High-voltage cable monitoring device and punching monitoring method

Abstract

The invention provides a high-voltage cable monitoring device and a punching monitoring method.The high-voltage cable monitoring device comprises a punching monitoring device body, a gas monitoring instrument set, a background system and a control module, the punching monitoring device body comprises a clamping assembly, a punching part and a gas taking pipe, and the punching part and the gas taking pipe are detachably installed on the clamping assembly; the clamping assembly is detachably installed on the periphery of the high-voltage cable, one end of the gas taking pipe is communicated with the gas monitoring instrument set in an on-off mode through a hose, the other end of the gas taking pipe extends into a gap between the water-blocking buffer layer and the corrugated aluminum sheath from the punched hole, and the gas monitoring instrument set is used for collecting and analyzing components and concentration of characteristic gas flowing through the gas taking pipe; the background system controls the start and stop of the gas monitoring instrument group and the on-off of the hose through the control module; the gas monitor group is electrically connected with the background system, and the background system judges the state of the high-voltage cable according to the analysis result of the gas monitor group. Through the technical scheme provided by the invention, the problem that no punching positioning device exists in the prior art can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage cable monitoring, and in particular to a high-voltage cable monitoring device and a drilling monitoring method. Background Art

[0002] In recent years, with the increasing rate of cable lines in large cities in my country, higher requirements have been placed on the operational reliability and status detection technology of power cables. Cable failures caused by cable buffer layer ablation have seriously affected the reliability of the cable system, especially the long-term development of high-voltage cable buffer layer defects such as poor electrical contact, water seepage and partial discharge, which may lead to buffer layer ablation failures and seriously endanger the safe and stable operation of the cable. Some studies have shown that the buffer layer ablation process will release gas products such as hydrogen, low molecular weight hydrocarbons, aromatic hydrocarbons, etc. These buffer layer ablation gas products are difficult to escape freely in actual high-voltage cables, and will remain in the relatively closed gap between the buffer layer and the aluminum sheath.

[0003] In recent years, the research on the gas detection technology for latent defects in the cable buffer layer has achieved remarkable results and improved the detection efficiency of latent defects in the buffer layer. For example, the patent application publication number CN117451446A, entitled "A high-voltage cable rope ablation layer signal characteristic gas collection system and use method", installs a gas extraction valve at the crest of the cable corrugated aluminum sheath to collect the characteristic gas of ablation of the buffer layer of the operating cable, and can perform regular gas extraction detection, and then measure and analyze the buffer layer burn-in defects through an infrared spectrometer.

[0004] However, the monitoring device in the prior art is not designed with a fixed positioning device before drilling. The drilling is completely subject to the skill level of the operator and the sensitivity of the sensor of the automatic stop hand drill. The drilling position is prone to deviation and the drilling effect cannot be well controlled, which affects the accuracy of characteristic gas collection. Summary of the invention

[0005] The present invention provides a high-voltage cable monitoring device and a drilling monitoring method to solve the problems in the prior art that there is no drilling positioning device, drilling deviation or poor drilling effect may occur, which may affect the monitoring effect of characteristic gas.

[0006] In order to achieve the above-mentioned object, according to one aspect of the present invention, the present invention provides a high-voltage cable monitoring device, the high-voltage cable comprises an outer casing, a corrugated aluminum sheath, a water-blocking buffer layer, an insulating layer and a conductor layer which are sequentially sleeved from the outside to the inside, the corrugated aluminum sheath extends in a winding manner along the axial direction of the high-voltage cable, the high-voltage cable monitoring device comprises: a perforating monitoring device, comprising a clamping assembly and a perforating member and an air extraction pipe which are detachably mounted on the clamping assembly, the clamping assembly being detachably mounted on the periphery of the high-voltage cable, the perforating monitoring device having a perforating state and an air extraction state, in which the perforating member is arranged on the clamping assembly and has A punching end is used to punch holes in the high-voltage cable; in the gas extraction state, the gas extraction pipe is arranged on the clamping assembly and one end thereof extends into the gap between the water-blocking buffer layer and the corrugated aluminum sheath; a gas monitoring instrument group, the other end of the gas extraction pipe is connected to the gas monitoring instrument group through a hose in an on-off manner, and the gas monitoring instrument group is used to collect and analyze the composition and concentration of the characteristic gas flowing through the gas extraction pipe; a background system and a control module, and the background system controls the start and stop of the gas monitoring instrument group and the on-off of the hose through the control module; the gas monitoring instrument group is electrically connected to the background system, and the background system determines the state of the high-voltage cable according to the analysis result of the gas monitoring instrument group.

[0007] Furthermore, the clamping assembly includes a first clamp and a second clamp, the first clamp includes a first clamping seat and a first adapter seat, the second clamp includes a second clamping seat and a second adapter seat, the first clamping seat and the second clamping seat cooperate to form a mounting hole whose shape is adapted to the periphery of the high-voltage cable; the first adapter seat and the second adapter seat are detachably connected by a first fastener, and the punching piece and the air extraction pipe are detachably arranged on the first clamping seat or the second clamping seat.

[0008] Furthermore, there are two first adapter seats and they are symmetrically distributed on both sides of the first clamping seat along the radial direction of the mounting hole; there are two second adapter seats and they are symmetrically distributed on both sides of the second clamping seat along the radial direction of the mounting hole; the first adapter seat has a plurality of adapter hole grooves, and the corresponding second adapter seat has a corresponding plurality of threaded holes; the first fastener is a bolt, which passes through the adapter hole groove and is threadedly connected to the corresponding threaded hole; a countersunk head is arranged on the side of the adapter hole groove facing away from the threaded hole, and the head of the bolt is pressed into the countersunk head of the corresponding adapter hole groove.

[0009] Furthermore, a first positioning boss is provided on the top of the first clamping seat, and the first clamp has a first limiting hole that passes through the first clamping seat and the first positioning boss. In the punching state, the punching member is at least partially installed in the first limiting hole; the punching monitoring device also includes a fixed seat, and the fixed seat has a second limiting hole that is coaxial with the first limiting hole. In the gas extraction state, the first positioning boss is passed through the second limiting hole and sealed with the inner wall of the second limiting hole. The fixed seat is installed on the first clamping seat through a second fastener, and the gas extraction pipe is at least partially installed in the first limiting hole and the second limiting hole. The fixed seat and the first clamping seat jointly limit the movement of the gas extraction pipe.

