Secondary cable detection and evaluation method

Abstract

The invention relates to the technical field of secondary cable detection, and discloses a secondary cable detection and evaluation method which is based on a secondary cable detection and evaluation device. The following detection and evaluation steps are carried out: the secondary cable detection and evaluation device is connected with a cable conductor and a cable insulating layer of a secondary cable through a test connecting line; selecting a corresponding DC voltage value based on the voltage grade of the secondary cable use scene; applying a corresponding DC voltage to the cable conductor, and receiving a current value passing through the high-resistance resistor at the same time; and finally, evaluating the insulation performance of the secondary cable based on the current value of the high-resistance resistor. According to the secondary cable detection and evaluation method, the cable insulation layer is regarded as a high-resistance resistor, and accurate voltage and current testing is utilized, so that the insulation performance of the cable can be evaluated more accurately, and potential insulation defects can be identified.

Description

Technical Field

[0001] The present invention relates to the technical field of secondary cable detection, and in particular to a secondary cable detection and evaluation method. Background Art

[0002] According to the relevant regulations of the Southern Power Grid, it is allowed not to replace the secondary cables in the protection device and station automation system renovation project, so as to improve the renovation efficiency, save money, reduce power outage time, and reduce work risks. However, this method requires an enhanced assessment of the risks and circuit norms of the secondary cables to ensure the safe and stable operation of the equipment.

[0003] At present, the detection and evaluation of secondary control cables (composed of multiple insulated wires, mainly used for signal acquisition and transmission) have the following technical problems:

[0004] 1. Lack of detection methods:

[0005] Currently, there is a lack of effective means of testing secondary cables, especially in the absence of standardized testing methods and equipment, which makes it impossible to fully evaluate the operating status of the cables.

[0006] 2. Cable aging monitoring is difficult:

[0007] As time goes by, the aging degree of the cable will increase, and the degradation of the cable insulation performance will gradually increase. However, it is difficult to accurately monitor and predict this aging process and its impact on cable performance with existing technical means.

[0008] 3. Insulation performance evaluation is insufficient:

[0009] The degradation of the insulation layer is an important factor leading to unstable operation of power system equipment. An effective method is needed to comprehensively evaluate the insulation performance of cables in order to detect potential risks in a timely manner.

[0010] 4. Lack of comprehensive testing solutions:

[0011] Currently, there is a lack of comprehensive testing and evaluation programs covering various aspects of cable performance, and it is impossible to systematically evaluate the operating risks of secondary cables.

[0012] 5. Insufficient circuit standardization:

[0013] When renovating secondary cables, the compliance and safety of the loops need to be evaluated urgently to ensure that the cable architecture and connections meet operational requirements.

[0014] In summary, in order to address the above technical issues, it is urgent to develop a comprehensive secondary cable detection and evaluation method.

[0015] To solve the above problems, the present invention provides a secondary cable detection and evaluation method. Through the secondary cable detection and evaluation method based on a secondary cable detection and evaluation device, the insulation resistance, electrostatic capacitance field, and resonance value of the secondary cable can be tested, thereby achieving a comprehensive evaluation of the secondary cable operation risks. Summary of the invention

[0016] To solve the above problems, the present invention proposes a secondary cable detection and evaluation method, which is based on a secondary cable detection and evaluation device, and can test the insulation resistance, electrostatic capacitance field, and resonance value of the secondary cable, thereby achieving a comprehensive evaluation of the operating risks of the secondary cable.

[0017] The technical solution adopted by the present invention is:

[0018] A secondary cable detection and evaluation method is provided. The secondary cable detection and evaluation method is based on a secondary cable detection and evaluation device. The cable insulation layer of the secondary cable is regarded as a resistor with a high resistance value, and the following detection and evaluation steps are performed:

[0019] Step 1, connecting the secondary cable detection and evaluation device to the cable conductor and the cable insulation layer of the secondary cable respectively through two test connection lines;

[0020] Step 2: Turn on the secondary cable detection and evaluation device, and select a corresponding DC voltage value on the secondary cable detection and evaluation device based on the voltage level of the secondary cable usage scenario;

[0021] Step 3, the secondary cable detection and evaluation device applies a corresponding DC voltage to the cable conductor through a test connection line, and simultaneously receives a current value passing through a high-resistance resistor through another test connection line;

[0022] Step 4: The secondary cable detection and evaluation device evaluates the insulation performance of the secondary cable based on the current value passing through the high-resistance resistor.

[0023] Further, the secondary cable detection device comprises a device housing, a data processing unit installed in the device housing, a lithium battery and a full-circuit bridge module, and a test connection line that can be plugged into the device housing;

[0024] The lithium battery is electrically connected to the data processing unit to supply power to it;

[0025] The data processing unit includes a liquid crystal touch screen located on the device housing, a processor, a memory, and a communication module installed on the liquid crystal touch screen, and the data processing unit is communicatively connected with the full circuit bridge module through the communication module;

[0026] The full-circuit bridge module is connected to the connection line between the lithium battery and the data processing unit, and the full-circuit bridge module is electrically connected to the test line interface located on the device housing.

[0027] Further, the full circuit bridge module includes a communication module and four sets of high frequency generators, which are connected to the data processing unit processor through the communication module, and control the output voltage of the test line interface by controlling the working number of the high frequency generator;

[0028] When a set of high-frequency generators are working, the full-circuit bridge module generates a 50V voltage output;

[0029] When the two sets of high-frequency generators are working, the full-circuit bridge module generates a 100V voltage output;

[0030] When the three sets of high-frequency generators are working, the full-circuit bridge module generates a 250V voltage output;

[0031] When the four sets of high-frequency generators are working, the full-circuit bridge module generates a 500V voltage output.

[0032] Furthermore, a power adapter electrically connected to the lithium battery is installed in the device housing, and the power adapter is electrically connected to a power cord interface located on the device housing, and a power cord can be plugged in through the power cord interface.

