figure shows two wave head times =0.0050071s and =0.0050213s, the distance between the cable breakpoint and the substation is calculated =1995.46m is 4.56m different from the set 2km, with a relative error of 0.23%, meeting the accuracy requirement of 1%; Cable break time =0.0050001s is 0.000001s different from the set value of 0.005s, and the relative error is 0.002%.

[0129] The second set of simulations:

[0130] When the breakpoint position is set to 1 km and the breakpoint time is set to 0.005 s, the frequency of the high-frequency pulse signal emitted by the low-voltage high-frequency signal generating module is set to 5000 Hz and the amplitude is set to 48V. Figure 8 This is the wave head extraction diagram of the second-order transient extraction algorithm when the breakpoint is 1 km away from the substation. Two wave head times can be obtained in the figure =0.0050036s and =0.0050107s, the distance between the cable breakpoint and the substation is calculated =997.73m is 2.27m different from the set 1km, and the relative error is 0.23%, which meets the accuracy requirement of 1%; Cable break time =0.00500005s is 0.0000005s different from the set value of 0.005s, and the relative error is 0.001%.

[0131] The third set of simulations:

[0132] When the breakpoint position is set to 3 km and the breakpoint time is set to 0.005 s, the frequency of the high-frequency pulse signal emitted by the low-voltage high-frequency signal generating module is set to 5000 Hz and the amplitude is set to 48V. Fig. 9 This is the wave head extraction diagram of the second-order transient extraction algorithm when the breakpoint is 3 km away from the substation. Two wave head times can be obtained in the figure =0.0050107s and =0.0050032s, the distance between the cable breakpoint and the substation is calculated =2993.18m is 6.82m different from the set 3km, and the relative error is 0.23%, which meets the accuracy requirement of 1%; Cable break time =0.00500005s is 0.0000005s different from the set value of 0.005s, and the relative error is 0.001%.

[0133] The fourth simulation:

[0134] When the breakpoint position is set to 4 km and the breakpoint time is set to 0.005 s, the frequency of the high-frequency pulse signal emitted by the low-voltage high-frequency signal generating module is set to 5000 Hz and the amplitude is set to 48V. Fig.10 This is the wave head extraction diagram of the second-order transient extraction algorithm when the breakpoint is 1 km away from the substation. Two wave head times can be obtained in the figure =0.0050142s and =0.0050427s, the distance between the cable breakpoint and the substation is calculated =4004.96m is 4.96m different from the set 4km, with a relative error of 0.12%, meeting the accuracy requirement of 1%; Cable break time =0.00499995s differs from the set value of 0.005s by 0.0000005s, and the relative error is 0.001%.

[0135] The fifth set of simulations:

[0136] When the breakpoint position is set to 5 km and the breakpoint time is set to 0.005 s, the frequency of the high-frequency pulse signal emitted by the low-voltage high-frequency signal generating module is set to 5000 Hz and the amplitude is set to 48V. Fig.11 This is the wave head extraction diagram of the second-order transient extraction algorithm when the breakpoint is 1 km away from the substation. Two wave head times can be obtained in the figure =0.0050178s and =0.0050534s, the distance between the cable breakpoint and the substation is calculated =5002.69m is 2.69m different from the set 5km, and the relative error is 0.12%, which meets the accuracy requirement of 1%; Cable break time =0.005s is the same as the set value of 0.005s, with no error.

[0137] The sixth simulation group:

[0138] To verify the superiority of the positioning method of the present invention, the method of the present invention is compared with the two methods of symplectic geometry mode decomposition-second-order transient extraction transform (symplectic geometry mode decomposition-second-order transient extraction transform, SGMD-STET) and variational mode decomposition-Teager energy operator (variational mode decomposition-teager energy operator, VMD-TEO), and the results are shown in Table 2; it can be seen from the table that at 1km, the absolute errors of SGM-STET and VMD-TEO are 25.83m and 30.38m, respectively, and the relative errors are 2.58% and 3.04%, respectively, both exceeding 1%, which cannot meet the positioning requirements. The average relative error of the method of the present invention is 0.20%, which is much lower than 1.26% and 1.81% of SGM-STET and VMD-TEO, indicating that the positioning accuracy of the method of the present invention is much higher than that of SGM-STET and VMD-TEO.

[0139] Table 2

[0140]

[0141] According to the second aspect of an embodiment of the present invention, a breakpoint locating system for a non-operating cable is provided, including a breakpoint locating method for a non-operating cable as described in any one of the above. Specifically comprising: a first module for executing step 1: injecting a high-frequency pulse signal into a non-operating cable in a normal state, and obtaining a pulse signal of the non-operating cable in a normal state; a second module for executing step 2: injecting a high-frequency pulse signal into the non-operating cable according to a preset time interval, and obtaining a pulse signal of the non-operating cable; a third module for executing step 3: performing differential processing on the pulse signal of the non-operating cable obtained each time and the pulse signal in a normal state, judging the differential signal, and in the case of a fault, using the differential signal as a fault signal; a fourth module for executing step 4: decomposing the fault signal to obtain a signal containing the cable breakpoint information. Component; The fifth module is used to perform step 5: The component is calibrated to obtain the two wave head arrival times of the fault signal in the component; the sixth module is used to execute step 6: combining the calibrated wave head arrival time, calculating the position and time of the cable breakpoint. For the parts not described in detail in the above modules, please refer to other descriptions of this embodiment.

