A method and apparatus for active detection of dc cable condition

Abstract

The application provides a direct current cable state active detection method and device. The state detection signal of the direct current cable can be determined according to the equivalent inverse filter coefficient of the signal amplifier. The reflection signal is identified according to the state detection signal. The state of the direct current cable is actively detected according to the state detection signal and the reflection signal. It can be seen that the application realizes the identification of the reflection signal based on the equivalent inverse filter coefficient, and then realizes the online detection of the state of the direct current cable. Not only the detection range is expanded, the detection precision is improved, but also the anti-interference ability of the state detection can be improved.

Description

Technical Field

[0001] This application relates to the field of power system technology, specifically to a method and apparatus for active detection of the condition of DC cables. Background Technology

[0002] With the rapid development of wind power technology, the number and length of DC cables (including submarine cables) are constantly increasing. The causes of failures are complex, generally including external damage, water erosion, and environmental corrosion. DC cable failures account for more than 70% of all economic losses caused by equipment failures, and the repair costs and power losses are significantly higher than other types of equipment. From the perspective of equipment operation and maintenance and ensuring safety, there is an urgent need for DC cable condition monitoring.

[0003] Related technologies typically detect the condition of DC cables by detecting the reflected pulse signal at the fault point. This is generally performed when the DC cable is de-energized, i.e., offline testing of the DC cable. However, pulse signals are significantly affected by transmission attenuation and waveform distortion. The amplitude of the pulse signal decreases considerably after long-distance transmission, affecting the detection range and reducing detection accuracy. Furthermore, the smoothing of the pulse signal peaks also limits the detection range and reduces its interference resistance. Summary of the Invention

[0004] To address the problems of small detection range, low accuracy, and poor anti-interference capability in existing technologies, this application provides an active detection method and apparatus for DC cable status.

[0005] Firstly, this application provides an active method for detecting the condition of a DC cable, which may include: The status detection signal of the DC cable is determined based on the equivalent inverse filter coefficient of the signal amplifier.

[0006] The reflected signal is identified based on the state detection signal.

[0007] The condition of the DC cable is actively detected based on the condition detection signal and the reflected signal.

[0008] In some possible implementations, the state detection signal of the DC cable is determined based on the equivalent inverse filter coefficient of the signal amplifier, including: Construct the correspondence between the input voltage and the output voltage of the signal amplifier.

[0009] The corresponding relationship is fitted using a nonlinear fitting method to obtain the equivalent inverse filter coefficients.

[0010] The state detection signal is obtained by convolving the linear frequency modulated signal with the inverse filter coefficients.

[0011] Furthermore, the correspondence satisfies:

[0012] in, Indicates that the signal amplifier is in t Input voltage during the time period, Indicates that the signal amplifier is in t Output voltage during the time period This represents the equivalent filtering coefficient of the signal amplifier.

[0013] In other possible implementations, the reflected signal is identified based on the state detection signal, including: The status detection signal is injected into the DC cable through high-frequency impedance.

[0014] Construct a matched filter based on the state detection signal.

[0015] The state detection signal and the reflected signal are filtered by a matched filter to obtain the filtered signal.

[0016] The reflected signal is identified based on the filtered signal.

[0017] Furthermore, the reflected signal is identified based on the filtered signal, including: Obtain the actual time difference. The actual time difference indicates the time difference between the arrival of the state detection signal and the largest amplitude reflected signal in the filtered signal at the measurement point.

[0018] If the time deviation between the actual time difference and the preset time difference is less than or equal to the preset first deviation threshold, and the amplitude deviation between the reflected signal and the preset amplitude is less than or equal to the preset second deviation threshold, the DC cable is determined to be operating normally.

[0019] If the time deviation between the actual time difference and the preset time difference is less than or equal to the preset first deviation threshold, and the amplitude deviation between the reflected signal and the preset amplitude is greater than the preset second deviation threshold, it is determined that a fault has occurred at the end of the DC cable.

[0020] If the actual time difference deviates from the preset time difference by less than the preset first deviation threshold, a fault occurs in the middle section of the DC cable.

[0021] Optionally, in the case of normal operation of the DC cable or failure at the end of the DC cable, the reflected signal is the reflected signal from the end of the DC cable.

[0022] In the event of a fault in the middle section of a DC cable, the reflected signal is the reflected signal from the fault point.

