Fault detection method of power cable terminal based on infrared thermal imaging signal reconstruction

Considering the low efficiency of traditional fault detection methods, this paper proposes a power cable terminal fault detection method based on infrared thermal imaging signal reconstruction. The method includes the following steps: first, establish the thermal resistance network structure of the power cable terminal to obtain the structural relationship between terminal components; second, collect operational data of the power cable terminal and perform calculations; finally, use an infrared imager to capture the infrared radiation of the power cable terminal and obtain fault detection results based on the calculation results. Experiments show that the detected results of this method are completely consistent with the actual situation, with an accuracy rate of up to 99%, and can achieve high-precision detection of power cable terminal faults.


Introduction
With the further expansion of the power system scale and continuous upgrading of electrical equipment, ensuring the safe transmission of electrical energy and stable power supply has become a crucial task.In this context, fault detection of power cable terminals has become particularly important.As power cable terminals may face various faults and issues such as short circuits and poor contacts, timely and effective detection and diagnosis of these issues are extremely important for maintaining the normal operation of the power system.Therefore, it is essential to develop and apply fault detection methods specifically for power cable terminals to ensure safe and stable transmission of electricity, providing reliable power supply services for social production and resident lives [1][2].However, there are inevitably some problems of wear, aging, and even failure of power cable terminals, which may lead to power system failure, and power grid accidents, and even have a great impact on people's production and life.
The fault diagnosis of the power transformer based on the optimized Bi-LSTM model is proposed in [3] and adds three parameters constructed by the three-ratio method as input features based on five transformer oil gas components.Using a particle swarm optimization algorithm to optimize the hyperparameters in the model, a PSO-Bi-LSTM is proposed for transformer fault diagnosis and analysis.However, the environment setting of this method is limited.A method for unmanned aerial vehicle (UAV) motor fault detection is proposed which is based on embedded feature extraction and support vector machine (SVM) classification.It uses Mel-frequency cepstral coefficients (MFCCs) to extract features from sound signals collected, and SVMs to classify the selected features.This method

Feature extraction of infrared thermal imaging signal reconstruction
The parameters such as the external contour of the inspection object are extracted, and the inspection edge areas are connected by smooth contour lines according to the equipment density of the power distribution network in the space.Calculate the equipment temperature difference based on infrared thermal imaging technology [5][6], and get the feature extraction result of infrared thermal imaging signal reconstruction: 10 In the Formula, H G stands for equipment temperature difference; 1 T represents the imaging temperature; 0 T represents initialization temperature; D J represents the reconstruction coefficient of infrared thermal imaging signal.

Data acquisition of power cable terminal
Based on the relationship between each component of the power cable terminal and the overall operating status, a thermal resistance network structure diagram of the power cable terminal is established.The thermal resistance network structure diagram demonstrates the connection mode and interaction relationship between various components of the power cable terminal, which helps to understand the thermal conduction process and operating status of the power cable terminal.By studying and analyzing this thermal resistance network structure, the fault condition of the power cable terminal can be diagnosed and detected more accurately, further improving the reliability and stability of the power system.See Figure 1.   1, the structural relationship between power cable terminal elements is obtained, and the operation data of the power cable terminal is calculated and collected by using this information.The specific calculation Formula is as follows: In the Formula, W Q represents the thermal conductivity of the power cable terminal, and W E represents the convective heat transfer coefficient of the power cable terminal.Based on the dynamic changes in the operational data of the power cable terminal, a preliminary judgment is made on whether there are any abnormal conditions during its operation process.To better achieve fault detection, infrared thermal imaging signals are used for real-time reconstruction and collecting operational data of the power cable terminal, which will provide reliable data for subsequent fault detection.This method can timely identify and solve potential faults, further improving the safety and reliability of the power cable terminal.

Fault detection of power cable terminal based on infrared thermal imaging
Through collecting and analysing the operational data of the power cable terminal, the fault detection result of the power cable terminal is obtained.Infrared thermal imaging signal reconstruction technology is introduced to achieve full-scale detection of the power cable terminal faults.With the help of an infrared imager, temperature information on the surface of the power cable terminal is obtained, further improving the safety and reliability of the power system.The specific detection structure is shown in Figure 2.

Infrared ray
The infrared thermal imager Liquid level Based on Figure 2, an infrared imager is used to capture infrared radiation from various directions of the power cable terminal, and by analyzing these infrared radiation results, temperature information on the surface of the power cable terminal is obtained.When there are abnormalities or hidden dangers in the power cable terminal, its temperature will undergo a certain degree of change.Therefore, a function expression is constructed for the input set to accurately capture any abnormalities in the power cable terminal and make timely corresponding processing and repairs.The function expression for the input set is as follows: In the Formula, n p represents the coefficients of the input set.For the output set, a function expression is defined to establish the relationship between the input and output, to determine the status and fault condition of the power cable terminal more accurately.The function expression of the output set is: { , , , , } n Q q q q q = (4) In the Formula, n q represents the coefficients of the output set.The fault detection result of the power cable terminal based on infrared thermal imaging signal reconstruction is calculated using the following Formula: In the Formula, m t represents the higher temperature value of the power cable terminal, n t represents the lower temperature value of the power cable terminal, and  represents the thermal conductivity of the power cable terminal.Currently, the photoelectric detector of the infrared imager transmits the signal to the surface of the power cable terminal, and after the imager amplifies the signal, the final fault detection result of the power cable terminal is displayed on the screen.Through infrared imaging technology, it is possible to visually observe and judge the thermal image of the power cable terminal, thereby quickly diagnosing potential faults, and enhancing the safety and reliability of the power system.

