Inner wall embedded type multi-dimensional state monitoring system for GIS (Gas Insulated Switchgear) transformer

Abstract

The invention provides an inner wall embedded type multi-dimensional state monitoring system for a GIS transformer. Comprising a transformer shell integrated with a comprehensive information management system, a temperature difference heating module for providing direct current for a multi-source synthesis energy management module, a piezoelectric module for rectifying, boosting and storing energy through an energy management system of the multi-source synthesis energy management module, and an ultrasonic partial discharge detection sensor deposited on the inner wall of the transformer shell, the temperature sensor and the SF6 degradation gas metal oxide semiconductor sensor are used for acquiring signals, and the main control module is used for processing the acquired signals. According to the invention, synchronous acquisition of electric-acoustic-thermal-chemical four-dimensional information in the GIS transformer is realized, all the sensors are deposited on the inner wall of the transformer to improve the accuracy and confidence of diagnosis, and the vibration-thermal energy comprehensive energy supply system solves the problem of stable energy supply of the internal sensors. And a feasible scheme is provided for full-life-cycle intelligent monitoring of the equipment.

Description

Technical Field

[0001] This invention belongs to the field of smart grid monitoring technology, and particularly relates to an embedded multidimensional condition monitoring system for the inner wall of a GIS transformer. Background Technology

[0002] To adapt to the convergence of the energy revolution and the digital revolution, the power grid is accelerating its evolution towards an energy internet. The power internet of things (IoT) serves as the foundation and carrier for the digitalization, networking, and intelligence of the energy internet, promoting comprehensive perception and ubiquitous interconnection of the power grid. However, against the backdrop of rapid smart grid development, the accuracy and reliability of power IoT status perception face significant challenges, particularly regarding the power supply and monitoring accuracy of sensors for large transformers.

[0003] Existing large transformer sensors are mostly powered by direct power supply or electromagnetic induction. Direct power supply relies on an external power source, increasing maintenance costs and complexity, and is susceptible to external factors such as power grid failures. Electromagnetic induction power supply is limited by the transformer's current and magnetic field distribution; when the current is low or the magnetic field distribution is uneven, the reliability of the power supply is difficult to guarantee. This invention uses vibration energy and thermal differential power, making full use of the transformer's additional losses and ensuring stability and reliability.

[0004] Existing transformer monitoring technologies largely rely on external or single-type sensors. Due to the shielding and attenuation effects of the transformer casing, external monitoring signals suffer from response lag and information isolation. Each parameter is collected and analyzed independently, lacking effective coordination and integration. Power maintenance personnel must manually assess fragmented information from different systems, which is asynchronous in time and space, resulting in low efficiency and difficulty in forming a unified and accurate assessment of the overall health status of the equipment.

[0005] The technical solution of this patent belongs to the field of smart grid monitoring technology, specifically addressing the need for multi-dimensional, real-time, and embedded monitoring of the internal status of GIS transformers. In existing technologies, the status monitoring of large transformers mostly uses external or independent sensors, which suffers from problems such as strong power supply dependence, signal lag, and information isolation. Although some existing patents involve solutions for vibration power generation, thermoelectric power generation, or partial discharge monitoring, most are single-function or external designs, lacking multi-dimensional information fusion and integrated embedded power supply and sensing solutions.

[0006] A search revealed that utility model patent CN209132374U discloses an integrated online monitoring system for UHF partial discharge and SF6 gas density. This system includes multiple integrated sensor modules, an online monitoring host, a coaxial cable, a monitoring host antenna, and integrated sensor module antennas. The UHF, SF6 gas pressure, and temperature sensors of the integrated sensor modules are all cast onto a flange using epoxy resin. Both the online monitoring host and the integrated sensors have antennas for transmitting SF6 gas density and temperature data. The online monitoring host provides power to the integrated sensors via the coaxial cable and simultaneously acquires UHF partial discharge signals through the same cable.

[0007] Chinese patent application CN111024156B discloses a multi-sensor integrated monitoring device for GIS information acquisition, comprising a GIS information acquisition sub-device and a GIS status diagnosis sub-device connected together. The GIS information acquisition sub-device includes a housing and a GIS information acquisition module, an information processing module, and an environmental data acquisition module disposed within the housing. The information processing module is connected to both the GIS information acquisition module and the environmental data acquisition module. A fixing mechanism is installed on the housing for mounting the GIS information acquisition sub-device to the surface of a GIS device housing. The GIS status diagnosis sub-device estimates and diagnoses the status of the GIS device based on the acquired information from the GIS information acquisition sub-device and an established GIS status diagnosis model.

