Plug-in multi-parameter integrated monitoring probe for power distribution transformer

Abstract

The utility model relates to a kind of plug-in multi-parameter integrated monitoring probe for distribution transformer, belong to the online monitoring technical field of electric power equipment.Techinical scheme:the head of sensing cavity is equipped with mechanical interface, and mechanical interface is connected with oil valve on distribution transformer by thread;Sealing partition is arranged in electronic cavity, and electronic cavity is divided into front cavity and rear cavity, circuit board and battery are arranged in rear cavity, sealing partition is integrated with isolation cavity tail, isolation cavity and sensing cavity tail are located in the front cavity of electronic cavity, and the front end of electronic cavity is matched with sensing cavity tail and is closed;Signal cable of oil level detection unit, hydrogen sensing unit and temperature sensing unit passes through isolation cavity and sealing partition and is connected with circuit board and battery in the rear cavity of electronic cavity.The utility model is compact in structure, highly integrated, convenient to install, ultra-low power consumption and can work reliably for a long time, with multi-parameter integrated sensing capability, and can be directly adapted to transformer oil valve, to realize plug and play.

Description

Technical Field

[0001] This utility model relates to a plug-in multi-parameter integrated monitoring probe for distribution transformers, and more particularly to a plug-in low-power integrated monitoring probe for distribution transformers that integrates hydrogen, temperature and oil level monitoring, belonging to the field of online monitoring technology for power equipment. Background Technology

[0002] Distribution transformers (hereinafter referred to as "transformers") are key equipment in power distribution networks for voltage transformation and power distribution. Their operational reliability directly affects the regional power supply quality and grid security. The insulation system of distribution transformers typically employs an oil-paper composite structure, which, during long-term operation, is subjected to multiple stresses including electrical, thermal, and mechanical stresses. This leads to gradual aging of the insulation material and may cause latent defects such as partial discharge and overheating. In their early stages, these defects produce characteristic gases (mainly hydrogen, as well as methane, acetylene, and ethylene) that dissolve in the insulating oil. Therefore, effective monitoring of characteristic gases in the insulating oil, especially hydrogen, which is the earliest and most sensitive to be produced, is a core means of diagnosing early insulation degradation and preventing faults.

[0003] Currently, monitoring the insulation condition of distribution transformers mainly relies on two technical approaches: offline testing and online monitoring. However, both approaches have significant bottlenecks when dealing with the large-scale, universal monitoring needs of numerous distribution transformers.

[0004] (1) Inherent limitations of offline experiments Traditional methods are represented by periodic power outage maintenance and laboratory oil chromatography (DGA). Although laboratory DGA is considered the standard for insulation fault diagnosis, it is essentially a periodic, offline sampling method. Its limitations are: (a) large monitoring blind zone: usually measured in years or several years, it cannot capture insulation defects that suddenly appear or develop rapidly between two tests; (b) high economic and maintenance costs: power outages affect power supply, and the sampling and testing process is complex, requiring significant investment of manpower and resources; (c) poor data timeliness: the cycle from sampling to obtaining results is long, and it cannot support real-time status assessment and early warning. This method can no longer meet the requirements of modern smart distribution networks for real-time perception and proactive early warning of equipment status.

[0005] (2) The main defects of existing online monitoring terminals in terms of structure and deployment To overcome the shortcomings of offline testing, online monitoring technology has emerged. However, existing monitoring terminals still have significant problems in structural design, installation methods, and long-term power supply, making large-scale deployment in the distribution transformer field difficult. The main equipment used has the following issues: ① Full-component online chromatographic monitoring instrument; This device attempts to bring the laboratory DGA process online and continuously monitor multiple characteristic gases. However, to achieve chromatographic separation, it must integrate complex modules such as a gas path system, carrier gas source, and detector, resulting in a large, complex, expensive, and power-consuming device. It also requires regular carrier gas replenishment and professional maintenance, making installation and maintenance extremely inconvenient. ② Low-cost single hydrogen monitoring device; Given that hydrogen is the earliest and most sensitive characteristic gas for most insulation defects, various single hydrogen online monitoring products based on electrochemical and semiconductor principles have appeared on the market, reducing costs. However, these devices still have significant shortcomings in terms of structure and use: (a) Limited functionality and low integration: Most devices only have hydrogen concentration monitoring capabilities and do not integrate sensors for key parameters such as oil temperature and oil level, failing to provide multi-dimensional data support for comprehensive diagnosis. Furthermore, they are often modular, requiring multiple sensor and lead wire placements during installation, resulting in low integration and reliability. (b) Difficult installation and power supply: Existing terminals mostly rely on external power supply, requiring power from the transformer itself or nearby. For outdoor pole-mounted transformers without pre-installed power supplies and old distribution rooms with limited space and difficult wiring, installation is difficult, costly, or even impossible. In addition, some equipment structures lack plug-and-play functionality, requiring power outages or oil circuit modifications during installation, resulting in poor deployment convenience. (c) High power consumption and short battery life: Most online monitoring terminals consume a large amount of power. If battery power is used, the battery life is short, requiring frequent battery replacements, leading to high maintenance costs and making long-term maintenance-free operation difficult. Utility Model Content