[0010] Furthermore, there are multiple perforation monitoring devices, which are arranged at intervals along the axial direction of the high-voltage cable, and the gas monitor group is connected to the multiple perforation monitoring devices through multiple hoses; or, there are multiple gas monitor groups, which are connected one-to-one to the multiple perforation monitoring devices through multiple hoses.

[0011] Furthermore, the perforation monitoring device also includes a solenoid valve arranged on the hose, and the background system controls the opening and closing of the solenoid valve through the control module to control the on-off of the corresponding hose.

[0012] Furthermore, the gas monitoring instrument group includes a miniature DC vacuum pump, a composite gas monitoring sensor and a characteristic gas monitoring terminal. The composite gas monitoring sensor and the characteristic gas monitoring terminal are used to detect and analyze the concentrations of various characteristic gases flowing through the gas extraction pipe. The other end of the gas extraction pipe is connected to the composite gas monitoring sensor through a hose. The miniature DC vacuum pump is arranged on the hose to pump the fluid in the buffer layer to the composite gas monitoring sensor; the background system controls the start and stop of the DC vacuum pump and the composite gas monitoring sensor through a control module.

[0013] According to another aspect of the present invention, a perforation monitoring method is provided, which is applied to the above-mentioned high-voltage cable monitoring device, and the perforation monitoring method comprises: selecting at least one detection point on the periphery of the high-voltage cable and installing a clamping assembly at the detection point; installing a perforating member on the clamping assembly and punching holes at the detection point position, and after the drilling is completed, replacing the perforating member with a gas extraction pipe connected to a gas monitoring instrument group; the background system and the control module control the connection and disconnection of the hose between the gas extraction pipe and the gas monitoring instrument group, and the start and stop of the gas monitoring instrument group, so as to regularly collect and analyze characteristic gases; the background system records the monitoring data of the gas monitoring instrument group and judges whether there is a defect in the high-voltage cable at the detection point based on it.

[0014] Furthermore, the gas monitoring instrument group collects and analyzes the components of characteristic gases including H2, C2H4, CH4, and CO, and the gas monitoring instrument group collects and analyzes the objects of characteristic gases including the concentration of H2, the concentration of C2H4, the concentration of CH4, and the concentration of CO.

[0015] Furthermore, the defects of high-voltage cables include slight corrosion, slight ablation and severe ablation. The judgment criteria for slight corrosion are: 1500 / ppm<H2<3500 / ppm, C2H4<10 / ppm, CH4<100 / ppm, CO<10 / ppm; the judgment criteria for slight ablation are: 3500 / ppm<H2<7500 / ppm, C2H4<110 / ppm, CH4<550 / ppm, CO<1300 / ppm; the judgment criteria for severe ablation are: H2>7500 / ppm, C2H4>110 / ppm, CH4>550 / ppm, CO>1300 / ppm.

[0016] Furthermore, the punching process includes: punching holes at the same detection point position step by step by means of a punching member, the punching depth is constant each time and the debris and residue generated during each punching process is cleaned up in time.

[0017] Furthermore, the regular collection and analysis of characteristic gases includes: presetting an interval collection time T, and collecting and analyzing the characteristic gases in the gap between the water-blocking buffer layer and the corrugated aluminum sheath every T time.

[0018] Furthermore, in the case where there are multiple detection points, the regular collection and analysis of characteristic gases also includes: the high-voltage cable monitoring device at each detection point is equipped with a timing module, the timing module is used to preset the interval collection time T, and limit the sampling time difference X between the two timing modules, X≥0, so as to synchronously collect and analyze or intervally collect and analyze the characteristic gases at the two detection points. In the case of synchronously collecting and analyzing the characteristic gases at the two detection points, 20ns≥X.

[0019] The technical solution of the present invention is applied to provide a high-voltage cable monitoring device, wherein the high-voltage cable comprises an outer casing, a corrugated aluminum sheath, a water-blocking buffer layer, an insulating layer and a conductor layer which are sequentially sleeved from the outside to the inside, and the corrugated aluminum sheath extends in a winding manner along the axial direction of the high-voltage cable. The high-voltage cable monitoring device comprises: a perforating monitoring device, comprising a clamping assembly and a perforating member and an air extraction pipe which are detachably mounted on the clamping assembly, the clamping assembly being detachably mounted on the outer periphery of the high-voltage cable, the perforating monitoring device having a perforating state and an air extraction state, in which the perforating member is arranged on the clamping assembly and has a perforating end to pass through the perforating end. A hole is punched on the high-voltage cable through the punching end; in the gas extraction state, the gas extraction pipe is arranged on the clamping assembly and one end extends into the gap between the water-blocking buffer layer and the corrugated aluminum sheath; a gas monitoring instrument group, the other end of the gas extraction pipe is connected to the gas monitoring instrument group through a hose in an on-off manner, and the gas monitoring instrument group is used to collect and analyze the composition and concentration of the characteristic gas flowing through the gas extraction pipe; a background system and a control module, the background system controls the start and stop of the gas monitoring instrument group and the on-off of the hose through the control module; the gas monitoring instrument group is electrically connected to the background system, and the background system determines the state of the high-voltage cable according to the analysis result of the gas monitoring instrument group.