[0033] Furthermore, the full-circuit bridge module is connected to the connection line between the lithium battery and the data processing unit through a step-down module.

[0034] Furthermore, there are two test line interfaces, including a cable core wire interface and a cable grounding interface; there are two test connection wires, including a first test connection wire and a second test connection wire; one end of the first test connection wire is a metal plug that can be inserted into the cable core wire interface, and the other end is an alligator clip that can support the cable conductor; one end of the second test connection wire is a metal plug that can be inserted into the cable grounding interface, and the other end is an alligator clip that can support the cable insulation layer.

[0035] Furthermore, the secondary cable detection and evaluation method can also perform electrostatic capacitance field detection on the cable insulation of the secondary cable based on the secondary cable detection and evaluation device; the detection method is as follows:

[0036] Step 1, connecting the secondary cable detection and evaluation device to the cable insulation layer of the secondary cable through two test connection wires;

[0037] Step 2, start the secondary cable detection and evaluation device, and select a corresponding DC voltage value on the secondary cable detection and evaluation device;

[0038] Step 3, the secondary cable detection and evaluation device applies a corresponding DC voltage to the cable conductor through the test connection line, and at the same time receives a detection current value through another test connection line;

[0039] Step 4, the full circuit bridge module of the secondary cable detection and evaluation device transmits the detection current value to the processor of the data processing unit through the communication module;

[0040] Step 5: The processor of the data processing unit performs calculation based on the detected current value, performs electrostatic capacitance field calculation based on the calculation result of the detected current value, and compares the electrostatic capacitance field calculation result with the electrostatic capacitance field reference threshold to generate an electrostatic capacitance field determination result.

[0041] Furthermore, the calculation formula of the processor of the data processing unit is as follows:

[0042]

[0043] Where, R10Min is the detection current value for 10 minutes; R1Min is the detection current value for 1 minute;

[0044] Based on the comparison of the electrostatic capacitance field calculation result with the electrostatic capacitance field reference thresholds 1 to 4;

[0045] If the result of the static capacitance field calculation is below 1, it is judged as defective;

[0046] If the result of the static capacitance field calculation is between 1 and 2, it is judged as requiring attention;

[0047] If the result of the static capacitance field calculation is between 2 and 4, it is judged as good;

[0048] If the electrostatic capacitance field calculation result is above 4, it is judged to be the best.

[0049] Furthermore, the secondary cable detection and evaluation method can also detect the resonance value of the cable insulation of the secondary cable based on the secondary cable detection and evaluation device; the detection method is as follows:

[0050] Step 1, connecting the secondary cable detection and evaluation device to the cable insulation layer of the secondary cable through two test connection wires;

[0051] Step 2, start the secondary cable detection and evaluation device, and select a corresponding DC voltage value on the secondary cable detection and evaluation device;

[0052] Step 3, the secondary cable detection and evaluation device applies a corresponding DC voltage to the cable conductor through the test connection line, and at the same time receives a detection current value through another test connection line;

[0053] Step 4, the full circuit bridge module of the secondary cable detection and evaluation device transmits the detection current value to the processor of the data processing unit through the communication module;

[0054] Step 5: The processor of the data processing unit calculates the resistance value based on the applied DC voltage value and the detected current value, calculates the resonance value based on the resistance value calculation result, and compares the resonance value calculation result with the resonance reference threshold value to generate a resonance value determination result.

[0055] Furthermore, the calculation formula of the processor of the data processing unit is as follows:

[0056]

[0057] Where, R60Sec is the resistance value measured at a DC voltage of 60 minutes; R30Sec is the resistance value measured at a DC voltage of 30 minutes;

[0058] Comparing the calculated result of the resonance value with the resonance reference thresholds of 1, 1.25, and 4;

[0059] If the calculated resonance value is below 1, it is judged as defective;

[0060] If the calculated resonance value is between 1 and 1.25, it is judged as good;

[0061] If the calculated resonance value is above 1.4, it is judged to be the best.

[0062] The beneficial effects of the present invention are:

[0063] This secondary cable detection and evaluation method can more accurately evaluate the insulation performance of the cable and identify potential insulation defects by treating the cable insulation layer as a high-resistance resistor and using precise voltage and current tests. The full-circuit bridge module provides a variety of voltage outputs (50V, 100V, 250V, 500V), so that the detection can adapt to secondary cables of different voltage levels and meet a variety of application requirements. With built-in lithium batteries and power adapters, the device can be used in a power-free environment, which increases the portability and flexibility of the device and is suitable for on-site detection. Equipped with an LCD touch screen and related operation interfaces, the user operation process is simplified, the ease of use of the device is improved, and the user can easily select the voltage level and view the test results. The current value after the voltage is applied to the cable conductor is accurately measured through the test connection line, providing a reliable insulation performance evaluation, which helps to quickly determine the availability and safety of the cable. The design of the device takes safety into consideration and adopts a high-resistance current test method to reduce the risk under high voltage conditions, thereby protecting the safety of the detection personnel. The close integration of the data processing unit and the full-circuit bridge module improves the stability and reliability of the system and ensures the accurate transmission and processing of data.

[0064] This secondary cable detection and evaluation method and device has significant advantages in the field of cable detection and is of great significance for improving the safety of cable use and extending the service life of cables.

[0065] In addition, the secondary cable detection and evaluation method can comprehensively evaluate the insulation performance of the secondary cable through the combined detection of the static capacitance field and the resonance value, thereby improving the accuracy and reliability of the detection results; it can timely detect the potential faults and insulation degradation problems of the cable, reduce the probability of cable accidents, and ensure the safe operation of the power system. The hierarchical judgment of the static capacitance field and the resonance value can help relevant personnel make more scientific maintenance and overhaul decisions, thereby effectively arranging maintenance work and saving time and cost. The integration of static capacitance field and resonance value detection in the same detection system simplifies the detection process, improves work efficiency, and reduces the consumption of human and material resources. The detection method is flexibly applicable to secondary cables of different types and models, enhances the versatility and scope of application of the equipment, and is helpful for cable maintenance and management in different scenarios. Based on the data processing capability of the test results, more in-depth analysis and research can be carried out to provide data support for subsequent technical improvements and the development of new technologies. Timely detection of cable insulation defects can effectively prevent electrical accidents caused by insulation failure, thereby ensuring the safety of operators and equipment.

