CN116879683B - A method and device for identifying local defects in high-voltage power cables - Google Patents

Abstract

The application discloses a method and a device for identifying local defects of a high-voltage power cable, and relates to the technical field of cable defect identification. According to the high-voltage power cable local defect identification method, automatic inspection is performed along the extending direction of the high-voltage power cable, the cable temperature is detected and acquired, the cable temperature is processed, if abnormal temperature is detected, early warning is sent out, the local defect position of the high-voltage power cable can be accurately positioned through various technical means such as temperature detection, time domain reflection, current response analysis and the like, and specific defect types can be identified according to comparison of current response data and a pre-stored defect model, so that defect diagnosis and maintenance become more accurate and reliable, accurate defect positioning and type identification can be provided, reliability and practicability of an early warning system are improved, current response data acquisition is realized, and the current response data can be analyzed in combination with parameters of the pre-stored defect model, so that the specific defect types of the defect positions can be determined.

Description

A method and device for identifying local defects in high-voltage power cables

Technical field

The present invention relates to the technical field of cable defect identification, specifically a method and device for identifying local defects in high-voltage power cables.

Background technique

As the years of operation increase, local defects in high-voltage power cables will further develop into hard cable faults and cause electrical accidents. Therefore, it is necessary to carry out research on local defect detection of high-voltage power cables, timely detect and locate the initial local defects of the cable, and accurately identify the types of local defects of the cable on this basis, which will help analyze the causes of local defects of the cable and Providing guidance for operation and maintenance engineers to repair cables can effectively reduce power operating costs, improve the safety and stability of power system operations, and promote the sustainable and healthy development of the power industry.

Existing cable local defect diagnosis methods only focus on locating local defects in cables, but it is difficult to determine the type of local defects in high-voltage power cables based on current response data. Therefore, an identification method that can effectively identify local defects in high-voltage power cables is provided. It is a technical problem that needs to be solved urgently by those skilled in the art.

Contents of the invention

In view of the shortcomings of the existing technology, the present invention provides a method and device for identifying local defects in high-voltage power cables, which solves the problem that the existing methods for diagnosing local defects in cables only focus on locating local defects in cables, but are difficult to determine based on current response data. High voltage power cable local defect type problem.

In order to achieve the above objectives, the present invention is implemented through the following technical solutions: a method for identifying local defects in high-voltage power cables, which includes the following steps: using an automatic inspection robot to perform automatic inspections along the extension direction of the high-voltage power cables to detect and obtain the cable temperature; The cable temperature is processed, and if an abnormal temperature is detected, an early warning is issued; after receiving the early warning, the processing center uses the time domain reflection detection method to determine the distance between the abnormal temperature area and the detection starting point, and marks it as a defect location. If the defect location is not marked, then Cancel the early warning; apply a low-frequency electric field signal at the defect location to obtain current response data; compare the obtained current response data with the parameters of the pre-stored defect model to determine the defect type at the defect location; perform automatic patrol along the extension direction of the high-voltage power cable Inspect, detect and obtain the cable temperature, and process the cable temperature as follows: periodically detect the cable temperature within a set distance from the starting point of the inspection, record the detected cable temperature, and pre-process the detected cable temperature. Processing, including deleting abnormal temperature data; calculating the normal temperature comparison value of high-voltage power cables based on the preprocessed cable temperature; periodically sampling the cable verification temperature after leaving the end point of the set distance, and comparing it with the normal temperature comparison value of the cable. Obtaining the abnormal temperature coefficient, the cable verification temperature includes the temperature data periodically obtained during the automatic inspection process when the end point leaves the set distance and continues to maintain the original direction, and returns to the starting point of the inspection after leaving the end point of the set distance. Temperature data obtained periodically; if the abnormal temperature coefficient is greater than the set temperature threshold coefficient, it is determined that an abnormal temperature has been detected and an early warning is issued; the time domain reflection detection method is used to determine the distance between the abnormal temperature area and the detection starting point, and it is marked as a defect location The steps are as follows: send a pulse signal through a high-voltage power cable at the detection starting point, and record the sending time; when the detection starting point receives the reflected signal, record the receiving time; calculate the distance between the area with abnormal temperature and the detection starting point based on the time difference between the sending time and the receiving time. , marked as the defect location; the formula for calculating the distance between the area where the abnormal temperature is located and the starting point of the detection is as follows:

,/> is the distance between the area where the abnormal temperature is located and the detection starting point, where,/> is the receiving time,/> is the sending time,/> is the reference temperature/> The pulse signal propagation speed under is the temperature coefficient,/> is the dielectric constant of the cable insulation material,/> is the magnetic permeability of the cable,/> For the first/> within the set distance The sampled cable temperature,/> is the number of samples within the set distance,/> , is the normal temperature comparison value of high-voltage power cable,/> Calibration factor for normal temperature of high-voltage power cables.