[0020] By adopting this scheme, the high-voltage cable monitoring device can realize the positioning of the punching position and the monitoring position (detection point) through the clamping assembly. The clamping assembly is used to locate the punching position before punching, so that the position of the punching piece is not easy to deviate during the punching process and the punching effect is guaranteed or improved. After the punching is completed, the clamping assembly is used to fix the gas extraction pipe, which is convenient for the installation of the gas extraction pipe and the punching and the limit installation of the gas extraction pipe, which is conducive to the realization of continuous and stable gas extraction. In this way, the clamping assembly is used to realize the integration of the clamping positioning installation and the gas extraction positioning installation functions, avoiding the situation that manual drilling is subject to the skill level of the operator and the sensitivity of the sensor of the automatic stop hand drill when there is no clamping assembly, the drilling position is prone to deviation and the drilling effect is difficult to control, improving the reliability, stability and convenience of drilling, reducing or eliminating the influence of drilling problems on the accuracy of characteristic gas collection, and the clamping assembly is also conducive to the installation guidance and limit of the gas extraction pipe, which is conducive to ensuring or improving the reliability and stability of characteristic gas monitoring. On the other hand, the perforation monitoring device combined with the gas monitoring instrument group, background system and control module can realize non-destructive monitoring of the internal state of the high-voltage cable. It is suitable for the health status assessment of various high-voltage cables in the power system. Especially during the operation of the cable, it can timely discover potential fault hazards, improve the safety of the power system, and help improve the remote control capability and accuracy of characteristic gas collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0022] Figure 1 It shows a schematic diagram of the application of the drilling monitoring device of the high-voltage cable monitoring device provided by the embodiment of the present invention;

[0023] Figure 2 Shows Figure 1 Exploded diagram of

[0024] Figure 3 Shows Figure 1 A front view of a clamping assembly;

[0025] Figure 4 A schematic structural diagram of a high-voltage cable monitoring device provided by an embodiment of the present invention is shown;

[0026] Figure 5 A flow chart of a monitoring method provided by an embodiment of the present invention is shown.

[0027] The above drawings include the following reference numerals:

[0028] 10. drilling monitoring device; 11. air extraction pipe; 12. first clamp; 121. first clamping seat; 1211. first positioning boss; 122. first adapter seat; 1221. adapter hole groove; 1201. first limiting hole; 13. second clamp; 131. second clamping seat; 132. second adapter seat; 1321. threaded hole; 14. fixing seat; 141. second positioning boss; 1401. second limiting hole; 15. first fastener; 16. second fastener;

[0029] 20. Gas monitoring instrument set; 21. DC vacuum pump; 22. Composite gas monitoring sensor;

[0030] 30. Control module;

[0031] 40. Backend system;

[0032] 50. Hose;

[0033] 60. Solenoid valve. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] like Figures 1 to 4As shown, the present invention provides a high-voltage cable monitoring device, the high-voltage cable includes an outer casing, a corrugated aluminum sheath, a water-blocking buffer layer, an insulating layer and a conductor layer which are sequentially sleeved from the outside to the inside, the corrugated aluminum sheath extends in a winding manner along the axial direction of the high-voltage cable, the high-voltage cable monitoring device includes a perforating monitoring device 10, a gas monitor group 20, a background system 40 and a control module 30, the perforating monitoring device 10 includes a clamping assembly and a perforating member and an air extraction pipe 11 which are detachably mounted on the clamping assembly, the clamping assembly is detachably mounted on the periphery of the high-voltage cable, the perforating monitoring device 10 has a perforating state and a air extraction state, in the perforating state, the perforating member is arranged on the clamping assembly and has a punching end so as to punch holes in the high-voltage cable through the punching end; in the gas taking state, the gas taking pipe 11 is arranged on the clamping assembly and one end extends into the gap between the water-blocking buffer layer and the corrugated aluminum sheath; the other end of the gas taking pipe 11 is connected to the gas monitor group 20 through the hose 50 in a switchable manner, and the gas monitor group 20 is used to collect and analyze the composition and concentration of the characteristic gas flowing through the gas taking pipe 11; the background system 40 controls the start and stop of the gas monitor group 20 and the switching on and off of the hose 50 through the control module 30; the gas monitor group 20 is electrically connected to the background system 40, and the background system 40 determines the state of the high-voltage cable according to the analysis result of the gas monitor group 20.

[0036] In this embodiment, the high-voltage cable monitoring device can realize the positioning of the punching position and the monitoring position (detection point) through the clamping assembly. The clamping assembly is used to locate the punching position before punching, so that the position of the punching piece is not easy to deviate during the punching process and the punching effect is guaranteed or improved. After the punching is completed, the clamping assembly is used to fix the gas extraction pipe 11, which is convenient for the installation of the gas extraction pipe 11 facing the punching and the limiting installation of the gas extraction pipe 11, which is conducive to the realization of continuous and stable gas extraction. In this way, the clamping assembly is used to realize the integration of the clamping positioning installation and the gas extraction positioning installation functions, avoiding the situation that manual drilling is subject to the skill level of the operator and the sensitivity of the self-stop hand drill sensor when there is no clamping assembly, the drilling position is prone to deviation and the drilling effect is difficult to control, improving the reliability, stability and convenience of drilling, reducing or eliminating the influence of drilling problems on the accuracy of characteristic gas collection, and the clamping assembly is also conducive to the installation guidance and limiting of the gas extraction pipe 11, which is conducive to ensuring or improving the reliability and stability of characteristic gas monitoring. On the other hand, the perforation monitoring device 10, combined with the gas monitoring instrument group 20, the background system 40 and the control module 30, can realize non-destructive monitoring of the internal state of the high-voltage cable, and is suitable for the health status assessment of various high-voltage cables in the power system. Especially during the operation of the cable, it can timely discover potential fault hazards, improve the safety of the power system, and is conducive to improving the remote control capability and accuracy of characteristic gas collection.

[0037] like Figures 1 to 4As shown, the clamping assembly includes a first clamp 12 and a second clamp 13, the first clamp 12 includes a first clamping seat 121 and a first adapter seat 122, the second clamp 13 includes a second clamping seat 131 and a second adapter seat 132, the first clamping seat 121 and the second clamping seat 131 cooperate to form a mounting hole whose shape is adapted to the outer periphery of the high-voltage cable; the first adapter seat 122 and the second adapter seat 132 are detachably connected by a first fastener 15, and the punching piece and the air extraction pipe 11 are detachably arranged on the first clamping seat 121 or the second clamping seat 131. This arrangement enables the perforation monitoring device 10 to be firmly fixed on the high-voltage cable, and the detachable design of the clamping assembly also improves the convenience of on-site operation and reduces the maintenance cost. On the other hand, the detachable design of the punching piece and the air extraction pipe 11 enables the perforation monitoring device 10 to flexibly switch between the perforation state and the monitoring state, realizing the integration of the perforation positioning and the installation positioning of the air extraction pipe 11. Furthermore, the clamping assembly can also protect the air intake pipe 11, thereby preventing external factors from affecting the internal state of the high-voltage cable.