[0066] This secondary cable detection and evaluation method helps to improve the management level and safety of the power system, while providing a solid data foundation for related maintenance decisions. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0068] Figure 1 It is a schematic diagram of the use state of the secondary cable detection device of the present invention;

[0069] Figure 2 It is the wiring diagram of the secondary cable detection device of the present invention;

[0070] Figure 3 This is a working principle diagram of the secondary cable detection device of the present invention;

[0071] Figure 4 It is a flow chart of the secondary cable detection and evaluation method of the present invention;

[0072] Figure 5 A flow chart of the static capacitance field evaluation of the secondary cable of the present invention;

[0073] Figure 6 A flow chart for evaluating the resonance value of the secondary cable of the present invention;

[0074] In the figure: 1. device housing; 2. data processing unit; 3. lithium battery; 4. full circuit bridge module; 5. LCD touch screen; 6. communication module; 7. switch; 8. cable core wire interface; 9. cable grounding interface; 10. first test connection line; 11. second test connection line; 12. communication module; 13. high frequency generator; 14. step-down module; 15. USB data export interface; 16. power adapter; 17. power cord interface. DETAILED DESCRIPTION

[0075] The following will be combined with the drawings of 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. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0076] Example 1

[0077] For secondary cable detection and evaluation, this embodiment provides a secondary cable detection and evaluation method, which is based on a secondary cable detection and evaluation device; Figure 1 and Figure 2 As shown, the secondary cable detection device includes a device housing 1, a data processing unit 2, a lithium battery 3 and a full-circuit bridge module 4 installed in the device housing 1, and a test connection line that can be plugged into the device housing 1.

[0078] The lithium battery 3 is a 24V polymer large-capacity lithium battery, and is structurally an aluminum-plastic soft package, which is safer, has sufficient capacity, and has a cycle number of about 1,500 times; the lithium battery 3 is electrically connected to the data processing unit 2 to supply power to it. At the same time, a switch 7 is provided on the connection line between the lithium battery 3 and the data processing unit 2, and the switch 7 is located on the device housing 1.

[0079] The data processing unit 2 includes a liquid crystal touch screen 5 located on the device housing 1, a processor, a memory, and a communication module 6 installed on the liquid crystal touch screen 5. The liquid crystal touch screen 5 can adopt the commercially available Nextion NX8048K070, which has a size of 7 inches and a resolution of 800x480. The liquid crystal touch screen 5 is a four-wire resistive type with a rated power of 5W. The liquid crystal touch screen 5 can be equipped with a processor, and the processor can adopt the commercially available FriendlyARM NanoPC-T4, which is equipped with a Cortex-A73 multi-core processor. The serial port interface of the liquid crystal touch screen 5 is RS232 or RS485, so that it can be connected to the commercially available FTDI RS232 communication module or the commercially available MAXIMIntegrated MAX485 communication module.

[0080] The data processing unit 2 is connected to the full-circuit bridge module 4 through the communication module 6. The data processing unit 2 enables the test personnel to select the corresponding voltage level according to the use environment of the secondary cable through the liquid crystal touch screen 5; the processor forms the corresponding control instructions to the full-circuit bridge module 4 based on the selected voltage level.

[0081] The full circuit bridge module 4 uses a commercially available Texas Instruments LMP90080 dense bridge measurement amplifier. The full circuit bridge module 4 has a serial port interface of RS232 or RS485, so that it can be connected to a commercially available FTDI RS232 communication module or a commercially available MAXIM Integrated MAX485 communication module, and communicates with the processor of the data processing unit 2 through the communication module 12. In addition, if Figure 2 As shown, the full circuit bridge module 4 also includes four groups of high frequency generators 13, and the high frequency generators 13 adopt the commercially available Parker Hannifin Plasma Series high frequency plasma generators. The full circuit bridge module 4 controls the output voltage of the test line interface by controlling the working number of the high frequency generators 13 based on the control instructions of the processor. When one group of high frequency generators 13 is working, the full circuit bridge module 4 generates a 50V voltage output; when two groups of high frequency generators 13 are working, the full circuit bridge module 4 generates a 100V voltage output; when three groups of high frequency generators 13 are working, the full circuit bridge module 4 generates a 250V voltage output; when four groups of high frequency generators 13 are working, the full circuit bridge module 4 generates a 500V voltage output, so as to adapt to the actual use environment of the secondary cable.

[0082] The full circuit bridge module 4 is connected to the connection line between the lithium battery 3 and the data processing unit 2, and is powered by the lithium battery 3. The full circuit bridge module 4 is electrically connected to the test line interface located on the device housing 1, and is connected to the test connection line through the test line interface, so as to detect the secondary cable.

[0083] Since the working voltage of the full circuit bridge module 4 is 12V, and the lithium battery 3 adopts a 24V polymer large-capacity lithium battery, Figure 1 and Figure 2 As shown, the circuit bridge module in this embodiment is connected to the connection line between the lithium battery 3 and the data processing unit 2 through the buck module 14, so that the lithium battery 3 can supply power to the full circuit bridge module 4. The buck module 14 adopts the commercially available LM2596 buck converter of Texas Instruments.

[0084] like Figure 1 and Figure 2As shown, there are two test line interfaces, including a cable core wire interface 8 and a cable grounding interface 9, and there are two test connection lines, including a first test connection line 10 and a second test connection line 11; one end of the first test connection line 10 is a metal plug that can be inserted into the cable core wire interface 8, and the other end is an alligator clip that can clamp the cable conductor; one end of the second test connection line 11 is a metal plug that can be inserted into the cable grounding interface 9, and the other end is an alligator clip that can clamp the cable insulation layer.

