220kv power high-voltage insulated cable fault non-electric quantity on-line detection device and detection method

Abstract

The application relates to a 220kV power high-voltage insulation cable fault non-electricity on-line detection device and a detection method, which comprises a high-voltage insulation cable, a high-purity nitrogen gas inlet module and a non-electricity on-line detection module arranged at two ends of the high-voltage insulation cable, and the outermost protective layer of the high-voltage insulation cable is respectively connected with an air inlet joint and an air outlet joint; the nitrogen gas inlet module is connected with the air inlet joint; the non-electricity on-line detection module comprises an air outlet pipe connected with the air outlet joint, and a low-molecular hydrocarbon gas sensor, a carbon dioxide sensor, a carbon monoxide sensor and a palladium shan hydrogen-sensitive sensor are sequentially arranged on the air outlet pipe along the gas flow direction. The characteristics that fault characteristic gas is generated when the high-voltage insulation cable is in fault are utilized, the fault characteristic gas filled in the multi-layer gap space of the high-voltage insulation cable is detected in a targeted manner, whether the high-voltage insulation cable is in fault or has hidden dangers is judged, and the high-voltage insulation cable in live operation can be timely and on-line detected.

Description

Technical fields:

[0001] This invention belongs to the field of high-voltage insulated cable testing technology in the power industry, and particularly relates to an online non-electrical quantity detection device and method for faults in 220kV high-voltage insulated cables. Background technology:

[0002] In recent years, with the continuous improvement of urban power grid transmission capacity and power quality requirements, high-voltage insulated cables have become an inevitable choice for building reliable urban power grids. High-voltage insulated cables have a multi-layered protective structure. The innermost layer is the conductor core, and the outer layers, from the inside out, generally consist of: conductor shielding, insulation, insulation shielding, water-blocking buffer layer, aluminum sheath, and outer sheath, etc. Figure 1 As shown, apart from the conductors at both ends being strictly sealed through the cable heads, the entire high-voltage insulated cable is also sealed to the outside world. However, gas can permeate between the layers inside the cable. When the internal layers of the high-voltage insulated cable are damaged, damp, or there are product quality issues, the innermost conductor operates at high voltage and high current. This will gradually cause the insulation material in the damp or damaged layers to accumulate heat and undergo chemical reactions, creating a vicious cycle that further exacerbates the fault. This leads to heating and discharge between the layers of the high-voltage insulated cable, ultimately causing the cable to break down and lose ground, resulting in a serious accident.

[0003] Because high-voltage insulated cables have a multi-layered armored structure and are mostly buried deep underground, it is difficult to detect in a timely manner if moisture or damage occurs in the interlayers of the armor during operation. Currently, when moisture or damage occurs in the interlayers of high-voltage insulated cable armor, it is generally necessary to wait until the fault develops to a certain extent and obvious electrical changes are detected by specialized electrical testing instruments, or to de-energize the high-voltage insulated cable and perform insulation, withstand voltage, or leakage current tests to detect the defect. This often results in a significant delay in the detection and development of the fault. Therefore, there is an urgent need to design a device and method that can detect high-voltage insulated cables in operation in a timely and online manner. Summary of the Invention:

[0004] The present invention addresses the problems existing in the prior art. Specifically, the technical problem to be solved by the present invention is to provide an online non-electrical quantity detection device and method for faults in 220kV high-voltage insulated cables. The device and method are reasonably designed and can detect non-electrical quantities of incoming high-voltage insulated cables online.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: an online non-electrical quantity detection device for faults in 220kV high-voltage insulated cables, comprising a high-voltage insulated cable, a high-purity nitrogen gas inlet module and an online non-electrical quantity detection module respectively disposed at both ends of the high-voltage insulated cable, wherein the outermost protective layer at both ends of the high-voltage insulated cable is respectively connected to an inlet connector and an outlet connector; the output end of the nitrogen gas inlet module is connected to the inlet connector; the online non-electrical quantity detection module includes an outlet pipe connected to the outlet connector, and a low-molecular-weight hydrocarbon gas sensor, a carbon dioxide sensor, a carbon monoxide sensor and a palladium-copper hydrogen sensor are sequentially disposed on the outlet pipe along the gas flow direction.