[0006] The purpose of this invention is to provide a plug-in multi-parameter integrated monitoring probe for distribution transformers. It features a compact structure, high integration, convenient installation, ultra-low power consumption, and long-term reliable operation. It has multi-parameter integrated sensing capabilities and can be directly adapted to transformer oil valves, enabling plug-and-play functionality. This provides a feasible front-end sensing solution for real-time, reliable, and universal monitoring of the insulation status of massive distribution transformers, and solves the aforementioned technical problems existing in the prior art.

[0007] The technical solution of this utility model is: A plug-in multi-parameter integrated monitoring probe for distribution transformers includes a sensing cavity, an isolation cavity, and an electronic cavity. The head of the sensing cavity has a mechanical interface that connects to an oil valve on the distribution transformer via a thread. The sensing cavity houses an oil level detection unit, a hydrogen sensing unit, and a temperature sensing unit. A channel within the mechanical interface connects to the oil circuit of the distribution transformer. The oil level detection unit, hydrogen sensing unit, and temperature sensing unit are in full contact with the transformer oil. The tail of the sensing cavity is integrated with the head of the isolation cavity. A sealing partition divides the electronic cavity into a front and rear cavity. A circuit board and a battery are housed in the rear cavity. The sealing partition is integrated with the tail of the isolation cavity. The isolation cavity and the tail of the sensing cavity are located within the front cavity of the electronic cavity, and the front end of the electronic cavity matches and seals with the tail of the sensing cavity. Signal cables from the oil level detection unit, hydrogen sensing unit, and temperature sensing unit pass through the isolation cavity and the sealing partition and connect to the circuit board and battery in the rear cavity of the electronic cavity. The sensing cavity, isolation cavity, and electronic cavity are all cylindrical and located on the same central axis.

[0008] Furthermore, the mechanical interface is an interface with external threads that match the internal threads of the oil valve interface of the distribution transformer. The mechanical interface is inserted into the oil valve interface of the transformer to achieve plug-and-play functionality.

[0009] Furthermore, the external thread of the mechanical interface is provided with a fluororubber O-ring, and a sealing ring is provided between the front end of the electronic cavity and the rear end of the sensing cavity.

[0010] Furthermore, the sensing cavity has multiple insulating supports on its tail circumference, which are matched with the inner wall of the front end of the electronic cavity. The insulating supports are connected to the inner wall of the front end of the electronic cavity by screws or buckles.

[0011] Furthermore, the output cables of the oil level detection unit, hydrogen sensing unit, and temperature sensing unit are connected to the corresponding interfaces on the circuit board through waterproof sealing connectors; the oil level detection unit, hydrogen sensing unit, and temperature sensing unit are respectively an oil level sensor, a hydrogen sensor, and a temperature sensor, and are evenly distributed on the inner circumference of the sensing cavity through their respective mounting brackets.

[0012] Furthermore, the rear cavity of the electronic cavity is filled with epoxy resin potting compound to encapsulate the sealing partition, circuit board, battery and output cable in the rear cavity of the electronic cavity together.

[0013] Furthermore, the outer wall of the electronic cavity is provided with an annular heat dissipation groove.

[0014] Furthermore, the sensing cavity, isolation cavity, and electronic cavity are integrated into a housing structure, which is a fully metal shielded and sealed housing.

