CN116381405A - Cable aging degradation state detection method - Google Patents
Cable aging degradation state detection method Download PDFInfo
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- 238000006731 degradation reaction Methods 0.000 title claims abstract description 48
- 238000000034 method Methods 0.000 claims abstract description 49
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/083—Locating faults in cables, transmission lines, or networks according to type of conductors in cables, e.g. underground
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
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- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
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Abstract
The invention belongs to the technical field of cable state detection, and particularly relates to a cable aging degradation state detection method; the method comprises the steps of 1, carrying out on-line detection on a cable, 2, determining the position of an aging degradation problem of the cable according to temperature change and cable sheath current change in the operation process of the cable by carrying out on-line detection on the cable, and carrying out partial discharge on the cable near the position of the aging degradation problem; step 3, performing off-line detection on the cable, including: determining a main problem section of the cable according to the cable partial discharge online detection result, and performing comprehensive offline detection comprising electrical performance indexes and non-electrical performance indexes on the cable in the problem section; the on-line detection and the off-line detection are combined, the cable ageing degradation problem position is determined through large-area on-line detection, the off-line detection is performed on the screened problem cable, the cable ageing degradation degree is determined, and the safe and stable operation of the power system is ensured.
Description
Technical Field
The invention belongs to the technical field of cable state detection, and particularly relates to a cable aging degradation state detection method.
Background
The operation reliability of the power cable directly affects the safe and stable operation of the power system, however, the cable is affected by aging factors such as electricity, heat, chemistry and machinery in the electrified operation process, the insulation state of the cable can age with time, even breakdown accidents can occur, and once the breakdown accidents occur, the cable needs to be powered off for maintenance, so that inconvenience is brought to normal production and life of vast users, and even serious economic loss can be caused.
Causes of cable degradation include: insulation and moisture regain, which is common, is typically created at cable joints in direct burial or pipe chases; chemical corrosion, the cable is buried in a region with strong acid and alkali effects, so that an armored cable, a tin pendant or an outer protective layer of the cable is corroded, the protective layer is invalid due to long-term chemical corrosion or electrolytic corrosion, insulation is reduced, and common faults of the cable can be caused; the overload operation is carried out for a long time, because of the thermoelectric effect of the current amount, the load current amount must cause the electric conductor to scald according to the cable, in addition, the skin effect of positive charge, the eddy current loss of the steel armor and the insulation dielectric loss can generate extra heating value at first sight, so that the temperature of the cable rises, and the aging of insulation can be accelerated due to the excessively high temperature during the overload operation for a long time, so that the insulation is penetrated, and particularly in the hot summer, the insulation deficiency part of the cable is always penetrated first due to the temperature rise of the cable, so that common faults of the cable are more in summer; common faults of the cable connector are weak points in a cable route, the common faults of the cable connector caused by immediate mistake of workers are often generated, and if original networks such as loose riveting and insufficient heating of the connector exist in the whole process of manufacturing the cable connector, the cable connector is reduced in insulation, so that safety accidents are caused; the natural environment and temperature, the external natural environment and pyrogen where the cable is located, can also cause the cable to be too hot, to penetrate through insulation, or even to catch fire from explosion.
In order to improve the operation reliability of the cable, on one hand, modification research can be carried out on cable materials, on the other hand, state detection is carried out on the cable which is put into operation, no effective preventive test means exist at present from the perspective of overhauling the high-voltage power cable, and once insulation breakdown accidents of the power cable occur, a large amount of personnel, material resources and financial resources are required to be put into the defect and the fault of the power cable which is laid underground and at a longer distance, and the normal life of residents and the production of enterprises are also influenced by the power failure accidents caused by the power failure; therefore, the scientific and effective detection method provides reasonable basis for cable operation and maintenance planning, and has important significance for improving the reliability of the power system.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a cable aging and degradation state detection method, which combines online detection with offline detection, firstly, determines the position of a cable aging and degradation problem through large-area online detection by preliminary screening, and then performs offline detection on the screened problem cable to determine the cable aging and degradation degree, thereby ensuring safe and stable operation of a power system.