[0038] Preferably, the first clamp 12 and the second clamp 13 are mainly made of high-strength anti-magnetic and anti-corrosion aluminum alloy, and the relative inner sides of the first clamp 12 and the second clamp 13 are at least partially lined with rubber pads to achieve buffering of the connection between the two and buffering clamping of the high-voltage cable by the two.

[0039] Specifically, there are two first adapter seats 122 and are symmetrically distributed on both sides of the first clamping seat 121 along the radial direction of the mounting hole. There are two second adapter seats 132 and are symmetrically distributed on both sides of the second clamping seat 131 along the radial direction of the mounting hole. The first adapter seat 122 has a plurality of adapter hole grooves 1221, and the corresponding second adapter seat 132 has a corresponding plurality of threaded holes 1321. The first fastener 15 is a bolt, which passes through the adapter hole groove 1221 and is threadedly connected to the corresponding threaded hole 1321. A countersunk head is set on the side of the adapter hole groove 1221 away from the threaded hole 1321, and the head of the bolt is pressed into the countersunk head of the corresponding adapter hole groove 1221.

[0040] In this embodiment, the first clamp 12 and the second clamp 13 are installed and clamped from both sides of the high-voltage cable in the radial direction. At this time, the two first adapter seats 122 are respectively opposite to the two second adapter seats 132, and the adapter hole groove 1221 and the threaded hole 1321 are opposite. The operator connects the corresponding first adapter seat 122 and the second adapter seat 132 by bolts. In this way, the symmetrical design of the first adapter seat 122 and the second adapter seat 132 ensures the stable connection of the first clamping seat 121 and the second clamping seat 131 on the opposite sides of the high-voltage cable, and improves the reliability and stability of the connection between the first clamp 12 and the second clamp 13. And the bolt connection is stable and reliable and easy to disassemble and assemble, which is conducive to improving the convenience of disassembly and assembly. On the other hand, the design of the adapter hole groove 1221 is conducive to its alignment with the threaded hole 1321, avoiding the situation that when the adapter hole groove 1221 is a transfer hole, the transfer hole and the threaded hole 1321 may be misaligned due to processing deviation or installation reasons, resulting in the two being unable to align and then unable to be connected by bolts. Furthermore, the countersunk design of the transition hole groove 1221 is conducive to reducing the thread length of the bolt or using a small-sized bolt.

[0041] Preferably, the first clamp 12 and the second clamp 13 can be fixed in a manner of bolts and springs, and the spring can provide a certain buffer for the fastening connection between the two, while facilitating the rapid separation of the first clamp 12 and the second clamp 13 after disassembly.

[0042] Furthermore, a first positioning boss 1211 is provided on the top of the first clamping seat 121, and the first clamp 12 has a first limiting hole 1201 that passes through the first clamping seat 121 and the first positioning boss 1211. In the punching state, the punching member is at least partially installed in the first limiting hole 1201; the punching monitoring device 10 also includes a fixed seat 14, and the fixed seat 14 has a second limiting hole 1401 that is coaxial with the first limiting hole 1201. In the gas extraction state, the first positioning boss 1211 is penetrated into the second limiting hole 1401 and sealed with the inner wall of the second limiting hole 1401. The fixed seat 14 is installed on the first clamping seat 121 through the second fastener 16, and the gas extraction pipe 11 is at least partially installed in the first limiting hole 1201 and the second limiting hole 1401. The fixed seat 14 and the first clamping seat 121 jointly limit the movement of the gas extraction pipe 11.

[0043] A second positioning boss 141 is disposed on the top of the fixing seat 14 , and the second limiting hole 1401 passes through the second positioning boss 141 . The second positioning boss 141 can increase the extension length of the second limiting hole 1401 , thereby ensuring or improving the limiting effect.

[0044] In this embodiment, in the punching state, the fixing seat 14 is not installed, and the punching member directly penetrates into the first limiting hole 1201. The first limiting hole 1201 guides the punching to avoid the situation where the punching is offset or unstable. In the process of switching to the air extraction state, the operator first installs the air extraction pipe 11 in the first limiting hole 1201, and then installs the fixing seat 14. During the installation of the fixing seat 14, the first positioning boss 1211 penetrates into the second limiting hole 1401 and cooperates with the inner wall of the second limiting hole 1401 to limit the seal, and the air extraction pipe 11 extends into the second limiting hole 1401 until the fixing seat 14 abuts against the first clamping seat 121. Preferably, a limiting structure for limiting the movement of the air intake pipe 11 away from the high-voltage cable is provided in the second limiting hole 1401, or a limiting structure for limiting the movement of the air intake pipe 11 away from the high-voltage cable is formed between the second limiting hole 1401 and the first limiting hole 1201, so as to limit the movement of the air intake pipe 11 in the first limiting hole 1201 through the fixing seat 14. This arrangement facilitates the limiting installation of the fixing seat 14 and the limiting installation of the air intake pipe 11, and improves the convenience of installation while ensuring the installation effect.

[0045] Preferably, the second fastener 16 in this embodiment is also a bolt.

[0046] like Figure 4 As shown, the perforation monitoring device 10 also includes a solenoid valve 60 disposed on the hose 50, and the background system 40 controls the opening and closing of the solenoid valve 60 through the control module 30 to control the opening and closing of the corresponding hose 50. Through the precise control of the solenoid valve 60, the on-demand collection of characteristic gases can be achieved, avoiding unnecessary gas waste, and also reducing the interference with the internal environment of the cable. It is suitable for long-term monitoring of high-voltage cables in power systems, especially when evaluating the aging status of cables, and can provide a stable data collection environment to ensure the accuracy and reliability of monitoring data.

[0047] Optionally, an electric actuator may be used instead of the solenoid valve 60 to execute the on-off command.

[0048] Preferably, the solenoid valve 60, the gas monitor group 20, the control module 30, and the background system 40 in this embodiment are connected via a communication cable using power supply and carrier co-cable technology.