[0085] Considering the charging problem of lithium battery 3, Figure 1 and Figure 2 As shown, in this embodiment, a power adapter 16 electrically connected to the lithium battery 3 is also installed in the device housing 1. The power adapter 16 adopts the commercially available Mean Well GST25A24 with overcurrent, overvoltage, short circuit protection and other functions. The power adapter 16 is electrically connected to the power line interface 17 located on the device housing 1, and the power line can be plugged in through the power line interface 17. The lithium battery 3 is connected to the 220V mains through the power adapter 16 and the power line, thereby realizing the charging function of the lithium battery 3.

[0086] Based on the above secondary cable detection and evaluation device, secondary cable insulation aging detection and evaluation are carried out, such as Figure 3 As shown, the secondary cable detection and evaluation method is to regard the cable insulation layer of the secondary cable as a resistor with a high resistance value; Figure 4 As shown, the following detection and evaluation steps are performed:

[0087] Step 1: Connect the secondary cable detection and evaluation device to the cable conductor and the cable insulation layer of the secondary cable through two test connection wires respectively; including a first test connection wire and a second test connection wire, ensure that the metal plug of the test connection wire is inserted into the cable core wire interface and the cable grounding interface, the alligator clip of the first test connection wire is clamped on the conductor of the secondary cable, and the alligator clip of the second test connection wire is clamped on the insulation layer of the cable; at this time, Figure 2 As shown, a detection circuit is formed between the full circuit bridge module, the cable core wire interface, the first test connection line, the secondary cable, the second test connection line, and the cable grounding interface.

[0088] Step 2: Turn on the secondary cable detection and evaluation device, and select the corresponding DC voltage value on the secondary cable detection and evaluation device based on the voltage level of the secondary cable usage scenario. Specifically, determine the rated voltage level of the secondary cable according to the usage scenario; select the corresponding DC voltage value on the LCD touch screen of the secondary cable detection and evaluation device, such as 50V, 100V, 250V or 500V.

[0089] Step 3: The secondary cable detection and evaluation device applies a corresponding DC voltage to the cable conductor through a test connection line, and receives the current value passing through a high-resistance resistor through another test connection line. Specifically, the secondary cable detection and evaluation device is turned on and ensures that the device works normally; it is controlled by a full-circuit bridge module to apply the selected DC voltage to the cable conductor, while continuously monitoring the current value flowing through the insulation layer.

[0090] Step 4: The secondary cable detection and evaluation device evaluates the insulation performance of the secondary cable based on the current value passing through the high-resistance resistor. Specifically, the current value passing through the high-resistance resistor is recorded to ensure accurate and stable data collection; the data processing unit will display the current value in real time and store the data for subsequent analysis; according to the collected current value, the insulation resistance is calculated through analysis; the calculation results of the data processing unit are integrated, and the insulation performance evaluation results of the secondary cable are displayed on the LCD touch screen; according to the evaluation results, it is determined whether the cable can continue to be used safely, or whether it needs to be replaced or repaired.

[0091] The secondary cable detection and evaluation method has simple operation steps and an intuitive interface, so that users can quickly complete the detection of secondary cables. The high-frequency generator is used to generate a variety of voltage outputs, which can effectively simulate the working state according to the actual use of the cable, so as to obtain more accurate insulation performance evaluation results; the device is equipped with an LCD touch screen to monitor and display various parameters in the detection process in real time, which is helpful to adjust the test conditions in time and ensure the accuracy of the data; it is powered by a lithium battery, which enhances the portability of the equipment and enables it to be used in different working environments, suitable for on-site detection; the current is measured by high-resistance resistors, which reduces the potential risks to personnel and equipment. At the same time, the equipment is designed with user safety in mind to ensure that no accidental injuries will occur during the test; the integrated communication module realizes intelligent processing and storage of data, which is convenient for subsequent analysis and record management and improves work efficiency.

[0092] Through the above steps and technical effects, the secondary cable detection and evaluation method can greatly improve the convenience and accuracy of detection in practical applications, and provide strong support for the maintenance and management of secondary cables.

[0093] Example 2

[0094] For the detection and evaluation of the electrostatic capacitance field of the secondary cable, this embodiment provides a secondary cable detection and evaluation method, which is based on a secondary cable detection and evaluation device; Figure 1 and Figure 2 As shown, the secondary cable detection device includes a device housing 1, a data processing unit 2, a lithium battery 3 and a full-circuit bridge module 4 installed in the device housing 1, and a test connection line that can be plugged into the device housing 1.

[0095] The lithium battery 3 is a 24V polymer large-capacity lithium battery, and is structurally an aluminum-plastic soft package, which is safer, has sufficient capacity, and has a cycle number of about 1,500 times; the lithium battery 3 is electrically connected to the data processing unit 2 to supply power to it. At the same time, a switch 7 is provided on the connection line between the lithium battery 3 and the data processing unit 2, and the switch 7 is located on the device housing 1.

[0096] The data processing unit 2 includes a liquid crystal touch screen 5 located on the device housing 1, a processor, a memory, and a communication module 6 installed on the liquid crystal touch screen 5. The liquid crystal touch screen 5 can adopt the commercially available Nextion NX8048K070, which has a size of 7 inches and a resolution of 800x480. The liquid crystal touch screen 5 is a four-wire resistive type with a rated power of 5W. The liquid crystal touch screen 5 can be equipped with a processor, and the processor can adopt the commercially available FriendlyARM NanoPC-T4, which is equipped with a Cortex-A73 multi-core processor. The serial port interface of the liquid crystal touch screen 5 is RS232 or RS485, so that it can be connected to the commercially available FTDI RS232 communication module or the commercially available MAXIMIntegrated MAX485 communication module.

[0097] The data processing unit 2 is connected to the full-circuit bridge module 4 through the communication module 6. The data processing unit 2 enables the test personnel to select the corresponding voltage level according to the use environment of the secondary cable through the liquid crystal touch screen 5; the processor forms the corresponding control instructions to the full-circuit bridge module 4 based on the selected voltage level.