[0015] Features of this utility model: 1. The all-metal shielded sealed housing structure is cylindrical, providing electromagnetic shielding, mechanical protection, and environmental protection. The mechanical interface adapted to the transformer oil valve is equipped with a standard thread (e.g., M20×1.5) or connected via a flange structure. The mechanical interface is equipped with one or more fluororubber O-rings to achieve reliable oil circuit sealing. Installation requires no power outage or additional wiring, achieving true "plug and play." Annular heat dissipation grooves on the electronic cavity surface increase the heat dissipation area to assist in the cooling of internal components.

[0016] 2. The oil level detection unit, hydrogen sensing unit, and temperature sensing unit are located near one end of the distribution transformer's oil circuit to ensure full contact between the sensing components and the transformer oil. Hydrogen Sensing Unit: Employs an electrochemical or thermally conductive miniature hydrogen sensor based on microelectromechanical systems (MEMS) technology. Its sensing element is exposed to the oil circuit environment to directly detect the dissolved hydrogen concentration (H2) in the insulating oil. Temperature Sensing Unit: Uses a high-precision platinum resistance temperature sensor (such as PT100), encapsulated in a metal sheath. The front end of the sheath contacts the oil to detect the top layer oil temperature (T). Oil Level Detection Unit: Employs a sensor based on radio frequency capacitive or ultrasonic principles. Its sensing element extends to an appropriate position inside the housing to detect the oil level (L) in the tank.

[0017] 3. Circuit Board: Main Control and Data Processing Module: A control circuit board with an ultra-low power microcontroller (MCU) at its core is used. This MCU connects to each unit of the integrated sensing module via an analog / digital input interface, controlling their synchronous sampling timing and performing preprocessing such as analog-to-digital conversion and digital filtering on the acquired raw signals. Low-Power Wireless Communication Module: This module uses a wireless communication chip based on technologies such as LoRa and its peripheral circuits. It connects to the main control MCU via a serial interface (such as SPI or UART) and is used to package and send the processed data to an external gateway. Power Management Module: Its core is connected to a battery, which is a high-energy-density battery (such as a lithium-thionyl chloride battery). The power management module includes a high-efficiency DC-DC voltage conversion circuit and a load switch array controlled by the main control MCU. The outputs of the load switch array are connected to the power supply terminals of the wireless communication module and the integrated sensing module, respectively. The main control MCU can completely cut off the power supply to high-power modules during non-acquisition and non-communication periods by controlling the on / off state of these switches.

[0018] The main control and data processing module is connected to the load switch array of the power management module via a control bus, and to the low-power wireless communication module via a data bus. The power management module draws power from the battery and provides a stable voltage to the main control and data processing module, the integrated sensing module, and the low-power wireless communication module. All modules are fixed in the electronic cavity with epoxy resin potting compound to enhance shock resistance and protection.

[0019] After installation, the built-in power management module begins supplying power to the system. The main control MCU, according to a preset program, periodically controls the power management module to power on the integrated sensor module, synchronously collecting H2, T, and L data, processing it, and storing it in local memory, then cutting off power to the sensor module. When the data upload cycle arrives, the main control MCU controls the power management module to power on the wireless communication module, reads multiple sets of cached data from memory, packages them, and sends them. After transmission, power to the communication module is immediately cut off. For the vast majority of the time, this invention is in a deep sleep state, with only the real-time clock and some power management circuitry maintaining extremely low power consumption.

[0020] The beneficial effects of this utility model are: (1) High integration and compact structure: The sensors, main control, communication and power supply of three key parameters such as hydrogen, temperature and oil level are all integrated into a cylindrical metal shell. The structure is highly compact and the size is small, which greatly saves installation space and is especially suitable for outdoor pole-mounted transformers with limited space.

[0021] (2) Plug and play: The standardized mechanical interface (thread / flange) design allows this utility model to be directly screwed into the existing oil valve of the transformer like an ordinary plug. The installation process does not require power outage, complex wiring, or external power supply. The deployment is extremely simple and fast, and the engineering adaptability is extremely strong.

[0022] (3) Integrated synchronous sensing of parameters: Through structural design, the three types of sensors are closely related in terms of physical location and sampling time sequence, realizing the synchronous measurement of multiple parameters at the same physical point, providing a high-quality and highly consistent raw data foundation for back-end analysis.