[0023] In some other possible implementations, the state of the DC cable is actively detected based on the state detection signal and the reflected signal, including: Calculate the distance from the fault point to the beginning of the DC cable based on the actual time difference.

[0024] If the distance from the fault point to the beginning of the DC cable is less than the length of the DC cable, it is determined that the shielding layer and / or armor layer in the DC cable are in a faulty state.

[0025] For example, the distance from the fault point to the beginning of the DC cable satisfies:

[0026] in, This indicates the distance from the fault point to the beginning of the DC cable. This indicates the speed at which a signal travels through the conductor of a DC cable. Indicates the actual time difference.

[0027] Secondly, this application provides an active detection device for the condition of a DC cable, which may include: The determination module is used to determine the state detection signal of the DC cable based on the equivalent inverse filter coefficient of the signal amplifier.

[0028] The identification module is used to identify the reflected signal based on the state detection signal.

[0029] The detection module is used to actively detect the status of the DC cable based on the status detection signal and the reflected signal.

[0030] In some possible implementations, the module is specifically used for: Construct the correspondence between the input voltage and the output voltage of the signal amplifier.

[0031] The corresponding relationship is fitted using a nonlinear fitting method to obtain the equivalent inverse filter coefficients.

[0032] The state detection signal is obtained by convolving the linear frequency modulated signal with the inverse filter coefficients.

[0033] Optional, the correspondence satisfies:

[0034] in, Indicates that the signal amplifier is in t Input voltage during the time period, Indicates that the signal amplifier is in t Output voltage during the time period This represents the equivalent filtering coefficient of the signal amplifier.

[0035] Furthermore, the identification module is specifically used for: The status detection signal is injected into the DC cable through high-frequency impedance.

[0036] Construct a matched filter based on the state detection signal.

[0037] The state detection signal and the reflected signal are filtered by a matched filter to obtain the filtered signal.

[0038] The reflected signal is identified based on the filtered signal.

[0039] In some other possible implementations, the identification module is used for: Obtain the actual time difference. The actual time difference indicates the time difference between the arrival of the state detection signal and the largest amplitude reflected signal in the filtered signal at the measurement point.

[0040] If the time deviation between the actual time difference and the preset time difference is less than or equal to the preset first deviation threshold, and the amplitude deviation between the reflected signal and the preset amplitude is less than or equal to the preset second deviation threshold, the DC cable is determined to be operating normally.

[0041] If the time deviation between the actual time difference and the preset time difference is less than or equal to the preset first deviation threshold, and the amplitude deviation between the reflected signal and the preset amplitude is greater than the preset second deviation threshold, it is determined that a fault has occurred at the end of the DC cable.

[0042] If the actual time difference deviates from the preset time difference by less than the preset first deviation threshold, a fault occurs in the middle section of the DC cable.

[0043] Optionally, in the case of normal operation of the DC cable or failure at the end of the DC cable, the reflected signal is the reflected signal from the end of the DC cable.

[0044] In the event of a fault in the middle section of a DC cable, the reflected signal is the reflected signal from the fault point.

[0045] In some other possible implementations, the detection module is specifically used for: Calculate the distance from the fault point to the beginning of the DC cable based on the actual time difference.

[0046] If the distance from the fault point to the beginning of the DC cable is less than the length of the DC cable, it is determined that the shielding layer and / or armor layer in the DC cable are in a faulty state.

[0047] Optionally, the distance from the fault point to the beginning of the DC cable must satisfy:

[0048] in, This indicates the distance from the fault point to the beginning of the DC cable. This indicates the speed at which a signal travels through the conductor of a DC cable. Indicates the actual time difference.

[0049] In another aspect, this application also provides a computer device, including: one or more processors.

[0050] A processor is used to execute one or more programs.

[0051] The detection method described above is implemented when one or more programs are executed by one or more processors.

[0052] Furthermore, this application also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed, it implements the detection method described above.

[0053] Compared with the prior art, the beneficial effects of this application are as follows: The active DC cable condition detection method provided in this application determines the DC cable condition detection signal based on the equivalent inverse filter coefficient of the signal amplifier. The reflected signal is then identified based on the condition detection signal. The condition of the DC cable is actively detected based on both the condition detection signal and the reflected signal. It can be seen that this application achieves the identification of the reflected signal based on the equivalent inverse filter coefficient, thereby realizing online detection of the DC cable condition. This not only expands the detection range and improves the detection accuracy but also enhances the anti-interference capability of the condition detection.