[0008] The invention patent with publication number CN112833954A discloses a GIS gas-insulated combined electrical appliance monitoring device and its assembly method. The device involves fixing a metal fixed electrode plate below a metal flange, with an insulating plate between them. An SF6 gas pressure and micro-moisture sensing component is inserted through the center of the metal flange, and a high-frequency loop antenna is fitted onto the SF6 gas pressure and micro-moisture sensing component, thus integrating the two components into one. Furthermore, a vibration sensing component, an ultrasonic detection sensing component, an infrared temperature sensing component, and an SF6 gas composition sensing component are arranged around the SF6 gas pressure and micro-moisture sensing component on the metal flange. This allows for the simultaneous acquisition of SF6 gas pressure, SF6 gas micro-moisture content, SF6 discharge product composition, GIS shell vibration, ultrasonic partial discharge state, and electromagnetic wave high-frequency discharge state in the monitored area using a single device.

[0009] The invention patent with publication number CN115728632A discloses an online monitoring system and method for internal defects of GIS associated with the operating state of disconnecting switches. This invention collects triple signals from GIS equipment using ultrasonic sensors, ultra-high frequency sensors, and optical sensors. Through the method of joint detection of source physical signals, it has a very comprehensive, effective, and reliable working effect in detecting internal defects of GIS equipment. This invention adopts a multi-source physical signal joint detection method associated with the operating state of disconnecting switches in GIS equipment. It can perform large-scale, high-resolution signal acquisition when strong partial discharge occurs after the disconnecting switch is operated. Under the premise of achieving high sampling rate acquisition of effective partial discharge signals, it reduces system energy consumption and storage costs.

[0010] The utility model patent with publication number CN218995540U discloses an online monitoring system for internal defects of GIS based on the operating state of disconnecting switches. This utility model uses an ultrasonic sensor, a pulse current sensor, and an optical sensor to form a multi-source physical signal joint detection device, which can perform a very comprehensive, effective, and reliable detection of internal defects of GIS equipment. The multi-source physical signal joint detection device of this utility model can be correlated with the operating state of the disconnecting switch, and can perform large-scale, high-resolution signal acquisition when strong partial discharge occurs in the defects after the disconnecting switch is operated.

[0011] This application differs from the aforementioned prior art documents in the following ways:

[0012] 1. Compared to CN209132374U, this application addresses the issue of isolated information that often only monitors a single or a few state variables (such as partial discharge or temperature), lacks multi-dimensional collaborative analysis and data fusion mechanisms. It integrates four-dimensional information acquisition of "electricity-acoustics-thermal-chemical" data, including multiple sensors such as ultrasonic partial discharge, temperature, and SF6 gas degradation, and achieves synchronous acquisition, fusion, and intelligent diagnosis of multi-source signals through the main control module.

[0013] 2. Compared to CN111024156B, this application improves upon existing sensors, which are mostly externally mounted or rigidly installed and easily affected by the shielding of the housing, resulting in signal acquisition lag and distortion. All sensors (ultrasonic, temperature, and gas sensors) are manufactured using flexible processes, directly deposited or embedded in the inner wall of the transformer housing, avoiding housing shielding and signal attenuation, and improving monitoring sensitivity and real-time performance.

[0014] 3. Compared with CN112833954A, this application utilizes an additive manufacturing solution. The ultrasonic sensor uses a flexible MFC structure to adapt to curved inner walls; the temperature sensor adopts a serpentine anti-strain design to reduce the influence of mechanical deformation; and the gas sensor uses a metal-doped carbon nanotube gas-sensitive layer to improve the sensitivity and selectivity to SF6 decomposition products.

[0015] 4. Compared to CN115728632A and CN218995540U, this application integrates a main control module, a communication module, and a comprehensive information management system, enabling data processing, diagnosis, and compression within the device to output structured data packets, reducing transmission pressure and supporting proactive predictive maintenance. This differs from traditional solutions that employ distributed data processing or direct uploading of raw data, resulting in low levels of intelligence and a primarily passive response-based operation and maintenance model. Summary of the Invention

[0016] This invention aims to overcome the shortcomings of existing technologies and provide an embedded multi-dimensional condition monitoring system for transformers, enabling monitoring of partial discharge without the need for additional power supply. Through multi-dimensional correlation analysis of partial discharge signals, temperature anomalies, and SF6 decomposition products, this system achieves accurate identification and three-dimensional localization of insulation faults, significantly improving diagnostic accuracy. Utilizing mechanical vibrations and temperature differences generated during equipment operation to generate electricity achieves energy self-sufficiency, enabling the built-in sensor network to operate with maintenance-free capability for the same lifespan as the equipment. The system directly outputs intelligently diagnosed status data packets, greatly reducing data transmission pressure and upgrading the operation and maintenance mode from passive response to proactive predictive maintenance, providing reliable technical support for the full lifecycle management of GIS equipment.