Further, the calculation formula of the abnormal temperature coefficient is as follows:

, where,/> is the abnormal temperature coefficient,/> For the first/> Sub-sampled cable verification temperature,/> For the first/> within the set distance The sampled cable temperature,/> is the number of samples within the set distance,/> Verify the temperature of the cable compared to the normal temperature of high-voltage power cables/> The allowable error,/> is the normal temperature calibration factor for high-voltage power cables,/> is the temperature coefficient modulation factor.

Further, the process of applying a low-frequency electric field signal at the defect location and obtaining the current response data is as follows: applying a low-frequency electric field signal around the defect location to induce a current response in the high-voltage power cable; measuring the current response in real time and recording the change of the current with time. The data is written as a current response curve; the current response data is obtained through the current response curve, and the current response data includes amplitude, phase and waveform.

Furthermore, the calculation formula for comparing the obtained current response data with the response data of the pre-stored defect model is as follows:

Among them,/> is the fitness value,/> ,/> ,/> respectively amplitude/> , phase/> and waveform/> The weighting factor of ,/> ,/> ,/> are the amplitude, phase and waveform of the defect model respectively; if the fitness value approaches the fitness value of the defect model, the defect type at the defect location is determined.

Further, after the early warning is canceled at the unmarked defect location, the processing center still marks the high-voltage power cable as having temperature anomalies, and receives environmental information sent by the automatic inspection equipment. The environmental information includes environmental image information and heat source information around the cable, which is used to determine Causes of abnormal temperature of high-voltage power cables.

A device for identifying local defects in high-voltage power cables, including a cable temperature processing module, a defect location determination module, a current response data acquisition module and a defect type determination module, wherein:

The cable temperature processing module is used to conduct automatic inspections along the extension direction of high-voltage power cables through automatic inspection robots, detect and obtain the cable temperature, process the cable temperature, and issue an early warning if abnormal temperatures are detected. The automatic inspection The robot includes a walking mechanism for moving on high-voltage power cables, a temperature detection mechanism for periodic temperature detection, and a communication module for wireless communication;

The defect location determination module is used to determine the distance between the abnormal temperature area and the detection starting point using the time domain reflection detection method after the processing center receives the early warning, and marks it as the defect location. If the defect location is not marked, the early warning is cancelled;

The current response data acquisition module is used to apply a low-frequency electric field signal at the defect location to obtain current response data;

The defect type determination module is used to compare the obtained current response data with the parameters of the pre-stored defect model to determine the defect type of the defect location;

The steps for performing automatic inspection along the extension direction of high-voltage power cables, detecting and obtaining the cable temperature, and processing the cable temperature are as follows:

Periodically detect the cable temperature within a set distance from the starting point of the inspection, record the detected cable temperature, and preprocess the detected cable temperature, including deleting abnormal temperature data;

Calculate the normal temperature comparison value of high-voltage power cables based on the pre-processed cable temperature;

After leaving the end point of the set distance, the cable verification temperature is periodically sampled and compared with the normal temperature comparison value of the cable to obtain the abnormal temperature coefficient. The cable verification temperature includes the end point leaving the set distance and continuing to maintain the original direction for automatic The temperature data obtained periodically during the inspection process and the temperature data obtained periodically during the process of returning to the starting point of the inspection after leaving the end point of the set distance;

If the abnormal temperature coefficient is greater than the set temperature threshold coefficient, it is determined that an abnormal temperature has been detected and an early warning is issued;

Use the time domain reflection detection method to determine the distance between the area where the abnormal temperature is located and the starting point of the detection. The steps to mark the defect location are as follows:

The pulse signal is sent through the high-voltage power cable at the starting point of the detection, and the sending time is recorded;

When the detection starting point receives the reflected signal, the reception time is recorded;

Calculate the distance between the area where the abnormal temperature is located and the detection starting point based on the time difference between the sending time and the receiving time, and mark it as the defect location;

The formula for calculating the distance between the area where the abnormal temperature is located and the detection starting point is as follows:

,/> is the distance between the area where the abnormal temperature is located and the detection starting point, where,/> is the receiving time,/> is the sending time,/> is the reference temperature/> The pulse signal propagation speed under is the temperature coefficient,/> is the dielectric constant of the cable insulation material,/> is the magnetic permeability of the cable,/> For the first/> within the set distance The sampled cable temperature,/> is the number of samples within the set distance,/> , is the normal temperature comparison value of high-voltage power cable,/> Calibration factor for normal temperature of high-voltage power cables.

