A cable insulation aging status assessment method based on operation data analysis

Abstract

The present invention discloses a cable insulation aging status assessment method based on operation data analysis, which belongs to the technical field of cable aging assessment, and includes step one, obtaining the electrical parameter difference value of the cable according to the electrical parameters of the cable; step two, obtaining the physical parameter difference value and the chemical parameter difference value of the cable according to the physical parameters and chemical parameters of the cable; step three, determining the environmental impact factor of the area where the cable is located; step four, performing a comprehensive analysis based on the acquired information, and generating an aging status value, and assessing the insulation aging status of the cable according to the aging status value. The present invention conducts a comprehensive analysis of the physical changes of the cable, the chemical decomposition products in the internal insulation layer of the cable during operation, and the changes in electrical parameters during operation in combination with environmental impacts, and can more accurately assess the aging status of the cable, thereby ensuring the accuracy of the assessment and facilitating subsequent maintenance and management of the cable.

Description

Technical Field

[0001] The present invention belongs to the technical field of cable aging assessment, and in particular relates to a cable insulation aging status assessment method based on operation data analysis. Background Art

[0002] Cables are made of one or more mutually insulated conductors and an outer insulating protective layer. They are wires that transmit electricity or information from one place to another. They are mainly used for information transmission in power and communication systems. In power and communication systems, the performance of cables directly affects the operation of the system. The aging of the cable insulation layer may cause leakage, short circuit and other faults, which in turn may cause safety accidents such as fire and electric shock. It will also reduce the transmission efficiency and carrying capacity of the cable, affecting the stability and reliability of the system. Therefore, it is necessary to evaluate the status of the cable to ensure the normal operation of the power and communication systems.

[0003] Currently, the aging status of cable insulation is mostly assessed through routine manual inspections, which observes changes in the appearance of the cable and then assesses the cable aging status based on experience. Manual assessments are easily affected by subjective factors, resulting in inaccurate assessments. In addition, cable aging is related to multiple factors, and judging the aging status of the cable from only one factor is not accurate enough. Summary of the invention

[0004] The purpose of the present invention is to provide a cable insulation aging status assessment method based on operation data analysis to solve the problems faced in the above-mentioned background technology.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A cable insulation aging status assessment method based on operation data analysis, the assessment method comprising:

[0007] Step 1: Connect the cable to the power grid, set n cable aging detection cycles, obtain the electrical parameters of the cable in each detection cycle, and thus obtain the difference value of the electrical parameters of the cable;

[0008] Step 2: At the beginning and end of each detection cycle, the physical parameters and chemical parameters of the cable are obtained, and the physical parameter difference value and chemical parameter difference value of the cable are obtained respectively;

[0009] Step 3: Obtain historical environmental information in the area where the cable is located, so as to determine the environmental impact factors of the area where the cable is located;

[0010] Step 4: Perform a comprehensive analysis based on the obtained electrical parameter difference values, physical parameter difference values, chemical parameter difference values ​​and environmental influencing factors to generate an aging condition value, and evaluate the insulation aging state of the cable according to the aging condition value.

[0011] Furthermore, the method for obtaining the electrical parameter difference value in step 1 is:

[0012] During the detection period, the insulation resistance value R of the cable and the detected partial discharge PD are obtained, and the insulation resistance value variation function over time is proposed. And the partial discharge amount as a function of time ;

[0013] By formula Get the electrical status value of each detection cycle ;

[0014] So through the formula Obtain the electrical parameter difference value of each detection cycle ;

[0015] in, is the start time of the detection cycle, is the end time of the detection cycle, is the maximum insulation resistance value within the detection cycle, is the minimum insulation resistance value within the detection cycle, is the average insulation resistance value within the insulation period, is the maximum partial discharge during the detection period, is the minimum partial discharge amount within the detection cycle, is the average partial discharge during the detection period, is the preset electrical condition standard value in the i-th detection cycle, and .

[0016] Furthermore, the method for obtaining the physical parameter difference value in step 2 is:

[0017] At the beginning and end of each detection cycle, the image of the cable is obtained through a camera probe near the cable, and then processed by image processing technology to obtain the crack characteristic values ​​at the beginning and end of the detection cycle. , ;

[0018] At the same time, obtain the distance between the lowest point of the cable and the ground at the beginning of the detection cycle and the distance between the lowest point of the cable and the ground at the end of the test cycle ;

[0019] So through the formula Get the difference value of physical parameters in each detection cycle ;

[0020] in, is the crack characteristic reference value, is the distance reference value.

