Intelligent insulated oil-immersed transformer and use method thereof

Abstract

The invention discloses an intelligent insulating oil-immersed transformer and a using method thereof, and relates to the technical field of oil-immersed transformers, the intelligent insulating oil-immersed transformer comprises a transformer body, an oil tank, a self-healing microcapsule, an intelligent control unit and a driving excitation unit, the oil tank installed in the transformer body is filled with nano-composite insulating oil, and in the nano-composite insulating oil, a self-healing microcapsule is arranged in the self-healing microcapsule; 0.5%-2% by mass of self-healing microcapsules with the dispersion diameter of 10-50 microns are used, and the wall material of the self-healing microcapsules is a polyurea-polyurethane copolymer and contains an epoxy resin repairing agent. By installing the self-healing microcapsules, the function of automatically filling the microcracks is achieved, the problem that the microcracks in a traditional transformer cannot be repaired on line is solved, the fault rate caused by insulation microcracks is greatly reduced, and the service life of equipment is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of oil-immersed transformers, and in particular to an intelligently insulated oil-immersed transformer and a use method thereof. Background Art

[0002] As the power system's requirements for transformer reliability and life continue to increase, traditional oil-immersed transformers frequently fail due to aging of the insulation medium, development of microcracks, uneven heat dissipation from hot spots, and accumulation of sediment in the oil. Most maintenance requires shutdown, and operation and maintenance costs and risks remain high.

[0003] Patent CN114628113B discloses an oil-immersed transformer, which achieves enhancing the insulation and heat dissipation effects of insulating oil and reducing the pressure in the accommodation cavity.

[0004] The above patent reduces the accumulation of gas generated by insulating oil by arranging an exhaust pipe on the box body, but cannot perform real-time online repair when micro cracks appear in the transformer.

[0005] To this end, the present application proposes an intelligently insulated oil-immersed transformer capable of online repair of microcracks and a method of using the same. Summary of the invention

[0006] The object of the present invention is to provide an intelligently insulated oil-immersed transformer and a method of using the same, so as to solve the technical problems of insulation medium aging and microcrack development causing failures mentioned in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions: an intelligently insulated oil-immersed transformer, comprising a transformer body, an oil tank, self-healing microcapsules, an intelligent control unit and a driving excitation unit, wherein the oil tank installed inside the transformer body is filled with nano-composite insulating oil, wherein self-healing microcapsules with a diameter of 10-50 um are dispersed in the nano-composite insulating oil at a mass fraction of 0.5%-2%, wherein the wall material of the self-healing microcapsules is a polyurea-polyurethane copolymer, and contains an epoxy resin repair agent; A data acquisition module and an intelligent control unit are fixedly installed in the transformer body. The data acquisition module includes a distributed ultrasonic sensor, an infrared temperature sensor and a three-axis accelerometer, which are used to obtain local discharge, oil temperature and vibration signals in real time. The intelligent control unit includes an FPGA and a microcontroller. The FPGA is responsible for high-speed signal preprocessing and feature extraction, and the microcontroller runs a fault diagnosis algorithm combining a random forest and a self-learning neural network. The drive excitation unit is connected to the intelligent control unit and is used to apply an electric field or ultrasonic wave to the oil medium when it is monitored that the local discharge intensity exceeds 50mVpp or the oil temperature exceeds 90°C, so as to trigger the rupture of the self-healing microcapsules for crack self-healing.

[0008] Preferably, an MRF thermal management unit is also installed in the fuel tank, and the MRF thermal management unit includes: A closed-loop stainless steel pipe filled with a silicone oil-based magnetorheological fluid containing 40%-60% ferromagnetic particles; The electromagnetic coil is wound on the outside of the stainless steel pipe, and the number of turns of the coil is 200-500 turns; The intelligent control unit adjusts the electromagnetic coil current through PWM according to the hot spot temperature data fed back by the infrared temperature sensor, so that the magnetic field strength varies in the range of 0-200mT, resulting in the MRF viscosity being controllably adjustable between 0.1-1Pa·s, thus achieving local fixed-point cooling and mechanical vibration suppression.

