High-voltage switch cabinet with insulation monitoring function

Abstract

The application discloses a high-voltage switch cabinet with insulation monitoring function, which comprises a cabinet body, a bus chamber and a cable chamber are arranged on the cabinet body respectively, a support is arranged on the cabinet body, a hollow plate is arranged on the support, a gas conveying pipe one is arranged on the hollow plate, a gas conveying pipe two is connected to the gas conveying pipe one, a shell is connected to the gas conveying pipe two, and a suction nozzle is arranged on the shell; one end of the gas conveying pipe one is connected with a gas conveying mechanism; and a monitoring mechanism is arranged on the hollow plate. Through the accurate switching of three intelligent control valves, the application realizes four functions of active sampling monitoring, gas chamber vacuumizing, old gas recycling and new gas recharging, integrates a sulfur hexafluoride compressor, a vacuum pump and a sulfur hexafluoride storage tank outside the switch cabinet body, does not need to carry a heavy external recycling device during power-off maintenance, and does not need to carry out complicated pipeline connection and leakage detection, and the system can automatically execute a complete "vacuumizing-recycling-recharging" process.

Description

Technical Field

[0001] This invention relates to the field of switchgear technology for power supply or distribution, and in particular to a high-voltage switchgear with insulation monitoring function. Background Technology

[0002] Sulfur hexafluoride (SF6) gas, with its excellent insulation and arc-extinguishing properties, has become the most widely used insulating medium in medium and high voltage switchgear. SF6 gas-insulated high-voltage switchgear has advantages such as small size, compact structure, reliable operation, and convenient maintenance. It is a core device in power transmission and distribution systems, and its operational stability is directly related to the safe power supply of the entire power grid.

[0003] The existing SF6 switchgear gas handling systems are all completely external, independent devices. When the switchgear requires power outage maintenance, maintenance personnel must transport the external SF6 gas recovery device to the site, and then connect the vacuuming pipeline, gas recovery pipeline, and gas filling pipeline separately. Each interface requires individual gas tightness testing. The entire process is time-consuming and labor-intensive, resulting in long maintenance times and impacting power supply reliability. Summary of the Invention

[0004] The purpose of this invention is to provide a high-voltage switchgear with insulation monitoring function to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A high-voltage switchgear with insulation monitoring function includes a cabinet, on which a busbar compartment and a cable compartment are respectively arranged. A bracket is provided on the cabinet, and a hollow plate is provided on the bracket. A gas supply pipe is provided on the hollow plate, and a second gas supply pipe is connected to the first gas supply pipe. A housing is connected to the second gas supply pipe, and a suction nozzle is provided on the housing. One end of the first gas supply pipe is connected to a gas supply mechanism. A monitoring mechanism is provided on the hollow plate. The monitoring mechanism includes a gas measuring tube with a slot. A miniature armored thermocouple is provided at the top of the slot, and a gas state sensor is provided at the bottom of the slot. A protective shell is also provided on the gas measuring tube, and a UHF antenna is provided on the protective shell.

[0007] In a preferred embodiment, the gas delivery mechanism includes a first connecting pipe; a second connecting pipe is connected to the first connecting pipe, a sulfur hexafluoride compressor is connected to the second connecting pipe, an intelligent control valve is installed on the second connecting pipe, and the sulfur hexafluoride compressor is located at one end of the cabinet; a third connecting pipe is connected to the first connecting pipe, a vacuum pump is connected to the third connecting pipe, an intelligent control valve is installed on the third connecting pipe, and the vacuum pump is located at one end of the cabinet; a fourth connecting pipe is connected to the first connecting pipe, a sulfur hexafluoride storage tank is connected to the fourth connecting pipe, an intelligent control valve is installed on the fourth connecting pipe, and the sulfur hexafluoride storage tank is located at one end of the cabinet.

[0008] In a preferred embodiment, the support is provided with an isolation plate.

[0009] In a preferred embodiment, the cable chamber is equipped with electrical equipment and insulators.

[0010] In a preferred embodiment, a support plate is provided on the cabinet, a composite plate is provided on the support plate, and a grounding wire is provided on the composite plate; an insulating support rod is provided on the top of the composite plate, and the insulating support rod is in close contact with the insulator.