[0054] This application obtains the status detection signal based on the linear frequency modulated signal and the inverse filter coefficient. It does not need to consider the peak shift problem caused by the difference in the attenuation rate of different frequency signals during submarine cable transmission. The linear frequency modulated signal has a stable wave velocity and is not affected by the transmission distance. In other words, the attenuation effect is small over long distances, making it more suitable for long-distance DC cables. Furthermore, the signal is compressed and enhanced by filtering, which further expands the detection range and significantly improves the accuracy of long-distance active fault location.

[0055] This application constructs a matched filter based on the state detection signal, and filters the state detection signal and the reflected signal based on the matched filter, thereby realizing the identification of the reflected signal, compensating for signal distortion, and further improving the accuracy of fault detection.

[0056] This application injects a status detection signal into a DC cable based on an externally shielded magnetic ring, which can increase the high-frequency impedance of the grounding. This increases the grounding impedance without affecting the power frequency grounding, thereby enabling the injected signal to directly enter the metal shielding layer and realize fault location and grounding detection.

[0057] This application enables the state detection signal to be injected into a metal shielding layer that is grounded at both ends. It is applicable not only to general DC cable fault location but also to grounding detection (i.e., state detection) of the metal shielding layer.

[0058] This application is based on a state detection signal with an amplitude lower than the safe operating voltage, and the signal injection point is in the metal shielding layer, which allows for live installation and operation, ensuring good safety. Attached Figure Description

[0059] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0060] Figure 1 This is a schematic flowchart of an active DC cable status detection method in an embodiment of this application; Figure 2 This is a schematic flowchart illustrating the determination of a DC cable status detection signal in an embodiment of this application. Figure 3 This is a schematic diagram of the impedance transformation wiring based on an externally shielded magnetic ring in an embodiment of this application; Figure 4 This is a comparison diagram of the waveforms of the state detection signal and the reflection signal before and after filtering in the embodiments of this application; Figure 5a This is a waveform comparison diagram of the DC cable under normal operation and fault conditions in the embodiments of this application; Figure 5b This is a waveform comparison diagram of the DC cable under normal operation and fault conditions in the embodiments of this application; Figure 6 This is a schematic structural diagram of an active DC cable status detection device in an embodiment of this application. Detailed Implementation

[0061] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0062] The terms "first," "second," etc., used in the specification, embodiments, claims, and drawings of this application are for distinguishing purposes only and should not be construed as indicating or implying relative importance or order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as including a series of steps or units. A method, system, product, or apparatus is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses.

[0063] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0064] Example 1: This application provides an active detection method for the status of a DC cable (such as a DC submarine cable). Figure 1 As shown, the detection method 100 includes the following steps: Step S1: Determine the state detection signal of the DC cable based on the equivalent inverse filter coefficient of the signal amplifier.

[0065] Step S2: Identify the reflected signal based on the state detection signal.

[0066] Step S3: Actively detect the status of the DC cable based on the status detection signal and the reflected signal.

[0067] In some possible implementations, in step S1, the state detection signal of the DC cable is determined based on the equivalent inverse filter coefficient of the signal amplifier, such as... Figure 2 As shown, it can specifically include: Step S11: Construct the correspondence between the input voltage and the output voltage of the signal amplifier.

[0068] Step S12: Use a nonlinear fitting method to fit the corresponding relationship to obtain the equivalent inverse filter coefficients.

[0069] Step S13: Convolve the linear frequency modulated signal with the inverse filter coefficients to obtain the state detection signal.

[0070] Furthermore, the correspondence satisfies: ; in, Indicates that the signal amplifier is in t Input voltage during the time period, Indicates that the signal amplifier is in t Output voltage during the time period This represents the equivalent filtering coefficient of the signal amplifier.

[0071] In some other possible implementations, step S2 involves identifying the reflected signal based on the state detection signal, including: The condition detection signal is injected into the DC cable through high-frequency impedance. For example... Figure 3 As shown, the high-frequency impedance (which can be a shielding magnetic ring, etc.) is connected in parallel with the signal amplifier, and the DC cable can include conductor 11, metal shielding layer 12 and armor layer 13.

[0072] Construct a matched filter based on the state detection signal.

