Current detection method and device, computer equipment, readable storage medium and program product

Abstract

The invention relates to a current detection method and device, computer equipment, a computer readable storage medium and a computer program product. The method comprises the following steps: acquiring target current data of a target cable at a target interval and a current range corresponding to the target current data; obtaining a time constant of the target interval based on the target current data of the target interval; based on the time constant of the target interval and the target current critical point, obtaining a predicted residual duration for reaching the target current critical point; determining a prediction starting moment for preheating a next range of the current range according to the prediction residual duration, and preheating the next range based on the prediction starting moment; and collecting new current data according to the target sampling frequency in the next range. By adopting the method, the current signal loss caused by the current signal in the measuring range switching process can be avoided, so that more complete current data can be detected.

Description

Technical Field

[0001] The present application relates to the technical field of power cable insulation performance detection technology, and in particular to a current detection method, device, computer equipment, computer-readable storage medium, and computer program product. Background Art

[0002] As a key transmission medium in modern power systems, the reliability of the insulation performance of cross-linked polyethylene cables is directly related to the safe and stable operation of the power grid.

[0003] Traditionally, polarization / depolarization current detection has the advantage of sensitively reflecting the polarization characteristics of insulating dielectrics. By measuring the relaxation current decay process after the test voltage is removed, this technique can obtain three key parameters reflecting the insulation state: steady-state current value, decay time constant, and relaxation spectrum characteristics.

[0004] However, the traditional relay-type range switching mechanism has an inherent delay of 20-100ms. Due to the hysteresis switching, the traditional device loses the current data generated during the rapid decay of the current. Summary of the Invention

[0005] Based on this, it is necessary to provide a current detection method, device, computer equipment, computer-readable storage medium and computer program product that can detect complete current data to address the above technical problems.

[0006] In a first aspect, the present application provides a current detection method, the method comprising:

[0007] Obtaining target current data of a target cable at a target interval and a current range corresponding to the target current data; wherein the target cable is the cable after the test voltage is removed;

[0008] Based on the target current data of the target interval, a time constant of the target interval is obtained; the time constant is used to reflect the speed of release of polarized charge in the insulating medium of the cable;

[0009] Obtaining a predicted remaining time to reach the target current critical point based on the time constant of the target interval and the target current critical point; wherein the target current critical point is determined according to the range of the current measuring range;

[0010] Determine the predicted start time for preheating the next range of the current range based on the predicted remaining time, and preheat the next range based on the predicted start time; collect new current data through the next range according to the target sampling frequency; wherein the target sampling frequency is the sampling frequency corresponding to the next range.

[0011] In one embodiment, obtaining target current data of a target cable at a target interval includes:

[0012] acquiring initial current data of the target cable at the target interval;

[0013] Correction processing is performed on the initial current data of the target interval through a sliding window to obtain the target current data of the target interval; wherein the time length of the sliding window is greater than or equal to the target interval.

[0014] In one embodiment, obtaining the time constant of the target interval based on the target current data of the target interval includes:

[0015] Taking the natural logarithm of the target current data of the target interval to obtain logarithmic data;

[0016] Calculating the logarithmic data using the least squares method to obtain the slope of the straight line fitted to the logarithmic data;

[0017] Based on the slope, the time constant of the target interval is determined.

[0018] In one embodiment, obtaining the target predicted remaining time to reach the target current critical point based on the time constant of the target interval and the target current critical point includes:

[0019] Determining a first predicted remaining time to reach the target current critical point based on a time constant of the current target interval and the target current critical point;

[0020] When the first predicted remaining time is greater than or equal to a time threshold, determining a second predicted remaining time to reach the target current critical point based on a time constant of a subsequent target interval and the target current critical point; wherein the time threshold is the sum of a preheating time of the next range and the target interval; and the subsequent target interval is a time interval after the current target interval;

[0021] Using the second predicted remaining time as the target predicted remaining time;

[0022] When the first predicted remaining time is less than a threshold, the first predicted remaining time is used as the target predicted remaining time.

