Micro-water density monitoring method and system based on multi-sensor fusion compensation

Abstract

The application discloses a kind of micro water density monitoring method and system based on multi-sensor fusion compensation, it is related to electric power equipment safety field.The micro water density monitoring method based on multi-sensor fusion compensation is by ceramic heater, humidity-sensitive capacitor collection piece, dew point, pressure and temperature sensor composition micro water collector Real-time acquisition parameter;4 layer PCB integrated signal conditioning circuit and analog-digital conversion module are used, and micro water collector is heated multiple times by main controller;The collected parameters are subjected to digital filtering processing, cross-validation operation and operation to eliminate the influence of ambient temperature;Through sensor self-calibration mechanism, the measurement accuracy is improved, and finally the standardized micro water density data is output, and the early warning function is triggered based on multi-stage threshold value.Through the application, the problem of low micro water density accuracy and poor reliability in the prior art is solved.Further, the accuracy of micro water density measurement under complex working conditions is effectively improved, and data support is provided for predictive maintenance of intelligent equipment.

Description

Technical Field

[0001] This invention relates to the field of power equipment safety, and more specifically, to a method and system for monitoring micro-water density based on multi-sensor fusion compensation. Background Technology

[0002] Micro-moisture density monitoring is a key technology for ensuring industrial gas quality and safe equipment operation. Pure... Insulating gas is a colorless, odorless, and non-toxic gas that does not burn. It is chemically stable and does not react with other substances at room temperature, possessing superior non-flammability compared to insulating oil. Therefore, it exhibits excellent insulation and arc-quenching properties, making it a relatively ideal insulating medium under normal conditions. In the field of power equipment safety, insulating gases (such as GIS switches and transformers) are used in high-voltage electrical equipment. Even trace amounts of moisture can significantly reduce insulation strength. Excessive moisture can lead to decreased insulation performance and corrosion of equipment by arc decomposition products. International standards (such as IEC 60376 and GB / T 12022) strictly regulate... The limits for trace moisture in gases (≤5 ppmv for fresh gas, ≤300 ppmv for operating gas). Therefore, both domestically and internationally... The analysis, monitoring, and control of trace moisture in gases are of great importance.

[0003] Currently, micro-moisture density monitoring mainly employs the following techniques: dew point method, which detects condensation temperature through a cooled mirror, but is easily affected by ambient temperature fluctuations, exhibiting significant errors in low-temperature, high-humidity environments; electrolysis method, based on the principle of phosphorus pentoxide hygroscopic electrolysis, offers fast response but has a short sensor lifespan, requiring frequent replacement; capacitive polymer thin-film method, which has good stability but exhibits drift over long-term use; and optical methods such as TDLAS, which offer high accuracy but are expensive and complex to maintain. These traditional techniques generally suffer from the limitations of single-parameter detection, making it difficult to comprehensively reflect the gas state. First, single-sensor measurements cannot eliminate environmental interference; a 1°C temperature fluctuation can lead to a 3% error in dew point measurement. Second, asynchronous sampling causes data asynchrony from multiple sources, resulting in the failure of compensation algorithms. Third, the lack of an effective self-calibration mechanism leads to a 5% / year decrease in sensor accuracy after long-term operation. Furthermore, traditional monitoring systems often use analog signal transmission, resulting in poor resistance to electromagnetic interference and failing to meet the digital requirements of smart substations. These problems severely restrict the accuracy and reliability of micro-moisture density monitoring in power equipment condition assessment, necessitating urgent technological upgrades through multi-sensor fusion and intelligent compensation algorithms. Summary of the Invention

[0004] The main objective of this invention is to provide a micro-water density monitoring method and system based on multi-sensor fusion compensation, to at least solve the problems of low monitoring accuracy caused by single-sensor measurement, asynchronous sampling, and environmental interference in existing technologies. This improves the accuracy of micro-water density measurement under complex operating conditions, providing data support for predictive maintenance of intelligent devices.

[0005] To achieve the above objectives, a micro-water density monitoring method and system based on multi-sensor fusion compensation is provided.

[0006] In a first aspect, the present invention provides a method for monitoring micro-water density based on multi-sensor fusion compensation, the method comprising:

[0007] A micro-water collector is constructed using a dew point sensor, a pressure sensor, a ceramic heater, a humidity-sensitive capacitor, and a temperature sensor, and is installed on the gas supply valve of a gas-insulated switchgear.

[0008] A four-layer printed circuit board is connected to the interface of the micro water collector, and an analog-to-digital converter is connected to the main controller. The four-layer printed circuit board, the main controller, and the analog-to-digital converter are placed in a chassis and assembled into a signal processing unit.