[0021] Furthermore, the method for obtaining the chemical parameter difference value in step 2 is:

[0022] At the beginning and end of each test cycle, a special sampling device is used to collect gas samples from inside the cable, and then chromatographic analysis technology is used to obtain the content of the gas sample. Content and content;

[0023] So through the formula Get the difference value of chemical parameters in each detection cycle ;

[0024] in, for Reference value of content, for Reference value of content, At the end of the test period content, The detection cycle starts content, At the end of the test period content, The detection cycle starts content.

[0025] Furthermore, the method for obtaining the environmental impact factor in step 3 is:

[0026] Obtain the number of days with high ultraviolet radiation in the area where the cable is located within the historical cycle of days M from the Meteorological Bureau , Number of days with high temperatures , Number of days with low temperatures , high humidity days and the number of days with acid rain ;

[0027] So through the formula Environmental impact factors .

[0028] Furthermore, the method for generating the aging status value in step 4 is:

[0029] The difference values ​​of electrical parameters obtained according to each detection cycle , physical parameter difference value , chemical parameter difference value , respectively, to develop the curves of electrical parameter difference value versus detection cycle number , Physical parameter difference value changes with the number of detection cycles , Chemical parameter difference value changes with the number of detection cycles ;

[0030] By formula Obtaining the aging condition value , ; ; ;

[0031] in, For the first detection cycle, For the last detection cycle, , as well as is the preset coefficient.

[0032] Furthermore, the method for evaluating the insulation aging state of the cable according to the aging condition value in step 4 is:

[0033] According to the historical evaluation data of cables in big data, the cable aging status is divided into five levels: ideal status, slight aging, general aging, moderate aging and severe aging. Each level has a corresponding aging status value range.

[0034] If it is determined that the obtained aging condition value falls within a corresponding aging condition value interval, the state of the cable is evaluated as a corresponding level.

[0035] Beneficial effects of the present invention:

[0036] The present invention obtains the electrical parameter difference value of the cable by obtaining the electrical parameter change of the cable during operation within a continuous detection cycle, obtains the chemical parameter difference value by the chemical parameter change generated inside the cable during operation, and obtains the physical parameter difference value by the physical change of the cable during the continuous detection cycle. The environmental impact factor of the area where the cable is located is determined by combining the historical environmental information of the area where the cable is located, and a comprehensive analysis is performed to obtain the aging condition value of the cable. The insulation aging state of the cable is evaluated according to the aging condition value. In this way, the physical change of the cable, the chemical decomposition product situation in the internal insulation layer of the cable during operation, and the electrical parameter change during operation can be combined with the environmental impact for comprehensive analysis, and the aging condition of the cable can be evaluated more accurately, thereby ensuring the accuracy of the evaluation and facilitating the subsequent maintenance and management of the cable.

[0037] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0039] Figure 1 The present invention is a flow chart of the method. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] In one embodiment, a cable insulation aging status assessment method based on operation data analysis is disclosed, such as Figure 1 As shown, the aging state assessment method mainly includes the following steps:

[0042] Step 1: Connect the cable to the power grid, set n cable aging detection cycles, obtain the electrical parameters of the cable in each detection cycle, and thus obtain the difference value of the electrical parameters of the cable;

[0043] Step 2: At the beginning and end of each detection cycle, the physical parameters and chemical parameters of the cable are obtained, and the physical parameter difference value and chemical parameter difference value of the cable are obtained respectively;

[0044] Step 3: Obtain historical environmental information in the area where the cable is located, so as to determine the environmental impact factors of the area where the cable is located;

[0045] Step 4: Perform a comprehensive analysis based on the obtained electrical parameter difference values, physical parameter difference values, chemical parameter difference values ​​and environmental influencing factors to generate an aging condition value, and evaluate the insulation aging state of the cable according to the aging condition value.

[0046] Through the above technical scheme, the present application obtains the electrical parameter difference value of the cable by obtaining the electrical parameter change of the cable during operation within the continuous detection cycle, obtains the chemical parameter difference value through the chemical parameter change generated inside the cable during operation, and obtains the physical parameter difference value through the physical change of the cable during the continuous detection cycle, and then combines the historical environmental information of the area where the cable is located to determine the environmental influencing factors of the area where the cable is located, and conducts a comprehensive analysis to obtain the aging condition value of the cable, thereby evaluating the insulation aging state of the cable according to the size of the aging condition value; in this way, the physical changes of the cable, the chemical decomposition products in the internal insulation layer of the cable during operation, and the electrical parameter changes during operation can be combined with environmental influences for comprehensive analysis, and the aging condition of the cable can be evaluated more accurately, thereby ensuring the accuracy of the evaluation and facilitating subsequent maintenance and management of the cable.