[0023] In one embodiment, the subsequent target interval includes at least one; each subsequent target interval corresponds to a candidate second predicted remaining time; and determining the second predicted remaining time to reach the target current critical point based on the time constant of the subsequent target interval and the target current critical point includes:

[0024] For each of the subsequent target intervals arranged in time sequence, determining a candidate second predicted remaining duration of each of the subsequent target intervals based on a time constant of the subsequent target interval and the target current critical point;

[0025] Until the candidate second predicted remaining time of the subsequent target interval is smaller than the threshold, the candidate second predicted remaining time of the subsequent target interval smaller than the threshold is determined as the second predicted remaining time to reach the target current critical point.

[0026] In one embodiment, the method further comprises:

[0027] Obtaining a predicted start time within a target cycle and an actual time when the target current critical point is reached; the duration of the target cycle is greater than the duration of the target interval;

[0028] Based on the predicted start time and the actual time, a prediction accuracy analysis result is obtained.

[0029] In a second aspect, the present application further provides a current detection device, comprising:

[0030] An acquisition module, configured to acquire target current data of a target cable at a target interval and a current range corresponding to the target current data; wherein the target cable is a cable after the test voltage is removed;

[0031] a time constant determination module, configured to obtain a time constant of the target interval based on target current data of the target interval; the time constant being configured to reflect a release rate of polarized charges in the insulating medium of the cable;

[0032] a prediction module, configured to obtain a predicted remaining time to reach the target current critical point based on the time constant of the target interval and the target current critical point; wherein the target current critical point is determined according to the range of the current measurement range;

[0033] A preheating switching module is used to determine the predicted start time of preheating the next range of the current range based on the predicted remaining time, and preheat the next range based on the predicted start time; new current data is collected through the next range according to the target sampling frequency; wherein the target sampling frequency is the sampling frequency corresponding to the next range.

[0034] In a third aspect, the present application further provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0035] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the above method when executed by a processor.

[0036] In a fifth aspect, the present application also provides a computer program product, comprising a computer program, which implements the steps of the above method when executed by a processor.

[0037] The above-mentioned current detection method, device, computer equipment, computer-readable storage medium and computer program product obtain the corresponding time constant through the target current data of the target interval; obtain the predicted remaining time to reach the target current critical point through the time constant and the target current critical point determined by the current range and the next range; analyze the target current data to predict the current attenuation trend, and predict the attenuation trend and the predicted remaining time in advance; determine the predicted start time according to the predicted remaining time, preheat the next range in advance at the predicted start time, and preheat the next range before the current data signal is lost, so that the complete current can be detected, avoiding the problem of current signal truncation caused by preheating and switching to the next range after reaching the target current critical point. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments of the present application or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 A diagram showing an application environment of a current detection method according to an embodiment;

[0040] Figure 2 1 is a flow chart of a current detection method according to an embodiment;

[0041] Figure 3 A schematic diagram of a process for determining a time constant in one embodiment;

[0042] Figure 4 A schematic diagram of a process for determining the remaining time of target prediction in one embodiment;

[0043] Figure 5 is a structural block diagram of a current detection device in one embodiment;

[0044] Figure 6 FIG. 1 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0046] The current detection method provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown. Among them, the current detection device 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be integrated on the server 104, or it can be placed on the cloud or other network servers. The server 104 obtains the target current data of the target cable in the target interval and the current range corresponding to the target current data; wherein, the target cable is the cable after the test voltage is removed; based on the target current data of the target interval, the time constant of the target interval is obtained; the time constant is used to reflect the speed of release of polarized charge in the insulating medium of the cable; based on the time constant of the target interval and the target current critical point, the predicted remaining time to reach the target current critical point is obtained; wherein the target current critical point is determined according to the range of the current range; the predicted start time of preheating the next range of the current range is determined according to the predicted remaining time, and the next range is preheated based on the predicted start time; the new current data is collected according to the target sampling frequency through the next range; wherein the target sampling frequency is the sampling frequency corresponding to the next range. The server 104 may be an independent physical server, a server cluster or a distributed system composed of multiple physical servers, or a cloud server that provides cloud computing services.

[0047] In an exemplary embodiment, Figure 2 As shown, a current detection method is provided, which is applied to Figure 1 The current detection device in the embodiment is used as an example to illustrate the method, which includes the following steps S202 to S208.

