Method and device for detecting defects of high-voltage cable terminal

Abstract

The invention discloses a method and device for detecting defects of a high-voltage cable terminal, and belongs to the technical field of electrical equipment.The method comprises the steps that target parameters of the high-voltage cable terminal are obtained, and the target parameters comprise the target component concentration and the micro-water content in silicone oil of the high-voltage cable terminal and the oil temperature of the silicone oil; defining a trapezoidal membership function for the target parameter of the high-voltage cable terminal, and mapping the degradation degree of the trapezoidal membership function to a target interval to obtain a mapping value; the accumulated service time of the high-voltage cable terminal is obtained, and parameter correction is carried out in combination with the obtained mapping value; and calculating a defect early-warning index of the high-voltage cable terminal according to the mapping value after parameter correction, and performing defect detection according to the defect early-warning index of the high-voltage cable terminal. Compared with a traditional method, the method can perform early warning and accurate judgment on defects.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical equipment, and in particular, to a method and device for detecting defects in high-voltage cable terminals. Background Art

[0002] Cable terminals are key components indispensable in the power system. It is installed at the end of the cable, connecting the cable with external equipment or lines, playing the roles of electrical connection and insulation protection. Cable terminals can ensure the safe and stable transmission of current, prevent the internal insulation layer of the cable from being affected by the external environment such as moisture and corrosion, thereby extending the service life of the cable. At the same time, it can effectively avoid insulation breakdown accidents caused by electric field concentration and ensure the reliable operation of the power system. In the fields of high-voltage power transmission, substations, industrial power distribution, etc., the performance and quality of cable terminals are directly related to the safety and stability of power transmission and are an important guarantee for the normal operation of the power grid.

[0003] When a cable terminal shows fault symptoms during operation (such as overheating, partial discharge or arc discharge), insulating silicone oil and solid insulating materials will decompose under the action of high temperature and electrical stress, generating gases such as hydrogen, methane, ethylene, and ethane. Different fault types and degrees will lead to changes in the characteristic gas components and concentration ratios.

[0004] Currently, the method of judging transformer defects through dissolved gases in oil has been relatively mature, but this judgment method is not applicable to the silicone oil in cable terminals. This is mainly because transformer oil is mineral oil, mainly composed of hydrocarbon compounds derived from petroleum, and its specific components include saturated hydrocarbons (such as naphthenes, alkanes), a small amount of aromatic hydrocarbons, and heterocyclic compounds, etc. Insulating silicone oil is a synthetic oil based on silicone, and its main component is polydimethylsiloxane. Due to the different types of oil, the "three-ratio" method for evaluating transformer oil faults cannot effectively guide the evaluation of silicone oil and the determination of defect types. At the same time, due to the operation years of cable terminals and the water content in silicone oil also have a significant impact on terminal defects, there is currently no relatively accurate method for judging cable terminal defects. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method and device for detecting defects in high-voltage cable terminals, so as to solve the technical problem of poor accuracy in judging existing high-voltage cable terminal defects.

[0006] To achieve the above purpose, the present invention is implemented by the following technical solutions:

[0007] In the first aspect, the present invention provides a method for detecting defects in high-voltage cable terminals, including:

[0008] Obtain the target parameters of the high-voltage cable terminal, where the target parameters include the concentration of the target component and the micro-water content in the silicone oil of the high-voltage cable terminal, and the oil temperature of the silicone oil;

[0009] Define a trapezoidal membership function for the target parameters of the high-voltage cable terminal, and map its degree of deterioration to the target interval to obtain a mapping value;

[0010] Obtain the cumulative service time of the high-voltage cable terminal, and perform parameter correction in combination with the obtained mapping value;

[0011] Calculate the defect warning index of the high-voltage cable terminal according to the mapping value after parameter correction, and perform defect detection according to the defect warning index of the high-voltage cable terminal.

[0012] Optionally, the trapezoidal membership function of the concentration of the target component in the silicone oil is:

[0013]

[0014] In the formula, is the total concentration of the target component, in ppm, is the mapping value of;

[0015] The trapezoidal membership function of the micro-water content is:

[0016]

[0017] In the formula, is the micro-water content, in ppm, is the mapping value of;

[0018] The trapezoidal membership function of the oil temperature of the silicone oil is:

[0019]

[0020] In the formula, is the oil temperature of the silicone oil, in °C, is the mapping value of.

[0021] Optionally, the performing parameter correction in combination with the obtained mapping value includes:

[0022] If and , then let ;

[0023] If and , then let ;

[0024] If And , then let ;

[0025] Wherein, is the total concentration of the target components, in ppm, is 's mapping value; is the micro water content, in ppm, is 's mapping value; is the oil temperature of the silicone oil, in °C, is 's mapping value; is the cumulative service time, in years.