[0009] The ceramic heater is triggered by the timer in the main controller to heat the micro water collector multiple times until the temperature collected by the micro water collector reaches a stable state.

[0010] The micro water collector is used to synchronously sample during the heating process and the sampling frequency is specified. Different types of signals collected by the micro water collector are digitally filtered and logically cross-validated to output an integrated data stream.

[0011] A dynamic environmental compensation method is composed of a gas-solid interface adsorption effect compensation method and a pressure-dew point nonlinear mapping and standardization method. The dynamic environmental compensation method is used to eliminate the influence of ambient temperature on the integrated data stream to obtain a data stream after eliminating ambient temperature.

[0012] The data stream after eliminating ambient temperature is self-calibrated and error-corrected using the self-calibration of the dew point sensor and the zero-point calibration of the pressure sensor to obtain micro-water density output data. The ceramic heater is then turned off and cooled to ambient temperature through the heat sink.

[0013] The micro-water density output data is output in ModBus data frame format and matched with preset multi-level early warning rules to issue corresponding early warning actions until the next sampling.

[0014] Specifically, the micro-water collector, composed of a dew point sensor, a pressure sensor, a ceramic heater, a humidity-sensitive capacitive sensing element, and a temperature sensor, and installed on the gas supply valve of the gas-insulated switchgear, includes:

[0015] The dew point sensor is vertically mounted on the gas supply valve, and the sealing surface between the dew point sensor and the gas supply valve is sealed with a fluororubber O-ring.

[0016] The pressure sensor and the dew point sensor share a flange interface, and the bellows of the pressure sensor faces downward.

[0017] Insert the probe of the temperature sensor directly. The air chamber and the temperature sensor use shielded twisted-pair cable as the lead wire;

[0018] The ceramic heater is fixed to the inside of the metal housing by laser welding, and the power pin is led out through an insulating ceramic sleeve.

[0019] The humidity-sensitive capacitor is bonded to the surface of the ceramic heater using conductive silver paste to ensure full contact.

[0020] Specifically, the method involves connecting a 4-layer printed circuit board to the interface of the micro-water collector and connecting the analog-to-digital converter to the main controller. The 4-layer printed circuit board, the main controller, and the analog-to-digital converter are then placed in a chassis to assemble a signal processing unit, comprising:

[0021] The four-layer printed circuit board includes: a top layer consisting of the interface of the micro water collector and analog signal traces, a first inner layer consisting of a fully copper-clad ground plane, a second inner layer consisting of power planes partitioned into 5V and 3.3V zones, and a bottom layer consisting of digital circuit traces.

[0022] The interface circuit of the micro water collector is adjusted by using a Pt100 three-wire connection and a 4-20mA signal processing method.

[0023] The analog-to-digital converter is connected to the main controller via SPI interface wiring;

[0024] The four-layer printed circuit board is installed at the bottom of the chassis. The interface of the micro water collector is connected to the chassis and silicone rubber is applied to the interface for waterproofing. The analog-to-digital converter is installed near the interface of the micro water collector. The main controller is installed on the left side of the chassis and the power supply is installed on the right side of the chassis. The whole assembly constitutes the signal processing unit.

[0025] Specifically, the step of using a timer in the main controller to trigger the ceramic heater to heat the micro-water collector multiple times until the temperature collected by the micro-water collector reaches a stable state includes:

[0026] An STM32 is used as the main controller, and the timer of the STM32 is used to trigger the ceramic heater to heat the micro water collector multiple times. The heating time of each heating is ≤2 minutes and the heating automatically stops when the temperature exceeds the ambient temperature by 15°C.

[0027] The stable state is reached when the temperature fluctuation collected by the micro water collector is less than ±0.1℃ for 10 consecutive times.

[0028] Specifically, the process involves using the micro-water collector to synchronously sample water during the heating process and specifying a sampling frequency. Different types of signals collected by the micro-water collector are digitally filtered, and logical cross-validation is performed on these different types of signals. The resulting integrated data stream is then output, including:

[0029] The cutoff frequency for synchronous sampling is 1Hz, and the resolution of the analog-to-digital converter is ≥16 bits.

[0030] The digital filtering process includes:

[0031] The dew point signal collected by the dew point sensor is processed using median filtering;

[0032] The pressure signal acquired by the pressure sensor is processed using a moving average filter;

[0033] The temperature signal acquired by the temperature sensor is processed using a first-order low-pass filter with a cutoff frequency of 0.1Hz;

[0034] The cross-validation includes: dew point-temperature physical logic check and pressure-density dynamic verification;

[0035] The data stream is integrated and output using time-aligned data packets and a real-time communication protocol.