[0006] Furthermore, the high-purity nitrogen inlet module includes a nitrogen inlet pipe with an electric heating jacket on the outside. One end of the nitrogen inlet pipe is connected to the shut-off valve at the output end of the high-purity nitrogen cylinder, and the other end of the nitrogen inlet pipe is connected to the inlet connector.

[0007] Furthermore, the nitrogen inlet pipe is provided with a pressure reducing valve, a pressure regulating valve, a pressure sensor, and a temperature sensor in sequence along the nitrogen delivery direction, with the pressure sensor and temperature sensor located on both sides of the electric heating jacket, respectively.

[0008] Furthermore, the air inlet connector is connected to a first three-way pipe, one end of which is connected to a nitrogen inlet pipe via a first solenoid valve, and the other end of which is connected to a first vent pipe via a first vent solenoid valve.

[0009] Furthermore, the air outlet connector is connected to a second three-way pipe via a connecting pipe, and a humidity sensor is installed on the connecting pipe; one end of the second three-way pipe is connected to the air outlet pipe via a second solenoid valve, and the other end of the second three-way pipe is connected to the second venting pipe via a second venting solenoid valve.

[0010] Furthermore, it also includes a control module, the input of which is electrically connected to the output of the palladium hydrogen phosphate sensor, carbon monoxide sensor, carbon dioxide sensor, low molecular weight hydrocarbon gas sensor, humidity sensor, temperature sensor and pressure sensor, respectively. The output of the control module is electrically connected to the pressure regulating valve, the first solenoid valve, the second solenoid valve, the first venting solenoid valve, the second venting solenoid valve, the electric heating mantle and the alarm, respectively.

[0011] Furthermore, the outermost protective layer at both ends of the high-voltage insulated cable is provided with connector holes.

[0012] Furthermore, both ends of the high-voltage insulated cable are connected to high-voltage insulated cable terminals, and a vertically installed cable support rod is fixed between the high-voltage insulated cable terminals and the ground.

[0013] Another technical solution adopted in this invention is: an online non-electrical quantity detection method for faults in 220kV high-voltage insulated cables, comprising the following steps:

[0014] (1) The control module presets alarm values ​​for humidity, hydrogen, carbon monoxide, carbon dioxide, and low molecular weight hydrocarbon gases, as well as the temperature and pressure stability settings for high-purity nitrogen.

[0015] (2) First turn on the temperature sensor and pressure sensor of the high-purity nitrogen inlet module;

[0016] (3) Open the first venting solenoid valve;

[0017] (4) Adjust the pressure reducing valve to the set output pressure, and then open the shut-off valve, pressure regulating valve and electric heating jacket on the high-purity nitrogen cylinder in sequence. At this time, the high-purity nitrogen gas that has been pressure regulated and heated is discharged through the first venting solenoid valve.

[0018] (5) When the temperature and pressure of the high-purity nitrogen gas are stable and reach the set value, open the first solenoid valve and close the first venting solenoid valve. The high-purity nitrogen gas with stable temperature and pressure enters the interlayer gap inside the high-voltage insulated cable through the inlet joint and fills the high-voltage insulated cable along the cable until the outlet joint at the other end of the high-voltage insulated cable.

[0019] (6) Once the pressure of the pressure sensor reaches the preset value, turn on the humidity sensor, palladium grid hydrogen sensor, carbon monoxide sensor, carbon dioxide sensor, and low molecular weight hydrocarbon gas sensor.

[0020] (7) Open the second solenoid valve of the non-electrical quantity online detection module;

[0021] (8) High-purity nitrogen carries various gases contained in the interlayer of the high-voltage insulated cable and flows through the humidity sensor, palladium grid hydrogen sensor, carbon monoxide sensor, carbon dioxide sensor and low molecular weight hydrocarbon gas sensor in sequence to detect the moisture content, hydrogen content, carbon monoxide content, carbon dioxide content and low molecular weight hydrocarbon gas content respectively. The detected gas flows out into the atmosphere.

[0022] (9) When one or more of the detected values ​​of moisture content, hydrogen content, carbon monoxide content, carbon dioxide content and low molecular weight hydrocarbon gas content exceed the preset standard, the alarm will sound and notify relevant personnel to come for further inspection and handling.

[0023] (10) After the test is completed, turn off the following in sequence: humidity sensor, palladium grid hydrogen sensor, carbon monoxide sensor, carbon dioxide sensor, and low molecular weight hydrocarbon gas sensor.