The invention has the following beneficial effects:

(1) This method of identifying local defects in high-voltage power cables can accurately locate local defects in high-voltage power cables through a variety of technical means, such as temperature detection, time domain reflection, current response analysis, etc., and can accurately locate local defects in high-voltage power cables based on current response data. Compared with the pre-existing defect model, specific defect types are identified, making defect diagnosis and maintenance more accurate and reliable, providing accurate defect location and type identification, reducing false alarm rates, and improving the reliability and practicality of the early warning system. It realizes the acquisition of current response data and combines it with the parameters of the pre-existing defect model to analyze the current response data to determine the specific defect type of the defect location;

(2) This high-voltage power cable local defect identification method not only focuses on the current response data of the cable, but also comprehensively considers multiple factors such as temperature anomalies, environmental image information, and heat source information around the cable. By comprehensively analyzing multi-source information, it can Accurately determine the cause of temperature anomalies, eliminate false alarms, and improve the credibility and effectiveness of the early warning system;

Of course, any product implementing the present invention does not necessarily need to achieve all the above-mentioned advantages at the same time.

Description of the drawings

Figure 1 is an overall flow chart of the method for identifying local defects in high-voltage power cables according to the present invention.

Figure 2 is a flow chart of the steps of processing the cable temperature by the local defect identification method of high-voltage power cable according to the present invention.

Figure 3 is a flow chart of the steps of determining the location of abnormal defects using the time domain reflection detection method in the high-voltage power cable local defect identification method of the present invention.

Figure 4 is a flow chart of the process of obtaining current response data by the high-voltage power cable local defect identification method of the present invention.

Detailed ways

The embodiments of this application realize the acquisition of current response data through the local defect identification method and device of high-voltage power cables. Combined with the parameters of the pre-stored defect model, the current response data can be analyzed to determine the specific defect type of the defect location.

The general ideas for the problems in the embodiments of this application are as follows:

Carry out automatic inspections along the extension direction of high-voltage power cables, monitor and obtain cable temperature data at the same time, process and analyze the cable temperature data, and detect whether there are abnormal temperature conditions. If abnormal temperatures are detected, an early warning signal will be sent to notify the processing center. After receiving the early warning signal, the processing center uses the time domain reflection detection method to determine the distance between the abnormal temperature area and the detection starting point by analyzing the reflection of the signal, thereby accurately locating the defect location.

Apply a low-frequency electric field signal at the defect location to stimulate the current response in the cable, and obtain current response data through sensors and other equipment. Use the parameters of the pre-stored defect model to compare the obtained current response data with the model. Based on the comparison with the defect model, analyze the difference or similarity of the current response data. Based on the difference, determine the specific defect type of the defect location, such as a cable. Bubbles, corrosion and other problems in the product.

Based on the defect type and location results, develop a maintenance plan and repair strategy, and record the defect type, location and related maintenance measures for subsequent tracking and management.

Please refer to Figure 1. An embodiment of the present invention provides a technical solution: a method for identifying local defects in high-voltage power cables, which includes the following steps: using an automatic inspection robot to perform automatic inspections along the extension direction of the high-voltage power cables, and detect and obtain the cable temperature. , process the cable temperature, and issue an early warning if abnormal temperature is detected; among them, the automatic inspection robot can use some existing inspection robots that can automatically walk on high-altitude and high-voltage cables, such as the Chinese invention patent with announcement number CN216565423U An automatic inspection device for high-voltage cable layer cables is disclosed, which includes a walking track, a mobile observation mechanism, and a driving mechanism. The driving mechanism includes a driving motor and a walking mechanism, which can make it run stably on the cable. Detection provides a basis and also includes a detection mechanism. The detection mechanism includes a high-definition camera and an infrared thermal imaging camera, which can realize shooting and temperature monitoring. In order to make it better adapt to the technical solution of this application, it can be built on it Install temperature sensors, including contact temperature sensors and non-contact temperature sensors, to realize automatic walking on the cable while performing periodic temperature detection through the internal control module. In addition, a communication module can be installed on it to realize the detection. The data is remotely transported to the ground for processing, or a processing unit can be set up inside to automatically process the temperature data, and when an abnormal temperature is detected, an early warning is sent through the communication module; after the processing center receives the early warning, it uses time domain reflection detection The method determines the distance between the abnormal temperature area and the starting point of the detection, and marks it as the defect position. If the defect position is not marked, the early warning is cancelled. A low-frequency electric field signal is applied at the defect position. The low-frequency electric field signal can be applied through the accelerator installed on the automatic inspection robot. Low-frequency electric field signal generating equipment can be implemented. After obtaining the defect location, the low-frequency electric field signal generating equipment can be manually placed at the defect location to obtain current response data; the obtained current response data can be compared with the parameters of the pre-stored defect model. Compare and determine the defect type at the defect location.