[0036] Furthermore, the dew point-temperature physical logic check and pressure-density dynamic verification include:

[0037] The dew point-temperature physical logic check includes:

[0038] When the dew point temperature is greater than or equal to the ambient temperature, a level 3 response is triggered:

[0039] a. Activate the self-heating calibration function of the dew point sensor;

[0040] b. An event log consisting of a timestamp and the temperature difference between the dew point temperature and the ambient temperature;

[0041] c. Send the pre-set warning code to the host computer;

[0042] The pressure-density dynamic verification includes:

[0043] according to The state equation calculation The density was used to verify the reasonableness of the pressure value:

[0044]

[0045] in, Representing the The density; Represents absolute pressure; Representing the The gas constant; Represents thermodynamic temperature;

[0046] If three consecutive abnormalities occur, the micro-water collector is determined to be faulty and the self-test mode of the micro-water density monitoring method based on multi-sensor fusion compensation is triggered.

[0047] Specifically, the dynamic environmental compensation method, which combines the gas-solid interface adsorption effect compensation method with the pressure-dew point nonlinear mapping and standardization method, is used to eliminate the influence of ambient temperature on the integrated data stream to obtain a data stream after eliminating ambient temperature. This includes:

[0048] The gas-solid interface adsorption effect compensation method includes:

[0049] A calibration data table was generated by simulating the micro-moisture content under different temperatures and pressures in the laboratory.

[0050] The calibration data table is dynamically checked to correct the measured values ​​based on the temperature collected by the temperature sensor and the pressure collected by the pressure sensor.

[0051] The pressure-dew point nonlinear mapping and normalization method includes:

[0052] The pressure-corrected micro-water value is calculated in real time using the volume fraction conversion formula in GB / T5832.2 standard;

[0053] Electricity standards are based on 20°C.

[0054] Specifically, the step of using the self-calibration of the dew point sensor and the zero-point calibration of the pressure sensor to perform self-calibration and error correction on the data stream after eliminating ambient temperature to obtain micro-water density output data, and then turning off the ceramic heater and cooling it to ambient temperature through the heat sink includes:

[0055] Compensation is performed using the temperature compensation function built into the dew point sensor;

[0056] Calibrate using the zero-point calibration function built into the pressure sensor;

[0057] The ceramic heater is turned off, and the micro-water collector is cooled to ambient temperature via the heat sink.

[0058] Specifically, the step of outputting the micro-water density output data in ModBus data frame format and matching it with preset multi-level early warning rules to issue corresponding early warning actions until the next sampling includes:

[0059] Output ModBus data frame format:

[0060] [Device Address Function Code Data Length Data Field CRC Check]

[0061] The data fields include: current pressure, current temperature, and current... The density, 20°C The volume fraction of gaseous water and the dew point-ambient temperature difference;

[0062] A Level 1 warning is triggered when the dew point-ambient temperature difference is ≤5℃.

[0063] When the 20℃ is A level-two warning is triggered when the volume fraction of gaseous water traces is >300 μL / L;

[0064] A level 3 warning is triggered when data conflicts persist for 60 seconds.

[0065] Secondly, the present invention provides a micro-water density monitoring system based on multi-sensor fusion compensation, wherein the monitoring system applies the monitoring method described in the first aspect, and the monitoring system includes:

[0066] The sensor selection and installation module is used to select suitable models of the dew point sensor, the pressure sensor, and the temperature sensor to form the micro-water collector and install it on the gas supply valve of the gas-insulated switchgear.

[0067] A signal processing unit assembly module is connected to the sensor selection and installation module. It is used to connect the interface of the 4-layer printed circuit board to the micro water collector and to connect the analog-to-digital converter to the main controller. The 4-layer printed circuit board, the main controller and the analog-to-digital converter are placed in the chassis to assemble the signal processing unit.

[0068] A data acquisition and preprocessing module, which is connected to the signal processing unit assembly module, is used to acquire data using the micro water collector after multiple heating operations, perform the preprocessing and integration operations on the acquired data, and output the integrated data stream.

[0069] A dynamic environment compensation module, which is connected to the data acquisition and preprocessing module, is used to eliminate the influence of the integrated data stream using the dynamic environment compensation method to obtain a data stream after eliminating the ambient temperature.

[0070] The self-calibration and error correction module is connected to the dynamic environment compensation module and is used to perform self-calibration and error correction of the micro-water density monitoring method based on multi-sensor fusion compensation using the built-in facilities of the micro-water collector.