[0024] (11) Open the second solenoid valve and close the second solenoid valve to release the gas in the interlayer gap inside the high-voltage insulated cable into the atmosphere;

[0025] (12) If only the humidity index exceeds the standard, in addition to the alarm, continue to keep the humidity sensor on and introduce hot high-purity nitrogen to heat and dry the interlayer gaps inside the damp high-voltage insulated cable until the humidity reaches the required level, and then turn off the humidity sensor.

[0026] (13) Turn off the electric heating mantle and temperature sensor;

[0027] (14) Close the shut-off valve, pressure regulating valve and first solenoid valve of the high-purity nitrogen cylinder, and keep the pressure reducing valve in the set pressure reducing position for the next test;

[0028] (15) Once the pressure drops to normal pressure, turn off the pressure sensor and the second venting solenoid valve;

[0029] (16) The non-electrical quantity test of the high-voltage insulated cable is completed and the next cycle of testing is awaited.

[0030] Compared with the prior art, the present invention has the following advantages: The present invention is reasonably designed and utilizes the characteristic of fault characteristic gas generated when a high-voltage insulated cable fails. It performs targeted non-electrical quantity detection on the fault characteristic gas filling the multi-layer gap space of the high-voltage insulated cable to determine whether the high-voltage insulated cable has failed or has hidden dangers. This enables timely online detection of high-voltage insulated cables in energized operation, effectively ensuring the safe operation of high-voltage insulated cables and overcoming the shortcomings of traditional methods that cannot quickly detect faults in high-voltage insulated cables in energized operation. Attached image description:

[0031] Figure 1 This is a schematic diagram of the multi-layered internal structure of a high-voltage insulated cable;

[0032] Figure 2 This is a schematic diagram of the structure of an embodiment of the present invention;

[0033] Figure 3 This is a structural view of the high-purity nitrogen gas inlet module in an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the structure of the non-electrical quantity online detection module in an embodiment of the present invention;

[0035] Figure 5 This is a block diagram illustrating the control principle of an embodiment of the present invention.

[0036] In the picture:

[0037] 1-High-voltage insulated cable terminal; 2-High-voltage insulated cable head; 3-High-voltage insulated cable; 301-Conductor; 302-Conductor shielding layer; 303-Insulation layer; 304-Insulation shielding layer; 305-Water-blocking buffer layer; 306-Aluminum sheath; 307-Outer sheath; 4-Cable support rod; 5-Air inlet connector; 6-High-purity nitrogen inlet module; 7-High-purity nitrogen cylinder; 8-Opposite high-voltage insulated cable terminal; 9-Air outlet connector; 10-Non-electrical quantity online detection module; 11-First tee pipe; 12-First solenoid valve; 13-First row 14-Temperature sensor; 15-Electric heating jacket; 16-Pressure sensor; 17-Pressure regulator; 18-Pressure reducing valve; 19-Stop valve; 20-Opening support sealing protection component; 21-Palladium-Shannon hydrogen sensor; 22-Carbon monoxide sensor; 23-Carbon dioxide sensor; 24-Low molecular weight hydrocarbon gas sensor; 25-Humidity sensor; 26-Second solenoid valve; 27-Second vent solenoid valve; 28-First vent pipe; 29-Second vent pipe; 30-Outlet pipe; 31-Second tee pipe; 32-Nitrogen inlet pipe. Detailed implementation method:

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0039] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0040] like Figures 2-4As shown, this invention discloses an online non-electrical quantity detection device for 220kV high-voltage insulated cables. Utilizing the characteristic that when a high-voltage insulated cable experiences a fault, the various insulating, waterproof, shielding, and protective materials it contains undergo pyrolysis or chemical reactions, generating fault-specific gases, the device performs targeted non-electrical quantity detection on the fault-specific gases filling the multi-layered gaps within the high-voltage insulated cable. This allows for the determination of whether the high-voltage insulated cable has a fault or potential hazards, enabling timely online detection of high-voltage insulated cables in energized operation. The specific structure of this detection device includes a high-voltage insulated cable 3, a high-purity nitrogen gas inlet module 6 located at both ends of the high-voltage insulated cable 3, and an online non-electrical quantity detection module 10. The outermost protective layers at both ends of the high-voltage insulated cable 3 are respectively connected to an inlet connector 5 and an outlet connector 9; the nitrogen gas... The output end of the air intake module 6 is connected to the air intake connector 5. The nitrogen intake module 6 introduces high-purity nitrogen into the high-voltage insulated cable 3 through the air intake connector 5 to provide the carrier gas for the operation of the non-electrical quantity online detection module. The non-electrical quantity online detection module 10 includes an outlet pipe 30 connected to the outlet connector 9. The fault characteristic gas and high-purity nitrogen in the high-voltage insulated cable 3 are output to the outlet pipe 30 through the outlet connector 9. The outlet pipe 60 is sequentially equipped with a low-molecular-weight hydrocarbon gas sensor 24, a carbon dioxide sensor 23, a carbon monoxide sensor 22, and a palladium-copper hydrogen sensor 21 along the gas flow direction. The low-molecular-weight hydrocarbon gas sensor 24, carbon dioxide sensor 23, carbon monoxide sensor 22, and palladium-copper hydrogen sensor 21 detect the content of low-molecular-weight hydrocarbon gas, carbon dioxide content, carbon monoxide content, and hydrogen content, respectively.

[0041] In this embodiment, the high-purity nitrogen inlet module 6 includes a nitrogen inlet pipe 32 with an electric heating sleeve 15 fitted on its outer side. One end of the nitrogen inlet pipe 32 is connected to the shut-off valve 19 on the output end of the high-purity nitrogen cylinder 7, and the other end of the nitrogen inlet pipe 32 is connected to the inlet connector 5. The high-purity nitrogen output from the high-purity nitrogen cylinder is transported to the inlet connector through the nitrogen inlet pipe. The inner diameter of the heating sleeve matches the inner diameter of the pipe to heat the high-purity nitrogen flowing into the interlayer gaps inside the high-voltage insulated cable to a set value.

[0042] In this embodiment, a pressure reducing valve 18, a pressure regulating valve 17, a pressure sensor 16, and a temperature sensor 14 are sequentially arranged on the nitrogen inlet pipe 32 along the nitrogen delivery direction. The pressure sensor 16 and the temperature sensor 14 are located on opposite sides of the electric heating jacket 15. The temperature sensor measures the temperature of the high-purity nitrogen entering the interlayer gap inside the high-voltage insulated cable; the pressure sensor detects the pressure of the high-purity nitrogen entering the interlayer gap inside the high-voltage insulated cable; and the pressure regulating valve controls the pressure of the high-purity nitrogen entering the interlayer gap inside the high-voltage insulated cable according to a preset pressure value.

[0043] In this embodiment, the air inlet connector 5 is connected to a first three-way pipe 11. One end of the first three-way pipe 11 is connected to the nitrogen inlet pipe 32 through a first solenoid valve 12, and the other end of the first three-way pipe 11 is connected to the first vent pipe 28 through a first vent solenoid valve 13.

[0044] In this embodiment, the air outlet connector 9 is connected to a second three-way pipe 31 via a connecting pipe. A humidity sensor 25 is installed on the connecting pipe, and its humidity detection probe is inserted into the pipe. One end of the second three-way pipe 31 is connected to the air outlet pipe 30 via a second solenoid valve 26, and the other end of the second three-way pipe 31 is connected to the second vent pipe 29 via a second vent solenoid valve 27.

[0045] In this embodiment, a control module is also included. The input terminals of the control module are electrically connected to the output terminals of the palladium hydrogen sensor, carbon monoxide sensor, carbon dioxide sensor, low-molecular-weight hydrocarbon gas sensor, humidity sensor, temperature sensor, and pressure sensor, respectively. The output terminals of the control module are electrically connected to the pressure regulating valve, the first solenoid valve, the second solenoid valve, the first venting solenoid valve, the second venting solenoid valve, the electric heating mantle, and the alarm, respectively. It should be noted that the control module is pre-programmed with alarm values ​​for exceeding limits for humidity, hydrogen, carbon monoxide, carbon dioxide, and low-molecular-weight hydrocarbon gases; a set range for controlling the temperature and pressure stability of high-purity nitrogen; and control programs for opening and stopping the solenoid valves and the electric heating mantle.

[0046] In this embodiment, the outermost protective layer at both ends of the high-voltage insulated cable is provided with connector holes. It should be noted that the connector holes are equipped with reinforced protective seals and supports.