[0011] In a preferred embodiment, the composite plate is made of a silicone rubber composite material doped with carbon nanotubes.

[0012] In a preferred embodiment, a temperature sensor is provided on the hollow plate.

[0013] In a preferred embodiment, a gas density sensor is provided on the hollow plate.

[0014] In a preferred embodiment, the opening of the busbar compartment is connected to a cabinet door via a hinge, and a control switch is provided on the cabinet door.

[0015] In a preferred embodiment, the opening of the cable compartment is connected to a cabinet door via a hinge.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] 1. This invention achieves four major functions—active sampling and monitoring, gas chamber vacuuming, old gas recovery, and new gas recharging—through the precise switching of three intelligent control valves. The sulfur hexafluoride compressor, vacuum pump, and sulfur hexafluoride storage tank are all integrated on the outside of the switch cabinet body. During power outage maintenance, there is no need to move the bulky external recovery device or perform complex pipeline connections and leak detection. The system can automatically execute the complete "vacuuming → recovery → recharging" process.

[0018] 2. This invention employs an active sampling method that generates a slight negative pressure using a vacuum pump. Compared to traditional passive point monitoring, this method can capture minute changes in the gas state inside the cabinet in real time, achieving real-time monitoring. The system does not simply judge whether a single parameter exceeds the standard, but rather uses cross-verification of temperature trends, decomposition products, and UHF partial discharge signals to effectively eliminate false alarms caused by normal load fluctuations and external electromagnetic interference. Simultaneously, by detecting decomposition products and UHF partial discharge signals, it can accurately identify all common insulation faults such as overheating, discharge, moisture, and leakage.

[0019] 3. This invention actively discharges harmful charges to the ground before the surface charge of the insulator accumulates to the flashover threshold, fundamentally preventing surface flashover accidents caused by pollution, moisture, and condensation; it operates based on the nonlinear conductivity characteristics of the material itself; after the charge discharge is completed, it automatically returns to a high-resistivity state, eliminating the need for regular replacement and maintenance; moreover, the charge discharge action itself is converted into an early warning signal, and by detecting the current pulse on the grounding wire, the degree of pollution and insulation status of the insulator can be monitored in real time, realizing the elimination of potential hazards as soon as they appear, and the elimination is detected at the same time. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0021] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, guided by the teachings of this invention, can select various possible shapes and proportions to implement the invention according to specific circumstances.

[0022] Figure 1 This is a three-dimensional structural diagram of a high-voltage switchgear with insulation monitoring function proposed in this invention. Figure 1 ;

[0023] Figure 2 This is a three-dimensional structural diagram of a high-voltage switchgear with insulation monitoring function proposed in this invention. Figure 2 ;

[0024] Figure 3 This is a schematic diagram of the monitoring mechanism structure of a high-voltage switchgear with insulation monitoring function proposed in this invention. Figure 1 ;

[0025] Figure 4 for Figure 3 A magnified structural diagram of node A in the middle;

[0026] Figure 5 for Figure 3 A magnified structural diagram of node B in the middle;

[0027] Figure 6 This is a schematic diagram of the monitoring mechanism structure of a high-voltage switchgear with insulation monitoring function proposed in this invention. Figure 2 ;

[0028] Figure 7 This is a three-dimensional structural diagram of a high-voltage switchgear with insulation monitoring function proposed in this invention. Figure 3 .

[0029] Figure label:

[0030] 1. Cabinet; 2. Busbar compartment; 3. Cabinet door one; 4. Control switch; 5. Cable compartment; 6. Cabinet door two; 7. Electrical equipment; 8. Insulator; 9. Insulating support rod; 10. Composite board; 11. Support plate; 12. Bracket; 13. Isolation plate; 14. Hollow plate; 15. Gas supply pipe one; 16. Gas supply pipe two; 17. Shell; 18. Nozzle; 19. Gas measuring tube; 20. Slot; 21. Miniature armored thermocouple; 22. Protective shell; 23. UHF antenna; 24. Gas state sensor; 25. Temperature sensor; 26. Gas density sensor; 27. Connecting pipe one; 28. Connecting pipe two; 29. ​​Intelligent control valve one; 30. Sulfur hexafluoride compressor; 31. Connecting pipe three; 32. Intelligent control valve two; 33. Vacuum pump; 34. Connecting pipe four; 35. Intelligent control valve three; 36. Sulfur hexafluoride storage tank; 37. Grounding wire. Detailed Implementation

[0031] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0032] In the description of the embodiments of the present invention, it should be noted that the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "top," "long," "short," "inner," "outer," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the embodiments of the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise stated, "a plurality of" means two or more.