[0017] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0018] An embedded multidimensional condition monitoring system for the inner wall of a GIS transformer includes: a transformer shell, which integrates a comprehensive information management system;

[0019] Thermoelectric heating module, located between the core and the outer casing of GIS transformer, provides DC power to the multi-source synthetic energy management circuit;

[0020] The piezoelectric module, located in the middle of the transformer casing, performs rectification, voltage boosting, and energy storage through the energy management system of the multi-source synthesized energy management module.

[0021] Ultrasonic partial discharge detection sensor, temperature sensor, and SF6 deterioration gas metal oxide semiconductor sensor deposited on the inner wall of transformer casing;

[0022] The main control module is used to process the signals collected by the ultrasonic partial discharge detection sensor, temperature sensor, and SF6 deteriorating gas metal oxide semiconductor sensor.

[0023] The communication module transmits the signals processed by the main control module to the external information platform through the ceramic insulator window.

[0024] Furthermore, the temperature difference heating module includes a hot-side electrically insulating ceramic as the hot end of the module, a cold-side electrically insulating ceramic as the cold end of the module, and a thermocouple pair; the hot-side electrically insulating ceramic and the cold-side electrically insulating ceramic are arranged opposite to each other to encapsulate the thermocouple pair; at least one pair of thermocouples is provided, including a P-type semiconductor and an N-type semiconductor; the P-type semiconductor and the N-type semiconductor are electrically connected at the hot end through a copper conductor to form an electrical junction; and adjacent thermocouple pairs are electrically connected in series at the cold end through a copper conductor to form a series circuit, the series circuit also having a positive and a negative electrode for connecting the multi-source synthesized energy management module.

[0025] Furthermore, the multi-source synthesized energy management module includes an electrically connected current / voltage detection circuit module, a state recognition module, an energy management circuit, a strain gauge voltage acquisition circuit, and a thermoelectric power generation acquisition circuit; the energy management circuit includes an electrically connected impedance matching circuit, a rectifier filter circuit, a boost circuit, and a supercapacitor.

[0026] Furthermore, the piezoelectric module is a cantilever piezoelectric structure, with its base fixed to the inner wall of the transformer housing to conduct transformer vibration. A weight is connected to the lower end of the cantilever, generating electrical energy through periodic deformation on both sides of the cantilever under the influence of the weight. Furthermore, the main control module includes an electrically connected ARM processor, signal conditioning circuit, high-speed AD conversion circuit, high-speed algorithm module, synchronization module, and storage module. Furthermore, the communication module includes a GPRS wireless communication module, which encapsulates the data transmitted from the lower-level machine into GPRS packet data and performs conversion between TCP / IP protocol and serial communication protocol. Furthermore, the ultrasonic partial discharge detection sensor, temperature sensor, and SF6 deteriorating gas metal oxide semiconductor sensor all have insulating protective layers; the temperature difference heating module, multi-source synthesis energy management module, main control module, and communication module are all embedded in the inner wall of the transformer housing and designed for electromagnetic compatibility to suppress electromagnetic interference. Furthermore, the ultrasonic partial discharge detection sensor is manufactured using a flexible process, with a polyimide film deposited on the inner wall of the transformer housing as a substrate, and copper wires deposited on the substrate using an aerosol process.

[0027] Furthermore, the temperature sensor has a serpentine structure, using polyimide as a flexible substrate. A thin film of metallic nickel is deposited on the surface of the flexible substrate using an aerosol process, and strain-resistant design is incorporated. Furthermore, the interdigitated electrode surface of the SF6 degraded gas metal oxide semiconductor sensor contains a gas-sensitive layer; this gas-sensitive layer is formed by uniformly dispersing carbon nanotubes on the interdigitated electrode surface using an aerosol process.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. This multi-dimensional condition monitoring system solves the problem of "information isolation" in traditional monitoring methods. Through correlation analysis of multi-dimensional information, it significantly improves the accuracy and confidence of fault diagnosis, and can achieve accurate identification and three-dimensional positioning of insulation faults.