[0071] The data frame output and early warning module is connected to the self-calibration and error correction module. It is used to output the micro-water density output data in ModBus data frame format and match it with preset multi-level early warning rules to make corresponding early warning actions.

[0072] This application provides a micro-moisture density monitoring method and system based on multi-sensor fusion compensation. The method first integrates a micro-moisture collector, consisting of dew point, pressure, and temperature sensors, onto the gas supply valve of a gas-insulated switchgear. A signal processing unit is constructed by connecting an analog-to-digital converter and a main controller via a four-layer printed circuit board. Next, the main controller triggers multiple heating cycles and synchronously samples the data, performing digital filtering and logical cross-validation on the multi-source sensor data. Then, a dynamic environmental compensation algorithm combining gas-solid interface adsorption effect compensation and pressure-dew point nonlinear mapping is used to eliminate temperature interference. Next, a sensor self-calibration mechanism corrects data errors, ultimately outputting accurate micro-moisture density data and shutting off the heater. Finally, the data is transmitted via the ModBus protocol, and intelligent early warning is achieved based on multi-level early warning rules, thus completing a high-precision monitoring process from data acquisition, processing, compensation to output. Compared with traditional methods, the micro-moisture density monitoring method based on multi-sensor fusion compensation provided in this application at least solves the problems of low accuracy and poor reliability caused by single-sensor measurement, environmental interference, and asynchronous sampling in existing technologies. This effectively improves the accuracy of micro-water density measurement under complex working conditions, providing data support for predictive maintenance of intelligent equipment. Attached Figure Description

[0073] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0074] Figure 1 A flowchart illustrating the micro-water density monitoring method based on multi-sensor fusion compensation provided in this application;

[0075] Figure 2 A connection diagram of the micro-water density monitoring system based on multi-sensor fusion compensation provided in this application. Detailed Implementation

[0076] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0077] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein.

[0078] In this invention, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0079] This application provides a micro-water density monitoring method and system based on multi-sensor fusion compensation. This method achieves synchronous acquisition of multi-source data by deploying a hybrid sensing unit integrating dew point, pressure, and temperature sensors at the air supply valve and combining it with a signal processing system constructed on a 4-layer PCB board. Digital filtering and logical cross-validation are used to ensure data reliability, and a dynamic environmental compensation algorithm is innovatively applied to eliminate temperature drift interference. After correcting errors through a dual self-calibration mechanism, standardized micro-water density data is output. Finally, intelligent multi-level early warning is achieved based on the ModBus communication protocol, comprehensively solving the problems of low accuracy and poor anti-interference ability of traditional monitoring methods.

[0080] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0081] Figure 1 This is a flowchart illustrating the micro-water density monitoring method based on multi-sensor fusion compensation provided in this application, as shown below. Figure 1 As shown, this embodiment provides a micro-water density monitoring method based on multi-sensor fusion compensation, which includes:

[0082] S101: A micro-water collector is composed of a dew point sensor, a pressure sensor, a ceramic heater, a humidity-sensitive capacitor, and a temperature sensor, and is installed on the gas supply valve of a gas-insulated switchgear.

[0083] Specifically, the micro-water collector, composed of a dew point sensor, a pressure sensor, a ceramic heater, a humidity-sensitive capacitive sensing element, and a temperature sensor, and installed on the gas supply valve of the gas-insulated switchgear, includes:

[0084] The dew point sensor is vertically mounted on the gas supply valve, and the sealing surface between the dew point sensor and the gas supply valve is sealed with a fluororubber O-ring.

[0085] The pressure sensor and the dew point sensor share a flange interface, and the bellows of the pressure sensor faces downward.

[0086] Insert the probe of the temperature sensor directly. The air chamber and the temperature sensor use shielded twisted-pair cable as the lead wire;

[0087] The ceramic heater is fixed to the inside of the metal housing by laser welding, and the power pin is led out through an insulating ceramic sleeve.

[0088] The humidity-sensitive capacitor is bonded to the surface of the ceramic heater using conductive silver paste to ensure full contact.

[0089] The implementation of S101 specifically includes:

[0090] 1. Dew point sensor selection and installation

[0091] 1.1 The Vaisala DMT142 dew point sensor was selected, with the following key parameters: range -60~+50℃, 4-20mA output, and self-heating calibration function.

[0092] 1.2 Vertically mount the selected dew point sensor onto the GIS make-up valve and use a fluororubber O-ring on the sealing surface between the selected dew point sensor and the GIS make-up valve.