Specifically, as shown in Figure 2, automatic inspection is performed along the extension direction of the high-voltage power cable to detect and obtain the cable temperature. The steps for processing the cable temperature are as follows: periodically detect the cable temperature within a set distance from the starting point of the inspection. , record the detected cable temperature, and preprocess the detected cable temperature, including deleting the abnormal temperature data. The reason why the abnormal temperature data is deleted is to obtain accurate calculation data and prevent the abnormal temperature data from affecting subsequent Calculation of normal temperature comparison values. As for the judgment of abnormal temperature data, the comparison method can be used. For example, the collected data are compared one by one. When it is found that a certain data is significantly larger or smaller than other data, the temperature data can be considered It is an abnormal value and can be deleted; calculate the normal temperature comparison value of high-voltage power cable based on the preprocessed cable temperature; periodically sample the cable verification temperature after leaving the end point of the set distance, and compare it with the normal temperature comparison value of the cable , to obtain the abnormal temperature coefficient, the cable verification temperature includes the temperature data periodically obtained during the automatic inspection process when the end point leaves the set distance and continues to maintain the original direction, and returns to the starting point of the inspection after leaving the end point of the set distance. Temperature data obtained periodically. After the automatic inspection robot moves to the end point of the set distance, it needs to be judged whether it needs to return to the starting point to verify the abnormal temperature of the cables within the set distance. The judgment rule is to During the periodic temperature detection process, whether the deletion of the above-mentioned abnormal temperature data occurs. If there is no operation to delete the abnormal temperature data, there is no need to return to the starting point of the inspection. Keep the original direction and continue to move until the movement reaches the end of the cable. End point; if the abnormal temperature coefficient is greater than the set temperature threshold coefficient, it is determined that an abnormal temperature has been detected and an early warning is issued.

In this implementation, starting from the starting point of the cable, a distance range is set, within which periodic cable temperature detection is performed, the detected cable temperature data is recorded, and based on the recorded cable temperature data, the normal temperature comparison value of the cable is calculated. , when the distance exceeds the set range, enter the verification stage, periodically sample the cable temperature at the end point, compare it with the calculated normal temperature comparison value of the cable, and calculate the abnormal temperature coefficient. If the abnormal temperature coefficient is greater than the set temperature threshold coefficient, the system determines that an abnormal temperature has been detected and issues an early warning message.

By setting the temperature threshold coefficient, when an abnormal temperature coefficient is detected to be greater than the threshold, an early warning message can be issued to remind operators of possible abnormalities and prompt them to take timely action. Automatic inspections and abnormal temperature warnings can speed up the response speed of maintenance personnel. , allowing them to more accurately locate and deal with potential problems, thereby improving maintenance efficiency.

Starting from the starting point of the inspection, set a distance range, and periodically detect the cable temperature within this range. If an abnormal temperature is detected, it will be deleted directly and will not be included in the calculation of the normal temperature comparison value of the high-voltage power cable. When the set value is reached, After the end point of the distance, the automatic inspection robot will return to the starting point of the inspection to conduct temperature detection again. During the inspection process after the return, the temperature of the cable will be sampled periodically, and these sampled temperatures will be compared with the previously recorded abnormal temperatures. To verify whether the abnormal temperature detected previously exists and ensure that it is not caused by temporary factors.

By returning to the starting point of the inspection and re-detecting the temperature, it is possible to verify whether the previously detected abnormal temperature actually exists, which helps to reduce false alarms and ensure the reliability of the system. By verifying and comparing abnormal temperatures, the system can make more accurate judgments Whether there are local defects and improve the accuracy of the entire system.

Based on the above solution, the normal temperature comparison value of high-voltage power cables can be calculated based on the temperature detected within the set distance, instead of using the preset comparison value or the comparison value obtained using the empirical method. It is more accurate to use temperature to represent the normal temperature of the entire cable. This is because the cable within the set distance is in the same environment as the entire cable, and the parameters are close, so the calculation is more accurate.

Specifically, the abnormal temperature coefficient The calculation formula is as follows:

, where,/> For the first/> Sub-sampled cable verification temperature,/> For the first/> within the set distance The sampled cable temperature,/> is the number of samples within the set distance,/> Verify the temperature of the cable compared to the normal temperature of high-voltage power cables/> The allowable error,/> is the normal temperature calibration factor for high-voltage power cables,/> is the temperature coefficient modulation factor.

In this implementation plan, the temperature of multiple samples within a set distance is synthesized through the summation term in the formula, which fully considers the diversity of sampling, helps to improve the stability and accuracy of the results, and introduces the normalization of high-voltage power cables. The temperature calibration factor and allowable error allow for temperature calibration and error tolerance, making the method more flexible and adaptable to different conditions and changes.