[0098] The full circuit bridge module 4 uses a commercially available Texas Instruments LMP90080 dense bridge measurement amplifier. The full circuit bridge module 4 has a serial port interface of RS232 or RS485, so that it can be connected to a commercially available FTDI RS232 communication module or a commercially available MAXIM Integrated MAX485 communication module, and communicates with the processor of the data processing unit 2 through the communication module 12. In addition, if Figure 2As shown, the full circuit bridge module 4 also includes four groups of high frequency generators 13, and the high frequency generators 13 adopt the commercially available Parker Hannifin Plasma Series high frequency plasma generators. The full circuit bridge module 4 controls the output voltage of the test line interface by controlling the working number of the high frequency generators 13 based on the control instructions of the processor. When one group of high frequency generators 13 is working, the full circuit bridge module 4 generates a 50V voltage output; when two groups of high frequency generators 13 are working, the full circuit bridge module 4 generates a 100V voltage output; when three groups of high frequency generators 13 are working, the full circuit bridge module 4 generates a 250V voltage output; when four groups of high frequency generators 13 are working, the full circuit bridge module 4 generates a 500V voltage output, so as to adapt to the actual use environment of the secondary cable.

[0099] The full circuit bridge module 4 is connected to the connection line between the lithium battery 3 and the data processing unit 2, and is powered by the lithium battery 3. The full circuit bridge module 4 is electrically connected to the test line interface located on the device housing 1, and is connected to the test connection line through the test line interface, so as to detect the secondary cable.

[0100] Since the working voltage of the full circuit bridge module 4 is 12V, and the lithium battery 3 adopts a 24V polymer large-capacity lithium battery, Figure 1 and Figure 2 As shown, the circuit bridge module in this embodiment is connected to the connection line between the lithium battery 3 and the data processing unit 2 through the buck module 14, so that the lithium battery 3 can supply power to the full circuit bridge module 4. The buck module 14 adopts the commercially available LM2596 buck converter of Texas Instruments.

[0101] like Figure 1 and Figure 2 As shown, there are two test line interfaces, including a cable core wire interface 8 and a cable grounding interface 9, and there are two test connection lines, including a first test connection line 10 and a second test connection line 11; one end of the first test connection line 10 is a metal plug that can be inserted into the cable core wire interface 8, and the other end is an alligator clip that can clamp the cable conductor; one end of the second test connection line 11 is a metal plug that can be inserted into the cable grounding interface 9, and the other end is an alligator clip that can clamp the cable insulation layer.

[0102] Considering the charging problem of lithium battery 3, Figure 1 and Figure 2As shown, in this embodiment, a power adapter 16 electrically connected to the lithium battery 3 is also installed in the device housing 1. The power adapter 16 adopts the commercially available Mean Well GST25A24 with overcurrent, overvoltage, short circuit protection and other functions. The power adapter 16 is electrically connected to the power line interface 17 located on the device housing 1, and the power line can be plugged in through the power line interface 17. The lithium battery 3 is connected to the 220V mains through the power adapter 16 and the power line, thereby realizing the charging function of the lithium battery 3.

[0103] Based on the above secondary cable detection and evaluation device, the static capacitance field detection and evaluation of the secondary cable is carried out, such as Figure 3 As shown, the secondary cable detection and evaluation method is to regard the cable insulation layer of the secondary cable as a resistor with a high resistance value; Figure 5 As shown, the following detection and evaluation steps are performed:

[0104] Step 1: Connect the secondary cable detection and evaluation device to the cable insulation layer of the secondary cable through two test connection wires; including a first test connection wire and a second test connection wire, ensure that the metal plug of the test connection wire is inserted into the cable core wire interface and the cable grounding interface, the alligator clip of the first test connection wire is clamped on the conductor of the secondary cable, and the alligator clip of the second test connection wire is clamped on the insulation layer of the cable; at this time, Figure 2 As shown, a detection circuit is formed between the full circuit bridge module, the cable core wire interface, the first test connection line, the secondary cable, the second test connection line, and the cable grounding interface.

[0105] Step 2, turn on the secondary cable detection and evaluation device, and select the corresponding DC voltage value on the secondary cable detection and evaluation device. Specifically, based on the voltage level of the secondary cable usage scenario, select the corresponding DC voltage value on the secondary cable detection and evaluation device. Specifically, according to the usage scenario of the secondary cable, determine its rated voltage level; select the corresponding DC voltage value on the LCD touch screen of the secondary cable detection and evaluation device, such as 50V, 100V, 250V or 500V.

[0106] Step 3: The secondary cable detection and evaluation device applies a corresponding DC voltage to the cable conductor through a test connection line, and at the same time receives a detection current value through another test connection line. Specifically, the secondary cable detection and evaluation device is turned on and the normal operation of the device is ensured; the full circuit bridge module is used to control the application of the selected DC voltage to the cable conductor, while continuously monitoring the current value flowing through the insulation layer.

[0107] Step 4: The full-circuit bridge module of the secondary cable detection and evaluation device transmits the detection current value to the processor of the data processing unit through the communication module.

[0108] Step 5: The processor of the data processing unit performs calculation based on the detected current value, performs electrostatic capacitance field calculation based on the calculation result of the detected current value, and compares the electrostatic capacitance field calculation result with the electrostatic capacitance field reference threshold to generate an electrostatic capacitance field determination result.