[0047] In this embodiment, both ends of the high-voltage insulated cable 3 are connected to high-voltage insulated cable terminals, and a vertically installed cable support rod 4 is fixed between the high-voltage insulated cable terminals and the ground.

[0048] In this embodiment, when the online detection device is working: the non-electrical quantity online detection module uses high-purity nitrogen output from the high-purity nitrogen inlet module installed at the other end of the high-voltage insulated cable as the carrier gas to detect the gas contained in the interlayer voids inside the high-voltage insulated cable. Among them, the humidity sensor detects moisture, the palladium grating hydrogen sensor detects hydrogen, the carbon monoxide sensor detects carbon monoxide, the carbon dioxide sensor detects carbon dioxide, and the low-molecular-weight hydrocarbon gas sensor detects low-molecular-weight hydrocarbon gas. When one or more of the above indicators exceed the preset standard, the alarm will sound, notifying relevant personnel to come for further inspection and handling as soon as possible.

[0049] In this embodiment, a non-electrical quantity online detection method for faults in 220kV high-voltage insulated power cables includes the following steps:

[0050] (1) The control module presets alarm values ​​for humidity, hydrogen, carbon monoxide, carbon dioxide, and low molecular weight hydrocarbon gases, as well as the temperature and pressure stability setting range of high-purity nitrogen, and the control program for opening and stopping each solenoid valve and the electric heating jacket.

[0051] (2) First turn on the temperature sensor 14 and pressure sensor 16 of the high-purity nitrogen gas inlet module 6;

[0052] (3) Open the first venting solenoid valve 13;

[0053] (4) Adjust the pressure reducing valve 18 to the set output pressure, and then open the shut-off valve 9, pressure regulating valve 17 and electric heating jacket 15 on the high-purity nitrogen cylinder 7 in sequence. At this time, the high-purity nitrogen gas that has been pressure regulated and heated is discharged through the first venting solenoid valve 13.

[0054] (5) When the temperature and pressure of the high-purity nitrogen gas are stable and reach the set value, open the first solenoid valve 12 and close the first venting solenoid valve 13. The high-purity nitrogen gas with stable temperature and pressure enters the interlayer gap inside the high-voltage insulated cable through the inlet connector 5 and fills the high-voltage insulated cable along the cable until the outlet connector 9 at the other end of the high-voltage insulated cable.

[0055] (6) When the pressure of the pressure sensor 16 reaches the preset value, the humidity sensor 20, palladium grid hydrogen sensor 21, carbon monoxide sensor 22, carbon dioxide sensor 23, and low molecular weight hydrocarbon gas sensor 24 are turned on.

[0056] (7) Open the second solenoid valve 26 of the non-electrical quantity online detection module 10;

[0057] (8) High-purity nitrogen carries various gases contained in the interlayer of the high-voltage insulated cable and flows through the humidity sensor 25, palladium grid hydrogen sensor 21, carbon monoxide sensor 22, carbon dioxide sensor 23, and low molecular weight hydrocarbon gas sensor 24 in sequence to detect the moisture content, hydrogen content, carbon monoxide content, carbon dioxide content and low molecular weight hydrocarbon gas content respectively. The detected gas flows out into the atmosphere.

[0058] (9) When one or more of the detected values ​​of moisture content, hydrogen content, carbon monoxide content, carbon dioxide content and low molecular weight hydrocarbon gas content exceed the preset standard, the alarm will sound and notify relevant personnel to come for further inspection and handling.

[0059] (10) After the test is completed, turn off the following in sequence: humidity sensor 25, palladium grating hydrogen sensor 21, carbon monoxide sensor 22, carbon dioxide sensor 23, and low molecular weight hydrocarbon gas sensor 24.

[0060] (11) Open the second venting solenoid valve 27 and close the second solenoid valve 26 to release the gas in the interlayer gap inside the high-voltage insulated cable into the atmosphere.

[0061] (12) If only the humidity index exceeds the standard, in addition to the alarm, continue to keep the humidity sensor 25 on and introduce hot high-purity nitrogen to heat and dry the gaps between the layers inside the damp high-voltage insulated cable until the humidity reaches the required level, and then turn off the humidity sensor 25.