[0073] The state detection signal and reflected signals (including reflected signals from the fault point and / or fault signals from the end) are filtered using a matched filter to obtain the filtered signal. It is understandable that when a DC cable experiences an abnormal grounding of its metal shield (abnormal grounding generally indicates a fault in the DC cable itself or damage to the protective sheath or armor layer), a grounding point reflected signal will appear.

[0074] The reflected signal is identified based on the filtered signal.

[0075] Optionally, the status detection signal needs to be limited by the following factors: (1) Amplitude: Low amplitude is required to meet on-site safety regulations, and reducing the output requirements of the signal generator can also improve operational safety and reduce costs.

[0076] (2) Time width: The compression gain is determined by the product of the time width and the bandwidth. Increasing the signal time width can improve the compression gain.

[0077] (3) Bandwidth: A large signal bandwidth can improve compression gain, but it also requires a higher center frequency. However, signals with higher frequencies attenuate relatively quickly, so the signal bandwidth should not be too wide.

[0078] Based on the above considerations, the linear frequency modulated (LFM) signal parameters are set as follows: amplitude not greater than 50V (safe operating voltage); center frequency not greater than 1MHz; bandwidth not greater than 2MHz; and duration not less than 200µs. Assuming a signal bandwidth of 400kHz and a total duration of 200µs, the theoretical compression gain is 40 times. That is, when a 50V LFM signal is injected, its signal-to-noise ratio can reach the level of a 2kV pulse signal after compression through matched filtering.

[0079] In this embodiment, a comparison of the waveforms of the state detection signal and the reflected signal before and after filtering is shown below. Figure 4 As shown. Figure 4In the diagram, the horizontal axis represents time, and the vertical axis represents the normalized amplitude. The orange solid line represents the waveforms of the state detection signal and the reflected signal before filtering, while the blue solid line represents the waveforms of the state detection signal and the reflected signal after filtering. It can be seen that the signal amplitude is unstable before filtering, and the midpoint of the waveform is offset, which will lead to subsequent positioning errors; the signal amplitude is stable after filtering, and the waveform is closer to the standard linear frequency modulated signal.

[0080] Furthermore, the reflected signal is identified based on the filtered signal, including: Obtain the actual time difference. The actual time difference indicates the time difference between the arrival of the state detection signal and the largest amplitude reflected signal in the filtered signal at the measurement point.

[0081] If the time deviation between the actual time difference and the preset time difference is less than or equal to the preset first deviation threshold, and the amplitude deviation between the reflected signal and the preset amplitude is less than or equal to the preset second deviation threshold, the DC cable is determined to be operating normally.

[0082] If the time deviation between the actual time difference and the preset time difference is less than or equal to the preset first deviation threshold, and the amplitude deviation between the reflected signal and the preset amplitude is greater than the preset second deviation threshold, it is determined that a fault has occurred at the end of the DC cable.

[0083] If the actual time difference deviates from the preset time difference by less than the preset first deviation threshold, a fault occurs in the middle section of the DC cable.

[0084] Optionally, in the case of normal operation of the DC cable or failure at the end of the DC cable, the reflected signal is the reflected signal from the end of the DC cable.

[0085] In the event of a fault in the middle section of a DC cable, the reflected signal is the reflected signal from the fault point.

[0086] In some other possible implementations, step S3 involves actively detecting the state of the DC cable based on the state detection signal and the reflected signal, including: The distance from the fault point to the beginning of the DC cable is calculated based on the actual time difference, that is, the fault point is located based on the actual time difference.

[0087] If the distance from the fault point to the beginning of the DC cable is less than the length of the DC cable, it is determined that the shielding layer and / or armor layer in the DC cable are in a faulty state.

[0088] For example, the distance from the fault point to the beginning of the DC cable satisfies:

[0089] in, This indicates the distance from the fault point to the beginning of the DC cable. This indicates the speed at which a signal travels through the conductor of a DC cable. Indicates the actual time difference.

[0090] In this embodiment, the waveforms of the DC cable under normal operation and fault conditions (including conductor, shielding, and armor faults) are compared as follows: Figure 5a and Figure 5b As shown. Figure 5a In the diagram, the horizontal axis represents time, and the vertical axis represents the normalized amplitude. The orange solid line represents the waveforms of the status detection signal and the end reflection signal under normal operating conditions, while the green solid line represents the waveforms of the status detection signal and the end reflection signal under fault conditions. Figure 5b In the diagram, the horizontal axis represents time, and the vertical axis represents compression gain. Figure 5b The solid blue line represents the waveform after filtering under normal operating conditions. Under normal operating conditions, the time difference between the beginning and end is fixed. Figure 5b The solid orange line represents the filtered waveform under fault conditions. Due to the fault in the DC cable, a fault-point reflection signal appears between the reflected signals at the ends, and its time difference is shorter than the time difference between the beginning and end under normal operating conditions. Furthermore, as... Figure 5a and Figure 5b As shown, the reflected signal is enhanced and the pulse width is compressed through filtering, thereby improving the anti-interference capability and positioning accuracy of active detection of DC cable status.