[0009] Preferably, a number of SMA guide plates are installed inside the oil tank. The material of the SMA guide plates is NiTi alloy, with a thickness of 0.2-0.5mm and a transition temperature of 85±2°C. When the oil temperature is lower than 80°C, they are flat, and when the temperature exceeds 85°C, they automatically bend and deflect 10-30° to guide the oil flow to the corresponding hot spot area. After the temperature recovers, the SMA guide plates automatically reset to reconstruct the oil flow channel.

[0010] Preferably, the data acquisition module further includes an FBG sensor network, the optical fiber is arranged along the inner winding and the inner wall of the oil tank, the node spacing is 0.3-0.7m, the sensor resolution is ±0.1℃ / ±1uε, the sampling speed is ≥500Hz, and the fiber optic demodulator communicates with the intelligent control unit at high speed to achieve online monitoring of temperature and strain.

[0011] Preferably, a telescopic soft robot cleaning arm is also installed in the transformer body. The cleaning arm is composed of medical-grade silicone and Kevlar fiber core, has an outer diameter of 20mm, and a telescopic length of 500-1500mm. An ultrasonic vibration cleaning head and a suction nozzle are installed at the end of the cleaning arm, which enter and exit through the DN50 quick-insert flange on the side wall of the oil tank, and are used to automatically remove metal chips and sediments in the oil during operation.

[0012] Preferably, the oil tank winding support structure adopts a modular quick-release design: Stainless steel half-ring fasteners are used to lock with positioning pins, and elastic polyester washers are installed inside the half-ring fasteners to ensure vibration resistance; The diameter of the positioning pin is 8mm, the insertion force is ≤50N, and the extraction force is ≥200N; The one-touch hydraulic locking mechanism can complete the disassembly and assembly of single-layer windings within 10 seconds.

[0013] Preferably, the inner wall of the oil tank is covered with a polymer-based acoustic metamaterial lining with a periodic cell size of 1.5-3mm and a thickness of 2mm. The metamaterial lining is used to focus the ultrasonic signal generated by local discharge in the frequency band of 100-300kHz to the piezoelectric transducer arranged in the corner of the oil tank cavity, thereby improving the sensing sensitivity by 2-3 times and reducing environmental noise interference.

[0014] Preferably, the intelligent control unit further integrates a remote communication interface, and the remote communication interface supports: Switch between three communication modes: Ethernet, WiFi and LoRaWAN; Data transmission uses TLS1.2 encryption, and the data packet transmission rate is not less than 10kbps; Supports OTA firmware upgrades and MQTT and HTTPS dual protocol reporting.

[0015] Preferably, the method of use comprises the following steps: S1. Installation and calibration: Connect the auxiliary power module, execute the self-healing microcapsule trigger threshold and each sensor calibration procedure, and the calibration accuracy is better than ±5%; S2. Online monitoring: The intelligent control unit collects sensor data at a frequency of 10 Hz and combines it with a deep learning model to classify fault types and conduct risk assessment; S3, self-healing and thermal management: When partial discharge or excessive oil temperature is detected, the control drive excitation unit triggers the microcapsule self-healing; when the oil temperature hot spot exceeds the threshold for 2 minutes, the MRF unit is automatically started to cool down in conjunction with the SMA guide plate; S4, online cleaning: If the concentration of suspended particles in the oil exceeds 500ppm, the soft robot cleaning arm is driven to perform ultrasonic cleaning and suction, and each cleaning time is ≤15min; S5. Operation and maintenance feedback: All operation and maintenance logs are reported to the cloud platform in real time through the MQTT protocol. The cloud AI system generates operation and maintenance suggestions based on historical data and pushes them in the form of APP messages.