The purpose of the invention is realized in the following way: a method for detecting the aging and degradation state of a cable, comprising the steps of:
step 1, carrying out on-line detection on a cable, including: carrying out cable sheath current monitoring, cable operation temperature monitoring and partial discharge online detection on the cable in the operation process of the cable;
step 2, determining the position of the aging and degradation problem of the cable according to the temperature change and the current change of the cable sheath in the operation process of the cable by carrying out online detection on the cable, and carrying out online detection on partial discharge on the cable near the position of the aging and degradation problem;
step 3, performing off-line detection on the cable, including: and determining a main problem section of the cable according to the cable partial discharge online detection result, and performing comprehensive offline detection comprising an electrical performance index and a non-electrical performance index on the cable in the problem section.
The cable sheath current monitoring in the step 1 in the cable operation process comprises the following steps:
the cable sheath grounding current collecting device is arranged on the cable sheath grounding wire to collect leakage current of the cable sheath grounding, and the grounding current collecting main station arranged in the monitoring center is used for monitoring the cable grounding current in real time; once the cable fails, the earth leakage current is increased to exceed a set threshold value, and an alarm is sent out immediately to prompt related personnel to process the cable failure;
the cable sheath grounding current collection device is used for achieving collection of leakage current of cable sheath grounding through grounding current induction, collection and coding, collected data are transmitted back to a grounding current collection main station arranged in a monitoring center through a communication link, and the cable sheath grounding current collection device is used for supplying power in a tunnel lighting or induction electricity taking mode.
The cable operation temperature monitoring in the step 1 during the cable operation process comprises the following steps:
real-time online monitoring is carried out on the temperature of the whole cable through a temperature measuring optical fiber arranged between the main insulating layer and the outer protective layer in the cable, a remote cable temperature monitoring host records temperature monitoring data of each section of the cable and corresponding positioning data, and when the real-time monitoring temperature of a certain section of the cable is abnormal, an alarm is sent to a worker to prompt related workers to process cable faults;
the method for monitoring the temperature of the cable in real time comprises the following steps: when the real-time monitoring temperature of a certain section of cable is higher than the overtemperature alarm threshold set by the section of cable, or when the real-time monitoring temperature rising rate of the certain section of cable is higher than the set temperature rising rate alarm threshold of the section of cable, or when the difference value between the real-time monitoring temperature of the certain section of cable and the historical contemporaneous average temperature of the section of cable exceeds the set temperature difference alarm threshold, or when the difference value between the real-time monitoring temperature of the certain section of cable and the temperature value of other sections of cables in 7m around the same section of cable exceeds the set temperature difference abnormality alarm threshold, an alarm is sent to a worker.
The online detection of partial discharge in the cable operation process in the step 1 comprises the following steps:
the high-frequency pulse current sensor is arranged on the cable connector grounding wire, the local discharge pulse current signals at the cable body and the connector are coupled, the coupled pulse current signals are transmitted to the local discharge collector through the coaxial cable, and the local discharge collector amplifies, filters and converts analog signals into digital signals and then transmits the digital signals to the monitoring host; the cable connector and the partial discharge condition of each section of cable are monitored through management software arranged on the monitoring host, and once a certain measuring point is abnormal, an alarm is sent to a worker to inform the relevant worker to process.
The step 3 of performing the comprehensive offline detection on the cable in the problem section, which includes the electrical performance index and the non-electrical performance index, includes:
performing an offline detection of an electrical performance index on a cable of a problem section, comprising: performing off-line partial discharge detection and insulation resistance detection on the cable in the problem section;
performing off-line detection of non-electrical performance indicators on a cable of a problem section, comprising: and carrying out tensile test detection and indentation test detection on the cable in the problem section.
The offline partial discharge detection of the cable of the problem section comprises the following steps:
simulating a 100nC-100pC partial discharge signal by using a calibrator, inputting the partial discharge signal into a cable sample of a problem section, determining a signal transmission condition by measuring the transmission attenuation of a high-frequency signal in a cable section and detecting a transmitting wave at the tail end of the cable, wherein the smaller the simulated partial discharge value is, the better the transmission of the cable to the partial discharge signal is; detecting a background interference value by using the shock wave, converting the field interference value into partial discharge intensity, and determining the influence of the background interference value on a test result; and pressurizing the cable step by step, analyzing and calculating concentrated partial discharge points and partial discharge values in the cable partial discharge evaluation set through each pulse, determining the partial discharge horizontal distribution condition, and positioning the cable problem position.