[0033] In the description of this invention, it should be understood that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intermediate component present simultaneously. When a component is considered to be "set" on another component, it can be directly set on the other component or there may be an intermediate component present simultaneously. It should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "installed," and "connected" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a mechanical connection or an electrical connection; it can refer to a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] The present invention will now be described in detail with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the scope of protection of the present invention.

[0035] See Figure 1-7 This embodiment provides a high-voltage switchgear with insulation monitoring function, including a cabinet 1, a busbar compartment 2 and a cable compartment 5 respectively provided on the cabinet 1, a bracket 12 provided on the cabinet 1, a hollow plate 14 provided on the bracket 12, a gas supply pipe 15 provided on the hollow plate 14, a second gas supply pipe 16 connected to the first gas supply pipe 15, a housing 17 connected to the second gas supply pipe 16, and a suction nozzle 18 provided on the housing 17; one end of the first gas supply pipe 15 is connected to a gas supply mechanism; a monitoring mechanism is provided on the hollow plate 14, the monitoring mechanism includes a gas measuring pipe 19, a slot 20 opened on the gas measuring pipe 19, a miniature armored thermocouple 21 provided at the top of the slot 20, and a gas state sensor 24 provided at the bottom of the slot 20; a protective shell 22 is also provided on the gas measuring pipe 19, and a UHF antenna 23 is provided on the protective shell 22.

[0036] The gas transmission mechanism includes a first connecting pipe 27; a second connecting pipe 28 is connected to the first connecting pipe 27, a sulfur hexafluoride compressor 30 is connected to the second connecting pipe 28, an intelligent control valve 29 is installed on the second connecting pipe 28, and the sulfur hexafluoride compressor 30 is located at one end of the cabinet 1; a third connecting pipe 31 is connected to the first connecting pipe 27, a vacuum pump 33 is connected to the third connecting pipe 31, an intelligent control valve 2 32 is installed on the third connecting pipe 31, and the vacuum pump 33 is located at one end of the cabinet 1; a fourth connecting pipe 34 is connected to the first connecting pipe 27, a sulfur hexafluoride storage tank 36 is connected to the fourth connecting pipe 34, an intelligent control valve 35 is installed on the fourth connecting pipe 34, and the sulfur hexafluoride storage tank 36 is located at one end of the cabinet 1.

[0037] In this embodiment, at least one miniature armored thermocouple 21, a gas state sensor 24, a temperature sensor 25, and a gas density sensor 26 are provided.

[0038] Among them, gas transmission pipe 15; gas transmission pipe 2 16; gas measuring pipe 19; connecting pipe 1 27; connecting pipe 2 28; connecting pipe 3 31; connecting pipe 4 34 are all made of polytetrafluoroethylene (PTFE) pipe.

[0039] After SF6 gas is introduced into cabinet 1, the external control system precisely controls the on / off state of three intelligent control valves to switch different gas flow directions, achieving four completely independent modes of function.

[0040] The piping setup includes:

[0041] Public main pipeline (connecting pipe 127);

[0042] Intelligent control valve 1 29 → connecting pipe 2 28 → SF6 dedicated sulfur hexafluoride compressor 30;

[0043] Intelligent control valve 2 32 → connecting pipe 3 31 → vacuum pump 33;

[0044] Intelligent control valve 35 → connecting pipe 4 34 → SF6 dedicated sulfur hexafluoride storage tank 36.

[0045] Mode 1 includes active sampling and monitoring mode;

[0046] The default operating mode of the switchgear during daily operation is based on the principle of "generating a slight negative pressure to draw in hot gas".