[0030] 2. A vibration-thermal energy integrated power supply system is adopted, which utilizes the inherent mechanical vibration of the transformer during operation (collected through a piezoelectric module) and the waste heat of the iron core (collected through a thermoelectric power generation module) to generate electricity. This achieves energy self-sufficiency and enables the built-in sensor network to have maintenance-free operation capabilities with the same lifespan as the equipment, fundamentally overcoming the limitations of external power supply or electromagnetic induction power supply.

[0031] 3. All sensors (such as ultrasonic, temperature, and gas sensors) are manufactured using flexible processes, directly deposited or embedded in the inner wall of the transformer housing. This design avoids signal shielding and attenuation by the transformer housing, enabling direct, hysteresis-free signal acquisition and improving monitoring sensitivity and real-time performance. Simultaneously, the embedded design ensures the integrity and sealing of the GIS housing, and the embedded circuitry is also shielded and protected by the housing.

[0032] 4. The system internally processes, integrates, and intelligently diagnoses the data, generating a data package containing diagnostic conclusions before uploading it. This significantly reduces data transmission pressure and upgrades the operation and maintenance model from the traditional "passive response" to "proactive predictive maintenance." It provides a feasible technical solution for the intelligent management of GIS equipment throughout its entire lifecycle.

[0033] 5. The new crab-claw-inspired bionic high-voltage clamp simplifies high-altitude operations and provides a more uniform stress distribution, increasing the clamp's reliability. The irregular structure creates turbulence, reducing wind resistance at the clamp location.

[0034] 6. The ultrasonic sensor adopts a flexible MFC structure, which can conform to the inner wall. The temperature sensor uses a "snake-shaped" anti-strain design to reduce the impact of mechanical deformation on measurement accuracy. The gas sensor uses new materials such as carbon nanotubes, which have high sensitivity to SF6 decomposition products. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of the present invention;

[0036] Figure 2 This is a schematic diagram of the temperature difference heating module in an embodiment of the present invention;

[0037] Figure 3 This is a design flowchart of the star-shaped damped energy harvesting device in an embodiment of the present invention;

[0038] Figure 4 This is a flowchart illustrating the energy harvesting circuit design of the vibration energy harvester in an embodiment of the present invention.

[0039] Figure 5 This is a schematic diagram of the structure of the ultrasonic partial discharge detection sensor in an embodiment of the present invention;

[0040] Figure 6 This is a schematic diagram of the temperature sensor structure in an embodiment of the present invention;

[0041] Figure 7 This is the main circuit design diagram in an embodiment of the present invention;

[0042] Figure 8 This is a communication circuit design diagram in an embodiment of the present invention.

[0043] List of reference numerals in the attached diagram: 1. Transformer casing; 2. Thermoelectric heating module; 21. Hot-side electrical insulating ceramic; 22. Cold-side electrical insulating ceramic; 23. P-type semiconductor; 24. Copper conductor; 25. N-type semiconductor; 26. Copper conductor; 27. Positive electrode; 28. Negative electrode; 3. Multi-source synthesized energy management module; 4. Piezoelectric module; 5. Main control module; 6. Communication module; 7. Ultrasonic partial discharge detection sensor; 8. Temperature sensor; 9. SF6 deteriorating gas metal oxide semiconductor sensor. Detailed Implementation

[0044] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The specific implementation methods of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] like Figure 1 As shown, this embodiment provides an embedded multi-dimensional condition monitoring system for the inner wall of a GIS transformer. It is characterized by comprising a transformer casing 1, a temperature difference heating module 2, a multi-source synthetic energy management module 3, a piezoelectric module 4, a main control module 5, a communication module 6, an ultrasonic partial discharge detection sensor 7, a temperature sensor 8, and an SF6 deterioration gas metal oxide semiconductor sensor 9. The transformer casing 1 integrates a comprehensive information management system.

[0046] The temperature difference heating module 2 is located between the iron core of the GIS transformer and the transformer shell 1, providing DC power to the multi-source synthetic energy management module 3.

[0047] The multi-source synthetic energy management module 3 includes an electrically connected current / voltage detection circuit module, a status identification module, an energy management circuit, a strain gauge voltage acquisition circuit, and a thermoelectric power generation acquisition circuit; the energy management circuit includes an electrically connected impedance matching circuit, a rectifier filter circuit, a boost circuit, and a supercapacitor.

[0048] The piezoelectric module 4 is located in the middle of the transformer casing 1 and is rectified, boosted and stored through the energy management system of the multi-source synthesized energy management module 3.