The insulation resistance detection of the cable of the problem section comprises the following steps:
the method comprises the steps that data interaction between a management host and a detection device is carried out in a CAN bus mode, a problem cable sample is detected through a distributed detection device, the management host is used as an upper computer and is interacted with a lower computer through a human-computer interface, a worker carries out relevant setting on a detected cable through detection software according to actual detection requirements and sends information required by detection to the distributed detection device, meanwhile, a detection result uploaded by the detection device is displayed on a PC interface, the cable detection device receives detection command information issued by the host, and the detection data is uploaded at the same time when cable detection is completed according to instructions; the personnel connects the PC with the detection device through the USB-CAN conversion device, so as to carry out CAN communication;
the tensile test detection and indentation test detection of the cable of the problem section comprise:
the tensile strength and the elongation at break of the cable sample in the problem section are detected through a tensile test, and the tensile strength and the elongation at break detected by the cable sample are compared with the original data thereof to judge the aging degradation degree of the cable in the problem section; the indentation modulus of the cable test specimen of the problem section is detected by carrying out indentation test, and the aging degradation degree of the cable of the problem section is judged by comparing the indentation modulus with the indentation modulus of cables with different service durations.
The invention has the beneficial effects that: the invention relates to a method for detecting the aging and degradation state of a cable, which comprises the following steps of: carrying out cable sheath current monitoring, cable operation temperature monitoring and partial discharge online detection on the cable in the operation process of the cable; step 2, determining the position of the aging and degradation problem of the cable according to the temperature change and the current change of the cable sheath in the operation process of the cable by carrying out online detection on the cable, and carrying out online detection on partial discharge on the cable near the position of the aging and degradation problem; step 3, performing off-line detection on the cable, including: determining a main problem section of the cable according to the cable partial discharge online detection result, and performing comprehensive offline detection comprising electrical performance indexes and non-electrical performance indexes on the cable in the problem section; the on-line detection and the off-line detection are combined, the cable ageing degradation problem position is determined through large-area on-line detection, the off-line detection is performed on the screened problem cable, the cable ageing degradation degree is determined, and the safe and stable operation of the power system is ensured.
Drawings
Fig. 1 is a flow chart of a method for detecting an aging and degradation state of a cable according to the present invention.
Description of the embodiments
The invention is further described below with reference to the accompanying drawings.
A method for detecting the aging and degradation state of a cable, as shown in fig. 1, comprising the following steps:
step 1, carrying out on-line detection on a cable, including: carrying out cable sheath current monitoring, cable operation temperature monitoring and partial discharge online detection on the cable in the operation process of the cable;
step 2, determining the position of the aging and degradation problem of the cable according to the temperature change and the current change of the cable sheath in the operation process of the cable by carrying out online detection on the cable, and carrying out online detection on partial discharge on the cable near the position of the aging and degradation problem;
step 3, performing off-line detection on the cable, including: and determining a main problem section of the cable according to the cable partial discharge online detection result, and performing comprehensive offline detection comprising an electrical performance index and a non-electrical performance index on the cable in the problem section.
For better effect, the cable sheath current monitoring in the cable operation process in the step 1 comprises the following steps:
the cable sheath grounding current collecting device is arranged on the cable sheath grounding wire to collect leakage current of the cable sheath grounding, and the grounding current collecting main station arranged in the monitoring center is used for monitoring the cable grounding current in real time; once the cable fails, the earth leakage current is increased to exceed a set threshold value, and an alarm is sent out immediately to prompt related personnel to process the cable failure;
the cable sheath grounding current collection device is used for achieving collection of leakage current of cable sheath grounding through grounding current induction, collection and coding, collected data are transmitted back to a grounding current collection main station arranged in a monitoring center through a communication link, and the cable sheath grounding current collection device is used for supplying power in a tunnel lighting or induction electricity taking mode.
The communication link is mainly used for connecting the acquisition device and the upper system, and the communication link can be realized by adopting an industrial 485 bus, an industrial field Ethernet bus and a GPRS wireless network.
The grounding current of the power cable is monitored in real time, the cable grounding current abnormality can be found out early, and treatment measures are taken for cable faults; the cable sheath grounding current collection device consists of a monitoring host, an energy acquisition CT, a current acquisition CT, a short message alarm module and a communication module, and can acquire the grounding current and the load current of the cable metal sheath in real time through CT energy acquisition and power supply, and upload the acquired data to the monitoring center through the 4G communication module, and when the grounding current exceeds 20% of the load current, the monitoring host sends alarm information.