[0109] It should be noted that the above secondary cable electrostatic capacitance field detection process lasts at least 10 minutes; wherein, the processor of the data processing unit has the following calculation formula:

[0110]

[0111] Where, R10Min is the detection current value for 10 minutes; R1Min is the detection current value for 1 minute;

[0112] Based on the comparison of the electrostatic capacitance field calculation result with the electrostatic capacitance field reference thresholds 1 to 4;

[0113] If the result of the static capacitance field calculation is below 1, it is judged as defective;

[0114] If the result of the static capacitance field calculation is between 1 and 2, it is judged as requiring attention;

[0115] If the result of the static capacitance field calculation is between 2 and 4, it is judged as good;

[0116] If the result of the static capacitance field calculation is above 4, it is judged to be the best, as shown in the following table:

[0117] Static capacitance field 4 or more 4～2 2.0～1.0 Below 1.0 determination most good Be careful bad

[0118] By applying the electrostatic capacitance field detection and evaluation method to secondary cables, the detection accuracy of the cable insulation layer status can be improved, ensuring accurate evaluation of the cable insulation performance. Using relatively low DC voltage (such as 50V, 100V, etc.) for evaluation reduces the safety risks to operators and equipment and avoids the potential dangers caused by high voltage. Using the LCD touch screen for voltage value selection and real-time monitoring simplifies the operation steps, improves the convenience of detection, and enables operators to quickly respond to various detection needs. Through the communication between the bridge module and the data processing unit, real-time monitoring and automatic data analysis can be achieved, which enhances the efficiency of the detection process and obtains cable status information in a timely manner. Providing clear electrostatic capacitance field judgment results and comparing them with the reference threshold value facilitates operators to quickly judge the health status of the cable and simplifies subsequent maintenance decisions. Selecting the appropriate test voltage according to different secondary cable usage scenarios makes it have good adaptability and suitable for various types of cable detection. By regularly evaluating the insulation performance of the cable, potential problems can be discovered in advance, thereby reducing unexpected power outages and maintenance costs caused by cable failures and improving overall operating efficiency. By monitoring the insulation layer condition, the service life of the cable can be effectively extended, the frequency of cable replacement can be reduced, and the long-term operation of the equipment can be promoted. Record the current value and judgment result of each detection to provide a data basis for subsequent statistical analysis, trend monitoring and decision support.

[0119] Overall, through comprehensive current monitoring, real-time data transmission and quantitative evaluation, the detection efficiency and safety of secondary cables are improved, providing strong support for cable maintenance and management.

[0120] Example 3

[0121] For the detection and evaluation of the electrostatic capacitance field of the secondary cable, this embodiment provides a secondary cable detection and evaluation method, which is based on a secondary cable detection and evaluation device; Figure 1 and Figure 2 As shown, the secondary cable detection device includes a device housing 1, a data processing unit 2, a lithium battery 3 and a full-circuit bridge module 4 installed in the device housing 1, and a test connection line that can be plugged into the device housing 1.

[0122] The lithium battery 3 is a 24V polymer large-capacity lithium battery, and is structurally an aluminum-plastic soft package, which is safer, has sufficient capacity, and has a cycle number of about 1,500 times; the lithium battery 3 is electrically connected to the data processing unit 2 to supply power to it. At the same time, a switch 7 is provided on the connection line between the lithium battery 3 and the data processing unit 2, and the switch 7 is located on the device housing 1.

[0123] The data processing unit 2 includes a liquid crystal touch screen 5 located on the device housing 1, a processor, a memory, and a communication module 6 installed on the liquid crystal touch screen 5. The liquid crystal touch screen 5 can adopt the commercially available Nextion NX8048K070, which has a size of 7 inches and a resolution of 800x480. The liquid crystal touch screen 5 is a four-wire resistive type with a rated power of 5W. The liquid crystal touch screen 5 can be equipped with a processor, and the processor can adopt the commercially available FriendlyARM NanoPC-T4, which is equipped with a Cortex-A73 multi-core processor. The serial port interface of the liquid crystal touch screen 5 is RS232 or RS485, so that it can be connected to the commercially available FTDI RS232 communication module or the commercially available MAXIMIntegrated MAX485 communication module.

[0124] The data processing unit 2 is connected to the full-circuit bridge module 4 through the communication module 6. The data processing unit 2 enables the test personnel to select the corresponding voltage level according to the use environment of the secondary cable through the liquid crystal touch screen 5; the processor forms the corresponding control instructions to the full-circuit bridge module 4 based on the selected voltage level.

[0125] The full circuit bridge module 4 uses a commercially available Texas Instruments LMP90080 dense bridge measurement amplifier. The full circuit bridge module 4 has a serial port interface of RS232 or RS485, so that it can be connected to a commercially available FTDI RS232 communication module or a commercially available MAXIM Integrated MAX485 communication module, and communicates with the processor of the data processing unit 2 through the communication module 12. In addition, if Figure 2 As shown, the full circuit bridge module 4 also includes four groups of high frequency generators 13, and the high frequency generators 13 adopt the commercially available Parker Hannifin Plasma Series high frequency plasma generators. The full circuit bridge module 4 controls the output voltage of the test line interface by controlling the working number of the high frequency generators 13 based on the control instructions of the processor. When one group of high frequency generators 13 is working, the full circuit bridge module 4 generates a 50V voltage output; when two groups of high frequency generators 13 are working, the full circuit bridge module 4 generates a 100V voltage output; when three groups of high frequency generators 13 are working, the full circuit bridge module 4 generates a 250V voltage output; when four groups of high frequency generators 13 are working, the full circuit bridge module 4 generates a 500V voltage output, so as to adapt to the actual use environment of the secondary cable.

[0126] The full circuit bridge module 4 is connected to the connection line between the lithium battery 3 and the data processing unit 2, and is powered by the lithium battery 3. The full circuit bridge module 4 is electrically connected to the test line interface located on the device housing 1, and is connected to the test connection line through the test line interface, so as to detect the secondary cable.

[0127] Since the working voltage of the full circuit bridge module 4 is 12V, and the lithium battery 3 adopts a 24V polymer large-capacity lithium battery, Figure 1 and Figure 2 As shown, the circuit bridge module in this embodiment is connected to the connection line between the lithium battery 3 and the data processing unit 2 through the buck module 14, so that the lithium battery 3 can supply power to the full circuit bridge module 4. The buck module 14 adopts the commercially available LM2596 buck converter of Texas Instruments.