[0049] An ultrasonic partial discharge detection sensor 7, a temperature sensor 8, and an SF6 deteriorating gas metal oxide semiconductor sensor 9 are deposited on the inner wall of the transformer casing 1. The ultrasonic partial discharge detection sensor, the temperature sensor, and the SF6 deteriorating gas metal oxide semiconductor sensor are all provided with an insulating protective layer. The temperature difference heating module, the multi-source synthesis energy management module, the main control module, and the communication module are all embedded in the inner wall of the transformer casing and are designed for electromagnetic compatibility to suppress electromagnetic interference.

[0050] The ultrasonic partial discharge detection sensor 7 is manufactured using a flexible process. A polyimide film is deposited on the inner wall of the transformer housing 1 as a substrate, and copper wires are deposited on the substrate using an aerosol process. The temperature sensor 8 has a serpentine structure, using polyimide as a flexible substrate. A thin film of metallic nickel is deposited on the surface of the flexible substrate using an aerosol process, and strain-resistant design is incorporated. The interdigitated electrode surface of the SF6 degraded gas metal oxide semiconductor sensor 9 contains a gas-sensitive layer; this gas-sensitive layer is formed by uniformly dispersing carbon nanotubes on the interdigitated electrode surface using an aerosol process.

[0051] The main control module 5 is used to process the signals collected by the ultrasonic partial discharge detection sensor 7, the temperature sensor 8, and the SF6 deteriorating gas metal oxide semiconductor sensor 9. The main control module 5 includes an electrically connected ARM processor, a signal conditioning circuit, a high-speed AD conversion circuit, a high-speed algorithm module, a synchronization module, and a storage module.

[0052] The communication module 6 transmits the signal processed by the main control module 5 to the external information platform through the ceramic insulator window. The communication module 6 includes a GPRS wireless communication module, which encapsulates the data transmitted by the lower-level machine into GPRS packet data and realizes the conversion between TCP / IP protocol and serial communication protocol.

[0053] like Figure 2 As shown, the temperature difference heating module 2 includes a hot-side electrically insulating ceramic 21 as the hot end of the module, a cold-side electrically insulating ceramic 22 as the cold end of the module, and a thermocouple pair; the hot-side electrically insulating ceramic 21 and the cold-side electrically insulating ceramic 22 are arranged opposite to each other to encapsulate the thermocouple pair; at least one thermocouple pair is provided, including a P-type semiconductor 23 and an N-type semiconductor 25; the P-type semiconductor 23 and the N-type semiconductor 25 are electrically connected at the hot end through a copper conductor 24 to form an electrical junction; and adjacent thermocouple pairs are electrically connected in series at the cold end through a copper conductor 26 to form a series circuit, the series circuit also has a positive electrode 27 and a negative electrode 28 for connecting the multi-source synthesized energy management module.

[0054] The workflow is as follows: The waste heat generated by the transformer core is transferred to the temperature difference heating module 2, which raises the temperature of the TEG hot end. The PCM absorbs and stores the waste heat from the core. When the waste heat is insufficient, it releases latent heat to maintain the TEG hot end temperature at a stable temperature difference of 55K. Based on the Seebeck effect, a temperature difference is formed between the hot end (PCM side) and the cold end (water-cooled plate side), driving the directional movement of holes in the P-type semiconductor 23 and electrons in the N-type semiconductor 25 to generate DC current, which is fed into the multi-source synthesis energy management module 3 through a filter and voltage regulation circuit. Further optimization control is to keep the water-cooled plate flow constant after the TEG output power tends to stabilize. If the TEG hot end temperature is detected to exceed 60℃, the flow rate is finely adjusted to avoid overheating and extend the module life.

[0055] Its coupling process is as follows: When the transformer is running, the residual heat of the iron core causes the hot end of the temperature difference heating module 2 to heat up, and at the same time the PCM begins to absorb heat and gradually melts; the TEG module continuously generates electricity by utilizing the temperature difference between the PCM and the water-cooled plate (stable at 55K), with a maximum output power of 475mW; when solar radiation weakens or vibration is small, the PCM releases latent heat to maintain the temperature of the hot end of the TEG, ensuring that it can still stably output ≥18mW of electrical energy in the absence of light; the multi-source synthesis energy management module 3 rectifies and filters the electrical energy output by the TEG, integrates it with piezoelectric and magnetic field energy, and stores it in the supercapacitor for voltage adaptation of 3.3~5V.