For better effect, the cable operation temperature monitoring in the cable operation process in the step 1 comprises the following steps:
real-time online monitoring is carried out on the temperature of the whole cable through a temperature measuring optical fiber arranged between the main insulating layer and the outer protective layer in the cable, a remote cable temperature monitoring host records temperature monitoring data of each section of the cable and corresponding positioning data, and when the real-time monitoring temperature of a certain section of the cable is abnormal, an alarm is sent to a worker to prompt related workers to process cable faults;
the method for monitoring the temperature of the cable in real time comprises the following steps: when the real-time monitoring temperature of a certain section of cable is higher than the overtemperature alarm threshold set by the section of cable, or when the real-time monitoring temperature rising rate of the certain section of cable is higher than the set temperature rising rate alarm threshold of the section of cable, or when the difference value between the real-time monitoring temperature of the certain section of cable and the historical contemporaneous average temperature of the section of cable exceeds the set temperature difference alarm threshold, or when the difference value between the real-time monitoring temperature of the certain section of cable and the temperature value of other sections of cables in 7m around the same section of cable exceeds the set temperature difference abnormality alarm threshold, an alarm is sent to a worker.
The overtemperature alarm threshold set by the section of cable is determined according to the highest allowable temperature of the cable structure layer where the temperature measuring optical fiber is positioned; the set temperature rise rate alarm threshold value of the section of cable is set to be that the temperature rises to more than 3 ℃ in the adjacent measurement period; the temperature difference alarm threshold value is set to be that the temperature difference exceeds 12 ℃; and the temperature difference abnormal alarm threshold value is set to be that the temperature difference exceeds 8 ℃.
For better effect, the online detection of partial discharge in the cable operation process in step 1 comprises the following steps:
the high-frequency pulse current sensor is arranged on the cable connector grounding wire, the local discharge pulse current signals at the cable body and the connector are coupled, the coupled pulse current signals are transmitted to the local discharge collector through the coaxial cable, and the local discharge collector amplifies, filters and converts analog signals into digital signals and then transmits the digital signals to the monitoring host; the cable connector and the partial discharge condition of each section of cable are monitored through management software arranged on the monitoring host, and once a certain measuring point is abnormal, an alarm is sent to a worker to inform the relevant worker to process.
For better effect, the step 3 of performing the comprehensive offline detection on the cable in the problem section, which includes the electrical performance index and the non-electrical performance index, includes:
performing an offline detection of an electrical performance index on a cable of a problem section, comprising: performing off-line partial discharge detection and insulation resistance detection on the cable in the problem section;
performing off-line detection of non-electrical performance indicators on a cable of a problem section, comprising: and carrying out tensile test detection and indentation test detection on the cable in the problem section.
For better effect, the off-line partial discharge detection of the cable in the problem section comprises:
simulating a 100nC-100pC partial discharge signal by using a calibrator, inputting the partial discharge signal into a cable sample of a problem section, determining a signal transmission condition by measuring the transmission attenuation of a high-frequency signal in a cable section and detecting a transmitting wave at the tail end of the cable, wherein the smaller the simulated partial discharge value is, the better the transmission of the cable to the partial discharge signal is; detecting a background interference value by using the shock wave, converting the field interference value into partial discharge intensity, and determining the influence of the background interference value on a test result; and pressurizing the cable step by step, analyzing and calculating concentrated partial discharge points and partial discharge values in the cable partial discharge evaluation set through each pulse, determining the partial discharge horizontal distribution condition, and positioning the cable problem position.
For better effect, the insulation resistance detection of the cable in the problem section comprises:
the method comprises the steps that data interaction between a management host and a detection device is carried out in a CAN bus mode, a problem cable sample is detected through a distributed detection device, the management host is used as an upper computer and is interacted with a lower computer through a human-computer interface, a worker carries out relevant setting on a detected cable through detection software according to actual detection requirements and sends information required by detection to the distributed detection device, meanwhile, a detection result uploaded by the detection device is displayed on a PC interface, the cable detection device receives detection command information issued by the host, and the detection data is uploaded at the same time when cable detection is completed according to instructions; the personnel connects the PC with the detection device through the USB-CAN conversion device, so as to carry out CAN communication;
for better effect, the tensile test detection and indentation test detection of the cable of the problem section comprise:
the tensile strength and the elongation at break of the cable sample in the problem section are detected through a tensile test, and the tensile strength and the elongation at break detected by the cable sample are compared with the original data thereof to judge the aging degradation degree of the cable in the problem section; the indentation modulus of the cable test specimen of the problem section is detected by carrying out indentation test, and the aging degradation degree of the cable of the problem section is judged by comparing the indentation modulus with the indentation modulus of cables with different service durations.