[0047] As an embodiment of the present invention, the method for obtaining the electrical parameter difference value in step 1 is: within the detection period, the insulation resistance value R of the cable and the detected partial discharge amount PD are obtained, and a function of the insulation resistance value changing with time is proposed. And the partial discharge amount as a function of time ;

[0048] By formula Get the electrical status value of each detection cycle ;

[0049] So through the formula Obtain the electrical parameter difference value of each detection cycle ;

[0050] in, is the start time of the detection cycle, is the end time of the detection cycle, is the maximum insulation resistance value within the detection cycle, is the minimum insulation resistance value within the detection cycle, is the average insulation resistance value within the insulation period, is the maximum partial discharge during the detection period, is the minimum partial discharge amount within the detection cycle, is the average partial discharge during the detection period, is the preset electrical condition standard value in the i-th detection cycle, and .

[0051] Through the above technical solution, this embodiment provides a method for obtaining the difference value of electrical parameters. The aging state of cable insulation is mainly related to the insulation resistance value and partial discharge of the cable. Generally, when the cable insulation ages, its insulation resistance will decrease and partial discharge will increase. Therefore, during the detection period, the insulation resistance value R of the cable and the detected partial discharge amount PD are obtained, and a function of the insulation resistance value changing with time is proposed. And the partial discharge amount as a function of time , first through the formula Get the electrical status value of each detection cycle Then, through the formula Obtain the electrical parameter difference value of each detection cycle ,formula Indicates the change of insulation resistance value during the detection cycle. The larger the value is, the greater the change in the insulation resistance value is during the detection cycle. The larger the value, the smaller the insulation resistance value is during the test cycle. Indicates the change of partial discharge during the detection cycle. The larger the value of, the greater the change in partial discharge. The larger the value, the more obvious the partial discharge phenomenon is during the detection period. Therefore, the formula Combined with the changes in insulation resistance and partial discharge, a comprehensive analysis is performed to obtain the electrical condition values ​​of each detection cycle. The obtained electrical condition values ​​are compared with the preset electrical condition standard values ​​in the detection cycle to obtain the electrical parameter difference values ​​of each detection cycle. Obviously, the larger the value, the more serious the aging of the cable. In this way, the difference in the electrical parameters of the cable can be obtained according to the insulation resistance and partial discharge conditions in each detection cycle, so as to facilitate the subsequent evaluation and judgment of the aging of the cable.

[0052] In the above technical solution, the duration of the detection cycle can be artificially formulated according to the actual situation, and the electrical condition standard value preset in each detection cycle It is an ideal value, which can be determined based on the historical operation data of the cable from big data, which will not be elaborated here.

[0053] As an implementation mode of the present invention, the method for obtaining the physical parameter difference value in step 2 is:

[0054] At the beginning and end of each detection cycle, the image of the cable is obtained through a camera probe near the cable, and then processed by image processing technology to obtain the crack characteristic values ​​at the beginning and end of the detection cycle. , ;

[0055] At the same time, obtain the distance between the lowest point of the cable and the ground at the beginning of the detection cycle and the distance between the lowest point of the cable and the ground at the end of the test cycle ;

[0056] So through the formula Get the difference value of physical parameters in each detection cycle ;

[0057] in, is the crack characteristic reference value, is a distance reference value, which can be determined based on empirical data.

[0058] Through the above technical solution, this embodiment provides a method for obtaining the difference value of physical parameters. First, at the beginning and end of each detection cycle, an image of the cable is obtained by a camera probe near the cable, and then processed by image processing technology, such as using contour extraction technology to obtain the crack feature value at the beginning and end of the detection cycle. , , and obtain the distance between the lowest point of the cable and the ground at the beginning of the detection cycle and the distance between the lowest point of the cable and the ground at the end of the test cycle , and then through the formula Get the difference value of physical parameters in each detection cycle ,if If the value is large, it means that cracks or wear appear on the cable surface during the test period, which may indicate that the cable has aged. The larger the value, the greater the cable sag during the detection period, indicating that the mechanical strength of the cable insulation layer has decreased, which may indicate that the cable has aged. Therefore, the greater the difference in physical parameters, the more serious the cable aging. In this way, the aging of the cable can be analyzed through the physical changes of the cable, which is convenient for subsequent evaluation and judgment of the aging of the cable.