[0048] Step S202 : acquiring target current data of a target cable at a target interval and a current range corresponding to the target current data.

[0049] The target cable is the cable after the test voltage is removed. During the cable stressing phase, a high DC voltage is applied to the cable (for example, 220 kV DC applied to a 110 kV cable means a 220 kV DC test voltage is applied to a cable rated at 110 kV). This polarizes the dipoles / interface charges in the cable's insulation, forming bound charges. kV stands for kilovolts, a unit of voltage; DC stands for direct current. The high DC voltage is also the test voltage. Then, during the stress removal phase, the test voltage is removed, allowing the polarized charges to relax from their bound states, generating a weak, decaying current, known as the depolarization current.

[0050] The time difference between two adjacent time points is called a target interval, for example, 10 seconds (s). The target interval starts at the moment the test voltage is removed, denoted as t0. The current moment is t1, and the time difference between the current moment and the starting point is the target interval. The time difference between the current moment t1 and the next moment t2 is also the target interval. The number of target intervals can be one or more.

[0051] The measurement range refers to the range between the maximum and minimum values ​​of a physical quantity that an instrument can accurately measure. The measured signal can vary greatly in strength. For example, the depolarization current of an XLPE cable rapidly decays from μA to pA after voltage is removed. A single range cannot detect the entire depolarization current. Therefore, multiple ranges are used to detect the depolarization current. For example, after the test voltage is removed, when the current is in the early stages of decay, a large sampling range can be used to capture high current values, but this results in lower resolution. In the later stages of decay, a small sampling range can be used to obtain higher-resolution current data. During the switching between large and small ranges, the range is unavailable and sampling is stopped, resulting in loss of decaying current data.

[0052] Optionally, the current detection device obtains a current measuring range and target current data of a target cable at a target interval detected by the current measuring range.

[0053] Optionally, the current detection device uses the current range to detect the current of the cable after the test voltage is removed, and obtains target current data for the target cable in the target interval. The current detection device sends the current range used and the target current data for the target cable in the target interval obtained using the current range to the server. The server obtains the target current data for the target cable in the target interval and the current range corresponding to the target current data.

[0054] Furthermore, if there are three measurement ranges, these ranges are 20μA to 200nA (Channel 0), used to attenuate strong initial currents; 200nA to 2nA (Channel 1), used to attenuate moderate currents in the middle phase; and 2nA to 1pA (Channel 2), used to attenuate extremely weak currents in the final phase. μA stands for microamperes; nA for nanoamperes; and pA for picoamperes, all current units. The currents are arranged in descending order of current strength: 20μA to 200nA, greater than 200nA to 2nA, greater than 2nA to 1pA. The current detection device obtains the current range, for example, 20μA to 200nA. This range corresponds to the target current data. The target current data is collected from the starting point of the target cable after the voltage is removed, with a target interval of 10 seconds. Among them, Channel 0 (20μA-200nA): uses the G6K-2F-Y relay with a built-in resettable fuse protection circuit; Channel 1 (200nA-2nA): uses the IM23GR relay with a TVS diode overvoltage protection; Channel 2 (2nA-1pA): uses the FTR-B3CA004Z relay with an integrated Faraday shield.

[0055] Step S204 : obtaining a time constant of the target interval based on the target current data of the target interval.

[0056] Among them, the time constant is used to reflect the speed of release of polarized charge in the insulating medium of the cable.

[0057] Optionally, the current detection device obtains a time constant τ for each target interval based on target current data for at least one target interval. For example, the current detection device uses the time difference between t0 and t1 as a first target interval and obtains the time constant τ1 for the first target interval based on the target current data for the first target interval. The current detection device uses the time difference between t1 and t2 as a second target interval and obtains the time constant τ2 for the second target interval based on the target current data for the second target interval.

[0058] Step S206 : obtaining a predicted remaining time to reach the target current critical point based on the time constant of the target interval and the target current critical point.