Introducing the temperature coefficient modulation factor can adjust the conditions of different temperature ranges in the calculation, which helps to make the calculation more adaptable to the actual situation under different temperature conditions. The statistical terms and physical parameters in the formula are combined to make the abnormal temperature coefficient The calculation is more practical and accurate, and also fully takes into account the changes and characteristics of the temperature data.

Specifically, as shown in Figure 3, the time domain reflection detection method is used to determine the distance between the abnormal temperature area and the detection starting point, and the steps to mark the defect location are as follows: send a pulse signal through the high-voltage power cable at the detection starting point, and record the sending time; when the detection After the starting point receives the reflected signal, the receiving time is recorded; based on the time difference between the sending time and the receiving time, the distance between the abnormal temperature area and the detection starting point is calculated and marked as the defect location.

In this embodiment, at the starting point of detection, a pulse signal is sent through a high-voltage power cable, and the time of sending the signal is recorded. When the starting point of detection receives the reflected signal of the pulse signal, the time of receiving the signal is recorded. According to the time of sending the signal and the time of receiving The time difference between the signal moments and the propagation speed of the signal in the cable are used to calculate the distance between the abnormal temperature area and the detection starting point. The calculated distance between the abnormal temperature area and the detection starting point is used as the defect location to provide an accurate reference for subsequent analysis and processing.

Through the time domain reflection detection method, the distance between the abnormal temperature area and the detection starting point can be accurately determined, thereby achieving precise positioning of the defect location and providing an accurate reference for subsequent maintenance and repair. The time domain reflection method is a non-destructive method. The detection method, by sending and receiving signals for analysis, will not cause damage to the cable itself, thus maintaining the integrity of the cable. It has high real-time performance. The reflected signal can be obtained and analyzed in a short time, making it possible to locate abnormal temperature areas. Quick response.

Specifically, the formula for calculating the distance between the abnormal temperature area and the detection starting point is as follows:

, where,/> is the distance between the area where the abnormal temperature is located and the detection starting point,/> is the receiving time,/> is the sending time,/> is the reference temperature/> The pulse signal propagation speed under is the temperature coefficient,/> is the dielectric constant of the cable insulation material,/> is the magnetic permeability of the cable.

In this implementation, multiple parameters such as the reception time, the transmission time, the pulse signal propagation speed at the reference temperature, the temperature coefficient, the dielectric constant of the cable insulation material, and the magnetic permeability of the cable are comprehensively considered. This makes the calculation more comprehensive and can estimate the distance of the abnormal temperature area more accurately. The temperature coefficient is introduced to consider the impact of temperature on the propagation speed, so that the method can still provide a more accurate distance estimate under different temperature conditions. The parameters involved are as follows: Dielectric constant and magnetic permeability are basic parameters of cable physical properties. Combining these parameters makes the calculation more practical.

In addition, multiple calibration factors and parameters are introduced into the formula, which helps reduce errors caused by factors such as temperature and material properties, and improves the accuracy of distance calculations.

Accurate measurement of the propagation velocity is the basis for accurately calculating the distance of the abnormal temperature area, so temperature correction can improve the accuracy of the measurement. By using the previously obtained cable temperature, temperature correction can be performed to more accurately calculate the propagation velocity of the pulse signal, which can improve Measurement accuracy, reduced errors, and comprehensive consideration of multiple factors make the results of calculating the distance of abnormal temperature areas more accurate and reliable.

Specifically, as shown in Figure 4, a low-frequency electric field signal is applied at the defect location and the process of obtaining current response data is as follows: a low-frequency electric field signal is applied around the defect location to induce a current response in the high-voltage power cable; the current response is measured in real time, Record the data of the current changing with time and write it as a current response curve; obtain the current response data through the current response curve. The current response data includes amplitude, phase and waveform.

In this embodiment, a low-frequency electric field signal is applied around the defect location, which will stimulate a current response in the cable. These low-frequency signals can be used to detect the current behavior at the defect location. With the application of the low-frequency signal, a current response will be triggered in the cable. By recording the data of current changes over time, a current response curve can be generated, which can reflect the current changes near the defect location.

By applying a low-frequency electric field signal, a current response is induced at the defect location, which can help detect and locate local defects. The characteristics of the current response can provide information about the type and location of the defect. The current response detection induced by this low-frequency electric field signal is a non-destructive method. It is a comprehensive method that will not cause damage to the cable and helps maintain the integrity of the cable. It measures the current response in real time and records the data of current changes over time. It can provide instant results and help quickly analyze and judge defects.

Specifically, the calculation formula for comparing the obtained current response data with the response data of the pre-stored defect model is as follows:

, among which,/> is the fitness value,/> ,/> ,/> respectively amplitude/> , phase/> and waveform/> The weighting factor of ,/> ,/> ,/> are the amplitude, phase and waveform of the defect model respectively; if the fitness value approaches the fitness value of the defect model, the defect type at the defect location is determined.