[0023] (4) Robust, reliable and highly adaptable to the environment: The all-metal shielded sealed housing provides excellent electromagnetic compatibility, mechanical strength and IP67 and above protection level, and can withstand harsh environments such as outdoor high temperature, low temperature, humidity, rain, salt spray and electromagnetic interference, ensuring long-term reliable operation. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model; Figure 2 This is a schematic diagram of the present invention after filling with epoxy resin potting compound; Figure 3 This is an internal schematic diagram of an embodiment of the present invention with the electronic cavity housing and sealing partition removed; In the diagram: 1. Oil level detection unit; 2. Fluororubber O-ring seal; 3. Sensing cavity; 4. Mechanical interface; 5. Hydrogen sensing unit; 6. Insulating bracket; 7. Temperature sensing unit; 8. Isolation cavity; 9. Sealing partition; 10. Annular heat dissipation groove; 11. Electronic cavity; 12. Epoxy resin potting compound; 13. Circuit board; 14. Battery; 15. Channel; 16. Mounting plate; 17. Back cover; 18. Waterproof sealing joint; 19. Sealing ring. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] See attached document Figure 1-3 A plug-in multi-parameter integrated monitoring probe for distribution transformers includes a sensing cavity 3, an isolation cavity 8, and an electronic cavity 11. The head of the sensing cavity 3 has a mechanical interface 4, which connects to an oil valve on the distribution transformer via a thread. The sensing cavity 3 houses an oil level detection unit 1, a hydrogen sensing unit 5, and a temperature sensing unit 7. The mechanical interface 4 has a channel 15 connecting to the oil circuit of the distribution transformer. The oil level detection unit 1, hydrogen sensing unit 5, and temperature sensing unit 7 are in full contact with the oil in the distribution transformer. The tail of the sensing cavity 3 is integrated with the head of the isolation cavity 8. The electronic cavity 11 contains… A sealing partition 9 divides the electronic cavity 11 into a front cavity and a rear cavity. The rear cavity houses a circuit board 13 and a battery 14. The sealing partition 9 is integrated with the tail of the isolation cavity 8. The isolation cavity 8 and the tail of the sensing cavity 3 are located in the front cavity of the electronic cavity 11. The front end of the electronic cavity 11 is matched and sealed with the tail of the sensing cavity 3. The signal cables of the oil level detection unit 1, the hydrogen sensing unit 5, and the temperature sensing unit 7 pass through the isolation cavity 8 and the sealing partition 9 and are connected to the circuit board 13 and the battery 14 in the rear cavity of the electronic cavity 11. The sensing cavity 3, the isolation cavity 8, and the electronic cavity 11 are all cylindrical in shape and located on the same central axis.

[0027] The circuit board 13 is a commonly used oil level detection unit 1, hydrogen sensing unit 5, and temperature sensing unit 7 processing module with data uploading function. The signals from the oil level detection unit 1, hydrogen sensing unit 5, and temperature sensing unit 7 of the distribution transformer are processed and uploaded to realize online monitoring of the distribution transformer.

[0028] See attached document Figure 1 and 2 The mechanical interface 4 is an interface with external threads, which matches the internal threads of the oil valve interface of the distribution transformer. The mechanical interface 4 is inserted into the oil valve interface of the transformer to achieve plug-and-play functionality.

[0029] See attached document Figure 1 and 2 The mechanical interface 4 is provided with a fluororubber O-ring 2 on its external thread, and a sealing ring 19 is provided between the front end of the electronic cavity 11 and the tail end of the sensing cavity 3 to increase the sealing performance.

[0030] See attached document Figure 1 and 2 The sensing cavity 3 has multiple insulating supports 6 on its tail circumference. The insulating supports 6 are matched with the inner wall of the front end of the electronic cavity 11 and are connected to the inner wall of the front end of the electronic cavity 11 by screws or buckles.

[0031] See attached document Figure 3 The output cables of the oil level detection unit 1, hydrogen sensing unit 5 and temperature sensing unit 7 are connected to the corresponding interfaces on the circuit board 13 through waterproof sealing connectors 18; the oil level detection unit 1, hydrogen sensing unit 5 and temperature sensing unit 7 are respectively an oil level sensor, a hydrogen sensor and a temperature sensor, and are evenly distributed on the inner circumference of the sensing cavity 3 through their respective mounting brackets.