[0059] The target current critical point is determined based on the range of the current measurement range. For example, if the current measurement range is 20μA to 200nA, the target current critical point is determined by using the lower limit of the current measurement range or the upper limit of the range of the next measurement range of the current measurement range. If the current detection device uses the lower limit of the current measurement range, that is, 200nA, when the current value decays to 120% of the lower limit of the current measurement range, that is, 240nA, the preheating of the next measurement range is triggered. The current detection device determines the predicted remaining time to decay to the target current critical point of 240nA based on the time constant τ of the target interval as of the current moment and the target current critical point of 240nA, such as x seconds.

[0060] Step S208 , determining a predicted start time for preheating the next range of the current range based on the predicted remaining time, and preheating the next range based on the predicted start time; and collecting new current data at the target sampling frequency through the next range.

[0061] The target sampling frequency is the sampling frequency corresponding to the next range.

[0062] Optionally, since the predicted remaining duration is a relative duration, we need to convert the relative duration into an absolute duration, which is the predicted start time. Therefore, the current detection device adds the current time to the predicted remaining duration to obtain the predicted start time. The predicted start time is the predicted start time for the next range to begin preheating. The current detection device preheats the next range when the time reaches the predicted start time; after the next range is preheated, the current detection device collects or detects new current data through the next range at the target sampling frequency.

[0063] For example, high-speed mode (1kHz) is used for μA-level current detection and utilizes a 5th-order Bessel filter; medium-speed mode (100Hz) is suitable for nA-level measurements and utilizes a 6th-order Butterworth filter; and low-speed mode (10Hz) is designed for pA-level signals and uses a 50ms integration time. The measurement range is 20μA to 200nA, which is channel 0, using a 1kHz standard sampling rate. The measurement range is 200nA to 2nA, which is channel 1, downsamples the 1kHz standard sampling rate to 100Hz. The measurement range is 200nA to 2nA, which is channel 2, downsamples the 100Hz sampling rate to 10Hz and increases the integration time by a factor of three. Sampling mode switching is automatic based on prediction results, ensuring a smooth and impactless transition.

[0064] Before acquiring the target current data for the target cable at the target interval and the corresponding current range, the current detection device performs zero and span calibration. Zero calibration involves continuously collecting data for 30 minutes with the input terminals short-circuited, ensuring a drift value of less than ±3fA (femtoamperes). Span calibration involves injecting a standard current using a Keithley 6430 source meter. Five calibration points, 10%, 30%, 50%, 70%, and 90%, are selected for each range.

[0065] In the above current detection method, the corresponding time constant is obtained through the target current data of the target interval; the predicted remaining time to reach the target current critical point is obtained through the time constant and the target current critical point determined by the current range and the next range; the target current data is analyzed to predict the current attenuation trend, and the attenuation trend and the predicted remaining time are predicted in advance; the predicted start time is determined according to the predicted remaining time, and the next range is preheated in advance at the predicted start time, and the next range is preheated before the current data signal is lost, so that the complete current can be detected, avoiding the problem of current signal interruption caused by preheating and switching to the next range after reaching the target current critical point.

[0066] In an exemplary embodiment, obtaining target current data of a target cable in a target interval includes: obtaining initial current data of the target cable in the target interval; and correcting the initial current data of the target interval through a sliding window to obtain target current data of the target interval.

[0067] The time length of the sliding window is greater than or equal to the target interval.

[0068] Optionally, the current detection device collects initial current data every 500 milliseconds (ms), collects data 20 times, and obtains initial current data within a target interval of 10 seconds. The initial current data collected in the last 10 seconds or more is collected through a sliding window to perform abnormal elimination processing to obtain target current data for the target interval.

[0069] Furthermore, the current time tn and the previous time tn-1 are considered. The starting point for voltage removal is t0. If the current time is t1, the time length of the sliding window is equal to the target interval. If the current time is not t1, but another time, such as t2, the time length of the sliding window is greater than the target interval. The sliding window can include times t0 to t2, that is, two target intervals, for a total of 40 initial current data points.

[0070] It should be noted that the target interval and sliding window are not limited.

[0071] In this embodiment, the accuracy of the data correction process can be guaranteed by using longer time series data.

[0072] In an exemplary embodiment, Figure 3 As shown, based on the target current data of the target interval, the time constant of the target interval is obtained, including steps S302 to S306.