[0142] According to a third aspect of an embodiment of the present invention, a processor is provided, wherein the processor is used to execute an operation, wherein the operation includes executing any one of the above-mentioned methods for locating a breakpoint of a non-operating cable.

[0143] The specific implementation modes of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A method for locating the breakpoint of a non-operating cable, characterized in that: The following steps are involved: Step 1: inject a high-frequency pulse signal into a non-operating cable in a normal state to obtain a pulse signal of the non-operating cable in a normal state; Step 2: injecting a high-frequency pulse signal into the non-operating cable at a preset time interval to obtain a pulse signal of the non-operating cable; Step 3: Perform differential processing on the pulse signal of the non-operating cable obtained each time and the pulse signal in the normal state, judge the differential signal, and use the differential signal as a fault signal if a fault exists; Step 4: Decompose the fault signal to obtain the cable breakpoint information Quantity; Step 5: Right The component is calibrated to obtain the arrival times of two wave heads of the fault signal in the component; Step 6: Calculate the location and time of the cable breakpoint based on the calibrated wave head arrival time.

2. The method for locating the breakpoint of a non-operating cable according to claim 1, characterized in that: The acquisition of the signals in steps 1 and 2 is specifically as follows: installing a low-voltage high-frequency signal generating module and a high-frequency reflected wave detection module at the incoming line of the substation; injecting a high-frequency pulse signal into the non-operating cable through the low-voltage high-frequency signal generating module according to a preset time interval; and acquiring the pulse signal of the cable in real time through the high-frequency reflected wave detection module.

3. The method for locating the breakpoint of a non-operating cable according to claim 1, characterized in that: The determination of the differential signal is performed by one of the following methods: obtaining an extreme value point of the differential signal, or determining the amplitude of the differential signal.

4. The method for locating the breakpoint of a non-operating cable according to claim 3, characterized in that: The step of obtaining extreme value points for the differential signal is as follows: if the number of extreme value points is greater than a first preset value, it is considered that the pulse signal of the non-operating cable currently obtained has a fault.

5. The method for locating the breakpoint of a non-operating cable according to claim 3, characterized in that: The amplitude of the differential signal is judged specifically as follows: if the maximum value of the amplitude of the differential signal is greater than a second preset value, it is considered that the pulse signal of the currently acquired non-operating cable has a fault.

6. The method for locating the breakpoint of a non-operating cable according to claim 1, characterized in that: The step 4 is specifically: using a clustering symplectic geometry algorithm to decompose the fault signal to obtain a signal containing cable breakpoint information. Quantity.

7. The method for locating the breakpoint of a non-operating cable according to claim 6, characterized in that: Decomposing the fault signal by using the clustering symplectic geometry algorithm comprises the following steps: Step 4.1: Reconstruct the fault signal to obtain the trajectory matrix; Step 4.2: construct the first Hamiltonian matrix through the trajectory matrix; construct the second Hamiltonian matrix based on the first Hamiltonian matrix; Step 4.3: The first Hamiltonian matrix and the second Hamiltonian matrix are both Hamiltonian matrices, so as to construct a symplectic orthogonal matrix to obtain the eigenvectors of the covariance symmetric matrix; the covariance symmetric matrix is ​​obtained by the autocorrelation analysis of the trajectory matrix; Step 4.4: Based on the eigenvectors of the covariance symmetric matrix and the trajectory matrix, calculate the conversion coefficient matrix to construct a single set of trajectory matrices ; Step 4.5: Transformed into a set of length The reconstructed signal of the output signal can be obtained by diagonally averaging the remaining single group trajectory matrices. Group reconstruction signal; Step 4.6: Use the clustering algorithm to select the reconstructed signal corresponding to the normal value and perform linear superposition to obtain the hth , then Removed from the fault signal, the residual signal is recorded as ; Step 4.7: Calculate the residual signal RMSE between the fault signal and Step 4.8: Set the iteration threshold :like , then the residual signal Construct a new trajectory matrix and repeat steps 4.2 to 4.7 with the number of iterations h=h+1 until .

8. The method for locating the breakpoint of a non-operating cable according to claim 7, characterized in that: The clustering algorithm is the DBSCAN clustering algorithm.

9. The method for locating the breakpoint of a non-operating cable according to claim 1, characterized in that: The step 5 specifically comprises: The second-order transient extraction algorithm is used to calibrate the arrival times of the two wave heads of the fault signal in this component.

10. The method for locating the breakpoint of a non-operating cable according to claim 1, characterized in that: The step 6 is specifically as follows: Step 6.1: Use the two wave head times obtained by STET and Substituting into the following formula we get: ； In the formula, is the distance between the cable breakpoint and the substation, is the wave velocity of the fault signal; and is the arrival time of the two wave heads of the fault signal; Step 6.2: Using the obtained Bring in , calculate the cable break time .

11. A breakpoint location system for a non-operating cable, characterized in that: The invention comprises a method for locating the breakpoint of a non-operating cable as described in any one of claims 1-10.

12. A processor, characterized in that: The processor is used to execute an operation, and the operation includes executing the breakpoint locating method of a non-operating cable as described in any one of claims 1-10.

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