In this implementation, the matching degree is obtained by calculating the relationship between the characteristic weight factor and the characteristic value, which can reflect the matching of the current response data and the defect model, and compare it with the preset fitness value. If the fitness value Approaching the adaptation value of the defect model, it can be determined that the defect type at the defect location is consistent with the model.

The calculation formula integrates multiple characteristics such as amplitude, phase, and waveform, which helps to more comprehensively analyze the matching degree between the current response data and the defect model, provides a more accurate determination of defect types, and introduces weighting factors. Factors allow weighting based on the importance of amplitude, phase, and waveform, helping to balance trade-offs between different features for more accurate matching results.

Specifically, after the unmarked defect location cancels the warning, the processing center still marks the high-voltage power cable as having temperature abnormalities, and receives environmental information sent by the automatic inspection equipment. The environmental information includes environmental image information and heat source information around the cable, which is used to determine the high-voltage power cable. Cause of abnormal cable temperature.

In this implementation, if the early warning is canceled when the defect location is not marked, it means that the processing center believes that there may be no actual defects, but there are still abnormal conditions. The processing center receives the environmental information sent by the automatic inspection equipment, including environmental image information and cables. Ambient heat source information, based on the received environmental information, further analyzes the temperature anomalies of high-voltage power cables. Compare the cable temperature abnormality with the environmental image and heat source information to comprehensively determine whether there are other abnormal causes.

A device for identifying local defects in high-voltage power cables, including a cable temperature processing module, a defect location determination module, a current response data acquisition module and a defect type determination module, wherein:

The cable temperature processing module is used to conduct automatic inspections along the extension direction of high-voltage power cables through automatic inspection robots, detect and obtain the cable temperature, process the cable temperature, and issue an early warning if abnormal temperatures are detected. The automatic inspection robot includes: A walking mechanism that allows it to move on high-voltage power cables, a temperature detection mechanism that implements periodic temperature detection, and a communication module that enables wireless communication;

The defect location determination module is used by the processing center to use the time domain reflection detection method to determine the distance between the abnormal temperature area and the detection starting point after receiving the early warning, and mark it as the defect location. If the defect location is not marked, the early warning is cancelled;

The current response data acquisition module is used to apply low-frequency electric field signals at the defect location to obtain current response data;

The defect type determination module is used to compare the acquired current response data with the parameters of the pre-stored defect model to determine the defect type at the defect location;

Carry out automatic inspection along the extension direction of high-voltage power cables to detect and obtain the cable temperature. The steps for processing the cable temperature are as follows:

Periodically detect the cable temperature within a set distance from the starting point of the inspection, record the detected cable temperature, and preprocess the detected cable temperature, including deleting abnormal temperature data;

Calculate the normal temperature comparison value of high-voltage power cables based on the pre-processed cable temperature;

After leaving the end point at a set distance, the cable verification temperature is periodically sampled and compared with the normal temperature comparison value of the cable to obtain the abnormal temperature coefficient. The cable verification temperature includes the end point leaving the set distance and continues to maintain the original direction for automatic inspection. The temperature data obtained periodically during the process and the temperature data obtained periodically during the process of returning to the starting point of the inspection after leaving the end point of the set distance;

If the abnormal temperature coefficient is greater than the set temperature threshold coefficient, it is determined that an abnormal temperature has been detected and an early warning is issued;

Use the time domain reflection detection method to determine the distance between the area where the abnormal temperature is located and the starting point of the detection. The steps to mark the defect location are as follows:

The pulse signal is sent through the high-voltage power cable at the starting point of the detection, and the sending time is recorded;

When the detection starting point receives the reflected signal, the reception time is recorded;

Calculate the distance between the area where the abnormal temperature is located and the detection starting point based on the time difference between the sending time and the receiving time, and mark it as the defect location;

The formula for calculating the distance between the area where the abnormal temperature is located and the detection starting point is as follows:

,/> is the distance between the area where the abnormal temperature is located and the detection starting point, where,/> is the receiving time,/> is the sending time,/> is the reference temperature/> The pulse signal propagation speed under is the temperature coefficient,/> is the dielectric constant of the cable insulation material,/> is the magnetic permeability of the cable,/> For the first/> within the set distance The sampled cable temperature,/> is the number of samples within the set distance,/> , is the normal temperature comparison value of high-voltage power cable,/> Calibration factor for normal temperature of high-voltage power cables.

To sum up, this application has at least the following effects:

Through a variety of technical means, such as temperature detection, time domain reflection, current response analysis, etc., the location of local defects in high-voltage power cables can be accurately located, and specific defect types can be identified based on comparison of current response data with pre-existing defect models. , making defect diagnosis and maintenance more accurate and reliable.