[0073] Step S302 , taking the natural logarithm of the target current data of the target interval to obtain logarithmic data.

[0074] Optionally, the current detection device obtains 6 target current data of the target interval, for example, the current I at the starting point of 0.0s is 1000pA, and the logarithm ln(I) is 6.908; the current I at 0.5s is 606pA, and the logarithm ln(I) is 6.407; the current I at 1s is 368pA, and the logarithm ln(I) is 5.908; the current I at 1.5s is 223pA, and the logarithm ln(I) is 5.412; the current I at 2s is 135pA, and the logarithm ln(I) is 4.905.

[0075] Step S304 , calculating the logarithmic data using the least square method to obtain the slope of the straight line fitted to the logarithmic data.

[0076] Since the current decay model is I(t) = I0 exp(-t / τ), taking the logarithm yields ln(I) = ln(I0) + (-1 / τ) t, it can be transformed into a linear equation, y = a + kt, where the slope k = -1 / τ. I0 is the initial current corresponding to the start of the target interval. If the target interval is the time difference between t0 and t1, then I0 is the current corresponding to t0. If the target interval is the time difference between t1 and t2, then I0 is the current corresponding to t1.

[0077] Optionally, the current detection device calculates the logarithmic data through linear regression using the least squares method. The actual process is to plot the logarithmic data in a scatter plot (the horizontal axis is time and the vertical axis is logarithmic data). The straight line where these points lie is the straight line fitted to the logarithmic data, such as ln(I)=-1.000·t+6.908, where the slope k=-1.000 and the intercept a=6.908.

[0078] Step S306: Determine the time constant of the target interval based on the slope.

[0079] Optionally, the current detection device determines the time constant of the target interval based on the slope k by -1 / k, such as time constant τ = -1 / k = 1.0 s. If there are multiple target intervals, multiple time constants are determined accordingly, and the process for determining each time constant is the same as the above process.

[0080] In this embodiment, the process of extracting the time constant by linear regression can be simplified by converting the exponential decay physical process into a linear analyzable problem.

[0081] In an exemplary embodiment, Figure 4 As shown, based on the time constant of the target interval and the target current critical point, the target predicted remaining time to reach the target current critical point is obtained, including steps S402 to S406.

[0082] Step S402 : determining a first predicted remaining time to reach the target current critical point based on the time constant of the current target interval and the target current critical point.

[0083] Optionally, the current moment is tn, and the current detection device obtains the current target interval corresponding to the current moment, that is, the time difference between tn and tn-1. The current detection device obtains the target current critical point, such as the target current critical point between 20μA~200nA and 200nA~2nA, such as 240nA; or the target current critical point between 200nA~2nA and 2nA~1pA, such as 2.40nA. The current detection device uses the current decay model I(t)=I0·exp(-t / τ), where the time constant τ, I0, and I(t) are known. I(t) assigns the value of the target current critical point, and the time t can be obtained. t can be the first predicted remaining time.

[0084] Step S404, when the first predicted remaining time is greater than or equal to the time threshold, based on the time constant of the subsequent target interval and the target current critical point, determine the second predicted remaining time to reach the target current critical point; and use the second predicted remaining time as the target predicted remaining time.

[0085] The duration threshold is the sum of the warm-up duration and the target interval of the next range; if the warm-up duration is, for example, 20 seconds and the target interval is, for example, 10 seconds, then the duration threshold is 30 seconds. The subsequent target interval is the time interval after the current target interval. The current target interval is the time difference between time tn and time tn-1, and the subsequent target interval is the target interval after tn. As time passes, the current time can be tn+1, tn+2... The subsequent target interval can be, for example, the time difference between time tn and time tn+1, or the time difference between time tn+1 and time tn+2, and so on, which are not limited here.