[0016] Preferably, the method of use further comprises the following steps: S31, the intelligent control unit combines the high-resolution temperature and strain data fed back by the FBG sensor network to update the local hotspot model in real time at a frequency of 1Hz, and uses the reinforcement learning algorithm to adaptively optimize the fixed-point cooling and self-healing triggering strategy within no less than 100 operating cycles to minimize the transformer insulation aging rate and operating losses.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention realizes the function of automatically filling microcracks by installing self-healing microcapsules, solves the problem that microcracks inside traditional transformers cannot be repaired online, greatly reduces the failure rate caused by insulation microcracks, and prolongs the life of the equipment; 2. The present invention realizes the functions of local fixed-point cooling and vibration damping adjustment by installing an MRF thermal management unit, solves the problems of uneven heat dissipation and difficulty in rapid cooling of hot spots in traditional methods, significantly improves the cooling rate of hot spots, and suppresses mechanical vibration by more than 50%; 3. The present invention realizes the function of reconstructing the oil flow channel in the hot spot area by installing an SMA guide plate, solves the problem of low heat dissipation efficiency caused by uneven oil flow distribution in a passive environment, and does not require an additional driver, thereby improving the local heat dissipation efficiency; 4. The present invention is equipped with a soft robot cleaning arm to realize the function of automatically removing metal chips and sediments in the oil in a moving state, thus solving the problems of traditional cleaning requiring downtime, high manual risk and long time consumption, and significantly reducing operation and maintenance costs and risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of an oil-immersed transformer assembly of the present invention; Figure 2 It is a schematic diagram of the working process of the oil-immersed transformer of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0020] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0021] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] See also Figure 1 and Figure 2 , an embodiment provided by the present invention: an intelligent insulated oil-immersed transformer, comprising a transformer body, an oil tank, self-healing microcapsules, an intelligent control unit and a driving excitation unit, wherein the oil tank installed inside the transformer body is filled with nano-composite insulating oil, in which self-healing microcapsules with a diameter of 10-50 um are dispersed at a mass fraction of 0.5%-2%, and the wall material of the self-healing microcapsules is a polyurea-polyurethane copolymer, which contains an epoxy resin repair agent; A data acquisition module and an intelligent control unit are fixedly installed in the transformer body. The data acquisition module includes a distributed ultrasonic sensor, an infrared temperature sensor and a triaxial accelerometer, which are used to obtain local discharge, oil temperature and vibration signals in real time. The intelligent control unit includes an FPGA and a microcontroller. The FPGA is responsible for high-speed signal preprocessing and feature extraction. The microcontroller runs a fault diagnosis algorithm combining a random forest and a self-learning neural network. The drive excitation unit is connected to the intelligent control unit and is used to apply an electric field or ultrasonic wave to the oil medium when the local discharge intensity exceeds 50mVpp or the oil temperature exceeds 90°C, so as to trigger the rupture of the self-healing microcapsules for crack self-healing. The data acquisition module further includes an FBG sensor network, with optical fibers arranged along the inner windings and inner walls of the tank, a node spacing of 0.3-0.7 m, a sensor resolution of ±0.1°C / ±1uε, a sampling rate of ≥500 Hz, and high-speed communication with the intelligent control unit through an optical fiber demodulator to achieve online monitoring of temperature and strain; Furthermore, after the transformer is installed, the oil tank is filled with nanocomposite insulating oil, in which the self-healing microcapsules contain 0.5%-2% and have a diameter of 10-50um. The oil tank is stirred at 100rpm for 30 minutes in a professional stirring device to ensure that the microcapsules are evenly dispersed in the oil body without obvious sedimentation or aggregation. The FPGA sends calibration commands to each sensor, including the ultrasonic sensor, infrared temperature sensor, triaxial accelerometer and FBG, and samples the baseline signals under no-load, standard temperature 25℃ and no vibration. The calibration results are stored in the microcontroller, and the baseline deviation is controlled within ±5%. The FPGA collects ultrasonic and vibration signals at a frequency of 1kHz, and infrared temperature and FBG temperature and strain data at a frequency of 10Hz. The collected data is sent to the microcontroller through a high-speed bus for real-time analysis and model reasoning; the microcontroller integrates the random forest algorithm and the self-learning neural network for secondary judgment, and outputs "normal" and "abnormal" labels and position coordinates; When the insulating medium forms tiny cracks under the action of local electric field stress or thermal stress, it is accompanied by partial discharge and slight temperature rise; judgment threshold: partial discharge amplitude ≥50mVpp or oil temperature node ≥90℃; the intelligent control unit issues a self-healing excitation instruction and records the triggering time, sensor reading and position; Drive excitation: Electric field triggering: The drive excitation unit applies a 1kV / cm-5kV / cm DC electric field in the oil area near the crack. The electric field is concentrated at the tip of the microcrack, and the self-healing microcapsule wall is ruptured by strong local stress; Ultrasonic triggering: When the ultrasonic mode is adopted, the drive excitation unit generates ultrasonic waves with a frequency of 20kHz-40kH and a power of 30W-60W, which are focused on the target area, triggering the mechanical vibration rupture of the microcapsule shell; the self-healing microcapsules after rupture release epoxy resin repairing agent, which automatically flows into the microcrack gap due to the oil phase interfacial tension and the capillary action of the crack. Under the external oil temperature conditions, the repairing agent uses its own curing agent to complete chemical cross-linking and curing within 5min-15min to seal the crack; 5 minutes after the repair, ultrasonic and vibration sampling were started again to verify whether the local discharge signal disappeared and whether the vibration spectrum returned to the baseline range; the FBG sensor network was continuously monitored for 10 minutes to confirm that the temperature drop rate of the node matched the surrounding area and there were no remaining hot spots; all data were stored in local and cloud logs for reference in subsequent algorithm optimization and operation and maintenance decisions.