[0091] Example 2: Based on the same inventive concept, this application also provides an active detection device for the condition of a DC cable. For example... Figure 6 As shown, the detection device 200 may include: The determination module 201 is used to determine the state detection signal of the DC cable based on the equivalent inverse filter coefficient of the signal amplifier.

[0092] The identification module 202 is used to identify the reflected signal based on the state detection signal.

[0093] The detection module 203 is used to actively detect the state of the DC cable based on the state detection signal and the reflected signal.

[0094] In some possible implementations, the determining module 201 is specifically used for: Construct the correspondence between the input voltage and the output voltage of the signal amplifier.

[0095] The corresponding relationship is fitted using a nonlinear fitting method to obtain the equivalent inverse filter coefficients.

[0096] The state detection signal is obtained by convolving the linear frequency modulated signal with the inverse filter coefficients.

[0097] Optional, the correspondence satisfies:

[0098] in, Indicates that the signal amplifier is in t Input voltage during the time period, Indicates that the signal amplifier is in t Output voltage during the time period This represents the equivalent filtering coefficient of the signal amplifier.

[0099] Furthermore, the identification module 202 is specifically used for: The condition detection signal is injected into the DC cable through high-frequency impedance. For example... Figure 3 As shown, the high-frequency impedance (which can be a shielding magnetic ring, etc.) is connected in parallel with the signal amplifier, and the DC cable can include conductor 11, metal shielding layer 12 and armor layer 13.

[0100] Construct a matched filter based on the state detection signal.

[0101] The state detection signal and reflected signals (including reflected signals from the fault point and / or fault signals from the end) are filtered using a matched filter to obtain the filtered signal. It is understandable that when a DC cable experiences an abnormal grounding of its metal shield (abnormal grounding generally indicates a fault in the DC cable itself or damage to the protective sheath or armor layer), a grounding point reflected signal will appear.

[0102] The reflected signal is identified based on the filtered signal.

[0103] In this embodiment, a comparison of the waveforms of the state detection signal and the reflected signal before and after filtering is shown below. Figure 4 As shown. Figure 4 In the diagram, the horizontal axis represents time, and the vertical axis represents the normalized amplitude. The orange solid line represents the waveforms of the state detection signal and the reflected signal before filtering, while the blue solid line represents the waveforms of the state detection signal and the reflected signal after filtering. It can be seen that the signal amplitude is unstable before filtering, and the midpoint of the waveform is offset, which will lead to subsequent positioning errors; the signal amplitude is stable after filtering, and the waveform is closer to the standard linear frequency modulated signal.

[0104] In some other possible implementations, the identification module 202 is used for: Obtain the actual time difference. The actual time difference indicates the time difference between the arrival of the state detection signal and the largest amplitude reflected signal in the filtered signal at the measurement point.

[0105] If the time deviation between the actual time difference and the preset time difference is less than or equal to the preset first deviation threshold, and the amplitude deviation between the reflected signal and the preset amplitude is less than or equal to the preset second deviation threshold, the DC cable is determined to be operating normally.

[0106] If the time deviation between the actual time difference and the preset time difference is less than or equal to the preset first deviation threshold, and the amplitude deviation between the reflected signal and the preset amplitude is greater than the preset second deviation threshold, it is determined that a fault has occurred at the end of the DC cable.

[0107] If the actual time difference deviates from the preset time difference by less than the preset first deviation threshold, a fault occurs in the middle section of the DC cable.

[0108] Optionally, in the case of normal operation of the DC cable or failure at the end of the DC cable, the reflected signal is the reflected signal from the end of the DC cable.

[0109] In the event of a fault in the middle section of a DC cable, the reflected signal is the reflected signal from the fault point.

[0110] In some other possible implementations, the detection module 203 is specifically used for: Calculate the distance from the fault point to the beginning of the DC cable based on the actual time difference.