[0086] Optionally, the current moment is tn, and the current target interval is the time difference between tn and tn-1. The current detection device performs the first calculation of the time constant τ1 and obtains the first predicted remaining duration, for example, 47.24 seconds, which is much greater than the duration threshold of 30 seconds. If the current moment plus the first predicted remaining duration is used to start the preheating range, that is, the predicted start time may not be enough to prepare, and there is enough time to calculate the time constant several times later. The current detection device can be based on the time difference between the subsequent target interval tn and tn+1. When the current moment at tn reaches tn+1, a new time constant τ2 is obtained by the time difference between tn and tn+1. Alternatively, when the current moment at tn+1 reaches tn+2, a new time constant τ3 is obtained by the time difference between tn+1 and tn+2. Due to cable aging, the second time constant τ2 is smaller than the first time constant τ1. Based on the current decay model, the second predicted remaining time to reach the target current critical point corresponding to the subsequent time interval is calculated. Since there will always be a second predicted remaining time that is less than the time threshold, that is, the second predicted remaining time is not enough to perform the next round of calculation plus the preheating time. Therefore, the second predicted remaining time closest to the current moment is used as the target predicted remaining time. The second predicted remaining time closest to the current moment can be obtained from the second calculation, the third calculation, or any calculation. The target predicted remaining time satisfies the conditions of being less than the time threshold and having the smallest time difference from the current moment.

[0087] Step S406 : When the first predicted remaining time is less than a threshold, the first predicted remaining time is used as a target predicted remaining time.

[0088] Optionally, if the first predicted remaining time is less than a threshold, it indicates that it is not enough to perform the next round of calculation and add the warm-up time. Therefore, the first predicted remaining time is used as the target predicted remaining time.

[0089] In this embodiment, the target prediction remaining time is calculated by obtaining the latest time constant, so as to ensure that the prediction start time is more accurate.

[0090] In an exemplary embodiment, the subsequent target interval includes at least one; each subsequent target interval corresponds to a candidate second predicted remaining time; based on the time constant of the subsequent target interval and the target current critical point, the second predicted remaining time to reach the target current critical point is determined, including: for each subsequent target interval arranged in time sequence, based on the time constant of the subsequent target interval and the target current critical point, the candidate second predicted remaining time of each subsequent target interval is determined; until there is a candidate second predicted remaining time of the subsequent target interval that is less than a threshold, the candidate second predicted remaining time of the subsequent target interval that is less than the threshold is determined as the second predicted remaining time to reach the target current critical point.

[0091] Optionally, the current detection device calculates a corresponding candidate second predicted remaining time for each subsequent target interval. Taking tn as the current moment, such as the time difference between moment tn and moment tn+1, a candidate second predicted remaining time 1 is obtained based on the current decay model. It can also be the time difference between moment tn+1 and moment tn+2, and a candidate second predicted remaining time 2 is obtained again based on the current decay model, and the candidate second predicted remaining time for each subsequent time interval can be further calculated. Since there will always be a candidate second predicted remaining time that is less than the time threshold, that is, the candidate second predicted remaining time is not enough to perform the next round of calculation plus the preheating time. Therefore, the second predicted remaining time closest to the current moment is used as the target predicted remaining time. That is, the candidate second predicted remaining time that satisfies the requirement of being less than the time threshold and having the smallest time difference from the current moment is selected as the target predicted remaining time.

[0092] In this embodiment, the remaining time is predicted through multiple rounds of calculations, thereby ensuring the accuracy of the predicted start time to the greatest extent.

[0093] In an exemplary embodiment, a predicted start time within a target cycle and an actual time when a target current critical point is reached are obtained; and a prediction accuracy analysis result is obtained based on the predicted start time and the actual time.

[0094] The target period is longer than the target interval; for example, if the target interval is 10 seconds, the target period is 2 hours.

[0095] Optionally, the current detection device counts the predicted start time within a target period of 2 hours and the actual time when the target current critical point is reached, and obtains a prediction accuracy analysis result based on the predicted start time and the actual time within a period of time.

[0096] Optionally, the predicted start time within the target period and the actual time when the target current critical point is reached are obtained, which may also include the adjustment of the sampling rate, the dwell time of each range, and the integrity of the target current data. The predicted start time, the actual time, the adjustment of the sampling rate, the dwell time of each range, and the integrity of the target current data are sent to the host computer; the host computer stores complete information including timestamp, current value, range status, etc. in SQLite format, and automatically outputs a test report, which includes statistics of the dwell time of each range; prediction accuracy analysis; signal integrity evaluation; and cable insulation status diagnosis conclusions.