[0093] 2. Pressure Sensor Selection and Installation

[0094] 2.1 The ZQ502 pressure sensor was selected, with the following key parameters: 0-1.2MPa, ±0.1% accuracy, and stainless steel welded housing;

[0095] 2.2 The selected pressure sensor and the selected dew point sensor share the same flange interface and the bellows is installed facing downwards to prevent water accumulation.

[0096] 3. Temperature Sensor Selection and Installation

[0097] 3.1 A Pt100 three-wire temperature sensor was selected, with the following key parameters: Class A accuracy (±0.15℃) and IP65 protection rating.

[0098] 3.2 Insert the probe of the selected temperature sensor directly. The gas chamber is located there, and shielded twisted-pair cables are used as the leads for the selected temperature sensor.

[0099] 4. Selection and installation of ceramic heaters

[0100] 4.1 Select a thickness of 1mm The substrate is used as a ceramic heater;

[0101] 4.2 The selected ceramic heater is fixed inside the 316L stainless steel metal shell by laser welding, and the power pin is led out through an insulating ceramic sleeve.

[0102] 5. Selection and installation of humidity-sensitive capacitive sensing chips

[0103] 5.1 A 50 μm thick polymer film was selected as the humidity-sensitive capacitor data acquisition chip;

[0104] 5.2 The humidity-sensitive capacitor is bonded to the surface of the ceramic heater using conductive silver paste to ensure full contact.

[0105] S102: A 4-layer printed circuit board is connected to the interface of the micro water collector, and the analog-to-digital converter is connected to the main controller. The 4-layer printed circuit board, the main controller, and the analog-to-digital converter are placed in a chassis and assembled into a signal processing unit.

[0106] Specifically, the method involves connecting a 4-layer printed circuit board to the interface of the micro-water collector and connecting the analog-to-digital converter to the main controller. The 4-layer printed circuit board, the main controller, and the analog-to-digital converter are then placed in a chassis to assemble a signal processing unit, comprising:

[0107] The four-layer printed circuit board includes: a top layer consisting of the interface of the micro water collector and analog signal traces, a first inner layer consisting of a fully copper-clad ground plane, a second inner layer consisting of power planes partitioned into 5V and 3.3V zones, and a bottom layer consisting of digital circuit traces.

[0108] The interface circuit of the micro water collector is adjusted by using a Pt100 three-wire connection and a 4-20mA signal processing method.

[0109] The analog-to-digital converter is connected to the main controller via SPI interface wiring;

[0110] The four-layer printed circuit board is installed at the bottom of the chassis. The interface of the micro water collector is connected to the chassis and silicone rubber is applied to the interface for waterproofing. The analog-to-digital converter is installed near the interface of the micro water collector. The main controller is installed on the left side of the chassis and the power supply is installed on the right side of the chassis. The whole assembly constitutes the signal processing unit.

[0111] The implementation of S102 specifically includes:

[0112] 1. Selection of Signal Processing Unit Component Model

[0113] 1.1 The STM32H743VIT6 is used as the main controller;

[0114] 1.2 The ADS1248, which supports Pt100 bridge and 4-20mA input, is used as the analog-to-digital converter;

[0115] 1.3 The MAX3485ESA is used as the communication module;

[0116] 1.4 The INA128 is used as the signal conditioning IC;

[0117] 1.5 The LM2596-5V with a 24V output is used as the power supply, of which 5V is output to the digital circuit;

[0118] 1.6 The TI ISO7840 is used as the isolated power supply to provide power isolation for the sensor.

[0119] 2. Circuit board design and assembly

[0120] 2.1 Circuit board layer design:

[0121] Design a 4-layer circuit board:

[0122] Top layer: Sensor interface and analog signal traces. Analog signal traces need to be short and straight to keep them away from the digital circuit section.

[0123] First inner layer: ground plane, which needs to be fully copper-clad to reduce noise;

[0124] Second inner layer: power plane, requiring 5V and 3.3V partitioning;

[0125] Bottom layer: Digital circuits;

[0126] 2.2 Sensor Interface Circuit:

[0127] The Pt100 temperature sensor uses a three-wire connection. The excitation terminal (wire 1) is connected to the output of a constant current source to provide 1mA excitation current; the detection terminal + (wire 2) is connected to the positive input terminal of the bridge circuit for measuring voltage; and the detection terminal - (wire 3) is connected to the negative input terminal of the bridge circuit for compensating for wire resistance.