[0062] (13) Turn off the electric heating jacket 15 and the temperature sensor 14;

[0063] (14) Close the shut-off valve 19, pressure regulating valve 17, and first solenoid valve 12 of the high-purity nitrogen cylinder, and keep the pressure reducing valve 18 in the set pressure reducing position for the next test;

[0064] (15) After the pressure drops to normal pressure, turn off the pressure sensor 16 and the second venting solenoid valve 27;

[0065] (16) The non-electrical quantity test of the high-voltage insulated cable is completed and the next cycle of testing is awaited.

[0066] The advantages of this invention are: (1) When a high-voltage insulated cable fails, the various insulating, waterproof, shielding, and protective materials wrapped in it will undergo pyrolysis or chemical reaction to generate fault characteristic gases. Targeted non-electrical quantity detection is performed on the fault characteristic gases filling the multi-layer gap space of the high-voltage insulated cable. This enables online non-electrical quantity detection of the high-voltage insulated cable during operation, timely detection of moisture and overheating faults in the armor layer of the high-voltage insulated cable, and effectively overcomes the shortcomings of traditional live operation where high-voltage insulated cables cannot be quickly detected online, thus contributing to the safe operation of the power grid; (2) A high-purity nitrogen gas inlet module with a stable heating temperature and voltage range provides the carrier gas for the online non-electrical quantity detection module and can heat, dry, and remove moisture from the moisture-affected and damaged interlayer gaps inside the high-voltage insulated cable, effectively ensuring the safe operation of the high-voltage insulated cable.

[0067] If this invention discloses or relates to mutually fixedly connected components or structural parts, then, unless otherwise stated, a fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws), or a non-detachable fixed connection (e.g., riveting, welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured in one piece using a casting process) (except where it is obviously impossible to use an integral molding process).

[0068] In addition, unless otherwise stated, the terms used in any of the technical solutions disclosed in this invention to indicate positional relationships or shapes include states or shapes that are similar to, close to, or approximate with those states or shapes.

[0069] Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured by a one-piece molding process.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A non-electrical quantity online detection device for faults in 220kV high-voltage insulated power cables, characterized in that: The device includes a high-voltage insulated cable, a high-purity nitrogen gas inlet module and a non-electrical quantity online detection module respectively located at both ends of the high-voltage insulated cable. The outermost protective layer at both ends of the high-voltage insulated cable is connected to an inlet connector and an outlet connector, respectively. The output end of the nitrogen gas inlet module is connected to the inlet connector. The non-electrical quantity online detection module includes an outlet pipe connected to the outlet connector. A low-molecular-weight hydrocarbon gas sensor, a carbon dioxide sensor, a carbon monoxide sensor and a palladium-copper hydrogen sensor are sequentially arranged on the outlet pipe along the gas flow direction. The high-purity nitrogen gas inlet module includes a nitrogen gas inlet pipe with an electric heating jacket on the outside. One end of the nitrogen gas inlet pipe is connected to the shut-off valve at the output end of the high-purity nitrogen cylinder, and the other end of the nitrogen gas inlet pipe is connected to the gas inlet connector. The nitrogen inlet pipe is equipped with a pressure reducing valve, a pressure regulating valve, a pressure sensor, and a temperature sensor in sequence along the nitrogen delivery direction. The pressure sensor and the temperature sensor are located on both sides of the electric heating jacket, respectively. The high-purity nitrogen gas inlet module, with a stable heating temperature and pressure range, provides the carrier gas for the operation of the non-electrical quantity online detection module, and can provide heating, drying and dehumidification for the moisture-affected and damaged interlayer gaps inside the high-voltage insulated cable.

2. The online non-electrical quantity detection device for faults in 220kV high-voltage insulated cables according to claim 1, characterized in that: The air inlet connector is connected to a first three-way pipe. One end of the first three-way pipe is connected to the nitrogen inlet pipe through a first solenoid valve, and the other end of the first three-way pipe is connected to the first vent pipe through a first vent solenoid valve.

3. The online non-electrical quantity detection device for faults in 220kV high-voltage insulated cables according to claim 2, characterized in that: The vent connector is connected to a second three-way pipe via a connecting pipe, and a humidity sensor is installed on the connecting pipe; one end of the second three-way pipe is connected to the vent pipe via a second solenoid valve, and the other end of the second three-way pipe is connected to the second vent pipe via a second vent solenoid valve.