[0111] If the distance from the fault point to the beginning of the DC cable is less than the length of the DC cable, it is determined that the shielding layer and / or armor layer in the DC cable are in a faulty state.

[0112] Optionally, the distance from the fault point to the beginning of the DC cable must satisfy:

[0113] in, This indicates the distance from the fault point to the beginning of the DC cable. This indicates the speed at which a signal travels through the conductor of a DC cable. Indicates the actual time difference.

[0114] In this embodiment, the waveforms of the DC cable under normal operation and fault conditions (including conductor, shielding, and armor faults) are compared as follows: Figure 5a and Figure 5b As shown. Figure 5a In the diagram, the horizontal axis represents time, and the vertical axis represents the normalized amplitude. The orange solid line represents the waveforms of the status detection signal and the end reflection signal under normal operating conditions, while the green solid line represents the waveforms of the status detection signal and the end reflection signal under fault conditions. Figure 5b In the diagram, the horizontal axis represents time, and the vertical axis represents compression gain. Figure 5b The solid blue line represents the waveform after filtering under normal operating conditions. Under normal operating conditions, the time difference between the beginning and end is fixed. Figure 5b The solid orange line represents the filtered waveform under fault conditions. Due to the fault in the DC cable, a fault-point reflection signal appears between the reflected signals at the ends, and its time difference is shorter than the time difference between the beginning and end under normal operating conditions. Furthermore, as... Figure 5a and Figure 5b As shown, the reflected signal is enhanced and the pulse width is compressed through filtering, thereby improving the anti-interference capability and positioning accuracy of active detection of DC cable status.

[0115] Example 3: Based on the same inventive concept, this application also provides a computer device, which includes a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, and is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function, so as to implement the steps of the detection method provided in the above embodiments.

[0116] Example 4: Based on the same inventive concept, this application also provides a computer-readable storage medium, specifically a computer-readable storage medium (Memory). A computer-readable storage medium is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be high-speed RAM or non-volatile memory, such as at least one disk storage device. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the detection method provided in the above embodiments.

[0117] Those skilled in the art will understand that the embodiments of the application can be provided as a method, system, or computer program product. Therefore, the application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0118] The application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0119] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0120] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0121] The above are merely examples of the application and are not intended to limit the application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the application shall be included within the scope of the claims of the pending application.

Claims

1. A method for actively detecting the condition of a DC cable, characterized in that, include: The state detection signal of the DC cable is determined based on the equivalent inverse filter coefficient of the signal amplifier; The reflected signal is identified based on the state detection signal; The state of the DC cable is actively detected based on the state detection signal and the reflected signal.

2. The detection method according to claim 1, characterized in that, The step of determining the state detection signal of the DC cable based on the equivalent inverse filter coefficient of the signal amplifier includes: Construct the correspondence between the input voltage and the output voltage of the signal amplifier; The corresponding relationship is fitted using a nonlinear fitting method to obtain the equivalent inverse filter coefficients; The state detection signal is obtained by convolving the linear frequency modulated signal with the inverse filter coefficients.

3. The detection method according to claim 2, characterized in that, The correspondence satisfies: in, This indicates that the signal amplifier is in t Input voltage during the time period, This indicates that the signal amplifier is in t Output voltage during the time period This represents the equivalent filtering coefficient of the signal amplifier.

4. The detection method according to claim 1, characterized in that, The step of identifying the reflected signal based on the state detection signal includes: The status detection signal is injected into the DC cable through high-frequency impedance; Construct a matched filter based on the state detection signal; The state detection signal and the reflected signal are filtered according to the matched filter to obtain the filtered signal; The reflected signal is identified based on the filtered signal.

5. The detection method according to claim 4, characterized in that, The step of identifying the reflected signal based on the filtered signal includes: Obtain the actual time difference; the actual time difference is used to indicate the time difference between the state detection signal and the reflection signal with the largest amplitude in the filtered signal reaching the measurement point. If the time deviation between the actual time difference and the preset time difference is less than or equal to a preset first deviation threshold, and the amplitude deviation between the reflected signal and the preset amplitude is less than or equal to a preset second deviation threshold, then the DC cable is determined to be operating normally. If the time deviation between the actual time difference and the preset time difference is less than or equal to a preset first deviation threshold, and the amplitude deviation between the reflected signal and the preset amplitude is greater than a preset second deviation threshold, it is determined that a fault has occurred at the end of the DC cable. If the time deviation between the actual time difference and the preset time difference is less than the preset first deviation threshold, a fault occurs in the middle section of the DC cable.