[0032] See attached document Figure 2 The rear cavity of the electronic cavity 11 is filled with epoxy resin potting compound 12 to encapsulate the sealing partition 9, circuit board 13, battery 14 and output cable in the rear cavity of the electronic cavity 11 together.

[0033] See attached document Figure 1 and 2 The outer wall of the electronic cavity 11 is provided with an annular heat dissipation groove 10.

[0034] Preferably, the sensing cavity 3, the isolation cavity 8, and the electronic cavity 11 are an integrated encapsulated housing structure, and the housing structure is an all-metal shielded and sealed housing.

[0035] See attached document Figure 3 The circuit board 13 and battery 14 are mounted on the mounting plate 16 and fixed to the housing or internal support of the electronic cavity 11 by screws. The rear end of the electronic cavity 11 is provided with a rear cover 17.

[0036] The circuit board 13 includes an integrated sensing module, a main control and data processing module, a low-power wireless communication module, and a power management module. All modules are integrated on the circuit board and built into the rear cavity of the electronic cavity 11, forming a fully functional independent sensing unit. The integrated sensing module, main control and data processing module, low-power wireless communication module, and power management module are all commonly known in the art. Example:

[0037] (1) This embodiment is an integrated cylindrical structure with an overall length of approximately 160 mm and a maximum outer diameter of approximately Φ45 mm. The electronic cavity 11 is constructed from a fully metal shielded and sealed shell, precision-machined from corrosion-resistant, high-strength 316 stainless steel. The surface of the electronic cavity 11 is polished or passivated and designed with annular heat dissipation grooves 10 to enhance heat dissipation under outdoor sunlight. The protection level reaches IP68, which can completely prevent dust intrusion and withstand long-term underwater immersion, adapting to extreme humid environments such as outdoor rainstorms and condensation.

[0038] (2) The mounting end is machined with a standardized external thread mechanical interface 4, specifically M20×1.5mm. This thread size matches the internal thread specifications of most sampling valves or special monitoring valves pre-installed on the low-voltage side of oil-immersed distribution transformers.

[0039] To ensure reliable sealing, two sealing grooves are designed at the root of the threaded interface, each containing a fluororubber O-ring 2. After being screwed into the transformer valve body and tightened, the two fluororubber O-rings 2 are compressed, forming a double sealing barrier to ensure that the transformer insulating oil does not leak.

[0040] During installation, there is no need to shut down the transformer. Operators simply need to use tools to screw the device directly into the existing sampling valve, replacing the original plug, and tighten to the specified torque to complete the physical installation and oil circuit sealing. The entire process requires no additional wiring, drilling, or connection to an external power source, achieving true "plug and play."

[0041] (3) Ensure that the sensing parts of each sensor can make full and direct contact with the flowing insulating oil.

[0042] Hydrogen sensing unit: A thermal conductivity hydrogen sensor based on microelectromechanical systems (MEMS) technology is used. Its miniaturized sensor chip is encapsulated within a special stainless steel filter sleeve that allows oil molecules to permeate, directly exposed to the oil for detecting dissolved hydrogen concentration. This unit has a measurement range of 0-2000 ppm, a typical accuracy of ±50 ppm, and a response time of less than 30 seconds.

[0043] Temperature sensing unit: Employs a PT100 platinum resistance temperature sensor. The platinum resistance element is encapsulated at the top of a slender, thermally conductive stainless steel sheath, which is threadedly sealed to the housing. Its measuring point extends into the oil passage for accurate measurement of the top layer oil temperature.

[0044] Oil level detection unit: Employs an RF capacitive level sensor. Its core is a coaxial cylindrical capacitive probe, with the probe's plates extending into the housing to a fixed height correlated with changes in the transformer tank's oil level. By detecting the capacitance change caused by the difference in dielectric constant between the oil medium (insulating oil) and the air medium, the percentage of oil level (L) in the tank is calculated. This unit outputs a standard analog current signal.

[0045] (4) The rear cavity of the electronic cavity 11 is used to accommodate the circuit board 13 and the battery 14.

[0046] Main Control and Data Processing Module: The core of this module is a multi-layer printed circuit board on which an ultra-low power microcontroller (MCU) is soldered. In this embodiment, the STMicroelectronics STM32L072 series chip is selected. This MCU has a built-in analog-to-digital converter (ADC), and its multiple ADC channels are connected to the voltage output of the hydrogen sensor, the measurement bridge output of the PT100, and the 4-20mA current receiver of the oil level sensor through onboard signal conditioning circuitry. The MCU is responsible for synchronously acquiring these three signals according to a preset timing sequence and performing digital filtering (such as median filtering) on ​​the raw data to eliminate spike interference.