The cable aging degradation state initial evaluation model can be established based on the historical operation data and the online monitoring indexes, and the positions of the corresponding cable problems can be judged when the initial evaluation model reaches the corresponding threshold value set by each index; the historical operation data comprise cable operation years, historical load, laying mode, laying environment (temperature, humidity, chemical corrosion), historical faults, family defects and the like, a linear weighted evaluation method can be adopted to establish an online initial evaluation model of the aging and degradation state of the cable, the cable aging state can be initially classified according to the model based on the online operation information of the cable, the cable with higher aging degree is sampled, sampling detection can be avoided on all the cables, and finally the sample is detected offline to determine the aging and degradation state of the cable.
In summary, the method for detecting the aging and degradation state of the cable according to the invention comprises the following steps: carrying out cable sheath current monitoring, cable operation temperature monitoring and partial discharge online detection on the cable in the operation process of the cable; step 2, determining the position of the aging and degradation problem of the cable according to the temperature change and the current change of the cable sheath in the operation process of the cable by carrying out online detection on the cable, and carrying out online detection on partial discharge on the cable near the position of the aging and degradation problem; step 3, performing off-line detection on the cable, including: determining a main problem section of the cable according to the cable partial discharge online detection result, and performing comprehensive offline detection comprising electrical performance indexes and non-electrical performance indexes on the cable in the problem section; the on-line detection and the off-line detection are combined, the cable ageing degradation problem position is determined through large-area on-line detection, the off-line detection is performed on the screened problem cable, the cable ageing degradation degree is determined, and the safe and stable operation of the power system is ensured.
Claims (8)
1. A method for detecting the aging and degradation state of a cable, comprising the steps of:
step 1, carrying out on-line detection on a cable, including: carrying out cable sheath current monitoring, cable operation temperature monitoring and partial discharge online detection on the cable in the operation process of the cable;
step 2, determining the position of the aging and degradation problem of the cable according to the temperature change and the current change of the cable sheath in the operation process of the cable by carrying out online detection on the cable, and carrying out online detection on partial discharge on the cable near the position of the aging and degradation problem;
step 3, performing off-line detection on the cable, including: and determining a main problem section of the cable according to the cable partial discharge online detection result, and performing comprehensive offline detection comprising an electrical performance index and a non-electrical performance index on the cable in the problem section.
2. The method for detecting the aging and degradation state of a cable according to claim 1, wherein the step 1 of monitoring the sheath current during the operation of the cable comprises:
the cable sheath grounding current collecting device is arranged on the cable sheath grounding wire to collect leakage current of the cable sheath grounding, and the grounding current collecting main station arranged in the monitoring center is used for monitoring the cable grounding current in real time; once the cable fails, the earth leakage current is increased to exceed a set threshold value, and an alarm is sent out immediately to prompt related personnel to process the cable failure;
the cable sheath grounding current collection device is used for achieving collection of leakage current of cable sheath grounding through grounding current induction, collection and coding, collected data are transmitted back to a grounding current collection main station arranged in a monitoring center through a communication link, and the cable sheath grounding current collection device is used for supplying power in a tunnel lighting or induction electricity taking mode.
3. The method for detecting the aging and degradation state of a cable according to claim 1, wherein the monitoring of the cable operation temperature during the operation of the cable in step 1 comprises:
real-time online monitoring is carried out on the temperature of the whole cable through a temperature measuring optical fiber arranged between the main insulating layer and the outer protective layer in the cable, a remote cable temperature monitoring host records temperature monitoring data of each section of the cable and corresponding positioning data, and when the real-time monitoring temperature of a certain section of the cable is abnormal, an alarm is sent to a worker to prompt related workers to process cable faults;
the method for monitoring the temperature of the cable in real time comprises the following steps: when the real-time monitoring temperature of a certain section of cable is higher than the overtemperature alarm threshold set by the section of cable, or when the real-time monitoring temperature rising rate of the certain section of cable is higher than the set temperature rising rate alarm threshold of the section of cable, or when the difference value between the real-time monitoring temperature of the certain section of cable and the historical contemporaneous average temperature of the section of cable exceeds the set temperature difference alarm threshold, or when the difference value between the real-time monitoring temperature of the certain section of cable and the temperature value of other sections of cables in 7m around the same section of cable exceeds the set temperature difference abnormality alarm threshold, an alarm is sent to a worker.