[0059] As an embodiment of the present invention, the method for obtaining the chemical parameter difference value in step 2 is:

[0060] At the beginning and end of each test cycle, a special sampling device is used to collect gas samples from inside the cable, and then chromatographic analysis technology is used to obtain the content of the gas sample. Content and content;

[0061] So through the formula Get the difference value of chemical parameters in each detection cycle ;

[0062] in, for Reference value of content, for Content reference values ​​can be determined based on empirical data. At the end of the test period content, The detection cycle starts content, At the end of the test period content, The detection cycle starts content.

[0063] Through the above technical solution, this embodiment provides a specific method for obtaining the difference value of chemical parameters. As the cable insulation layer ages, the insulation layer will decompose a large amount of as well as Therefore, at the beginning and end of each test cycle, a special sampling device is used to collect gas samples from the inside of the cable, and then chromatographic analysis technology is used to obtain the gas samples. Content and content, so through the formula Get the difference value of chemical parameters in each detection cycle ;if Value or The larger the value, the more the cable insulation decomposition will occur at the end of the test cycle. as well as The more the number, the more serious the cable aging. In this way, the aging of the cable can be analyzed through the chemical changes of the cable, which is convenient for subsequent evaluation and judgment of the aging of the cable.

[0064] As an implementation mode of the present invention, the method for obtaining the environmental impact factor in step 3 is:

[0065] Obtain the number of days with high ultraviolet radiation in the area where the cable is located within the historical cycle of days M from the Meteorological Bureau , Number of days with high temperatures , Number of days with low temperatures , high humidity days and the number of days with acid rain ;

[0066] So through the formula Environmental impact factors .

[0067] Through the above technical solution, this embodiment provides a method for obtaining environmental impact factors. Since the environment also affects the aging of cables, especially high temperature, high humidity, and low temperature weather have a great impact on the aging of cables. Similarly, acid rain and strong ultraviolet radiation will also affect the aging of cables and accelerate the aging of cables. Therefore, the number of days with high ultraviolet radiation in the historical cycle days M days in the area where the cable is located is obtained from the meteorological bureau. , Number of days with high temperatures , Number of days with low temperature , high humidity days and the number of days with acid rain , so that through the formula Environmental impact factors It can be seen that the larger the value of the environmental impact factor is, the greater the impact of the environment in this area on cable aging is.

[0068] As an implementation mode of the present invention, the method for generating the aging status value in step 4 is:

[0069] The difference values ​​of electrical parameters obtained according to each detection cycle , physical parameter difference value , chemical parameter difference value , respectively, to develop the curves of electrical parameter difference value versus detection cycle number , Physical parameter difference value changes with the number of detection cycles , Chemical parameter difference value changes with the number of detection cycles ;

[0070] By formula Obtaining the aging condition value , ; ; ;

[0071] in, For the first detection cycle, For the last detection cycle, , as well as is the preset coefficient;

[0072] The method for evaluating the insulation aging state of the cable according to the aging state value in step 4 is as follows: according to the historical evaluation data of the cable in the big data, the cable aging state is divided into five levels: ideal state, slight aging, general aging, moderate aging and severe aging, and each level corresponds to a corresponding aging state value interval;

[0073] If it is determined that the obtained aging condition value falls within a corresponding aging condition value interval, the state of the cable is evaluated as a corresponding level.

[0074] Through the above technical solution, this embodiment provides a method for obtaining an aging status value and a method for evaluating the insulation aging state of a cable according to the aging status value. First, the electrical parameter difference values ​​obtained in each detection cycle are , physical parameter difference value , chemical parameter difference value , respectively, to develop the curves of electrical parameter difference value versus detection cycle number , Physical parameter difference value changes with the number of detection cycles , Chemical parameter difference value changes with the number of detection cycles , and then by the formula Obtaining the aging condition value ,in ; ; ,formula Indicates the change of electrical parameter difference value in all detection cycles, where Indicates the fluctuation of the electrical parameter difference value obtained in each detection cycle. The smaller the value, the smaller the fluctuation, which means the cable aging phenomenon is lighter. It represents the cumulative change of the electrical parameter difference value in all detection cycles. It can be seen that the smaller the value is, the smaller the electrical difference parameter value in the entire detection cycle is, which means that the cable aging phenomenon is lighter. Similarly, through the formula The changes in the difference values ​​of physical parameters in all detection cycles are obtained through the formula The changes in the difference values ​​of chemical parameters in all test cycles are obtained, and a comprehensive analysis is performed in combination with environmental influencing factors. The formula is used to obtain Obtaining the aging condition value From the formula, we can know that when the aging condition value The smaller the value, the lighter the aging phenomenon of the cable. On the contrary, when the aging condition value is The larger the value, the more serious the aging of the cable. Therefore, in order to facilitate the evaluation of the aging of the cable, the cable aging status is divided into five levels: ideal state, slight aging, general aging, moderate aging and severe aging according to the historical evaluation data of the cable in the big data. Each level has a corresponding aging condition value interval. The obtained aging condition value falls into which corresponding aging condition value interval, and the cable status is evaluated as the corresponding level. In this way, the electrical parameters of the cable during operation, the chemical parameters generated during operation, and the physical parameters of the cable can be combined with the local environmental impact for comprehensive analysis, so as to more accurately evaluate or predict the aging phenomenon of the cable, and facilitate the subsequent precise maintenance and management of the cable.