[0128] Constant current source driver:

[0129] A precision constant current source is used to output a constant current of 1mA through Pt100 and line 1. The current accuracy must be ≤0.1% to avoid self-heating error and leave a voltage margin to ensure that the constant current source can still work when Pt100 is at the highest temperature.

[0130] Bridge configuration:

[0131] The two arms of the bridge have fixed resistors R1=R2=100Ω to match the 0℃ resistance of Pt100;

[0132] Pt100 is connected to the detection terminals (line 2, line 3) of the bridge to form a differential signal;

[0133] Instrument amplifier parameter settings:

[0134]

[0135] Where G represents gain; Represents the gain resistor;

[0136] Instrumentation amplifier output signal:

[0137]

[0138] in, This represents the output signal voltage of the instrumentation amplifier; and This represents the voltage at the sensing end of the temperature sensor.

[0139] Analog-to-digital converter connection method:

[0140] The output of INA128 is connected to the differential input channels AIN0 / AIN1 of ADS1248;

[0141] Temperature calculation and compensation:

[0142] Resistance calculation formula:

[0143]

[0144] in, Represents the resistance of the temperature sensor; Represents the analog-to-digital converter voltage; Represents the constant current source current; This represents the resistance of the wires between the temperature sensor and the measuring circuit.

[0145] Temperature conversion:

[0146] Use a lookup table to convert the resistance value into a temperature value;

[0147] 2.3 Analog-to-Digital Converter 4-20mA Signal Processing;

[0148] 2.3.1 Current-to-voltage conversion: Converting 4-20mA current to 1-5V voltage using a 250Ω precision resistor.

[0149]

[0150] in, This represents the voltage of the dew point sensor; Represents a current of 4-20mA; The resistance value representing a precision resistor;

[0151] 2.3.2 An RC filter is selected for low-pass filtering to suppress high-frequency noise, wherein... =1kΩ, =100nF, the cutoff frequency is calculated using the following formula:

[0152]

[0153] in, Represents the cutoff frequency;

[0154] 2.3.3 Analog-to-Digital Converter Configuration:

[0155] The input channel is a differential input AIN2 (AINP2 / AINN2), which measures 1-5V signals. An external 5V reference voltage is selected to ensure the full-scale accuracy of the ADC.

[0156] 2.3.4 The protection circuit uses a TVS diode and is placed close to the AIN2 pin of the ADS1248;

[0157] 2.3.5 Calibration Calculation Formula:

[0158] Zero-point calibration, input 4mA, record ADC value. ;

[0159] Full-scale calibration, input 20mA, record the ADC value. ;

[0160] The actual analog-to-digital converter current value is calculated using the linear conversion formula:

[0161]

[0162] in, This represents the actual analog-to-digital converter current value after calibration. This represents the analog-to-digital converter reading during measurement.

[0163] 3. Chassis assembly and wiring

[0164] 3.1 Shell Selection: The material is aluminum alloy, with dimensions of 120mm×80mm×40mm for lightweight design;

[0165] 3.2 Interface Definition:

[0166] The sensor input uses an M12-4 pin aviation connector to connect Pt100, DMT142 and ZQ502, and the connection cable is a 0.5mm² shielded twisted pair cable;

[0167] The power input uses Phoenix MC1.5 / 2 to connect to 24V DC, and the connection cable is a 1mm² cable.

[0168] The RS485 output uses Phoenix MC1.5 / 2 to connect to the host computer or the next node, and the connection cable is 0.75mm² shielded twisted pair cable;

[0169] 3.3 Internal Layout Design of the Chassis:

[0170] The main controller PCB is mounted on the left, the RS485 isolation module and power conversion circuit are mounted on the right, and the ADC module is mounted at the bottom, forming a signal processing unit.

[0171] S103: The timer in the main controller is used to trigger the ceramic heater to heat the micro water collector multiple times until the temperature collected by the micro water collector reaches a stable state.

[0172] Specifically, the step of using a timer in the main controller to trigger the ceramic heater to heat the micro-water collector multiple times until the temperature collected by the micro-water collector reaches a stable state includes:

[0173] An STM32 is used as the main controller, and the timer of the STM32 is used to trigger the ceramic heater to heat the micro water collector multiple times. The heating time of each heating is ≤2 minutes and the heating automatically stops when the temperature exceeds the ambient temperature by 15°C.

[0174] The stable state is reached when the temperature fluctuation collected by the micro water collector is less than ±0.1℃ for 10 consecutive times.

[0175] The implementation of S103 specifically includes:

[0176] 1. Use STM32 timer TIM2 to set a one-hour period;

[0177] 2. The micro water collector is heated using a ceramic heater, and the heating time for a single heating cycle is ≤2 minutes;

[0178] 3. The heating will automatically stop if the heating temperature exceeds the ambient temperature by 15°C.