[0047] Low-power wireless communication module: This module integrates a LoRa wireless communication module based on the Semtech SX1276 chip. It operates in the 470MHz band and connects to the main control MCU via an SPI interface. Its antenna is either a miniaturized onboard antenna or a patch antenna connected to the outer wall via a sealed connector.

[0048] Power management module: Core power supply: Employs the TI BQ25504 ultra-low power energy management chip, whose input is connected to an ER34615 lithium-thionyl chloride battery (rated voltage 3.6V, capacity 19Ah). The BQ25504 chip is responsible for efficiently and stably converting the battery voltage to the 3.3V isoelectric rail required by the system.

[0049] Load switch array: The power management section includes load switches controlled by multiple MCU GPIO ports. One switch controls the power supply to the integrated sensing modules (including power supply circuits for hydrogen, temperature, and oil level sensors); another switch controls the power supply to the LoRa wireless communication module. When data acquisition or communication is not required, the MCU can output control signals to physically cut off the power supply to these relatively high-power modules through the load switches, reducing their power consumption to near zero.

[0050] The circuit board also features local non-volatile memory: it integrates an FRAM (ferroelectric random access memory) chip, which connects to the MCU via an I²C or SPI interface to cache pre-processed sensor data and device operation logs.

[0051] Internal reinforcement and protection: The entire circuit board and the gaps within the electronic cavity 11 are filled and encapsulated with highly thermally conductive and insulating epoxy resin potting compound 12. This enhances resistance to vibration and impact, and further improves the overall sealing, moisture-proof, and heat dissipation performance.

[0052] (5) Mechanical connection: The oil level detection unit 1, hydrogen sensing unit 5 and temperature sensing unit 7 are fixed to the housing of sensing cavity 3 by their respective mounting brackets; the circuit board 13 and battery 14 are mounted on the mounting plate 16 and fixed to the housing or internal bracket of electronic cavity 11 by screws. The rear end of the electronic cavity 11 is provided with a rear cover 17.

[0053] Electrical Connections: The output cables of the oil level detection unit 1, hydrogen sensing unit 5, and temperature sensing unit 7 are connected to the corresponding interfaces on the circuit board 13 via waterproof sealing connectors 18. The battery 14 is connected to the input terminal of the power management module via wires. The output of the power management module provides constant power to the core circuits such as the MCU and memory, and provides controlled power to the sensors and communication modules through a load switch.

[0054] Signal and control flow: Sensor signals are sent to the MCU's ADC; the MCU controls the load switch via GPIO; the MCU communicates with the LoRa module via SPI and with the FRAM via I²C / SPI.

[0055] (6) Brief description of the work process After installation and activation, this utility model will cycle through the following process to achieve ultra-low power consumption operation: Deep Sleep Mode: For most of the time, the MCU controls the shutdown of all load switches, keeping the hydrogen sensing unit, temperature sensing unit, oil level detection unit, and LoRa wireless communication module completely powered down. The MCU itself also enters a shutdown mode, maintaining only the basic operation of an external ultra-low power real-time clock circuit and the power management module, with the overall quiescent current less than 5μA.

[0056] Timed wake-up and data acquisition: The real-time clock generates an interrupt every 5 minutes, waking up the MCU. The MCU first controls the load switch connected to the integrated sensor module to turn on, supplying power to all sensors. After the sensors stabilize, the MCU synchronously acquires one reading of three parameters: hydrogen concentration, oil temperature, and oil level. After acquisition, median filtering is immediately performed, and the obtained valid data is written to the FRAM memory. Subsequently, the MCU controls the load switch to turn off the sensor power supply, preparing to return to sleep mode or enter the upload process.

[0057] Data aggregation and wireless transmission: The real-time clock triggers a data upload task every hour. After the MCU is woken up, it first reads 12 sets of data stored in the FRAM from the past hour. The MCU packages this data along with information such as the device's unique ID and battery voltage into a data frame. Next, the MCU controls the load switch connected to the LoRa communication module to turn on, supplying power to the module. After the module initializes, the data frame is transmitted via the LoRa wireless network to a gateway within a range of approximately 500 meters. The transmission process lasts approximately 3 seconds. After transmission is complete, the MCU immediately controls the power supply to the LoRa module to turn off. Subsequently, the MCU re-enters deep sleep mode.