[0049] Specifically, the gas monitor group 20 includes a micro DC vacuum pump 21, a composite gas monitoring sensor 22 and a characteristic gas monitoring terminal. The composite gas monitoring sensor 22 and the characteristic gas monitoring terminal are used to detect and analyze the concentrations of multiple characteristic gases flowing through the gas extraction pipe 11. The other end of the gas extraction pipe 11 is connected to the composite gas monitoring sensor 22 through a hose 50. The micro DC vacuum pump 21 is arranged on the hose 50 to pump the fluid in the buffer layer to the composite gas monitoring sensor 22; the background system 40 controls the start and stop of the DC vacuum pump and the composite gas monitoring sensor 22 through the control module 30. In this way, the combination of the micro DC vacuum pump 21, the composite gas monitoring sensor 22 and the characteristic gas monitoring terminal enables the high-voltage cable monitoring device to extract characteristic gases from the inside of the high-voltage cable (the gap between the water-blocking buffer layer and the corrugated aluminum sheath) and perform accurate gas composition and concentration analysis, which is suitable for comprehensive health status monitoring of high-voltage cables in power systems, especially when evaluating the operating status of cables, it can provide comprehensive gas analysis data to help accurately judge the operating status of the cable.

[0050] Preferably, the gas monitor group 20 mainly adopts PID photoionization detection technology, is equipped with a miniature DC vacuum pump 21 (vacuum pump) and multiple required gas monitoring sensors (the composite gas monitoring sensor 22 in this embodiment includes multiple gas monitoring sensors, each gas monitoring sensor corresponds to monitoring the concentration of a gas component), to achieve real-time continuous measurement of gas parameter data such as C2H4, CH4, CO, etc., with the characteristics of small size, light weight, high sensitivity, fast response, etc., and has good sensitivity and accuracy for PPM-level characteristic gases, can perform multi-gas concentration measurements simultaneously, and improves the real-time continuous measurement capability.

[0051] In this embodiment, the main parameters of the gas monitoring instrument group 20 include:

[0052] Sensor (composite gas monitoring sensor 22) type: PID photoionization;

[0053] Sampling method: pump suction (i.e. using a micro DC vacuum pump 21);

[0054] Flow rate: 15L / min;

[0055] Vacuum degree: -80kpa;

[0056] Characteristic gas detection range includes:

[0057] C2H4 detection range 0~10000ppm, detection accuracy ±20ppm;

[0058] CH4 detection range 5-100%VOL, detection accuracy ±0.06%VOL (≤1%VOL) ±6%VOL of true value (>1%VOL);

[0059] The CO detection range is 0~1000ppm, and the detection accuracy is <±3%.

[0060] It should be noted that the composite gas monitoring sensor 22 of the gas monitoring instrument group 20 of this embodiment includes a characteristic gas monitoring terminal and multiple gas monitoring sensors. The characteristic gas monitoring terminal is used to automatically monitor, collect and store gas parameter data such as C2H4, CH4, CO, etc. at defective parts of the cable buffer layer.

[0061] Optionally, in other embodiments, the gas monitor group 20 may also use temperature measurement spectroscopy technology to implement the gas detection function.

[0062] Among them, there can be multiple perforation monitoring devices 10, and multiple perforation monitoring devices 10 are arranged at intervals along the axial direction of the high-voltage cable, and the gas monitor group 20 is connected to the multiple perforation monitoring devices 10 through multiple hoses 50; or, there are multiple gas monitor groups 20, and multiple gas monitor groups 20 are connected to the multiple perforation monitoring devices 10 one by one through multiple hoses 50. Such an arrangement can realize the monitoring of different positions in the axial direction of the high-voltage cable, and improve the monitoring range and reliability. And combined with the use of the perforation monitoring device and the gas extraction method (the background system 40 controls the micro DC vacuum pump 21 to start gas extraction through the control module 30), the gas extraction process is more stable and modular, so that multiple specific position detection points can be set at the same time, and characteristic gas parameter comparison and analysis of multiple detection points can be realized, thereby improving the efficiency and comparability of detection.

[0063] It is understandable that multiple detection points can be monitored synchronously or at intervals according to actual needs. In the case of synchronous monitoring of multiple detection points, the acquisition time needs to be precisely synchronized so that the characteristic gas parameters of multiple detection points can be compared and analyzed at the same time. It should be noted that the characteristic gases of multiple detection points can be sent to the same gas monitoring instrument group 20 for collection and analysis, or a gas monitoring instrument group 20 can be set for each detection point to independently analyze the characteristic gas of each detection point.

[0064] like Figure 5As shown, another embodiment of the present invention provides a perforation monitoring method, which is applied to the above-mentioned high-voltage cable monitoring device, and the perforation monitoring method includes: selecting at least one detection point on the periphery of the high-voltage cable and installing a clamping assembly at the detection point; installing a perforating member on the clamping assembly and punching a hole at the detection point position, and after the drilling is completed, replacing the perforating member with a gas extraction pipe 11 connected to the gas monitoring instrument group 20; the background system 40 and the control module 30 control the connection and disconnection of the hose 50 between the gas extraction pipe 11 and the gas monitoring instrument group 20, and the start and stop of the gas monitoring instrument group 20, so as to regularly collect and analyze characteristic gases; the background system 40 records the monitoring data of the gas monitoring instrument group 20 and judges whether there is a defect in the high-voltage cable at the detection point based on it.

[0065] With such arrangement, the clamping assembly realizes the integration of the clamping positioning installation and gas extraction positioning installation functions, avoiding the situation that manual drilling is subject to the skill level of the operator and the sensitivity of the self-stop hand drill sensor when there is no clamping assembly, the drilling position is prone to deviation and the drilling effect is difficult to control, improving the reliability, stability and convenience of drilling, reducing or eliminating the influence of drilling problems on the accuracy of characteristic gas collection, and the clamping assembly is also conducive to realizing the installation guidance and limit of the gas extraction pipe 11, so as to ensure or improve the reliability and stability of characteristic gas monitoring. Regularly collecting and analyzing characteristic gases, in conjunction with the data analysis capabilities of the background system, can provide continuous health status monitoring data. By tracking the changes in the gas inside the cable for a long time, a dynamic model of the cable health status can be established to predict the fault trend of the cable and take measures in advance. This drilling monitoring method is particularly suitable for the automatic monitoring system of the power grid, realizing remote and automatic cable health status monitoring, reducing the frequency of manual monitoring, and improving the accuracy and timeliness of monitoring.