[0047] Valve status: Only intelligent control valve 2 32 is open; intelligent control valve 1 29 and intelligent control valve 3 35 are all closed.

[0048] Operating equipment: Start vacuum pump 33;

[0049] Airflow direction: Cabinet air chamber → suction nozzle 18 → shell 17 → air supply pipe 2 16 → air supply pipe 1 15 → connecting pipe 1 27 → intelligent control valve 2 32 → connecting pipe 3 31 → vacuum pump 33 → exhaust port (exhausted to atmosphere);

[0050] Working principle: Vacuum pump 33 continuously draws gas from the common main pipeline connection pipe 27, forming a stable micro-negative pressure in the entire sampling pipeline. Under the action of pressure difference, the SF6 gas in cabinet 1 is continuously drawn into the suction nozzle 18, flows through the gas measuring tube 19 to complete parameter detection, and is finally discharged by vacuum pump 33.

[0051] It enables active, continuous, and real-time gas sampling, rather than traditional passive point monitoring, thus improving the timeliness of fault detection.

[0052] Mode 2 includes the gas chamber vacuum mode;

[0053] When the switchgear needs to be shut down for maintenance, the air chamber must first be evacuated to a high vacuum to remove moisture and air impurities.

[0054] Valve status: Only intelligent control valve 2 (32) is open; all other valves are closed.

[0055] Operating equipment: Start vacuum pump 33;

[0056] Airflow direction: Cabinet air chamber → suction nozzle 18 → shell 17 → air supply pipe 2 16 → air supply pipe 1 15 → connecting pipe 1 27 → intelligent control valve 2 32 → connecting pipe 3 31 → vacuum pump 33 → exhaust port (exhausted to atmosphere);

[0057] Working principle: The only difference between the sampling and monitoring modes is the operating time and vacuum requirements. The sampling mode only requires a slight negative pressure, while the vacuum mode requires continuous operation of the vacuum pump until the pressure in the gas chamber is reduced to a high vacuum state below 133 Pa.

[0058] Mode 3 includes SF6 gas recovery mode (recovering old gas);

[0059] After the vacuum is completed, all the remaining SF6 gas in the gas chamber is recovered into the sulfur hexafluoride storage tank 36.

[0060] Valve status: Intelligent control valve 1 29 and intelligent control valve 3 35 are open, intelligent control valve 2 32 is closed;

[0061] Operating equipment: Start the SF6-specific sulfur hexafluoride compressor 30;

[0062] Gas flow direction: Inner chamber → Suction nozzle 18 → Shell 17 → Gas supply pipe 2 16 → Gas supply pipe 1 15 → Hollow plate 14 → Connecting pipe 1 27 → Intelligent control valve 1 29 → Connecting pipe 2 28 → Sulfur hexafluoride compressor 30 (pressurized to 3.5~5MPa) → Intelligent control valve 3 35 → Connecting pipe 4 34 → Sulfur hexafluoride storage tank 36 (liquid storage);

[0063] Working principle: The sulfur hexafluoride compressor 30 extracts the low-pressure SF6 gas from the gas chamber and pressurizes it to a high-pressure liquid state, which is then stored in a storage tank.

[0064] Mode 4 includes SF6 gas recharge mode (gas replenishment after maintenance);

[0065] After the maintenance is completed, the qualified SF6 gas in the sulfur hexafluoride storage tank 36 will be refilled into the gas chamber 1 of the switchgear.

[0066] Valve status: Only intelligent control valve 35 is open; all other valves are closed.

[0067] Operating equipment: No power equipment needs to be started;

[0068] Gas flow direction: Sulfur hexafluoride storage tank 36 (high pressure liquid) → pressure reducing valve (not shown in the figure), integrated in the outlet of sulfur hexafluoride storage tank 36 → connecting pipe 4 34 → intelligent control valve 3 35 → connecting pipe 1 27 → hollow plate 14 → gas transmission pipe 1 15 → gas transmission pipe 2 16 → shell 17 → suction nozzle 18 → gas chamber inside the cabinet.