[0023] See also Figure 1 and Figure 2 , an embodiment provided by the present invention: an intelligently insulated oil-immersed transformer, wherein an MRF thermal management unit is also installed in the oil tank, and the MRF thermal management unit comprises: A closed-loop stainless steel pipe filled with a silicone oil-based magnetorheological fluid containing 40%-60% ferromagnetic particles; The electromagnetic coil is wound on the outside of the stainless steel pipe, and the number of turns of the coil is 200-500 turns; The intelligent control unit adjusts the electromagnetic coil current through PWM according to the hot spot temperature data fed back by the infrared temperature sensor, so that the magnetic field strength varies within the range of 0-200mT, resulting in the MRF viscosity being controllably adjustable between 0.1-1Pa·s, thus achieving local fixed-point cooling and mechanical vibration suppression; A plurality of SMA guide plates are installed inside the oil tank. The SMA guide plates are made of NiTi alloy, have a thickness of 0.2-0.5 mm, and a transition temperature of 85±2°C. When the oil temperature is lower than 80°C, they are flat. When the temperature exceeds 85°C, they automatically bend and deflect 10-30° to guide the oil flow to the corresponding hot spot area. After the temperature recovers, the SMA guide plates automatically reset to reconstruct the oil flow channel. Furthermore, the prefabricated magnetorheological fluid was injected into the closed-loop stainless steel pipeline, and the electromagnetic coil was energized for testing. The duty cycle was gradually adjusted from 0 to 100% in PWM mode to verify that the viscosity of the fluid in the pipeline can be controlled to change within the range of 0.1Pa·s to 1Pa·s. The NiTi guide plate was subjected to a thermal deformation test in a constant temperature box: its flat state was verified at 80°C; its bending angle was measured at 85°C±2°C and should be between 10-30°, and the cooling time required for the guide plate to reset was recorded; the infrared temperature sensor was arranged in the candidate hot spot area of ​​the oil tank with a calibration accuracy of ±0.5°C, and the triaxial accelerometer was arranged on the transformer box shell to calibrate the vibration baseline. The intelligent control unit read and stored all sensor baseline data, with a cycle period of 10Hz. The intelligent control unit reads infrared temperature at a frequency of 10Hz and accelerometer vibration data at a frequency of 1kHz. When the temperature in a certain area exceeds 80°C for three consecutive sampling cycles or the vibration acceleration exceeds 0.5g, it is marked as a "potential hot spot"; If the infrared sensor detects that the inverted temperature is ≥85℃ or the accelerometer detects that the vibration peak is ≥0.8g, the intelligent control unit switches to the "emergency cooling / vibration suppression" mode; the intelligent control unit adjusts the coil duty cycle from 0-80% through PWM, so that the magnetic field strength increases from 0mT to 160mT, and the MRF viscosity increases from 0.1Pa·s to 0.8Pa·s with the magnetic field, so that the fluid resistance in the hot spot area is reduced or enhanced, achieving accelerated cooling and vibration suppression respectively; When the local oil temperature is ≥85℃, the SMA guide plate located near the area crosses the phase change point due to heat and automatically bends 15-25° within 30 seconds. The bent guide plate redirects the original parallel oil flow channel, delivers more oil to the hot spot, and enhances directional cooling. When the hot spot temperature drops to ≤80℃, the guide plate automatically cools and resets within 2 minutes to restore the average flow channel of the entire field.