[0097] In this embodiment, by obtaining the prediction accuracy analysis result, a method for adjusting the prediction start time in real time can be implemented according to the prediction accuracy analysis result.

[0098] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0099] Based on the same inventive concept, the present application also provides a current detection device for implementing the current detection method described above. The solution provided by this device is similar to the solution described in the method described above. Therefore, the specific limitations of one or more current detection device embodiments provided below can be found in the above-mentioned limitations of the current detection method and will not be repeated here.

[0100] In an exemplary embodiment, Figure 5 As shown, a current detection device is provided, including: an acquisition module 501, a time constant determination module 502, a prediction module 503 and a preheating switching module 504, wherein:

[0101] The acquisition module 501 is configured to acquire target current data of a target cable at a target interval and a current range corresponding to the target current data; wherein the target cable is a cable after the test voltage is removed.

[0102] The time constant determination module 502 is used to obtain the time constant of the target interval based on the target current data of the target interval; the time constant is used to reflect the speed of release of polarized charges in the insulation medium of the cable.

[0103] The prediction module 503 is used to obtain a predicted remaining time to reach the target current critical point based on the time constant of the target interval and the target current critical point; wherein the target current critical point is determined according to the range of the current measurement range.

[0104] The preheating switching module 504 is used to determine the predicted start time of the next range of the preheating of the current range based on the predicted remaining time, and preheat the next range based on the predicted start time; collect new current data according to the target sampling frequency through the next range; wherein the target sampling frequency is the sampling frequency corresponding to the next range.

[0105] In an exemplary embodiment, the acquisition module 501 is also used to obtain the initial current data of the target cable in the target interval; the initial current data of the target interval is corrected through a sliding window to obtain the target current data of the target interval; wherein the time length of the sliding window is greater than or equal to the target interval.

[0106] In an exemplary embodiment, the time constant determination module 502 is further used to take the natural logarithm of the target current data of the target interval to obtain logarithmic data; calculate the logarithmic data by the least squares method to obtain the slope of the straight line fitted by the logarithmic data; and determine the time constant of the target interval based on the slope.

[0107] In an exemplary embodiment, the prediction module 503 is also used to determine a first predicted remaining time to reach the target current critical point based on the time constant of the current target interval and the target current critical point; when the first predicted remaining time is greater than or equal to the time threshold, the second predicted remaining time to reach the target current critical point is determined based on the time constant of the subsequent target interval and the target current critical point; wherein the time threshold is the sum of the preheating time of the next range and the target interval; the subsequent target interval is the time interval after the current target interval; the second predicted remaining time is used as the target predicted remaining time; when the first predicted remaining time is less than the threshold, the first predicted remaining time is used as the target predicted remaining time.

[0108] In an exemplary embodiment, the subsequent target interval includes at least one; each subsequent target interval corresponds to a candidate second predicted remaining time; the prediction module 503 is further used to determine the candidate second predicted remaining time of each subsequent target interval arranged in time sequence based on the time constant of the subsequent target interval and the target current critical point; until there is a candidate second predicted remaining time of the subsequent target interval that is less than a threshold, the candidate second predicted remaining time of the subsequent target interval that is less than the threshold is determined as the second predicted remaining time that reaches the target current critical point.

[0109] In an exemplary embodiment, a current detection device further includes an analysis module for obtaining a predicted start time within a target cycle and an actual time when a target current critical point is reached; the duration of the target cycle is greater than the duration of the target interval; and based on the predicted start time and the actual time, a prediction accuracy analysis result is obtained.

[0110] Each module in the above-mentioned current detection device can be implemented in whole or in part through software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the corresponding operations of each module.

[0111] In an exemplary embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as shown in FIG. Figure 6 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O) and a communication interface. The processor, memory and input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the computer device is used to store current data. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a current detection method is implemented.

[0112] Those skilled in the art will understand that Figure 6The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0113] In one embodiment, a computer device is further provided, including a memory and a processor. The memory stores a computer program, and the processor implements the steps in the above method embodiments when executing the computer program.