[0026] Optionally, the high-voltage cable terminal defect warning index is:

[0027]

[0028] In the formula, is the total concentration of the target components, in ppm, is 's mapping value; is the micro water content, in ppm, is 's mapping value; is the oil temperature of the silicone oil, in °C, is 's mapping value.

[0029] Optionally, the defect detection according to the high-voltage cable terminal defect warning index includes:

[0030] If , it is determined that the high-voltage cable terminal has a defect, and the defect type is diagnosed according to the concentration of the target components in the silicone oil;

[0031] If , it is determined that the high-voltage cable terminal is about to have a defect, and a warning is given;

[0032] If , it is determined that the high-voltage cable terminal is operating normally;

[0033] Wherein, is the high-voltage cable terminal defect warning index.

[0034] Optionally, the target components include hydrogen, methane, ethylene, and ethane.

[0035] Optionally, the defect type diagnosis according to the concentration of the target components in the silicone oil includes:

[0036] If and , the defect type is overheating;

[0037] If and , the defect type is partial discharge;

[0038] If and , the defect type is arc discharge;

[0039] Among them, are the concentrations of hydrogen, methane, ethylene, and ethane respectively, with the unit of ppm.

[0040] In a second aspect, the present invention provides a detection device for defects in a high-voltage cable terminal, including:

[0041] A parameter acquisition module configured to acquire target parameters of the high-voltage cable terminal, where the target parameters include the concentration of the target component and the micro-water content in the silicone oil of the high-voltage cable terminal, and the oil temperature of the silicone oil;

[0042] A parameter mapping module configured to define a trapezoidal membership function for the target parameters of the high-voltage cable terminal and map its deterioration degree to a target interval to obtain a mapping value;

[0043] A parameter correction module configured to acquire the cumulative service time of the high-voltage cable terminal and perform parameter correction in combination with the obtained mapping value;

[0044] A defect detection module configured to calculate a defect warning index of the high-voltage cable terminal according to the mapping value after parameter correction and perform defect detection according to the defect warning index of the high-voltage cable terminal.

[0045] In a third aspect, the present invention provides an electronic device, including a processor and a storage medium;

[0046] The storage medium is used to store instructions;

[0047] The processor is used to operate according to the instructions to execute the steps of the above method.

[0048] In a fourth aspect, the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps of the above method are implemented.

[0049] Compared with the prior art, the beneficial effects achieved by the present invention:

[0050] A detection method and device for high-voltage cable terminal defects provided by the present invention obtain target parameters, perform mapping and correction, thereby improving the efficiency and accuracy of subsequent processing; by calculating the high-voltage cable terminal defect warning index, defects can be warned. After a defect occurs, the defect type is diagnosed according to the concentration of the target component in the silicone oil, improving the detection performance of high-voltage cable terminal defects. Description of the Drawings

[0051] Figure 1 is a schematic flowchart of the detection method for high-voltage cable terminal defects provided by an embodiment of the present invention;

[0052] Figure 2 is a working schematic diagram of the detection method for high-voltage cable terminal defects provided by an embodiment of the present invention. Detailed Embodiments

[0053] The present invention will be further described below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and cannot be used to limit the protection scope of the present invention.

[0054] Embodiment 1:

[0055] As Figure 1 , Figure 2 shown, an embodiment of the present invention provides a detection method for high-voltage cable terminal defects, including the following steps:

[0056] Step S1, obtain the target parameters of the high-voltage cable terminal, where the target parameters include the concentration of the target component and the micro-water content in the silicone oil of the high-voltage cable terminal, and the oil temperature of the silicone oil.

[0057] Specifically, in this embodiment, the target components include hydrogen , methane , ethylene and ethane . In other alternative embodiments, the component types can be adjusted according to needs.

[0058] Step S2, define a trapezoidal membership function for the target parameters of the high-voltage cable terminal, and map its deterioration degree to the target interval to obtain a mapping value.

[0059] Specifically, in this embodiment, the target interval is :

[0060] (1) The trapezoidal membership function of the concentration of the target component in the silicone oil is:

[0061]

[0062] In the formula, is the total concentration of the target component , with the unit of ppm, The mapping value of ;

[0063] (2) The trapezoidal membership function of the micro water content is:

[0064]

[0065] In the formula, is the micro water content, with the unit of ppm, is 's mapping value;

[0066] (3) The trapezoidal membership function of the oil temperature of silicone oil is:

[0067]

[0068] In the formula, is the oil temperature of silicone oil, with the unit of °C, is 's mapping value.