[0128] like Figure 1 and Figure 2 As shown, there are two test line interfaces, including a cable core wire interface 8 and a cable grounding interface 9, and there are two test connection lines, including a first test connection line 10 and a second test connection line 11; one end of the first test connection line 10 is a metal plug that can be inserted into the cable core wire interface 8, and the other end is an alligator clip that can clamp the cable conductor; one end of the second test connection line 11 is a metal plug that can be inserted into the cable grounding interface 9, and the other end is an alligator clip that can clamp the cable insulation layer.

[0129] Considering the charging problem of lithium battery 3, Figure 1 and Figure 2 As shown, in this embodiment, a power adapter 16 electrically connected to the lithium battery 3 is also installed in the device housing 1. The power adapter 16 adopts the commercially available Mean Well GST25A24 with overcurrent, overvoltage, short circuit protection and other functions. The power adapter 16 is electrically connected to the power line interface 17 located on the device housing 1, and the power line can be plugged in through the power line interface 17. The lithium battery 3 is connected to the 220V mains through the power adapter 16 and the power line, thereby realizing the charging function of the lithium battery 3.

[0130] Based on the above secondary cable detection and evaluation device, the resonance value of the secondary cable is detected and evaluated, such as Figure 3 As shown, the secondary cable detection and evaluation method is to regard the cable insulation layer of the secondary cable as a resistor with a high resistance value; Figure 6 As shown, the following detection and evaluation steps are performed:

[0131] Step 1: Connect the secondary cable detection and evaluation device to the cable insulation layer of the secondary cable through two test connection wires; including a first test connection wire and a second test connection wire, ensure that the metal plug of the test connection wire is inserted into the cable core wire interface and the cable grounding interface, the alligator clip of the first test connection wire is clamped on the conductor of the secondary cable, and the alligator clip of the second test connection wire is clamped on the insulation layer of the cable; at this time, Figure 2 As shown, a detection circuit is formed between the full circuit bridge module, the cable core wire interface, the first test connection line, the secondary cable, the second test connection line, and the cable grounding interface.

[0132] Step 2, turn on the secondary cable detection and evaluation device, and select the corresponding DC voltage value on the secondary cable detection and evaluation device. Specifically, based on the voltage level of the secondary cable usage scenario, select the corresponding DC voltage value on the secondary cable detection and evaluation device. Specifically, according to the usage scenario of the secondary cable, determine its rated voltage level; select the corresponding DC voltage value on the LCD touch screen of the secondary cable detection and evaluation device, such as 50V, 100V, 250V or 500V.

[0133] Step 3: The secondary cable detection and evaluation device applies a corresponding DC voltage to the cable conductor through a test connection line, and at the same time receives a detection current value through another test connection line. Specifically, the secondary cable detection and evaluation device is turned on and the normal operation of the device is ensured; the full circuit bridge module is used to control the application of the selected DC voltage to the cable conductor, while continuously monitoring the current value flowing through the insulation layer.

[0134] Step 4, the full circuit bridge module of the secondary cable detection and evaluation device transmits the detection current value to the processor of the data processing unit through the communication module;

[0135] Step 5: The processor of the data processing unit calculates the resistance value based on the applied DC voltage value and the detected current value, calculates the resonance value based on the resistance value calculation result, and compares the resonance value calculation result with the resonance reference threshold value to generate a resonance value determination result.

[0136] It should be noted that the above secondary cable resonance value detection process lasts for at least 60 minutes; the calculation formula of the processor of the data processing unit is as follows:

[0137]

[0138] Where, R60Sec is the resistance value measured at a DC voltage of 60 minutes; R30Sec is the resistance value measured at a DC voltage of 30 minutes;

[0139] Comparing the calculated result of the resonance value with the resonance reference thresholds of 1, 1.25, and 4;

[0140] If the calculated resonance value is below 1, it is judged as defective;

[0141] If the calculated resonance value is between 1 and 1.25, it is judged as good;

[0142] If the calculated resonance value is above 1.4, it is considered the best; as shown in the following table:

[0143] Resonance value 1.4 or above 1.25～1.0 Below 1.0 determination most good bad

[0144] By using a full-circuit bridge module for high-precision resistance measurement, the insulation performance and overall health of the secondary cable can be more accurately evaluated. This high-resistance resistance detection method can effectively identify potential insulation faults and partial discharge phenomena, thereby reducing the risk of cable failure. Long-term detection (at least 60 minutes) can reflect the insulation performance of the cable in the actual use environment, adapt to the voltage level changes in different use scenarios, and avoid misjudgment caused by short-term testing. The insulation condition of the cable is divided into three levels: bad, good and best by the resonance value determination method, which is convenient for users to quickly understand the health status of the cable and facilitate subsequent maintenance and management decisions. Selecting the appropriate DC voltage value through the LCD touch screen simplifies the operation process, making the use of the equipment more intuitive and convenient, and reducing the risk of operator misoperation. The automatic transmission of the detection current value and the calculation of the resistance value based on voltage and current reduce manual intervention, improve detection efficiency, and also reduce human errors. Selecting appropriate test parameters according to different scenarios and voltage levels enables it to be widely used in various types of secondary cable detection and has good adaptability. Through regular detection and evaluation, potential problems of the cable can be identified early, so that preventive maintenance measures can be taken to extend the service life of the cable and reduce maintenance costs. The detection scheme can effectively improve the reliability and safety of the power system, reduce accidents caused by cable problems, and ensure the normal operation of power equipment.

[0145] To sum up, it not only improves the accuracy and efficiency of cable detection, but also enhances the safety of the power system and provides effective technical support for cable maintenance and management.