[0024] See also Figure 1 and Figure 2 , an embodiment provided by the present invention: an intelligent insulated oil-immersed transformer, wherein a telescopic soft robot cleaning arm is installed in the transformer body, the cleaning arm is composed of medical grade silicone and Kevlar fiber core, with an outer diameter of 20mm and a telescopic length of 500-1500mm; an ultrasonic vibration cleaning head and a suction nozzle are installed at the end of the cleaning arm, which are inserted and removed through a DN50 quick-insert flange on the side wall of the oil tank, and are used to automatically remove metal chips and sediments in the oil under operation; Furthermore, the system reads the oil turbidity sensor and particle counter data at a frequency of 1kHz. When the concentration of suspended solid particles in the oil exceeds 500ppm or the metal shavings content exceeds 200mg / L, the intelligent control unit determines that "cleaning is required" and starts the cleaning process; The intelligent control unit first closes the corresponding oil circuit isolation valve, opens the DN50 quick-insert flange valve, maintains the internal pressure balance of the oil tank, and issues an "extend" command. The cleaning arm enters the oil tank from the flange at a speed of 50mm / s and extends to a predetermined depth. The position is confirmed by feedback from the stroke sensor. The micro magnetic positioning ring on the arm continuously sends position and direction information. The intelligent control unit performs spatial positioning in combination with the oil tank CAD model. The vibrating head at the end of the cleaning arm vibrates continuously at 25kHz and 50W. The microbubbles and high-frequency vibrations generated by the ultrasound desorb the sediments and particles in the oil and form microemulsions, which is convenient for subsequent suction. In the vibration mode, the cleaning arm slowly sweeps along the preset trajectory at a speed of 10mm / s to ensure that the vibration energy acts evenly on each treatment surface. During vibration cleaning, the suction nozzle sucks out the mixture of suspended particles and oil at a vacuum degree of 0.3 bar. The sucked oil first enters the external microfilter, and after the metal chips and large particles are separated, the clean oil returns to the oil tank through the return pipe. The filtered metal chips and sediments are accumulated in the detachable collection tank. After a 15-minute cleaning cycle, about 100g of particles are collected; The above-mentioned ultrasonic vibration and dirt suction process lasts for 5 minutes as a cycle, and is executed for 3-5 rounds by default until the oil turbidity drops to <300ppm; at the end of each round, the cleaning arm is retracted 20cm, and the turbidity sensor and particle counter re-measure and upload the results to the intelligent control unit to decide whether to continue or end the cleaning.

[0025] See also Figure 1 and Figure 2 , an embodiment provided by the present invention: an intelligent insulated oil-immersed transformer, the oil tank winding support structure adopts a modular quick-disassembly design: Stainless steel half-ring fasteners are used to lock with positioning pins, and elastic polyester washers are installed inside the half-ring fasteners to ensure vibration resistance; The diameter of the positioning pin is 8mm, the insertion force is ≤50N, and the extraction force is ≥200N; The one-touch hydraulic locking mechanism can complete the disassembly and assembly of single-layer windings within 10 seconds; Furthermore, a semi-circular stainless steel fastener (with an inner diameter matching the outer diameter of the winding bracket) is matched with the corresponding positioning pin, and an elastic polyester gasket is pre-installed on the inner side of the fastener to ensure vibration isolation between the fastener and the winding bracket after fastening; the prefabricated winding bracket is inserted into the reserved guide groove of the oil tank, and the positioning pin is inserted into the alignment hole of the fastener and the bracket. It can be smoothly positioned when the insertion force is ≤50N; the hydraulic locking mechanism is started: the hydraulic cylinder pushes the semi-circular fastener to close and clamp the positioning pin under a driving pressure of 0.5MPa, and the locking completion time is ≤1 0s, the pull-out force of the locating pin is ≥200N to ensure that the winding does not loosen under high vibration conditions; apply ±1g, 5Hz-500Hz sinusoidal sweep vibration table test, there is no looseness or resonance peak superposition between the winding bracket and the oil tank, and after the hydraulic locking mechanism is cycled for ≥100 times, repeat the above vibration test to ensure the life and reliability of the mechanism; drive the hydraulic cylinder in reverse to quickly release the clamping force of the fastener. The locating pin can be easily removed when the pull-out force is ≤50N, and the winding bracket can be pulled out as a whole for inspection or replacement.