Experimental analysis
The experiment is carried out in a laboratory environment, ensuring that the laboratory space is enough to accommodate the required equipment, cable samples, and operating areas, so that the temperature in the laboratory is stable and equivalent to the normal working temperature of power cables.According to the safety requirements of power equipment operation, necessary safety measures are taken, and an infrared thermal imager is used as the main equipment to collect thermal signals related to power cable terminal failure.In addition, it is necessary to ensure that all the parameters involved in the experiment are fully controlled and adjusted during the experiment.The experimental parameters set in the above research environment are shown in Table 1.Apply the method to the actual operating environment of the power cable terminal for fault detection.To ensure the comparability of the experimental results, this article sets the method as the experimental group, and sets [3] and [4] as Control Group A and Control Group B, respectively.Under the same experimental parameters, apply these three methods to the experiment and compare their detection results.Through comparison, it is possible to evaluate the effectiveness of different methods in power cable terminal fault detection, providing important reference and guidance for further improving and optimizing power cable terminal fault detection technology.Because the power cable terminal equipment generally has abnormal possibilities, to test the fault tolerance of the above three methods, the data used to describe the abnormal state of three devices in the power cable terminal are selected as the test set, and the three devices are numbered #1, #2 and #3 respectively.The fault tolerance of the three methods is tested, and the abnormal data are manually set in different sections, and numbered from section A to section G, with a total of five sections.Table 2 records the faults of each section.Based on the data comparison in Table 2, a clearer understanding of the performance of various methods in power cable terminal fault detection can be obtained through analysis of these data.The specific results are shown in Table 3.  2 and 3, the test results of the experimental group method are completely consistent with the actual situation.However, there are some issues with the test results of Control Group A and Control Group B, including failure to detect actual segment faults or fault detection results that do not match the actual situation.This indicates that the experimental group method is more reliable and accurate than the other two groups in power cable terminal fault detection, and can better reflect the actual condition of the power cable terminal.This comparative result is of great significance for guiding power system operation and maintenance, providing a reference basis for rational selection and application of fault detection methods.Therefore, the proposed method can realize high-precision detection of power cable terminal faults.Figure 3 shows the accuracy test results of the three methods.According to Figure 3, under the same quantity of cases, the detection accuracy of using [3] and [4] is lower.This indicates that these two methods have certain limitations in power cable terminal fault detection and may not be able to accurately detect all fault conditions.In comparison, the experimental group method has shown higher fault detection accuracy under the same quantity of cases, which can timely detect and address issues with the power cable terminal and ensure stable operation of the power system.When the proposed method is used for detection, the highest accuracy can reach 99%.In summary, [3] and [4] have certain limitations in fault detection and cannot accurately determine the abnormal conditions of the equipment.However, the method based on infrared thermal imaging signal reconstruction for power cable terminal fault detection is easier to operate and can provide more accurate fault judgments, thereby effectively ensuring the safety of the equipment.This research result provides important guidance for power system maintenance and operation management, helping us timely detect and address potential faults and improve the reliability and safety of power equipment.By adopting the fault detection method based on infrared thermal imaging technology, timely monitoring and diagnosis of power cable terminals can be achieved, providing an important decisionmaking basis for maintenance personnel, and minimizing potential fault risks and losses.

Conclusion
The fault detection method for power cable terminals based on infrared thermal imaging signal reconstruction has multiple advantages and tremendous potential.By utilizing infrared thermal imaging technology, it can accurately detect the faults of power cable terminals, thereby significantly improving the accuracy of fault detection.This method not only quickly captures and diagnoses the faults of power cable terminals, but also has the advantages of non-contact detection, avoiding direct contact with the equipment and improving safety and convenience.At the same time, this method can also realize the detection of the power system, reduce the interruption and influence on the power supply, and ensure the stable operation of the power system.
Future research can further expand the application fields of infrared thermal imaging signal reconstruction, such as fault detection in other parts of power equipment and local fault analysis of power systems.By combining the fault detection method for power cable terminals based on infrared thermal imaging signal reconstruction with other sensor technologies and machine learning algorithms, a more comprehensive and efficient fault detection system for power cable terminals can be constructed.For example, by integrating temperature sensors, current sensors, and other sensors, more comprehensive information about the power cable terminal can be obtained and various physical quantities can be monitored in real-time.Additionally, the application of machine learning algorithms can help us mine and analyze a large amount of data, identify potential abnormal patterns, and fault features, and provide early warning and diagnosis of the fault risk of power cable terminals.With the continuous advancement and innovation of technology, the fault detection method based on infrared thermal imaging signal reconstruction for power cable terminals will play a greater role in promoting the development and innovation of the power industry.

Figure 1 .
Figure 1.Structure diagram of thermal resistance network of power cable terminal.

Figure 2 .
Figure 2. Fault detection diagram of infrared thermal imaging signal reconstruction.

Figure 3 .
Figure 3. Fault detection accuracy of different methods.

Table 1 .
Experimental Parameter Setting Table.

Table 2 .
Comparison table of whether there are faults and reasons in each section of the power cable terminal.

Table 3 .
Test results of three methods.