[0069] Step S3: Obtain the cumulative service time of the high-voltage cable terminal, and correct the parameters by combining the obtained mapping values.

[0070] Under actual operating conditions, the gas content, water content in the oil, and the temperature of silicone oil in the high-voltage cable terminal affect each other. Therefore, based on the trapezoidal membership functions of the three variables, an interaction compensation matrix is established to correct the functions:

[0071] If and , then let ;

[0072] If and , then let ;

[0073] If and , then let .

[0074] Among them, is the cumulative service time, with the unit of year.

[0075] Step S4: Calculate the defect warning index of the high-voltage cable terminal according to the mapping value after parameter correction, and perform defect detection based on the defect warning index of the high-voltage cable terminal.

[0076] Specifically, in this embodiment, the defect warning index of the high-voltage cable terminal is:

[0077]

[0078] Defect detection based on the high-voltage cable terminal defect warning index includes:

[0079] If , it is determined that there is a defect in the high-voltage cable terminal, and the defect type is diagnosed according to the concentration of the target component in the silicone oil;

[0080] If , it is determined that a defect in the high-voltage cable terminal is about to occur, and a warning is issued (it is necessary to increase detection means for real-time monitoring or perform preventive detection and maintenance in advance);

[0081] If , it is determined that the high-voltage cable terminal is operating normally.

[0082] Among them, defect type diagnosis according to the concentration of the target component in the silicone oil includes:

[0083] If and , the defect type is overheating;

[0084] If and , the defect type is partial discharge;

[0085] If and , the defect type is arc discharge;

[0086] Among them, are the concentrations of hydrogen, methane, ethylene, and ethane, respectively, with the unit of ppm.

[0087] Taking the operation of the high-voltage cable terminal in an 110 kV substation for 7 years as an example, it is recently monitored that the temperature of the silicone oil has abnormally risen to 42 °C, and the micro-water content is 50 ppm.

[0088] 1), The gas concentrations obtained by oil chromatographic sampling: H 2 = 120 ppm, CH 4 = 80 ppm, C 2 H 4 = 60 ppm, C 2 H 6 = 30 ppm.

[0089] 2), Through the calculation of the trapezoidal membership function, g_total = (290 - 100) / 200 = 0.95; W = 0.5; T = 0.28.

[0090] 3), Perform data correction:

[0091] g_total > 100 ppm and t f>5 years, correction +0.6→g_total=0.95+0.6=1.55;

[0092] W>40ppm and T>40℃, correction×1.2→W=0.5×1.2=0.6;

[0093] T>37℃ and t f >3 years, correction +0.23→T=0.28+0.23=0.51.

[0094] 4) Calculate the high-voltage cable terminal defect warning index C:

[0095] C=0.25×1.55+0.25×0.6+0.5×0.51=0.7925.

[0096] 5) Defect determination:

[0097] C=0.7925>0.65, it is determined that the high-voltage cable terminal has defects;

[0098] Gas ratio: H 2 / CH 4 =120 / 80=1.5>1, C 2 H 4 / C 2 H 6 =60 / 30=2>1→determined as overheating defect.

[0099] Processing results:

[0100] After the maintenance personnel optimized the cooling system and replaced the silicone oil of the terminal, the remeasured C value dropped to 0.15 and the equipment resumed normal operation, verifying the effectiveness of this method.

[0101] According to experimental statistics, the classification accuracy of overheating defects, partial discharges and arc discharges in the embodiments of the present invention reached 92%, 88% and 85% respectively, which is about 20%-30% higher than the traditional method.

[0102] Embodiment 2:

[0103] An embodiment of the present invention provides a device for detecting defects of a high-voltage cable terminal, comprising:

[0104] A parameter acquisition module is configured to acquire target parameters of the high-voltage cable terminal, wherein the target parameters include target component concentration and trace water content in the silicone oil of the high-voltage cable terminal, and oil temperature of the silicone oil;

[0105] A parameter mapping module is configured to define a trapezoidal membership function for a target parameter of a high-voltage cable terminal, and map its degradation degree to a target interval to obtain a mapping value;

[0106] A parameter correction module, configured to obtain the cumulative service time of the high-voltage cable terminal and perform parameter correction in combination with the obtained mapping value;

[0107] A defect detection module, configured to calculate a defect warning index of the high-voltage cable terminal according to the mapping value after parameter correction and perform defect detection according to the defect warning index of the high-voltage cable terminal.