[0069] Working principle: Utilizing the pressure of the high-pressure SF6 gas within the sulfur hexafluoride storage tank 36, the pressure is reduced to the rated working pressure of the switchgear (0.4~0.6MPa) via a pressure reducing valve, and then automatically filled into the gas chamber. When the storage tank pressure is insufficient, the sulfur hexafluoride compressor 30 can be started for pressurization and refilling.

[0070] The bracket 12 is equipped with an isolation plate 13 for isolating the cable compartment 5 and the busbar compartment 2.

[0071] The cable compartment 5 is equipped with electrical equipment 7 and insulators 8.

[0072] A support plate 11 is provided on the cabinet 1, a composite plate 10 is provided on the support plate 11, and a grounding wire 37 is provided on the composite plate 10; an insulating support rod 9 is provided on the top of the composite plate 10, and the insulating support rod 9 is in close contact with the insulator 8.

[0073] The composite plate 10 is made of a silicone rubber composite material doped with carbon nanotubes.

[0074] Specifically, a nonlinear composite material doped with carboxylated multi-walled carbon nanotubes (MWCNT-COOH) and methyl vinyl silicone rubber (MVQ) is used. This material utilizes the quantum tunneling effect near the percolation threshold to achieve switching characteristics of low electric field with high resistance and high electric field with low resistance. The core components and formulation matrix include: methyl vinyl silicone rubber (vinyl content 0.15%~0.3%); conductive filler: carboxylated multi-walled carbon nanotubes (diameter 8~15nm, purity ≥98%); additives: KH-550 coupling agent, bis(2,5-dimethyl)sulfide agent, and fumed silica reinforcing agent; key parameters: by adjusting the carbon nanotube doping amount (1.5~2.5 parts / 100 parts silicone rubber), the trigger electric field threshold (1.5~4.0kV / mm) can be precisely controlled, corresponding to different voltage levels from 10kV to 110kV, with a resistance change of ≥6~7 orders of magnitude. The preparation method includes a standard four-step process: carbon nanotube surface modification → open mill mixing → flat vulcanization molding → secondary vulcanization. Commercially available nonlinear silicone rubber products such as Suzhou Saiwu SW-NLR-100, Shenzhen Huicheng HC-NL-200, and Dow Corning Silastic™ NR series can be directly purchased and used after cutting. It is understood that, based on the above, those skilled in the art can achieve this without inventive effort.

[0075] Specifically, the composite plate 10 is in close contact with the surface of the insulator 8 inside the cable chamber 5 through the insulating support rod 9; the bottom of the composite plate 10 is connected to the grounding wire 37 through the support plate 11 for reliable grounding;

[0076] When the insulator surface is clean, dry, and free of accumulated charge, composite plate 10 is in an extremely high resistance state (resistance ≥ 10). 12The composite plate 10 (Ω) has no effect on the original electric field distribution inside the switchgear, acting like a "standby sentinel." When surface charge gradually accumulates on the insulator surface due to dirt, moisture, or condensation, causing the local electric field strength at the location of the composite plate 10 to exceed its trigger threshold, quantum tunneling occurs inside the material, causing the resistance to drop by 6-8 orders of magnitude instantaneously, forming a low-resistance conductive channel. The harmful charge accumulated on the insulator surface will immediately pass through this low-resistance channel, through the support plate 11 and the grounding wire 37, and be safely discharged to the ground, thus actively eliminating insulation hazards before surface flashover occurs. After the charge discharge is completed, the local electric field strength quickly drops back below the threshold, and the composite plate 10 will automatically return to a high-resistance state, waiting for the next trigger, achieving complete self-healing without any manual intervention. At the moment of charge discharge, a tiny current pulse will be generated on the grounding wire 37. By capturing this pulse signal through an external current monitoring device (not shown in the figure) connected to the grounding wire, the charge discharge action itself can be converted into an early warning signal and transmitted to the external control system. By analyzing the frequency of the pulse, we can determine the rate of contamination accumulation on the insulator surface. By analyzing the amplitude of the pulse, we can determine the amount of charge discharged in a single instance and the severity of the fault, thus achieving the effect of eliminating potential hazards as soon as they appear and being detected at the same time as they are eliminated.

[0077] A temperature sensor 25 is installed on the hollow panel 14 to monitor the temperature inside the cabinet 1.