[0056] The piezoelectric module 4 uses an alloy sheet as the core material for vibration power generation. It employs a cantilever mounting system, with the alloy sheet fixed to the main frame of the spacer via connecting screws. Pre-magnetization is achieved through permanent magnets at both ends of the sheet. The electromechanical coupling primarily satisfies the Jiles-Atherton model. The relationship between the magnetization intensity of the Fe-Ga alloy sheet and the rate of stress change is shown in the following formula:

[0057] ;

[0058] ;

[0059] ;

[0060] Where M is the average magnetization. The internal stress experienced by the thin sheet. Let be the Young's modulus of GMM, and c be the irreversible loss coefficient. The energy coupling parameter per unit volume of the material. The magnetization is hysteresis-free. Irreversible magnetization, It represents the reversible magnetization intensity.

[0061] Pre-magnetizing with a permanent magnet ensures the alloy sheet enters the domain deflection stage, enhancing the magnetostrictive inverse effect. This pre-magnetization eliminates the need for a current-carrying coil to generate a magnetic field, reducing energy loss and minimizing size. The pickup coil embedded within the double-pendulum anti-dash device has an inner diameter similar to the sheet to minimize the air gap. Based on Faraday's law of electromagnetic induction, the induced electromotive force generated by the pickup coil around the Fe-Ga alloy sheet is as follows:

[0062] ;

[0063] The vibration energy harvester outputs alternating current, but its output voltage is random and unstable due to environmental influences, making it unsuitable for normal operation of the main circuit. A corresponding matching circuit needs to be designed, including rectification and filtering, DC-DC boost, and energy storage. The magnetostrictive circuit is inductive overall. To maximize the load power while meeting bandwidth requirements, maximum output power matching from dynamic impedance matching is used, with a series matching capacitor C to achieve resonance. The design flowchart of the star-shaped damped energy harvesting device is shown below. Figure 3 As shown, when the line vibrates, the load block at the center of the spacer bar and the spacer bar frame move relative to each other, thereby driving the piston sheath and the permanent magnet on it to move. The permanent magnet cuts the coil inside the piston wall to generate an induced electromotive force, providing suitable voltage and current to improve energy conversion efficiency. This energy harvesting system has a matching energy management circuit, which is integrated into the final energy storage circuit. The main body of the load block is a spherical metal ball with a pre-cut bearing groove. The bearing is embedded in the pre-cut groove and connected to the piston sheath through a connecting rod.

[0064] The design flowchart of the energy harvesting circuit for the vibration energy harvester is as follows: Figure 4 As shown, to maximize the power to the load, the load impedance and internal impedance must satisfy a conjugate relationship. The vibration energy harvester is inductive overall. After power matching calculation, a matching resistor is connected in series. Due to the low output voltage of the vibration energy harvester, a voltage doubler rectifier circuit is used to process the output electrical signal of the magnetostrictive energy harvesting unit, and a CRC filter circuit is connected at the back end to eliminate ripple. An appropriate DC-DC chip is selected based on the rated voltage of the main control chip. A supercapacitor is selected for the energy storage circuit.

[0065] Ultrasonic partial discharge detection sensor, such as Figure 5As shown, it employs flexible MFC (macro-fiber composite) material with polyimide as the substrate. Copper conductors are deposited and covered with a shielding layer using an aerosol process to adapt to the curved surface of the transformer's inner wall. Its principle is based on the propagation of ultrasonic waves generated by the partial discharge source in the form of spherical waves inside the transformer, and the time difference between the arrival times of the signals by ultrasonic sensors at different locations. Based on the constant propagation speed of sound waves in media such as insulating oil and metal, the time difference (TDOA) of the signal reaching each sensor is calculated. A hyperboloid equation is constructed with the sensor coordinates as the focus, and the three-dimensional spatial coordinates of the partial discharge source are solved by multiple sets of hyperboloid intersections. Let the coordinates of three or more ultrasonic sensors be... The signal arrival times are respectively The speed of sound wave propagation is Then the local discharge power supply satisfy: ;

[0066] By solving this set of nonlinear equations and combining path identification to eliminate interference from non-direct waves, the accurate location of the local discharge source can be obtained.

[0067] The signal acquisition and transmission process is as follows: An embedded sensor array on the inner wall synchronously acquires partial discharge ultrasonic signals. The ultrasonic sensors capture signals in the 100kHz~400kHz frequency band. After adaptation to a flexible substrate and anti-interference processing by a shielding layer, signal integrity is ensured. After signal acquisition, the acquired analog signals are transmitted to the main control circuit. After amplification and filtering by the signal conditioning circuit, they are converted into digital signals by a high-speed AD conversion circuit. Narrowband noise and white noise are filtered out using a layered denoising model, and then multi-dimensional information is integrated by a data fusion algorithm to generate a data packet containing positioning results and equipment status. The data packet is encapsulated into TCP / IP protocol packets by the GPRS module of the communication circuit, completing the conversion between serial communication protocol and network protocol. Through the ceramic insulator window on the transformer tank, the data is wirelessly uploaded to the intelligent substation data platform in the form of radio frequency signals, realizing real-time data sharing and remote monitoring.