[0026] See also Figure 1 and Figure 2 , an embodiment provided by the present invention: an intelligent insulated oil-immersed transformer, wherein the inner wall of the oil tank is covered with a polymer-based acoustic metamaterial lining with a periodic cell size of 1.5-3mm and a thickness of 2mm, the metamaterial lining is used to focus the ultrasonic signal generated by partial discharge in the frequency band of 100-300kHz to the piezoelectric transducer arranged at the corner of the oil tank cavity, thereby improving the sensing sensitivity by 2-3 times and reducing the interference of environmental noise; Furthermore, a periodic metamaterial plate with a thickness of 2 mm and a cell size of 1.5 mm × 1.5 mm-3 mm × 3 mm was prepared by micro-injection molding of polymer-based materials such as PDMS. After the inner wall surface of the fuel tank was roughened by sandblasting, the metamaterial plates were attached separately using oil-resistant silicone adhesive to ensure that there were no bubbles and warping. The phonon band gap and refraction characteristics of the metamaterial cells caused the ultrasonic waves in the frequency band of 100 kHz-300 kHz to undergo secondary diffraction and focusing on the plate surface. The focusing target was located at the center of the piezoelectric transducer array in a corner of the fuel tank, which increased the sensor receiving sound pressure level by about 6 dB. Four piezoelectric transducers were arranged. , receiving the ultrasonic signal released by local discharge in real time, the intelligent control unit triggers broadband amplification and FFT spectrum analysis at a sampling frequency of 1MHz, effectively distinguishing the focused signal from the ambient noise, and improving the signal-to-noise ratio by ≥10dB; under the laboratory artificial discharge simulation conditions, the traditional point sensor can detect a minimum discharge time of 20nJ. After adding the metamaterial lining, a single discharge energy of 10nJ can be stably captured, and the detection success rate is increased from 60% to 95%; the metamaterial adopts modular assembly and can be partially replaced when contaminated or damaged. The ultrasonic sensor calibration test is carried out once a year, and the bonding integrity of the lining is checked.

[0027] See also Figure 1 and Figure 2, an embodiment of the present invention provides: an intelligent insulated oil-immersed transformer, wherein the intelligent control unit further integrates a remote communication interface, and the remote communication interface supports: Switch between three communication modes: Ethernet, WiFi and LoRaWAN; Data transmission uses TLS1.2 encryption, and the data packet transmission rate is not less than 10kbps; Support OTA firmware upgrade and MQTT and HTTPS dual protocol reporting; Furthermore, three PHY chips are integrated on the mainboard of the intelligent control unit: 100Base-TX Ethernet, 802.11nWIFI, and 868MHzLoRaWAN; the driver software is based on RTOS, and multi-threaded management of three network ports, with Ethernet priority by default, followed by WiFi, and then LoRaWAN; power-on self-test: detect the physical connectivity of each interface, and enable it if the Ethernet link is normal; during operation: if the Ethernet is disconnected for ≥30s, it will automatically switch to WiFi; if the WiFi connection fails for ≥60s, it will switch to LoRaWAN; the switching process maintains data caching and orderly retransmission, without packet loss and interruption; all TCP / IP links use TLS1.2 handshake and data encryption, integers are based on the ECC algorithm, and the handshake time is ≤200m s; The upload protocol supports MQTT and HTTPS, which back up each other; The data packet size is controlled between 512B-1KB, and the transmission rate is not less than 10kbps to ensure that key monitoring data and early warning information arrive in real time; After receiving the OTA command through MQTT, the device automatically downloads the encrypted firmware package, verifies the SHA-256 integrity, switches to the backup partition to write the new firmware, and performs a CRC self-check after the writing is completed. If it passes, the partition is restarted, otherwise the original firmware is rolled back and a fault is reported. The entire upgrade process is ≤3min, and the upgrade success rate is ≥99.5%; The intelligent control unit reports a heartbeat packet every 60s, including the current network mode, signal strength and error count. When multiple handshake failures occur or the packet loss rate is greater than 5%, a local alarm is issued and the next available interface is switched at the same time.