[0179] 4. When the temperature fluctuation recorded by the micro water collector is less than ±0.1℃ for 10 consecutive times, start collecting micro water density related data.

[0180] S104: The micro water collector is used to synchronously sample during the heating process and the sampling frequency is specified. Different types of signals collected by the micro water collector are digitally filtered and logically cross-validated to output the integrated data stream.

[0181] Specifically, the process involves using the micro-water collector to synchronously sample water during the heating process and specifying a sampling frequency. Different types of signals collected by the micro-water collector are digitally filtered, and logical cross-validation is performed on these different types of signals. The resulting integrated data stream is then output, including:

[0182] The cutoff frequency for synchronous sampling is 1Hz, and the resolution of the analog-to-digital converter is ≥16 bits.

[0183] The digital filtering process includes:

[0184] The dew point signal collected by the dew point sensor is processed using median filtering;

[0185] The pressure signal acquired by the pressure sensor is processed using a moving average filter;

[0186] The temperature signal acquired by the temperature sensor is processed using a first-order low-pass filter with a cutoff frequency of 0.1Hz;

[0187] The cross-validation includes: dew point-temperature physical logic check and pressure-density dynamic verification;

[0188] The data stream is integrated and output using time-aligned data packets and a real-time communication protocol.

[0189] Furthermore, the dew point-temperature physical logic check and pressure-density dynamic verification include:

[0190] The dew point-temperature physical logic check includes:

[0191] When the dew point temperature is greater than or equal to the ambient temperature, a level 3 response is triggered:

[0192] a. Activate the self-heating calibration function of the dew point sensor;

[0193] b. An event log consisting of a timestamp and the temperature difference between the dew point temperature and the ambient temperature;

[0194] c. Send the pre-set warning code to the host computer;

[0195] The pressure-density dynamic verification includes:

[0196] according to The state equation calculation The density was used to verify the reasonableness of the pressure value:

[0197]

[0198] in, Representing the The density; Represents absolute pressure; Representing the The gas constant; Represents thermodynamic temperature;

[0199] If three consecutive abnormalities occur, the micro-water collector is determined to be faulty and the self-test mode of the micro-water density monitoring method based on multi-sensor fusion compensation is triggered.

[0200] The implementation of S104 specifically includes:

[0201] 1. Synchronous sampling configuration

[0202] 1.1 Hardware-triggered synchronization;

[0203] 1.1.1 Trigger source configuration:

[0204] Use STM32 timer TIM2 to generate a 1Hz PWM wave (1s period, 1% duty cycle), and start all ADC channels to sample synchronously via hardware trigger mode;

[0205] 1.1.2 Channel Allocation:

[0206] ADC1_IN0: Pt100 temperature (differential input);

[0207] ADC1_IN1: Dew point sensor 4-20mA (single-ended);

[0208] ADC1_IN2: Pressure sensor 4-20mA (single-ended);

[0209] 1.2 Sampling timing guarantee;

[0210] 1.2.1 Time window constraint: all channel sampling must be completed within 1ms, and the ADC clock is set to 10MHz;

[0211] 1.2.2 Data alignment: Use DMA to store the ADC results into a memory buffer and align them by timestamp (error <10μs).

[0212] 2. Digital Filtering Implementation

[0213] 2.1 Median filtering algorithm is used to process the dew point signal: the median of the five most recent sampled values ​​is taken after sorting. This suppresses the pulse noise caused by mirror condensation. If self-heating is detected, the window is temporarily expanded to cover the heating cycle.

[0214] 2.2 The moving average filtering algorithm is used to process the pressure signal: the arithmetic mean of 10 consecutive sampled values ​​is calculated, and the weights are evenly distributed;

[0215] 2.3 A first-order low-pass filter algorithm with a cutoff frequency of 0.1Hz is used to process the temperature signal: cutoff frequency 0.1Hz, time constant τ=1.59 seconds.

[0216] 3. Sensor cross-validation logic

[0217] 3.1 Dew point-temperature physical logic check: When the dew point temperature is greater than or equal to the ambient temperature, a level 3 response is triggered.

[0218] a. Activate the self-heating calibration function of the dew point sensor;

[0219] b. An event log consisting of a timestamp and the temperature difference between the dew point temperature and the ambient temperature;

[0220] c. Send the pre-set warning code to the host computer;

[0221] 3.2 Pressure-density dynamic verification;

[0222] according to The state equation calculation The density was used to verify the reasonableness of the pressure value:

[0223]

[0224] in, Representing the The density; Represents absolute pressure; Representing the The gas constant; Represents thermodynamic temperature;

[0225] If three consecutive abnormalities occur, the micro-water collector is determined to be faulty and the self-test mode of the micro-water density monitoring method based on multi-sensor fusion compensation is triggered.