[0058] Power consumption and battery life calculation: Based on the above operating mode, the overall average power consumption is calculated to be less than 25mW. Combined with the 19Ah lithium-thionyl chloride battery used, it can theoretically support continuous operation for more than 6 years, fully meeting the design requirement of "more than 5 years of maintenance-free battery life".

Claims

1. A plug-in multi-parameter integrated monitoring probe for distribution transformers, characterized in that: The device includes a sensing cavity (3), an isolation cavity (8), and an electronic cavity (11). The head of the sensing cavity (3) is provided with a mechanical interface (4), which is connected to the oil valve on the distribution transformer via a thread. The sensing cavity (3) is provided with an oil level detection unit (1), a hydrogen sensing unit (5), and a temperature sensing unit (7). The mechanical interface (4) is provided with a channel (15) that connects to the oil circuit of the distribution transformer. The oil level detection unit (1), the hydrogen sensing unit (5), and the temperature sensing unit (7) are in full contact with the oil of the distribution transformer. The tail of the sensing cavity (3) is connected to the head of the isolation cavity (8). The electronic cavity (11) is provided with a sealing partition (9) that divides the electronic cavity (11) into three parts. The device consists of a front cavity and a rear cavity. The rear cavity contains a circuit board (13) and a battery (14). The sealing partition (9) is integrated with the tail of the isolation cavity (8). The isolation cavity (8) and the tail of the sensing cavity (3) are located in the front cavity of the electronic cavity (11). The front end of the electronic cavity (11) is matched and sealed with the tail of the sensing cavity (3). The signal cables of the oil level detection unit (1), the hydrogen sensing unit (5), and the temperature sensing unit (7) pass through the isolation cavity (8) and the sealing partition (9) and are connected to the circuit board (13) and the battery (14) in the rear cavity of the electronic cavity (11). The sensing cavity (3), the isolation cavity (8), and the electronic cavity (11) are all cylindrical in shape and located on the same central axis.

2. The plug-in multi-parameter integrated monitoring probe for distribution transformers according to claim 1, characterized in that: The mechanical interface (4) is an interface with external threads, which matches the internal threads of the oil valve interface of the power distribution transformer. The mechanical interface (4) is inserted into the oil valve interface of the power distribution transformer.

3. A plug-in multi-parameter integrated monitoring probe for distribution transformers according to claim 1 or 2, characterized in that: The external thread of the mechanical interface (4) is provided with a fluororubber O-ring (2), and a sealing ring (19) is provided between the front end of the electronic cavity (11) and the tail end of the sensing cavity (3).

4. A plug-in multi-parameter integrated monitoring probe for distribution transformers according to claim 1 or 2, characterized in that: The sensing cavity (3) has multiple insulating supports (6) on its tail circumference. The insulating supports (6) match the inner wall of the front end of the electronic cavity (11). The insulating supports (6) are connected to the inner wall of the front end of the electronic cavity (11) by screws or buckles.

5. A plug-in multi-parameter integrated monitoring probe for distribution transformers according to claim 1 or 2, characterized in that: The output cables of the oil level detection unit (1), hydrogen sensing unit (5) and temperature sensing unit (7) are connected to the corresponding interfaces on the circuit board (13) through waterproof sealing connectors (18); the oil level detection unit (1), hydrogen sensing unit (5) and temperature sensing unit (7) are respectively oil level sensor, hydrogen sensor and temperature sensor, and are evenly distributed on the inner circumference of the sensing cavity (3) through their respective mounting brackets.

6. A plug-in multi-parameter integrated monitoring probe for distribution transformers according to claim 1 or 2, characterized in that: The rear cavity of the electronic cavity (11) is filled with epoxy resin potting compound (12) to encapsulate the sealing partition (9), circuit board (13), battery (14) and output cable in the rear cavity of the electronic cavity (11).

7. A plug-in multi-parameter integrated monitoring probe for distribution transformers according to claim 1 or 2, characterized in that: The outer wall of the electronic cavity (11) is provided with an annular heat dissipation groove (10).

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