[0146] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A secondary cable detection and evaluation method, characterized in that: The secondary cable detection and evaluation method is based on a secondary cable detection and evaluation device, and the cable insulation layer of the secondary cable is regarded as a resistor with a high resistance value, and the following detection and evaluation steps are performed: Step 1, connecting the secondary cable detection and evaluation device to the cable conductor and the cable insulation layer of the secondary cable respectively through two test connection lines; Step 2: Turn on the secondary cable detection and evaluation device, and select a corresponding DC voltage value on the secondary cable detection and evaluation device based on the voltage level of the secondary cable usage scenario; Step 3, the secondary cable detection and evaluation device applies a corresponding DC voltage to the cable conductor through a test connection line, and simultaneously receives a current value passing through a high-resistance resistor through another test connection line; Step 4: The secondary cable detection and evaluation device evaluates the insulation performance of the secondary cable based on the current value passing through the high-resistance resistor.

2. The secondary cable detection and evaluation method according to claim 1, characterized in that: The secondary cable detection device comprises a device housing, a data processing unit installed in the device housing, a lithium battery and a full-circuit bridge module, and a test connection line that can be plugged into the device housing; The lithium battery is electrically connected to the data processing unit to supply power to it; The data processing unit includes a liquid crystal touch screen located on the device housing, a processor, a memory, and a communication module installed on the liquid crystal touch screen, and the data processing unit is communicatively connected with the full circuit bridge module through the communication module; The full-circuit bridge module is connected to the connection line between the lithium battery and the data processing unit, and the full-circuit bridge module is electrically connected to the test line interface located on the device housing.

3. The secondary cable detection and evaluation method according to claim 2 is characterized in that: The full circuit bridge module includes a communication module and four sets of high frequency generators, which are connected to the data processing unit processor through the communication module, and control the output voltage of the test line interface by controlling the working number of the high frequency generator; When a set of high-frequency generators are working, the full-circuit bridge module generates a 50V voltage output; When the two sets of high-frequency generators are working, the full-circuit bridge module generates a 100V voltage output; When the three sets of high-frequency generators are working, the full-circuit bridge module generates a 250V voltage output; When the four sets of high-frequency generators are working, the full-circuit bridge module generates a 500V voltage output.

4. The secondary cable detection and evaluation method according to claim 2 is characterized in that: A power adapter electrically connected to the lithium battery is also installed in the device housing. The power adapter is electrically connected to a power line interface on the device housing, and a power line can be plugged in through the power line interface.

5. The secondary cable detection and evaluation method according to claim 2, characterized in that: The full-circuit bridge module is connected to the connection line between the lithium battery and the data processing unit through the step-down module.

6. The secondary cable detection and evaluation method according to claim 2, characterized in that: There are two test line interfaces, including a cable core wire interface and a cable grounding interface; there are two test connection wires, including a first test connection wire and a second test connection wire; one end of the first test connection wire is a metal plug that can be inserted into the cable core wire interface, and the other end is an alligator clip that can support the cable conductor; one end of the second test connection wire is a metal plug that can be inserted into the cable grounding interface, and the other end is an alligator clip that can support the cable insulation layer.

7. The secondary cable detection and evaluation method according to claim 1, characterized in that: The secondary cable detection and evaluation method can also perform electrostatic capacitance field detection on the cable insulation of the secondary cable based on the secondary cable detection and evaluation device; the detection method is as follows: Step 1, connecting the secondary cable detection and evaluation device to the cable insulation layer of the secondary cable through two test connection wires; Step 2, start the secondary cable detection and evaluation device, and select a corresponding DC voltage value on the secondary cable detection and evaluation device; Step 3, the secondary cable detection and evaluation device applies a corresponding DC voltage to the cable conductor through the test connection line, and at the same time receives a detection current value through another test connection line; Step 4, the full circuit bridge module of the secondary cable detection and evaluation device transmits the detection current value to the processor of the data processing unit through the communication module; Step 5: The processor of the data processing unit performs calculation based on the detected current value, performs electrostatic capacitance field calculation based on the calculation result of the detected current value, and compares the electrostatic capacitance field calculation result with the electrostatic capacitance field reference threshold to generate an electrostatic capacitance field determination result.

8. The secondary cable detection and evaluation method according to claim 7 is characterized in that: The calculation formula of the processor of the data processing unit is as follows: Where, R10Min is the detection current value for 10 minutes; R1Min is the detection current value for 1 minute; Based on the comparison of the electrostatic capacitance field calculation result with the electrostatic capacitance field reference thresholds 1 to 4; If the result of the static capacitance field calculation is below 1, it is judged as defective; If the result of the static capacitance field calculation is between 1 and 2, it is judged as requiring attention; If the result of the static capacitance field calculation is between 2 and 4, it is judged as good; If the electrostatic capacitance field calculation result is above 4, it is judged to be the best.

9. The secondary cable detection and evaluation method according to claim 1, characterized in that: The secondary cable detection and evaluation method can also detect the resonance value of the cable insulation of the secondary cable based on the secondary cable detection and evaluation device; the detection method is as follows: Step 1, connecting the secondary cable detection and evaluation device to the cable insulation layer of the secondary cable through two test connection wires; Step 2, start the secondary cable detection and evaluation device, and select a corresponding DC voltage value on the secondary cable detection and evaluation device; Step 3, the secondary cable detection and evaluation device applies a corresponding DC voltage to the cable conductor through the test connection line, and at the same time receives a detection current value through another test connection line; Step 4, the full circuit bridge module of the secondary cable detection and evaluation device transmits the detection current value to the processor of the data processing unit through the communication module; Step 5: The processor of the data processing unit calculates the resistance value based on the applied DC voltage value and the detected current value, calculates the resonance value based on the resistance value calculation result, and compares the resonance value calculation result with the resonance reference threshold value to generate a resonance value determination result.

10. The secondary cable detection and evaluation method according to claim 9, characterized in that: The calculation formula of the processor of the data processing unit is as follows: Where, R60Sec is the resistance value measured at a DC voltage of 60 minutes; R30Sec is the resistance value measured at a DC voltage of 30 minutes; Comparing the calculated result of the resonance value with the resonance reference thresholds of 1, 1.25, and 4; If the calculated resonance value is below 1, it is judged as defective; If the calculated resonance value is between 1 and 1.25, it is judged as good; If the calculated resonance value is above 1.4, it is judged to be the best.

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