[0078] A gas density sensor 26 is installed on the hollow plate 14.

[0079] Gas state sensor 24 includes, but is not limited to, density sensor and micro-water (humidity) sensor.

[0080] The opening of busbar compartment 2 is connected to cabinet door 3 via a hinge, and a control switch 4 is installed on cabinet door 3.

[0081] The opening of the cable compartment 5 is connected to cabinet door 6 via a hinge.

[0082] In this embodiment, the SF6 gas state is fully monitored while actively sampling.

[0083] When the conductor inside the cabinet heats up due to the Joule effect (I²R), generating convective hot gas that rises, it is drawn into the gas measuring tube 19 by the suction nozzle 18. As the gas flows through the gas measuring tube 19, the sensor array integrated on the tube wall sequentially and synchronously collects the following key parameters:

[0084] The gas first contacts the miniature armored thermocouple 21 at the top of the slot 20, directly and rapidly measuring the gas's true temperature with a response time in the millisecond range. The gas then flows through the gas state sensor 24 at the bottom of the slot 20, simultaneously detecting three core parameters: SF6 gas density (to determine if there is a leak); gas moisture content (humidity, to determine insulation performance); and SF6 arc decomposition products (SO2, HF, H2S, etc., to determine if partial discharge has occurred). Simultaneously, the UHF antenna 23 inside the protective shell 22 of the gas measuring pipe simultaneously captures the ultra-high frequency partial discharge signal generated within the gas chamber due to insulation defects.

[0085] All signals collected by the sensors are sent to the data processing unit of the external control system for fusion analysis. The external control system combines the trend of gas temperature changes to determine whether there is an overheating fault; combines the type and concentration of decomposition products to determine the severity and type of the fault; and combines the amplitude and spectrum of partial discharge signals to accurately locate the location of insulation defects, ultimately achieving early, accurate, and comprehensive diagnosis of the insulation status and potential faults inside the switchgear.

[0086] Specifically, the information that each sensor can independently provide includes the information shown in Table 1 below:

[0087] Table 1

[0088]

[0089] The external control system first performs real-time threshold monitoring on all parameters. When any parameter exceeds the preset warning threshold, a secondary warning is triggered, and the system automatically enters the fusion analysis mode.

[0090] For example: if the gas temperature exceeds 80℃, or the SO2 concentration exceeds 1μL / L, or the UHF signal amplitude exceeds 100mV; no trip command will be issued during this stage, only maintenance personnel will be alerted.

[0091] Case 1: Eliminating false temperature alarms caused by "normal load increase";

[0092] Initial screening anomaly: The miniature armored thermocouple detected that the gas temperature rose from 40℃ to 70℃, dT / dt=5℃ / h;

[0093] Integration verification: Load data from the substation's SCADA system was retrieved, revealing that the line load increased from 50% to 90%; the concentration of decomposition products, such as SO2 and H2S, was checked and found to be 0; the UHF signal was checked and no abnormal discharge waveform was found.

[0094] Diagnostic conclusion: Temperature rise due to normal load fluctuations; warning lifted, continued monitoring.

[0095] Case 2: Eliminating false alarms caused by "external electromagnetic interference";

[0096] Initial screening anomaly: The UHF antenna detected a continuous high-frequency signal with an amplitude of 150mV;

[0097] Fusion verification:

[0098] The concentration of decomposition products was checked and all parameters were 0; the gas temperature was checked and no abnormal changes were found; the UHF data of the adjacent switchgear was retrieved and the same signal was found to be present at the same time.

[0099] Diagnosis: Electromagnetic interference from external mobile phone base stations or welding machines; warning lifted.

[0100] Once cross-validation confirms the existence of a real anomaly, the system will determine the specific type of fault based on the combination of different parameters.

[0101] SF6 gas and solid insulating materials produce different decomposition products at different temperatures, which is the core basis for judging overheating temperature and fault type (Table 2).

[0102] Table 2

[0103]

[0104] Furthermore, the fusion logic is: temperature change trend + types of decomposition products + concentration ratio of decomposition products;

[0105] For example:

[0106] The temperature rises slowly (2℃ / h), and CO and CF4 appear simultaneously, with CO / CF4>10 → indicating overheating of the solid insulation material (such as aging of epoxy resin insulators); different types of insulation defects will produce different partial discharge patterns and decomposition product combinations (refer to Table 3).