[0068] Temperature sensor such as Figure 6 As shown, a "snake-like" structure is designed using polyimide as a flexible substrate and a thin film of metallic nickel as an electrode to reduce the stretching of the electrode caused by deformation. The electrode is fabricated by magnetron sputtering and photolithography. The electrode linewidth is about 100 μm, the temperature coefficient of resistance is 0.0099 / ℃, it is resistant to strain interference, and the temperature measurement error is ≤0.3%.

[0069] Main circuit such as Figure 7As shown, the voltage signal acquired by the strain gauge is filtered and then converted from digital to analog by the A / D conversion section of the main control chip. The corresponding digital quantity is obtained through a conversion program based on the stress-voltage fitting function obtained experimentally. After being encoded by the radio frequency section of the main control chip, the data is transmitted for communication via the radio frequency antenna. To ensure communication efficiency, the radio frequency antenna also needs to be equipped with a corresponding matching filtering circuit.

[0070] A schematic diagram of the interconnection and communication network between spacer relays and smart grids is shown below. Figure 8 As shown, the main chip encodes the stress data and then transmits it to the adjacent smart grid terminal spacer via a relay chip. The data includes a check bit, a start bit, the spacer position number, the stress data, and a stop bit. The data is then merged into a data packet and transmitted to the nearest terminal. The smart grid terminal collects data packets representing half of the line, allowing for a comprehensive assessment of the line's condition and avoiding false alarms caused by stress detection failures in a single spacer. Furthermore, the relay transmission method reduces energy loss and the data processing load on the information acquisition segment. Bidirectional transmission supports the information acquisition end sending data requests to the spacer.

[0071] Working Principle: Based on the line requirements and the meteorological conditions of the usage location, the mechanical structure and aerodynamic design of the spacer are performed through simulation. According to the required transmission distance, communication protocol type, and digital-to-analog conversion accuracy, an appropriate main control chip is selected. Based on the spacer model obtained from the structural design, the location of maximum stress is selected as the printing position. An appropriate strain gauge is designed according to the requirements of response speed and sampling accuracy. The stress-voltage curve is obtained experimentally, and the curve is fitted using a function and written into the main program. The voltage sensor is placed at the location where voltage monitoring is required. An appropriate vibration energy harvester and energy collection circuit are designed according to the power requirements of the main control chip. The main program also includes relay and communication protocols.

[0072] The SF6 deterioration gas metal oxide semiconductor sensor is a metal-doped carbon nanotube resistive sensor. Its core function is to monitor the characteristic decomposition products generated by SF6 insulation gas fault discharge in GIS transformers, including four gases: SO2, H2S, SOF2, and SO2F2. By observing the correlation between gas concentration and sensor resistance, the fault type and severity can be determined. It employs a composite gas-sensitive material of "intrinsic carbon nanotubes + metal doping," with the metal being one of Ni, Pd, or Al. The Ni-doped carbon nanotube sensor has a detection limit as low as 1 μL / L and exhibits the strongest response to H2S, reaching -9.5% at a concentration of 100 μL / L, making it suitable for precise detection of trace gases. The Pd-doped carbon nanotube sensor demonstrates excellent stability, with a response of -13.5% for 100 μL / L H2S and -11% for SO2, suitable for general monitoring scenarios. The Al-doped carbon nanotube sensor exhibits the strongest gas adsorption capacity, with a response of 2.3% for 100 μL / L SOF2, making it suitable for high-concentration gas detection.

[0073] Working Principle: When an insulation fault occurs inside the GIS transformer, SF6 gas reacts with trace amounts of H2O and O2 to generate four decomposition products: SO2, H2S, SOF2, and SO2F2. After the gas molecules diffuse to the surface of the sensor's gas-sensitive thin film, they adhere to the metal-doped active sites through physical or chemical adsorption, causing a redistribution of electrons within the sensor and resulting in a regular change in resistance. When SO2 and H2S are adsorbed, the sensor resistance decreases, and its response value is negative. When a portion of SOF2 and SO2F2 are adsorbed, the resistance may increase, and its response value is positive. After the main control module 5 collects the resistance change signal, it combines it with the preset "concentration-resistance" correspondence to quantify the gas concentration. This is then fused with ultrasonic partial discharge signals and temperature signals to achieve accurate fault location and diagnosis.