4. The online non-electrical quantity detection device for faults in 220kV high-voltage insulated cables according to claim 3, characterized in that: It also includes a control module, the input of which is electrically connected to the output of a palladium hydrogen phosphate sensor, a carbon monoxide sensor, a carbon dioxide sensor, a low molecular weight hydrocarbon gas sensor, a humidity sensor, a temperature sensor, and a pressure sensor, respectively. The output of the control module is electrically connected to a pressure regulating valve, a first solenoid valve, a second solenoid valve, a first venting solenoid valve, a second venting solenoid valve, an electric heating mantle, and an alarm, respectively.

5. The online non-electrical quantity detection device for faults in 220kV high-voltage insulated cables according to claim 1, characterized in that: Both ends of the high-voltage insulated cable have joint connection holes on their outermost protective layers.

6. The online non-electrical quantity detection device for faults in 220kV high-voltage insulated cables according to claim 1, characterized in that: Both ends of the high-voltage insulated cable are connected to high-voltage insulated cable terminals, and a vertically installed cable support rod is fixed between the high-voltage insulated cable terminals and the ground.

7. A method for online detection of non-electrical quantities of faults in 220kV high-voltage insulated cables, characterized in that: The non-electrical quantity online detection device for faults in 220kV high-voltage insulated cables, as described in claim 4, includes the following steps: (1) The control module presets alarm values ​​for humidity, hydrogen, carbon monoxide, carbon dioxide, and low molecular weight hydrocarbon gases, as well as the temperature and pressure stability settings for high-purity nitrogen. (2) First turn on the temperature sensor and pressure sensor of the high-purity nitrogen inlet module; (3) Open the first venting solenoid valve; (4) Adjust the pressure reducing valve to the set output pressure, and then open the shut-off valve, pressure regulating valve and electric heating jacket on the high-purity nitrogen cylinder in sequence. At this time, the high-purity nitrogen gas that has been pressure regulated and heated is discharged through the first venting solenoid valve. (5) When the temperature and pressure of the high-purity nitrogen gas are stable and reach the set value, open the first solenoid valve and close the first venting solenoid valve. The high-purity nitrogen gas with stable temperature and pressure enters the interlayer gap inside the high-voltage insulated cable through the inlet joint and fills the high-voltage insulated cable along the cable until the outlet joint at the other end of the high-voltage insulated cable. (6) Once the pressure of the pressure sensor reaches the preset value, turn on the humidity sensor, palladium grid hydrogen sensor, carbon monoxide sensor, carbon dioxide sensor, and low molecular weight hydrocarbon gas sensor. (7) Open the second solenoid valve of the non-electrical quantity online detection module; (8) High-purity nitrogen carries various gases contained in the interlayer of the high-voltage insulated cable and flows through the humidity sensor, palladium grid hydrogen sensor, carbon monoxide sensor, carbon dioxide sensor and low molecular weight hydrocarbon gas sensor in sequence to detect the moisture content, hydrogen content, carbon monoxide content, carbon dioxide content and low molecular weight hydrocarbon gas content respectively. The detected gas flows out into the atmosphere. (9) When one or more of the detected values ​​of moisture content, hydrogen content, carbon monoxide content, carbon dioxide content and low molecular weight hydrocarbon gas content exceed the preset standard, the alarm will sound and notify relevant personnel to come for further inspection and handling. (10) After the test is completed, turn off the following in sequence: humidity sensor, palladium grid hydrogen sensor, carbon monoxide sensor, carbon dioxide sensor, and low molecular weight hydrocarbon gas sensor. (11) Open the second solenoid valve and close the second solenoid valve to release the gas in the interlayer gap inside the high-voltage insulated cable into the atmosphere; (12) If only the humidity index exceeds the standard, in addition to the alarm, continue to keep the humidity sensor on and introduce hot high-purity nitrogen to heat and dry the interlayer gaps inside the damp high-voltage insulated cable until the humidity reaches the required level, and then turn off the humidity sensor. (13) Turn off the electric heating mantle and temperature sensor; (14) Close the shut-off valve, pressure regulating valve and first solenoid valve of the high-purity nitrogen cylinder, and keep the pressure reducing valve in the set pressure reducing position for the next test; (15) Once the pressure drops to normal pressure, turn off the pressure sensor and the second venting solenoid valve; (16) The non-electrical quantity test of the high-voltage insulated cable is completed and the next cycle of testing is awaited.

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