It not only focuses on the current response data of the cable, but also comprehensively considers multiple factors such as temperature anomalies, environmental image information, and heat source information around the cable. By comprehensively analyzing multi-source information, the cause of the temperature anomaly can be accurately determined, eliminating false alarms, and improving early warnings. System credibility and effectiveness.

It adopts a non-destructive detection method to determine defects through the signal response in the cable without causing additional damage to the cable. At the same time, this method performs well in real-time and can quickly collect, analyze and process data to provide timely maintenance. It provides strong support and repair, can provide accurate defect location and type identification, reduce false alarm rates, and improve the reliability and practicality of the early warning system.

Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The invention is described with reference to flowchart illustrations and/or block diagrams of systems, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each process and/or block in the flowchart illustrations and/or block diagrams, and combinations of processes and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions executed by the processor of the computer or other programmable data processing device produce a use A device for realizing the functions specified in a process or processes in a flowchart and/or a block or blocks in a block diagram.

These computer program instructions may also be stored in a computer-readable memory that causes a computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including the instruction means, the instructions The device implements the functions specified in a process or processes in the flowchart and/or in a block or blocks in the block diagram.

These computer program instructions may also be loaded onto a computer or other programmable data processing device, causing a series of operating steps to be performed on the computer or other programmable device to produce computer-implemented processing, thereby executing on the computer or other programmable device. Instructions provide steps for implementing the functions specified in a process or processes of a flowchart diagram and/or a block or blocks of a block diagram.

Although the preferred embodiments of the present invention have been described, those skilled in the art will be able to make additional changes and modifications to these embodiments once the basic inventive concepts are apparent. Therefore, it is intended that the appended claims be construed to include the preferred embodiments and all changes and modifications that fall within the scope of the invention.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the invention. In this way, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims (6)

1. The method for identifying the local defect of the high-voltage power cable is characterized by comprising the following steps of:

the automatic inspection robot is used for automatically inspecting along the extending direction of the high-voltage power cable, detecting and acquiring the cable temperature, processing the cable temperature, and sending out early warning if the abnormal temperature is detected, wherein the automatic inspection robot comprises a travelling mechanism for enabling the automatic inspection robot to move on the high-voltage power cable, a temperature detection mechanism for realizing periodic temperature detection and a communication module capable of realizing wireless communication;

after the processing center receives the early warning, determining the distance between the area where the abnormal temperature is located and the detection starting point by using a time domain reflection detection method, marking the area as a defect position, and if the defect position is not marked, canceling the early warning;

applying a low-frequency electric field signal at the defect position to obtain current response data;

comparing the obtained current response data with parameters of a pre-stored defect model to determine the defect type of the defect position;

the automatic inspection is carried out along the extending direction of the high-voltage power cable, the cable temperature is detected and obtained, and the cable temperature is processed as follows:

periodically detecting the cable temperature within a set distance from the inspection starting point, recording the detected cable temperature, and preprocessing the detected cable temperature, wherein the preprocessing comprises deleting abnormal temperature data;

calculating a normal temperature contrast value of the high-voltage power cable according to the pretreated cable temperature;

periodically sampling the cable verification temperature after leaving the tail end point of the set distance, and comparing the cable verification temperature with the normal temperature contrast value of the cable to obtain an abnormal temperature coefficient, wherein the cable verification temperature comprises temperature data periodically obtained in the process of continuously keeping the original direction from the tail end point of the set distance for automatic inspection and temperature data periodically obtained in the process of returning to the inspection starting point after leaving the tail end point of the set distance;

if the abnormal temperature coefficient is larger than the set temperature threshold coefficient, judging that the abnormal temperature is detected, and sending out early warning;

the method for determining the distance between the region where the abnormal temperature is located and the detection starting point by using the time domain reflection detection method comprises the following steps of:

the detection starting point sends a pulse signal through a high-voltage power cable, and the sending time is recorded;

recording the receiving moment when the detection starting point receives the reflected signal;

calculating the distance from the region where the abnormal temperature is located to the detection starting point according to the time difference between the sending time and the receiving time, and marking the distance as a defect position;

the formula for calculating the distance of the region where the abnormal temperature is located from the detection start point is as follows:

wherein->For the distance of the region of the abnormal temperature from the detection start point, < >>For the moment of reception +.>For the moment of transmission->Is the reference temperature->Pulse signal propagation speed, < >>Is a temperature coefficient>Is the dielectric constant of the cable insulation material +.>For the magnetic permeability of the cable->To be within a set distance->Subsampled cable temperature, +.>For the number of samplings within a set distance, +.>Is the normal temperature contrast value of the high-voltage power cable, < + >>Is a normal temperature calibration factor of the high-voltage power cable.