[0107] Table 3

[0108]

[0109] The fusion logic is as follows: UHF spectral characteristics + types of decomposition products + changes in discharge frequency;

[0110] For example: UHF signal shows high amplitude discharge symmetrically in the positive and negative half cycles, while SO2 and HF concentrations continue to rise → it is determined to be a floating potential discharge (such as metal parts floating due to loose bolts); the system uses the method of "UHF time difference positioning + temperature gradient assistance" to pinpoint the location of insulation defects to a specific area inside the cabinet.

[0111] In another embodiment, a UHF antenna 23 is installed in both the busbar compartment and the cable compartment. When partial discharge occurs, the electromagnetic waves propagate at the speed of light in all directions, and the arrival time at different antennas will vary slightly.

[0112] The system can accurately calculate the three-dimensional coordinates of the discharge source by calculating the time difference between the signals received by the three antennas.

[0113] In the event of an overheating fault, the system compares the readings of the miniature armored thermocouple 21 (which measures gas temperature) with those of the multiple temperature sensors 25 on the hollow plate (which measure the temperature at different locations in the cabinet).

[0114] For example: if the temperature sensor 25 reading in cable compartment 5 is 15°C higher than that in bus compartment 2, and the gas temperature detected by miniature armored thermocouple 21 is also the highest, then the fault point is determined to be inside cable compartment 5. The system classifies the fault into four levels based on the absolute value, rate of change, and duration of the parameters, and takes different countermeasures.

[0115] Level 1 (Normal); All parameters are within the normal range; Operating normally, generating a health report every 24 hours;

[0116] Level 2 (Attention): A single parameter is close to the threshold, or multiple parameters are slightly abnormal; issue an early warning and shorten the monitoring cycle to 1 hour;

[0117] Level 3 (Alarm): Multiple parameters are significantly abnormal, confirming an early-stage fault; an audible and visual alarm is issued, notifying maintenance personnel to inspect the site within 72 hours.

[0118] Level 4 (Emergency): Parameters change drastically, confirming a serious fault; an emergency trip command is issued, and the gas circuit system's protection process is automatically activated.

[0119] Indicatively: Overheating fault caused by poor contact of the stationary contact in the cable compartment;

[0120] Time T0: The system is operating normally, and all parameters are normal; Time T1: The miniature armored thermocouple detects that the gas temperature has risen from 45℃ to 65℃, dT / dt = 3℃ / h → triggering an initial screening anomaly; Time T1+5: The system automatically performs cross-validation; SCADA load data is retrieved, and the load is stable at 60%, with no significant changes; Decomposition products are checked, and trace amounts of CO (0.5μL / L) and CF4 (0.1μL / L) are found; UHF signal is checked, and no abnormal discharge waveform is found; Time T1+10: The system issues a level-two warning, which is determined to be an "early overheating fault," and the monitoring cycle is shortened to 10 minutes; Time T2 (after 24 hours): The gas temperature rises to 85℃, dT / dt =1.5℃ / h; decomposition products CO rises to 3μL / L, CF4 rises to 0.5μL / L, CO / CF4=6; the temperature sensor reading in the cable compartment is 12℃ higher than that in the busbar compartment; T2+5 minutes: the system performs fusion analysis; the temperature continues to rise, eliminating load fluctuations; the decomposition products are mainly CO and CF4, with no SO2 and H2S, indicating a medium-temperature overheating fault; the cable compartment temperature is the highest, indicating the fault point is in the stationary contact of the cable compartment; T2+10 minutes: the system upgrades to a level 3 alarm, notifying maintenance personnel to arrive on-site within 72 hours; after the maintenance personnel arrive: inspection reveals that the bolts of the stationary contact in the cable compartment are loose, and the contact resistance is too high → after tightening the bolts, the temperature and decomposition products gradually return to normal.