6. The detection method according to claim 5, characterized in that, In the event that the DC cable is operating normally or that a fault occurs at the end of the DC cable, the reflected signal is a reflected signal from the end of the DC cable. In the event of a fault in the middle section of the DC cable, the reflected signal is a reflected signal from the fault point.

7. The detection method according to claim 5, characterized in that, The active detection of the state of the DC cable based on the state detection signal and the reflected signal includes: Calculate the distance from the fault point to the beginning of the DC cable based on the actual time difference; If the distance from the fault point to the beginning of the DC cable is less than the length of the DC cable, it is determined that the shielding layer and / or armor layer of the DC cable are in a fault state.

8. The detection method according to claim 7, characterized in that, The distance from the fault point to the beginning of the DC cable satisfies: in, This indicates the distance from the fault point to the beginning of the DC cable. This indicates the speed at which the signal travels through the conductor of the DC cable. This represents the actual time difference.

9. An active detection device for the condition of a DC cable, characterized in that, include: The determination module is used to determine the state detection signal of the DC cable based on the equivalent inverse filter coefficient of the signal amplifier; The identification module is used to identify the reflected signal based on the state detection signal; The detection module is used to actively detect the state of the DC cable based on the state detection signal and the reflected signal.

10. The detection device according to claim 9, characterized in that, The determining module is specifically used for: Construct the correspondence between the input voltage and the output voltage of the signal amplifier; The corresponding relationship is fitted using a nonlinear fitting method to obtain the equivalent inverse filter coefficients; The state detection signal is obtained by convolving the linear frequency modulated signal with the inverse filter coefficients.

11. The detection device according to claim 10, characterized in that, The correspondence satisfies: in, This indicates that the signal amplifier is in t Input voltage during the time period, This indicates that the signal amplifier is in t Output voltage during the time period This represents the equivalent filtering coefficient of the signal amplifier.

12. The detection device according to claim 9, characterized in that, The identification module is specifically used for: The status detection signal is injected into the DC cable through high-frequency impedance; Construct a matched filter based on the state detection signal; The state detection signal and the reflected signal are filtered according to the matched filter to obtain the filtered signal; The reflected signal is identified based on the filtered signal.

13. The detection device according to claim 12, characterized in that, The identification module is used for: Obtain the actual time difference; the actual time difference is used to indicate the time difference between the state detection signal and the reflection signal with the largest amplitude in the filtered signal reaching the measurement point. If the time deviation between the actual time difference and the preset time difference is less than or equal to a preset first deviation threshold, and the amplitude deviation between the reflected signal and the preset amplitude is less than or equal to a preset second deviation threshold, then the DC cable is determined to be operating normally. If the time deviation between the actual time difference and the preset time difference is less than or equal to a preset first deviation threshold, and the amplitude deviation between the reflected signal and the preset amplitude is greater than a preset second deviation threshold, it is determined that a fault has occurred at the end of the DC cable. If the time deviation between the actual time difference and the preset time difference is less than the preset first deviation threshold, a fault occurs in the middle section of the DC cable.

14. The detection device according to claim 13, characterized in that, In the event that the DC cable is operating normally or that a fault occurs at the end of the DC cable, the reflected signal is a reflected signal from the end of the DC cable. In the event of a fault in the middle section of the DC cable, the reflected signal is a reflected signal from the fault point.

15. The detection device according to claim 13, characterized in that, The detection module is specifically used for: Calculate the distance from the fault point to the beginning of the DC cable based on the actual time difference; If the distance from the fault point to the beginning of the DC cable is less than the length of the DC cable, it is determined that the shielding layer and / or armor layer of the DC cable are in a fault state.

16. The detection device according to claim 15, characterized in that, The distance from the fault point to the beginning of the DC cable satisfies: in, This indicates the distance from the fault point to the beginning of the DC cable. This indicates the speed at which the signal travels through the conductor of the DC cable. This represents the actual time difference.

17. A computer device, characterized in that, include: One or more processors; The processor is used to store one or more programs; When the one or more programs are executed by the one or more processors, the detection method as described in any one of claims 1 to 8 is implemented.

18. A computer-readable storage medium, characterized in that, It contains a computer program, which, when executed, implements the detection method as described in any one of claims 1 to 8.

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