2. The method for identifying local defects of high-voltage power cable according to claim 1, wherein the abnormal temperature coefficient is recorded asThe calculation formula is as follows: />Wherein->Is->Subsampled cable validation temperature, +.>Verifying the comparison value of the temperature and the normal temperature of the high-voltage power cable for the cableAllowable error of +.>For the normal temperature calibration factor of the high voltage power cable, < >>Is a temperature coefficient modulation factor.

3. The method for identifying local defects of high-voltage power cable according to claim 1, wherein the step of applying a low-frequency electric field signal to the defect position and obtaining current response data comprises the steps of:

applying a low frequency electric field signal around the defect location causing it to induce a current response in the high voltage power cable;

measuring current response in real time, recording data of current change along with time, and forming a current response curve;

current response data including amplitude, phase and waveform are obtained from the current response curve.

4. A method for identifying a local defect in a high voltage power cable according to claim 3, wherein the calculation formula for comparing the obtained current response data with the response data of a pre-stored defect model is as follows:

wherein->For the fitness value, +.>，/>，/>Amplitude +.>Phase->And waveform->Weight factor of->，/>，/>The amplitude, phase and waveform of the defect model are respectively;

and if the adaptation value approaches to the adaptation value of the defect model, determining the defect type of the defect position.

5. The method for identifying the local defect of the high-voltage power cable according to claim 1, wherein after the position of the unlabeled defect is canceled and pre-warned, the processing center still marks the temperature abnormality of the high-voltage power cable, receives environment information sent by automatic inspection equipment, wherein the environment information comprises environment image information and heat source information around the cable and is used for determining the reason of the temperature abnormality of the high-voltage power cable.

6. The device for identifying the local defect of the high-voltage power cable is characterized by comprising a cable temperature processing module, a defect position determining module, a current response data acquisition module and a defect type determining module, wherein:

the cable temperature processing module is used for automatically inspecting along the extending direction of the high-voltage power cable through the automatic inspection robot, detecting and acquiring the cable temperature, processing the cable temperature, and sending out early warning if the abnormal temperature is detected, wherein the automatic inspection robot comprises a travelling mechanism for enabling the automatic inspection robot to move on the high-voltage power cable, a temperature detection mechanism for realizing periodic temperature detection and a communication module capable of realizing wireless communication;

the defect position determining module is used for determining the distance between the area where the abnormal temperature is located and the detection starting point by using a time domain reflection detection method after the processing center receives the early warning, marking the area as a defect position, and canceling the early warning if the defect position is not marked;

the current response data acquisition module is used for applying a low-frequency electric field signal to a defect position to acquire current response data;

the defect type determining module is used for comparing the acquired current response data with parameters of a pre-stored defect model to determine the defect type of the defect position;

the automatic inspection is carried out along the extending direction of the high-voltage power cable, the cable temperature is detected and obtained, and the cable temperature is processed as follows:

periodically detecting the cable temperature within a set distance from the inspection starting point, recording the detected cable temperature, and preprocessing the detected cable temperature, wherein the preprocessing comprises deleting abnormal temperature data;

calculating a normal temperature contrast value of the high-voltage power cable according to the pretreated cable temperature;

periodically sampling the cable verification temperature after leaving the tail end point of the set distance, and comparing the cable verification temperature with the normal temperature contrast value of the cable to obtain an abnormal temperature coefficient, wherein the cable verification temperature comprises temperature data periodically obtained in the process of continuously keeping the original direction from the tail end point of the set distance for automatic inspection and temperature data periodically obtained in the process of returning to the inspection starting point after leaving the tail end point of the set distance;

if the abnormal temperature coefficient is larger than the set temperature threshold coefficient, judging that the abnormal temperature is detected, and sending out early warning;

the method for determining the distance between the region where the abnormal temperature is located and the detection starting point by using the time domain reflection detection method comprises the following steps of:

the detection starting point sends a pulse signal through a high-voltage power cable, and the sending time is recorded;

recording the receiving moment when the detection starting point receives the reflected signal;

calculating the distance from the region where the abnormal temperature is located to the detection starting point according to the time difference between the sending time and the receiving time, and marking the distance as a defect position;

the formula for calculating the distance of the region where the abnormal temperature is located from the detection start point is as follows:

wherein->For the distance of the region of the abnormal temperature from the detection start point, < >>For the moment of reception +.>For the moment of transmission->Is the reference temperature->Pulse signal propagation speed, < >>Is a temperature coefficient>Is the dielectric constant of the cable insulation material +.>For the magnetic permeability of the cable->To be within a set distance->Subsampled cable temperature, +.>For the number of samplings within a set distance, +.>Is the normal temperature contrast value of the high-voltage power cable, < + >>Is a normal temperature calibration factor of the high-voltage power cable.