[0028] Working principle: The transformer has multiple sensors built in: distributed ultrasonic sensors, infrared temperature sensors, triaxial accelerometers and FBG fiber grating networks. The FPGA collects partial discharge, electrical temperature and vibration strain data in parallel at 1 kHz / 500 Hz, and sends the characteristic information to the microcontroller in real time; The microcontroller runs random forest and self-learning neural network fault diagnosis algorithms to analyze the monitoring data online. Once the discharge intensity exceeds 50 mVpp or the oil temperature and strain exceed the threshold, the corresponding drive excitation unit electric field or ultrasonic wave is immediately triggered to start the MRF thermal management, SMA guide plate deformation or microcapsule self-healing repair mechanism. The self-healing microcapsules rupture under electric field and ultrasonic stimulation, releasing epoxy resin repair agent to fill microcracks and solidify; the MRF thermal management unit + SMA guide plate are linked to achieve hot spot fixed-point cooling and vibration suppression; the soft robot cleaning arm retracts and retracts in the oil, ultrasonically vibrates and sucks suspended particles to automatically remove sediments; At the same time, all operation and maintenance logs are encrypted with TLS1.2 and reported to the cloud via MQTT / HTTPS, supporting OTA upgrades and operation and maintenance guidance.

[0029] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. An intelligent insulated oil-immersed transformer, comprising a transformer body, an oil tank, a self-healing microcapsule, an intelligent control unit and a drive excitation unit, characterized in that: The oil tank installed inside the transformer body is filled with nano-composite insulating oil, in which self-healing microcapsules with a diameter of 10-50 um are dispersed at a mass fraction of 0.5%-2%, and the wall material of the self-healing microcapsules is polyurea-polyurethane copolymer, which contains epoxy resin repair agent; A data acquisition module and an intelligent control unit are fixedly installed in the transformer body. The data acquisition module includes a distributed ultrasonic sensor, an infrared temperature sensor and a three-axis accelerometer, which are used to obtain local discharge, oil temperature and vibration signals in real time. The intelligent control unit includes an FPGA and a microcontroller. The FPGA is responsible for high-speed signal preprocessing and feature extraction, and the microcontroller runs a fault diagnosis algorithm combining a random forest and a self-learning neural network. The drive excitation unit is connected to the intelligent control unit and is used to apply an electric field or ultrasonic wave to the oil medium when it is monitored that the local discharge intensity exceeds 50mVpp or the oil temperature exceeds 90°C, so as to trigger the rupture of the self-healing microcapsules for crack self-healing.

2. The intelligent insulated oil-immersed transformer according to claim 1, characterized in that: The fuel tank is also equipped with an MRF thermal management unit, which includes: A closed-loop stainless steel pipe filled with a silicone oil-based magnetorheological fluid containing 40%-60% ferromagnetic particles; The electromagnetic coil is wound on the outside of the stainless steel pipe, and the number of turns of the coil is 200-500 turns; The intelligent control unit adjusts the electromagnetic coil current through PWM according to the hot spot temperature data fed back by the infrared temperature sensor, so that the magnetic field strength varies in the range of 0-200mT, resulting in the MRF viscosity being controllably adjustable between 0.1-1Pa·s, thus achieving local fixed-point cooling and mechanical vibration suppression.

3. The intelligent insulated oil-immersed transformer according to claim 1, characterized in that: A number of SMA guide plates are installed inside the oil tank. The material of the SMA guide plates is NiTi alloy, with a thickness of 0.2-0.5 mm and a transition temperature of 85±2°C. When the oil temperature is lower than 80°C, the guide plates are flat. When the temperature exceeds 85°C, the guide plates automatically bend and deflect 10-30° to guide the oil flow to the corresponding hot spot area. After the temperature recovers, the SMA guide plates automatically reset to reconstruct the oil flow channel.