[0121] When the diagnostic system determines a Level 4 emergency fault, it will automatically link with the integrated SF6 gas circuit control system to perform the following protective actions: immediately close all intelligent control valves to completely isolate the switchgear gas chamber from the external gas circuit; start the sulfur hexafluoride compressor 30 to quickly recover the gas in the gas chamber to the sulfur hexafluoride storage tank 36 to prevent the fault from escalating and causing gas leakage; generate a complete fault diagnosis report, including the fault type, location, severity, and recommended handling solutions; and automatically execute the gas recharging and vacuuming process after the fault is cleared to restore the switchgear to normal operation.

[0122] In addition, the hollow plate 14 also integrates a temperature sensor 25 and a gas density sensor 26 as backup and redundancy for the main monitoring system, further improving reliability.

[0123] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0124] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-voltage switchgear with insulation monitoring function, comprising a cabinet (1), wherein a busbar compartment (2) and a cable compartment (5) are respectively provided on the cabinet (1), characterized in that, The cabinet (1) is provided with a support (12), the support (12) is provided with a hollow plate (14), the hollow plate (14) is provided with an air supply pipe (15), the air supply pipe (15) is connected to an air supply pipe (2) (16), the air supply pipe (2) (16) is connected to a housing (17), and the housing (17) is provided with a suction nozzle (18). One end of the gas pipeline (15) is connected to a gas delivery mechanism; The gas transmission mechanism includes a connecting pipe (27); Connecting pipe one (27) is connected to connecting pipe two (28), connecting pipe two (28) is connected to sulfur hexafluoride compressor (30), and intelligent control valve one (29) is provided on connecting pipe two (28). The first connecting pipe (27) is connected to the third connecting pipe (31), the third connecting pipe (31) is connected to the vacuum pump (33), and the third connecting pipe (31) is equipped with the second intelligent control valve (32). Connecting pipe one (27) is connected to connecting pipe four (34), connecting pipe four (34) is connected to sulfur hexafluoride storage tank (36), and intelligent control valve three (35) is installed on connecting pipe four (34). The hollow plate (14) is provided with a monitoring mechanism, which includes a gas measuring tube (19). The gas measuring tube (19) has a slot (20). A miniature armored thermocouple (21) is provided at the top of the slot (20), and a gas state sensor (24) is provided at the bottom of the slot (20). The gas measuring tube (19) is also provided with a protective shell (22), and a UHF antenna (23) is provided on the protective shell (22).

2. A high-voltage switchgear with insulation monitoring function according to claim 1, characterized in that, The sulfur hexafluoride compressor (30) is located at one end of the cabinet (1); The vacuum pump (33) is located at one end of the cabinet (1); The sulfur hexafluoride storage tank (36) is located at one end of the cabinet (1).

3. A high-voltage switchgear with insulation monitoring function according to claim 1, characterized in that, The bracket (12) is provided with an isolation plate (13).

4. A high-voltage switchgear with insulation monitoring function according to claim 1, characterized in that, The cable compartment (5) is equipped with electrical equipment (7) and insulators (8).

5. A high-voltage switchgear with insulation monitoring function according to claim 1, characterized in that, A support plate (11) is provided on the cabinet (1), a composite plate (10) is provided on the support plate (11), and a grounding wire (37) is provided on the composite plate (10). An insulating support rod (9) is provided on the top of the composite plate (10), and the insulating support rod (9) is in close contact with the insulator (8).

6. A high-voltage switchgear with insulation monitoring function according to claim 5, characterized in that, The composite plate (10) is made of a silicone rubber composite material doped with carbon nanotubes.

7. A high-voltage switchgear with insulation monitoring function according to claim 1, characterized in that, A temperature sensor (25) is provided on the hollow plate (14).

8. A high-voltage switchgear with insulation monitoring function according to claim 7, characterized in that, A gas density sensor (26) is installed on the hollow plate (14).

9. A high-voltage switchgear with insulation monitoring function according to claim 1, characterized in that, The opening of the busbar compartment (2) is connected to a cabinet door (3) via a hinge, and a control switch (4) is provided on the cabinet door (3).

10. A high-voltage switchgear with insulation monitoring function according to claim 1, characterized in that, The opening of the cable compartment (5) is connected to a cabinet door (6) via a hinge.

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