[0075] In the above technical solution, the preset coefficient , as well as It is the weight coefficient, which can be determined based on historical data and local actual conditions, and will not be described in detail here.

[0076] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A cable insulation aging status assessment method based on operation data analysis, characterized in that: The evaluation methods include: Step 1: Connect the cable to the power grid, set n cable aging detection cycles, obtain the electrical parameters of the cable in each detection cycle, and thus obtain the difference value of the electrical parameters of the cable; Step 2: At the beginning and end of each detection cycle, the physical parameters and chemical parameters of the cable are obtained, and the physical parameter difference value and chemical parameter difference value of the cable are obtained respectively; Step 3: Obtain historical environmental information in the area where the cable is located, so as to determine the environmental impact factors of the area where the cable is located; Step 4: Perform a comprehensive analysis based on the obtained electrical parameter difference values, physical parameter difference values, chemical parameter difference values ​​and environmental influencing factors to generate an aging condition value, and evaluate the insulation aging state of the cable according to the aging condition value; The method for obtaining the electrical parameter difference value in step 1 is: within the detection period, obtain the insulation resistance value R of the cable and the detected partial discharge amount PD, and formulate a function of the insulation resistance value changing with time. And the partial discharge amount as a function of time ; By formula Get the electrical status value of each detection cycle ; So through the formula Obtain the electrical parameter difference value of each detection cycle ; in, is the start time of the detection cycle, is the end time of the detection cycle, is the maximum insulation resistance value within the detection cycle, is the minimum insulation resistance value within the detection cycle, is the average insulation resistance value within the insulation period, is the maximum partial discharge during the detection period, is the minimum partial discharge amount within the detection cycle, is the average partial discharge during the detection period, is the preset electrical condition standard value in the i-th detection cycle, and ; The method for obtaining the physical parameter difference value in step 2 is: at the beginning and end of each detection cycle, an image of the cable is obtained by a camera probe near the cable, and then processed by image processing technology to obtain the crack characteristic value at the beginning and end of the detection cycle. 、 ； At the same time, obtain the distance between the lowest point of the cable and the ground at the beginning of the detection cycle and the distance between the lowest point of the cable and the ground at the end of the test cycle ; So through the formula Get the difference value of physical parameters in each detection cycle ; in, is the crack characteristic reference value, is the distance reference value; The method for obtaining the chemical parameter difference value in step 2 is: at the beginning and end of each detection cycle, a special sampling device is used to collect gas samples from the inside of the cable, and then a chromatographic analysis technique is used to obtain the chemical parameter difference value in the gas sample. Content and content; So through the formula Get the difference value of chemical parameters in each detection cycle ; in, for Reference value of content, for Reference value of content, At the end of the test period content, The detection cycle starts content, At the end of the test period content, The detection cycle starts content; The method for obtaining the environmental impact factor in step 3 is: obtain the number of days with high ultraviolet radiation in the area where the cable is located within the historical cycle of days M from the meteorological bureau. , Number of days with high temperatures , Number of days with low temperatures , high humidity days and the number of days with acid rain ; So through the formula Environmental impact factors ; The method for generating the aging status value in step 4 is: according to the electrical parameter difference value obtained in each detection cycle , physical parameter difference value , chemical parameter difference value , respectively, to develop the curves of electrical parameter difference value versus detection cycle number , Physical parameter difference value changes with the number of detection cycles , Chemical parameter difference value changes with the number of detection cycles ; By formula Obtaining the aging condition value , ; ; ; in, For the first detection cycle, For the last detection cycle, , as well as is the preset coefficient.

2. A cable insulation aging status assessment method based on operation data analysis according to claim 1, characterized in that: The method for evaluating the insulation aging state of the cable according to the aging condition value in step 4 is: According to the historical evaluation data of cables in big data, the cable aging status is divided into five levels: ideal status, slight aging, general aging, moderate aging and severe aging. Each level has a corresponding aging status value range. If it is determined that the obtained aging condition value falls within a corresponding aging condition value interval, the state of the cable is evaluated as a corresponding level.

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