4. The method for detecting the aging and degradation state of the cable according to claim 1, wherein the online detection of partial discharge of the cable in the operation process of the cable in the step 1 comprises:
the high-frequency pulse current sensor is arranged on the cable connector grounding wire, the local discharge pulse current signals at the cable body and the connector are coupled, the coupled pulse current signals are transmitted to the local discharge collector through the coaxial cable, and the local discharge collector amplifies, filters and converts analog signals into digital signals and then transmits the digital signals to the monitoring host; the cable connector and the partial discharge condition of each section of cable are monitored through management software arranged on the monitoring host, and once a certain measuring point is abnormal, an alarm is sent to a worker to inform the relevant worker to process.
5. The method for detecting the aging degradation state of a cable according to claim 1, wherein the step 3 of performing the comprehensive offline detection of the cable in the problematic section, including the electrical performance index and the non-electrical performance index, comprises:
performing an offline detection of an electrical performance index on a cable of a problem section, comprising: performing off-line partial discharge detection and insulation resistance detection on the cable in the problem section;
performing off-line detection of non-electrical performance indicators on a cable of a problem section, comprising: and carrying out tensile test detection and indentation test detection on the cable in the problem section.
6. The method for detecting an aged degradation state of a cable according to claim 5, wherein the detecting an offline partial discharge of the cable in the problematic section comprises:
simulating a 100nC-100pC partial discharge signal by using a calibrator, inputting the partial discharge signal into a cable sample of a problem section, determining a signal transmission condition by measuring the transmission attenuation of a high-frequency signal in a cable section and detecting a transmitting wave at the tail end of the cable, wherein the smaller the simulated partial discharge value is, the better the transmission of the cable to the partial discharge signal is; detecting a background interference value by using the shock wave, converting the field interference value into partial discharge intensity, and determining the influence of the background interference value on a test result; and pressurizing the cable step by step, analyzing and calculating concentrated partial discharge points and partial discharge values in the cable partial discharge evaluation set through each pulse, determining the partial discharge horizontal distribution condition, and positioning the cable problem position.
7. The method of detecting an aged degradation state of a cable according to claim 5, wherein the detecting insulation resistance of the cable in the problematic section comprises:
the method comprises the steps that data interaction between a management host and a detection device is carried out in a CAN bus mode, a problem cable sample is detected through a distributed detection device, the management host is used as an upper computer and is interacted with a lower computer through a human-computer interface, a worker carries out relevant setting on a detected cable through detection software according to actual detection requirements and sends information required by detection to the distributed detection device, meanwhile, a detection result uploaded by the detection device is displayed on a PC interface, the cable detection device receives detection command information issued by the host, and the detection data is uploaded at the same time when cable detection is completed according to instructions; the staff connects the PC with the detection device through the USB-CAN conversion device, so as to carry out CAN communication.
8. The method for detecting an aged degradation state of a cable according to claim 5, wherein the tensile test detection and indentation test detection of the cable of the problem section comprise:
the tensile strength and the elongation at break of the cable sample in the problem section are detected through a tensile test, and the tensile strength and the elongation at break detected by the cable sample are compared with the original data thereof to judge the aging degradation degree of the cable in the problem section; the indentation modulus of the cable test specimen of the problem section is detected by carrying out indentation test, and the aging degradation degree of the cable of the problem section is judged by comparing the indentation modulus with the indentation modulus of cables with different service durations.
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| CN116559599A (en) * | 2023-07-12 | 2023-08-08 | 保定天威宝乾电力设备有限公司 | Distribution network cable fault early warning method and system based on big data |
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| CN116559599A (en) * | 2023-07-12 | 2023-08-08 | 保定天威宝乾电力设备有限公司 | Distribution network cable fault early warning method and system based on big data |
| CN116559599B (en) * | 2023-07-12 | 2023-09-12 | 保定天威宝乾电力设备有限公司 | Distribution network cable fault early warning method and system based on big data |
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