[0066] Among them, when the perforation monitoring device 10 is switched from the perforation state to the gas extraction state, the diameter of the gas extraction pipe 11 should match the diameter of the hole, or be slightly larger than the diameter of the hole. After fixing the gas extraction pipe 11 and the solenoid valve 60, gas is extracted on site or online through background remote control. Furthermore, the gas extraction pipe 11 should be made of a material that is not easy to deform or bend. The connector of the gas extraction pipe 11 should be tightly sealed.

[0067] It should be noted that during the on-site gas extraction process, it is necessary to monitor the gas composition concentration in real time, and to store the gas in gas sampling bags for laboratory testing and analysis. Four 1L gas sampling bags are used for each hole, and care is taken to prevent the gas bags from being damaged due to excessive pressure.

[0068] Specifically, the gas monitoring instrument group 20 collects and analyzes the characteristic gas components including H2, C2H4, CH4, and CO, and the gas monitoring instrument group 20 collects and analyzes the characteristic gas objects including the concentration of H2, the concentration of C2H4, the concentration of CH4, and the concentration of CO. The defects of the high-voltage cable include slight corrosion, slight ablation, and severe ablation. The judgment standard for slight corrosion is: 1500 / ppm<H2<3500 / ppm, C2H4<10 / ppm, CH4<100 / ppm, CO<10 / ppm; the judgment standard for slight ablation is: 3500 / ppm<H2<7500 / ppm, C2H4<110 / ppm, CH4<550 / ppm, CO<1300 / ppm; the judgment standard for severe ablation is: H2>7500 / ppm, C2H4>110 / ppm, CH4>550 / ppm, CO>1300 / ppm. This defect judgment standard based on characteristic gas concentration can accurately distinguish the different health states of high-voltage cables and is suitable for fault diagnosis of high-voltage cables in power systems. Especially during cable maintenance and troubleshooting, it can provide a clear basis for judging the fault type, help quickly locate the problem, reduce troubleshooting time, and improve the operating efficiency of the power system.

[0069] Preferably, the location of the hole is selected at the crest of the corrugated aluminum sheath away from the water-blocking buffer layer, and the location where the gap between the corrugated aluminum sheath and the water-blocking buffer layer is larger. It should be noted that the location of the hole should not be selected at the convex part of the crest of the corrugated aluminum sheath close to the water-blocking buffer layer, where the gap between the corrugated aluminum sheath and the water-blocking buffer layer is smaller, which is not conducive to the extraction of characteristic gases.

[0070] Optionally, the preset defect determination rules include: by collecting water-blocking buffer layer samples of high-voltage cables of different operating years, different manufacturers and operating environments, classifying the water-blocking buffer layer of the high-voltage cable according to normal operation, latent defects and ablation heating defects, analyzing the characteristic gas parameters of the water-blocking buffer layer under different operating conditions and operating states, establishing the correlation between the characteristic gas parameters of the water-blocking buffer layer and the operating state, and proposing characteristic parameters related to latent defects and ablation of the water-blocking buffer layer. Preferably, the characteristic parameters can be imported into the automatic statistical analysis rules. Through machine learning technology, the system automatically conducts analysis and determination based on the characteristic gas data extracted by the front end and forms a water-blocking buffer layer operating status report, which is displayed on the platform, effectively improving the efficiency of determining defects in the water-blocking buffer layer.

[0071] Preferably, the background system 40 (background main station) is responsible for unified processing, comprehensive analysis and diagnosis of the various monitoring data detected and collected by the drilling monitoring device 10 and the gas monitoring instrument group 20, and real-time extraction of gas parameter data such as C2H4, CH4, CO, etc. at the defective parts of the water-blocking buffer layer, and displaying them in the form of numerical values ​​or current curves.

[0072] The punching process includes: punching holes at the same detection point position step by step by using a punching piece, the punching depth is certain each time and the debris and residue generated during each punching process are cleaned up in time.

[0073] In this embodiment, the punching member uses a pistol drill with a limit function and a start-stop function. It has a pressure sensing function and can stop automatically and quickly when there is no pressure. The limit function is used to limit the punching depth. The total depth of the limit punching should be less than the distance from the outer surface of the high-voltage cable outer casing to the inner surface of the corrugated aluminum sheath. Before drilling, the pistol drill should be vertically aligned with the detection point. When drilling, the drilling speed is selected to be medium speed. First, a certain depth is drilled. The debris inside the hole is sucked out with a vacuum device and the debris on the drill bit is cleaned to prevent the drill bit from overheating. The drilling process is stopped several times. When the resistance is very small, the drilling stops, leaving the last thin layer. The debris in the hole is quickly cleaned with a vacuum device to complete the drilling. This step-by-step drilling method can effectively control the drilling depth and avoid excessive damage to the internal structure of the high-voltage cable. At the same time, the debris residue is cleaned in time to keep the punching channel unobstructed, thereby ensuring the cleanliness and unobstructedness of the characteristic gas collection channel and avoiding the problem of inaccurate monitoring data caused by channel blockage or pollution.

[0074] Specifically, the regular collection and analysis of characteristic gases includes: presetting the interval collection time T, and collecting and analyzing the characteristic gases in the gap between the water-blocking buffer layer and the corrugated aluminum sheath every T time. This setting is conducive to realizing intermittent monitoring of the same position, ensuring the reliability of monitoring, and facilitating timely detection of problems.

[0075] In this embodiment, the background system 40 includes a monitoring host and a monitoring center. The monitoring host is set in the substation and communicates with the monitoring center through the power network. The composite gas monitoring sensor 22 and the characteristic gas monitoring terminal can automatically monitor, collect and store the gas parameter data of C2H4, CH4, CO and other gas parameters in the defective parts of the cable buffer layer. The gas data in the internal air gap is collected every 5 minutes, and the gas data is transmitted to the monitoring host in the substation through the remote power supply carrier communication cable. The monitoring host collects gas information and communicates with the monitoring center through the power network. The characteristic gas analysis monitoring terminal sends the collected real-time data such as gas composition and concentration and the device heartbeat information in a specified message format or in a communication mode such as the power network to the monitoring center of the background system 40. The monitoring terminal can automatically save the collected monitoring data when the communication is interrupted, and transmit the stored data back to the monitoring center in time after the terminal communication is restored.