[0074] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A multi-dimensional condition monitoring system embedded in the inner wall of a GIS transformer, characterized in that, Includes: transformer casing, which integrates a comprehensive information management system; Thermoelectric heating module, located between the core and the outer casing of GIS transformer, provides DC power to the multi-source synthetic energy management module; The piezoelectric module, located in the middle of the transformer casing, performs rectification, voltage boosting, and energy storage through the energy management system of the multi-source synthesized energy management module. Ultrasonic partial discharge detection sensor, temperature sensor, and SF6 deterioration gas metal oxide semiconductor sensor deposited on the inner wall of transformer casing; The main control module is used to process the signals collected by the ultrasonic partial discharge detection sensor, temperature sensor, and SF6 deteriorating gas metal oxide semiconductor sensor. The communication module transmits the signals processed by the main control module to the external information platform through the ceramic insulator window.

2. The embedded multi-dimensional condition monitoring system for the inner wall of a GIS transformer according to claim 1, characterized in that, The temperature difference heating module includes a hot-side electrically insulating ceramic as the hot end of the module, a cold-side electrically insulating ceramic as the cold end of the module, and a thermocouple pair. The hot-side electrically insulating ceramic and the cold-side electrically insulating ceramic are arranged opposite each other to encapsulate the thermocouple pair. The thermocouple pair is provided in at least one pair, including a P-type semiconductor and an N-type semiconductor. The P-type semiconductor and the N-type semiconductor are electrically connected at the hot end through a copper conductor to form an electrical junction. Adjacent thermocouple pairs are electrically connected in series at the cold end through a copper conductor to form a series circuit. The series circuit also has a positive and a negative electrode for connecting the multi-source synthesized energy management module.

3. The embedded multi-dimensional condition monitoring system for the inner wall of a GIS transformer according to claim 1, characterized in that, The multi-source synthesized energy management module includes an electrically connected current / voltage detection circuit module, a state recognition module, an energy management circuit, a strain gauge voltage acquisition circuit, and a thermoelectric power generation acquisition circuit; the energy management circuit includes an electrically connected impedance matching circuit, a rectifier filter circuit, a boost circuit, and a supercapacitor.

4. The embedded multidimensional condition monitoring system for the inner wall of a GIS transformer according to claim 1, characterized in that, The piezoelectric module is a cantilever piezoelectric structure. Its base is fixed to the inner wall of the transformer shell to conduct transformer vibration. A weight is connected to the lower end of the cantilever, and electrical energy is generated by the periodic deformation of both sides of the cantilever under the influence of the weight.

5. The embedded multi-dimensional condition monitoring system for the inner wall of a GIS transformer according to claim 1, characterized in that, The main control module includes an electrically connected ARM processor, a signal conditioning circuit, a high-speed AD conversion circuit, a high-speed algorithm module, a synchronization module, and a storage module.

6. The embedded multi-dimensional condition monitoring system for the inner wall of a GIS transformer according to claim 1, characterized in that, The communication module includes a GPRS wireless communication module, which encapsulates the data transmitted by the lower-level machine into GPRS packet data and realizes the conversion between TCP / IP protocol and serial communication protocol.

7. The embedded multidimensional condition monitoring system for the inner wall of a GIS transformer according to claim 1, characterized in that, The ultrasonic partial discharge detection sensor, temperature sensor, and SF6 deteriorated gas metal oxide semiconductor sensor are all equipped with an insulating protective layer; the temperature difference heating module, multi-source synthesis energy management module, main control module, and communication module are all embedded in the inner wall of the transformer shell and are designed for electromagnetic compatibility to suppress electromagnetic interference.

8. The embedded multidimensional condition monitoring system for the inner wall of a GIS transformer according to claim 7, characterized in that, The ultrasonic partial discharge detection sensor is manufactured using a flexible process, in which a polyimide film is deposited on the inner wall of the transformer housing as a substrate, and copper wires are deposited on the substrate using an aerosol process.

9. A multi-dimensional condition monitoring system embedded in the inner wall of a GIS transformer according to claim 7, characterized in that, The temperature sensor has a serpentine structure, using polyimide as a flexible substrate. A thin film of metallic nickel is deposited on the surface of the flexible substrate using an aerosol process, and strain-resistant design is incorporated.

10. A multi-dimensional condition monitoring system embedded in the inner wall of a GIS transformer according to claim 7, characterized in that, The interdigitated electrode surface of the SF6 degraded gas metal oxide semiconductor sensor contains a gas-sensitive layer; the gas-sensitive layer is formed by uniformly dispersing carbon nanotubes on the interdigitated electrode surface through an aerosol process.

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