[0114] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0115] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0116] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. In particular, any reference to memory, database, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the various embodiments provided herein may be, but are not limited to, general-purpose processors, central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), programmable logic devices (PLDs), quantum computing-based data processing logic devices, artificial intelligence (AI) processors, and the like.

[0117] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0118] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A current detection method, characterized in that: The method comprises: Obtaining target current data of a target cable at a target interval and a current range corresponding to the target current data; wherein the target cable is the cable after the test voltage is removed; Based on the target current data of the target interval, a time constant of the target interval is obtained; the time constant is used to reflect the speed of release of polarized charge in the insulating medium of the cable; Obtaining a predicted remaining time to reach the target current critical point based on the time constant of the target interval and the target current critical point; wherein the target current critical point is determined according to the range of the current measuring range; Determine the predicted start time for preheating the next range of the current range based on the predicted remaining time, and preheat the next range based on the predicted start time; collect new current data through the next range according to the target sampling frequency; wherein the target sampling frequency is the sampling frequency corresponding to the next range.

2. The method according to claim 1, characterized in that The obtaining of target current data of the target cable at the target interval includes: acquiring initial current data of the target cable at the target interval; Correction processing is performed on the initial current data of the target interval through a sliding window to obtain the target current data of the target interval; wherein the time length of the sliding window is greater than or equal to the target interval.

3. The method according to claim 1, characterized in that The step of obtaining the time constant of the target interval based on the target current data of the target interval includes: Taking the natural logarithm of the target current data of the target interval to obtain logarithmic data; Calculating the logarithmic data using the least squares method to obtain the slope of the straight line fitted to the logarithmic data; Based on the slope, the time constant of the target interval is determined.

4. The method according to claim 1, wherein The step of obtaining a target predicted remaining time to reach the target current critical point based on the time constant of the target interval and the target current critical point includes: Determining a first predicted remaining time to reach the target current critical point based on a time constant of the current target interval and the target current critical point; When the first predicted remaining time is greater than or equal to a time threshold, determining a second predicted remaining time to reach the target current critical point based on a time constant of a subsequent target interval and the target current critical point; wherein the time threshold is the sum of a preheating time of the next range and the target interval; and the subsequent target interval is a time interval after the current target interval; Using the second predicted remaining time as the target predicted remaining time; When the first predicted remaining time is less than a threshold, the first predicted remaining time is used as the target predicted remaining time.

5. The method according to claim 4, characterized in that The subsequent target interval includes at least one; each subsequent target interval corresponds to a candidate second predicted remaining time; and determining the second predicted remaining time to reach the target current critical point based on the time constant of the subsequent target interval and the target current critical point includes: For each of the subsequent target intervals arranged in time sequence, determining a candidate second predicted remaining duration of each of the subsequent target intervals based on a time constant of the subsequent target interval and the target current critical point; Until the candidate second predicted remaining time of the subsequent target interval is smaller than the threshold, the candidate second predicted remaining time of the subsequent target interval smaller than the threshold is determined as the second predicted remaining time to reach the target current critical point.

6. The method according to claim 1, characterized in that The method further comprises: Obtaining a predicted start time within a target cycle and an actual time when the target current critical point is reached; the duration of the target cycle is greater than the duration of the target interval; Based on the predicted start time and the actual time, a prediction accuracy analysis result is obtained.

7. A current detection device, characterized in that: The device comprises: An acquisition module, configured to acquire target current data of a target cable at a target interval and a current range corresponding to the target current data; wherein the target cable is a cable after the test voltage is removed; a time constant determination module, configured to obtain a time constant of the target interval based on target current data of the target interval; the time constant being configured to reflect a release rate of polarized charges in the insulating medium of the cable; a prediction module, configured to obtain a predicted remaining time to reach the target current critical point based on the time constant of the target interval and the target current critical point; wherein the target current critical point is determined according to the range of the current measurement range; A preheating switching module is used to determine the predicted start time of preheating the next range of the current range based on the predicted remaining time, and preheat the next range based on the predicted start time; new current data is collected through the next range according to the target sampling frequency; wherein the target sampling frequency is the sampling frequency corresponding to the next range.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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