[0076] Among them, the front-end equipment (composite gas monitoring sensor 22 and characteristic gas monitoring terminal) is connected to the back-end system 40 through a remote power supply carrier communication cable and a power private network communication method, and can also be connected to data through an APN private network wireless network communication transmission method.

[0077] It is understandable that the background system 40, control module 30, characteristic gas monitoring terminal, etc. all have communication protocol extension functions, and can perform data upload, event confirmation, etc. in accordance with the requirements of the station-level monitoring platform protocol. The software interface is in Chinese, and the interface connector status display has a componentized display. The system application platform can automatically generate statistical tables for all monitoring data. The system uses a standard SQL or ORACLE database, and the historical data is kept for ≥3 years. At the same time, it should have functions such as data import and export, database scheduled cleanup, backup, and restore. The background system is configured with a server and a standard screen cabinet. The server meets the software and hardware requirements for software installation, data storage and data forwarding, and access compatibility for the realization of system functions.

[0078] Preferably, the high-voltage cable monitoring device can also be connected to a system platform (it can also be used directly) to study the online detection technology of characteristic gases of water-blocking buffer layer ablation defects. In addition to passively receiving characteristic gas data for analysis and display on the system platform, the system platform focuses on building a task management and control mode. Based on the constructed network of characteristic gas extraction, detection, upload, and display, the system platform will classify the various detection points set at the high-voltage cable according to the time dimension, collection frequency dimension, gas data parameters and other logics, and refer to the inspection task issuance, order acceptance, and execution mode to homogenize the online monitoring system of characteristic gases of water-blocking buffer layer ablation defects according to the inspection task management mode. When the characteristic gas online monitoring system is required to monitor a certain (group) detection point of the high-voltage cable, the background personnel refer to the cable inspection mode, select the corresponding detection point, and select the corresponding sensor (solenoid valve 60) control route, and pass the task to the high-voltage cable monitoring device. The high-voltage cable monitoring device will automatically collect and analyze the characteristic gas according to the set monitoring time, selected detection point, and detection frequency. The high-voltage cable monitoring device will execute the key links in the set parameter set one by one, and automatically form an online monitoring report of the characteristic gas of a certain (group) detection point.

[0079] Furthermore, in the case of multiple detection points, the regular collection and analysis of characteristic gases also includes: the high-voltage cable monitoring device at each detection point cooperates with a timing module, the timing module is used to preset the interval collection time T, and limit the sampling time difference X between the two timing modules, X≥0, so as to synchronously collect and analyze the characteristic gases at the two detection points or collect and analyze them at intervals. In the case of synchronous collection and analysis of the characteristic gases at the two detection points, 20ns≥X. With this arrangement, multiple specific detection points can be monitored synchronously and / or at intervals at the same time, so that the characteristic gas parameters of multiple detection points can be compared and analyzed simultaneously and / or at intervals. When there are multiple buffer layer defects in the high-voltage cable, the setting of multiple detection points can perform more comprehensive real-time monitoring of the state of the water-blocking buffer layer, reduce the risk of high-voltage cable line failures, and improve the operating efficiency and safety of the power system.

[0080] When the perforation monitoring method provided in this embodiment is applied and characteristic gas monitoring is required for a certain detection point, the background system 40 issues a work instruction, which is a computer program including task information such as monitoring time, selected detection point, and detection frequency. The control module 30 controls the solenoid valve 60 and the gas monitor group 20 to operate according to the program instructions. The solenoid valve 60 opens, and the gas monitor group 20 collects characteristic gas and analyzes it. The obtained gas online monitoring data is connected to the background system 40 through the communication line, and the background system 40 displays and determines the status.

[0081] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0082] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0083] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0084] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0085] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-voltage cable monitoring device, the high-voltage cable comprises an outer casing, a corrugated aluminum sheath, a water-blocking buffer layer, an insulating layer and a conductor layer which are sequentially sleeved from the outside to the inside, the corrugated aluminum sheath extends in a winding manner along the axial direction of the high-voltage cable, characterized in that: The high voltage cable monitoring device comprises: A perforation monitoring device (10) comprises a clamping assembly, a perforating member and an air extraction pipe (11) detachably mounted on the clamping assembly, wherein the clamping assembly is detachably mounted on the periphery of the high-voltage cable, and the perforation monitoring device (10) has a perforation state and an air extraction state. In the perforation state, the perforating member is arranged on the clamping assembly and has a perforating end so as to perforate the high-voltage cable through the perforating end; in the air extraction state, the air extraction pipe (11) is arranged on the clamping assembly and one end of the perforating pipe extends into the gap between the water-blocking buffer layer and the corrugated aluminum sheath. A gas monitoring instrument group (20), wherein the other end of the gas extraction pipe (11) is connected to the gas monitoring instrument group (20) through a hose (50) in an on-off manner, and the gas monitoring instrument group (20) is used to collect and analyze the composition and concentration of the characteristic gas flowing through the gas extraction pipe (11); A background system (40) and a control module (30), wherein the background system (40) controls the start and stop of the gas monitor group (20) and the connection and disconnection of the hose (50) through the control module (30); the gas monitor group (20) is electrically connected to the background system (40), and the background system (40) determines the state of the high-voltage cable according to the analysis result of the gas monitor group (20).

2. The high voltage cable monitoring device according to claim 1, characterized in that: The clamping assembly comprises a first clamp (12) and a second clamp (13), wherein the first clamp (12) comprises a first clamping seat (121) and a first adapter seat (122), and the second clamp (13) comprises a second clamping seat (131) and a second adapter seat (132), wherein the first clamping seat (121) and the second clamping seat (131) cooperate to form a mounting hole whose shape is adapted to the periphery of the high-voltage cable; the first adapter seat (122) and the second adapter seat (132) are detachably connected via a first fastener (15), and the punching piece and the air extraction pipe (11) are detachably arranged on the first clamping seat (121) or the second clamping seat (131).