[0108] Embodiment III:

[0109] Based on the method for detecting defects in a high-voltage cable terminal provided in Embodiment I, an embodiment of the present invention provides an electronic device, including a processor and a storage medium;

[0110] The storage medium is used to store instructions;

[0111] The processor is used to operate according to the instructions to execute the steps of the above method.

[0112] Embodiment IV:

[0113] Based on the method for detecting defects in a high-voltage cable terminal provided in Embodiment I, an embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps of the above method are implemented.

[0114] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0115] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of flows and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0116] These computer program instructions can also be stored in a computer-readable memory that can direct 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 a manufacture including an instruction device that implements the functions specified in one or more of the processes and / or blocks Figure 1 one or more of the processes and / or blocks Figure 1 specified in one or more of the blocks or blocks.

[0117] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in one or more of the processes and / or blocks Figure 1 one or more of the processes and / or blocks Figure 1 specified in one or more of the blocks or blocks.

[0118] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for detecting defects in high-voltage cable terminals, characterized in that: include: Acquiring target parameters of the high-voltage cable terminal, the target parameters including target component concentration and trace water content in the silicone oil of the high-voltage cable terminal, and oil temperature of the silicone oil; defining a trapezoidal membership function for the target parameters of the high-voltage cable terminal, and mapping the degradation degree thereof to the target interval to obtain a mapping value; Acquire the accumulated service time of the high-voltage cable terminal, and perform parameter correction based on the acquired mapping value; A high-voltage cable terminal defect warning index is calculated according to the mapping value after parameter correction, and defect detection is performed according to the high-voltage cable terminal defect warning index.

2. The method for detecting defects of high-voltage cable terminals according to claim 1, characterized in that: The trapezoidal membership function of the target component concentration in the silicone oil is: In the formula, is the total concentration of the target component in ppm, for The mapping value of The trapezoidal membership function of the trace water content is: In the formula, It is the trace water content, the unit is ppm, for The mapping value of The trapezoidal membership function of the oil temperature of the silicone oil is: In the formula, is the oil temperature of silicone oil, in °C, for The mapping value of .

3. The method for detecting defects of high-voltage cable terminals according to claim 1, characterized in that: The performing parameter correction in combination with the acquired mapping value includes: like and , then let ; like and , then let ; like and , then let ; in, is the total concentration of the target component in ppm, for The mapping value of It is the trace water content, the unit is ppm, for The mapping value of is the oil temperature of silicone oil, in °C, for The mapping value of It is the accumulated service time in years.

4. The method for detecting defects of high-voltage cable terminals according to claim 1, characterized in that: The high voltage cable terminal defect warning index for: In the formula, is the total concentration of the target component in ppm, for The mapping value of It is the trace water content, the unit is ppm, for The mapping value of is the oil temperature of silicone oil, in °C, for The mapping value of .

5. The method for detecting defects of high-voltage cable terminals according to claim 1, characterized in that: The defect detection according to the high-voltage cable terminal defect warning index comprises: like , it is determined that the high-voltage cable terminal has a defect, and the defect type is diagnosed according to the concentration of the target component in the silicone oil; like , it is determined that the high-voltage cable terminal is about to have a defect and an early warning is issued; like , it is deemed that the high-voltage cable terminal is operating normally; in, It is the high-voltage cable terminal defect warning index.

6. The method for detecting defects of high-voltage cable terminals according to claim 5, characterized in that: The target components include hydrogen, methane, ethylene and ethane.

7. The method for detecting defects of high-voltage cable terminals according to claim 6, characterized in that: The defect type diagnosis according to the concentration of the target component in the silicone oil includes: like and , then the defect type is overheating; like and , then the defect type is partial discharge; like and , then the defect type is arc discharge; in, They are the concentrations of hydrogen, methane, ethylene and ethane, in ppm.

8. A device for detecting defects at high-voltage cable terminals, characterized in that: include: A parameter acquisition module is configured to acquire target parameters of the high-voltage cable terminal, wherein the target parameters include target component concentration and trace water content in the silicone oil of the high-voltage cable terminal, and oil temperature of the silicone oil; A parameter mapping module is configured to define a trapezoidal membership function for a target parameter of the high-voltage cable terminal, and map its degradation degree to a target interval to obtain a mapping value; A parameter correction module is configured to obtain the accumulated service time of the high-voltage cable terminal and perform parameter correction in combination with the obtained mapping value; The defect detection module is configured to calculate a high-voltage cable terminal defect warning index according to the mapping value after parameter correction, and perform defect detection according to the high-voltage cable terminal defect warning index.

9. An electronic device, characterized in that: including processor and storage medium; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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