4. The intelligent insulated oil-immersed transformer according to claim 1, characterized in that: The data acquisition module further includes an FBG sensor network, with optical fibers arranged along the inner windings and inner walls of the oil tank, a node spacing of 0.3-0.7 m, a sensor resolution of ±0.1°C / ±1uε, a sampling speed of ≥500 Hz, and high-speed communication between the optical fiber demodulator and the intelligent control unit to achieve online monitoring of temperature and strain.

5. The intelligent insulated oil-immersed transformer according to claim 1, characterized in that: A telescopic soft robot cleaning arm is also installed in the transformer body. The cleaning arm is made of medical-grade silicone and Kevlar fiber core, with an outer diameter of 20mm and a telescopic length of 500-1500mm. An ultrasonic vibration cleaning head and a suction nozzle are installed at the end of the cleaning arm, which enter and exit through the DN50 quick-insert flange on the side wall of the oil tank, and are used to automatically remove metal chips and sediments in the oil during operation.

6. The intelligent insulated oil-immersed transformer according to claim 4, characterized in that: The oil tank winding support structure adopts a modular quick-disassembly design: Stainless steel half-ring fasteners are used to lock with positioning pins, and elastic polyester washers are installed inside the half-ring fasteners to ensure vibration resistance; The diameter of the positioning pin is 8mm, the insertion force is ≤50N, and the extraction force is ≥200N; The one-touch hydraulic locking mechanism can complete the disassembly and assembly of single-layer windings within 10 seconds.

7. The intelligent insulated oil-immersed transformer according to claim 1, characterized in that: The inner wall of the oil tank is covered with a polymer-based acoustic metamaterial lining with a periodic cell size of 1.5-3mm and a thickness of 2mm. The metamaterial lining is used to focus the ultrasonic signal generated by local discharge in the 100-300kHz frequency band to the piezoelectric transducer arranged in the corner of the oil tank cavity, thereby improving the sensing sensitivity by 2-3 times and reducing environmental noise interference.

8. The intelligent insulated oil-immersed transformer according to claim 1, characterized in that: The intelligent control unit further integrates a remote communication interface, which supports: Switch between three communication modes: Ethernet, WiFi and LoRaWAN; Data transmission uses TLS1.2 encryption, and the data packet transmission rate is not less than 10kbps; Supports OTA firmware upgrades and MQTT and HTTPS dual protocol reporting.

9. A method for using an intelligent insulated oil-immersed transformer, applicable to an intelligent insulated oil-immersed transformer according to any one of claims 1 to 8, characterized in that: The method of use comprises the following steps: S1. Installation and calibration: Connect the auxiliary power module, execute the self-healing microcapsule trigger threshold and each sensor calibration procedure, and the calibration accuracy is better than ±5%; S2. Online monitoring: The intelligent control unit collects sensor data at a frequency of 10 Hz and combines it with a deep learning model to classify fault types and conduct risk assessment; S3, self-healing and thermal management: When partial discharge or excessive oil temperature is detected, the control drive excitation unit triggers the microcapsule self-healing; when the oil temperature hot spot exceeds the threshold for 2 minutes, the MRF unit is automatically started to cool down in conjunction with the SMA guide plate; S4, online cleaning: If the concentration of suspended particles in the oil exceeds 500ppm, the soft robot cleaning arm is driven to perform ultrasonic cleaning and suction, and each cleaning time is ≤15min; S5. Operation and maintenance feedback: All operation and maintenance logs are reported to the cloud platform in real time through the MQTT protocol. The cloud AI system generates operation and maintenance suggestions based on historical data and pushes them in the form of APP messages.

10. The method for using a smart insulated oil-immersed transformer according to claim 9, characterized in that: The method of use also includes the following steps: S31, the intelligent control unit combines the high-resolution temperature and strain data fed back by the FBG sensor network to update the local hotspot model in real time at a frequency of 1Hz, and uses the reinforcement learning algorithm to adaptively optimize the fixed-point cooling and self-healing triggering strategy within no less than 100 operating cycles to minimize the transformer insulation aging rate and operating losses.

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