3. The high voltage cable monitoring device according to claim 2, characterized in that: There are two first adapter seats (122) and they are symmetrically distributed on both sides of the first clamping seat (121) along the radial direction of the mounting hole. There are two second adapter seats (132) and they are symmetrically distributed on both sides of the second clamping seat (131) along the radial direction of the mounting hole. The first adapter seat (122) has a plurality of adapter hole grooves (1221), and the corresponding second adapter seat (132) has a plurality of corresponding threaded holes (1321). The first fastener (15) is a bolt, and the bolt passes through the adapter hole groove (1221) and is threadedly connected to the corresponding threaded hole (1321). A countersunk head is set on the side of the adapter hole groove (1221) away from the threaded hole (1321), and the head of the bolt is press-fitted into the countersunk head corresponding to the adapter hole groove (1221).

4. The high voltage cable monitoring device according to claim 2, characterized in that: A first positioning boss (1211) is provided on the top of the first clamping seat (121), and the first clamp (12) has a first limiting hole (1201) penetrating the first clamping seat (121) and the first positioning boss (1211), and in the punching state, the punching member is at least partially installed in the first limiting hole (1201); The perforation monitoring device (10) also includes a fixed seat (14), and the fixed seat (14) has a second limiting hole (1401) coaxial with the first limiting hole (1201). In the air extraction state, the first positioning boss (1211) is inserted into the second limiting hole (1401) and is sealed with the inner wall of the second limiting hole (1401). The fixed seat (14) is installed on the first clamping seat (121) through a second fastener (16). The air extraction pipe (11) is at least partially limitedly installed in the first limiting hole (1201) and the second limiting hole (1401). The fixed seat (14) and the first clamping seat (121) jointly limit the movement of the air extraction pipe (11).

5. The high voltage cable monitoring device according to claim 1, characterized in that: There are a plurality of the perforation monitoring devices (10), the plurality of the perforation monitoring devices (10) are arranged at intervals along the axial direction of the high-voltage cable, and the gas monitoring instrument group (20) is connected to the plurality of the perforation monitoring devices (10) via a plurality of the hoses (50); Alternatively, there are a plurality of gas monitor groups (20), and the plurality of gas monitor groups (20) are connected to the plurality of perforation monitoring devices (10) in a one-to-one correspondence via the plurality of hoses (50).

6. The high voltage cable monitoring device according to claim 1, characterized in that: The perforation monitoring device (10) further comprises a solenoid valve (60) arranged on the hose (50), and the background system (40) controls the opening and closing of the solenoid valve (60) through the control module (30) to control the opening and closing of the corresponding hose (50).

7. The high voltage cable monitoring device according to claim 1, characterized in that: The gas monitoring instrument group (20) comprises a micro DC vacuum pump (21), a composite gas monitoring sensor (22) and a characteristic gas monitoring terminal. The composite gas monitoring sensor (22) and the characteristic gas monitoring terminal are used to detect and analyze the concentrations of multiple characteristic gases flowing through the gas extraction pipe (11). The other end of the gas extraction pipe (11) is connected to the composite gas monitoring sensor (22) through the hose (50). The micro DC vacuum pump (21) is arranged on the hose (50) to pump the fluid in the buffer layer to the composite gas monitoring sensor (22). The background system (40) controls the start and stop of the DC vacuum pump and the composite gas monitoring sensor (22) through the control module (30).

8. A drilling monitoring method, characterized in that: The perforation monitoring method is applied to the high-voltage cable monitoring device according to any one of claims 1 to 7, and the perforation monitoring method comprises: Select at least one detection point on the periphery of the high-voltage cable and install the clamping assembly at the detection point; The punching member is installed on the clamping assembly and a hole is punched at the detection point position. After the punching is completed, the punching member is replaced with the gas extraction pipe (11) connected to the gas monitoring instrument group (20); The background system (40) and the control module (30) control the opening and closing of the hose (50) between the gas extraction pipe (11) and the gas monitoring instrument group (20) and the start and stop of the gas monitoring instrument group (20) to regularly collect and analyze characteristic gases; The background system (40) records the monitoring data of the gas monitoring instrument group (20) and judges whether the high-voltage cable has a defect at the detection point based on the monitoring data.

9. The drilling monitoring method according to claim 8, characterized in that: The gas monitoring instrument group (20) collects and analyzes the characteristic gas components including H2, C2H4, CH4, and CO, and the gas monitoring instrument group (20) collects and analyzes the characteristic gas objects including the concentration of H2, the concentration of C2H4, the concentration of CH4, and the concentration of CO.

10. The drilling monitoring method according to claim 9, characterized in that: The defects of the high voltage cable include slight corrosion, slight ablation and severe ablation. The judgment criteria for slight corrosion are: 1500 / ppm<H2<3500 / ppm, C2H4<10 / ppm, CH4<100 / ppm, CO<10 / ppm; The judgment criteria for mild ablation are: 3500 / ppm<H2<7500 / ppm, C2H4<110 / ppm, CH4<550 / ppm, CO<1300 / ppm; The criteria for determining severe ablation are: H2>7500 / ppm, C2H4>110 / ppm, CH4>550 / ppm, CO>1300 / ppm.

11. The drilling monitoring method according to claim 8, characterized in that: The drilling process includes: The punching member is used to gradually punch holes at the same detection point position, the punching depth is constant each time, and the debris and residue generated during each punching process are cleaned up in time.

12. The drilling monitoring method according to claim 8, characterized in that: Regular collection and analysis of characteristic gases include: A collection interval time T is preset, and the characteristic gas in the gap between the water-blocking buffer layer and the corrugated aluminum sheath is collected and analyzed once every T time.

13. The drilling monitoring method according to claim 12, characterized in that: In the case where there are multiple detection points, the regularity collection and analysis of characteristic gases also includes: The high-voltage cable monitoring device at each detection point is equipped with a timing module, which is used to preset the interval collection time T and limit the sampling time difference X between the two timing modules, X≥0, so as to perform synchronous collection and analysis or interval collection and analysis on the characteristic gases at the two detection points. When the characteristic gases at the two detection points are collected and analyzed synchronously, 20ns≥X.

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