[0226] S105: A dynamic environmental compensation method is formed by combining the gas-solid interface adsorption effect compensation method with the pressure-dew point nonlinear mapping and standardization method. The dynamic environmental compensation method is used to eliminate the influence of ambient temperature on the integrated data stream to obtain the data stream after eliminating ambient temperature.

[0227] Specifically, the dynamic environmental compensation method, which combines the gas-solid interface adsorption effect compensation method with the pressure-dew point nonlinear mapping and standardization method, is used to eliminate the influence of ambient temperature on the integrated data stream to obtain a data stream after eliminating ambient temperature. This includes:

[0228] The gas-solid interface adsorption effect compensation method includes:

[0229] A calibration data table was generated by simulating the micro-moisture content under different temperatures and pressures in the laboratory.

[0230] The calibration data table is dynamically checked to correct the measured values ​​based on the temperature collected by the temperature sensor and the pressure collected by the pressure sensor.

[0231] The pressure-dew point nonlinear mapping and normalization method includes:

[0232] The pressure-corrected micro-water value is calculated in real time using the volume fraction conversion formula in GB / T5832.2 standard;

[0233] Electricity standards are based on 20°C.

[0234] The implementation of S105 specifically includes:

[0235] 1. Gas-solid interface adsorption effect compensation method;

[0236] 1.1 Fabrication of a two-dimensional temperature and pressure compensation gauge: By simulating the trace moisture content at different temperatures (-30~60℃) and pressures (0.1~0.7MPa) in the laboratory, a calibration data table was generated, as shown in Table 1:

[0237] Table 1

[0238]

[0239] 1.2 Real-time interpolation calculation: dynamically look up tables based on current temperature and pressure to correct measured values.

[0240] 2. Pressure-dew point nonlinear mapping and standardization method;

[0241] 2.1 The pressure-corrected micro-water value is calculated in real time using the standard formula of GB / T 5832.2:

[0242]

[0243] in, Represents the volume fraction of water. Represents the dew point value; This represents the air pressure value inside the SF6 gas chamber;

[0244] 2.2 Standardized output at 20℃, with power standards based on 20℃.

[0245] S106: The data stream after eliminating ambient temperature is self-calibrated and error corrected using the self-calibration of the dew point sensor and the zero-point calibration of the pressure sensor to obtain micro-water density output data. The ceramic heater is then turned off and cooled to ambient temperature through the heat sink.

[0246] Specifically, the step of using the self-calibration of the dew point sensor and the zero-point calibration of the pressure sensor to perform self-calibration and error correction on the data stream after eliminating ambient temperature to obtain micro-water density output data, and then turning off the ceramic heater and cooling it to ambient temperature through the heat sink includes:

[0247] Compensation is performed using the temperature compensation function built into the dew point sensor;

[0248] Calibrate using the zero-point calibration function built into the pressure sensor;

[0249] The ceramic heater is turned off, and the micro-water collector is cooled to ambient temperature via the heat sink.

[0250] The implementation of S106 specifically includes:

[0251] 1. Dew point sensor self-calibration

[0252] 1.1 When the dew point sensor starts working, the temperature rises and the relative humidity decreases;

[0253] 1.2 After a brief heating period, the sensor begins to cool down, and the RH value gradually increases;

[0254] 1.3 Record the temperature and relative humidity during the cooling process, linearize the recorded data, and obtain the drift amount;

[0255] 1.4 When the sensor resumes normal measurement, the drift error will be eliminated;

[0256] 1.5 Set the automatic calibration cycle to once per hour.

[0257] 2. Zero-point calibration of pressure sensor

[0258] 2.1 After turning on the power to the pressure sensor, keep it warm for 30 minutes to eliminate the influence of temperature drift;

[0259] 2.2 Start loading from zero pressure, increasing the range by 20% each time, and gradually depressurize after reaching full range;

[0260] 2.3 Take a reading after each pressure point has stabilized for 3 minutes;

[0261] 2.4 Record the displayed value of the standard pressure source and the output signal of the pressure sensor;

[0262] 2.5 Calculate the linearity error at each point, with the allowable deviation not exceeding +0.5% of full scale;

[0263] 2.6 When an error exceeding the standard is found at a certain point, the mechanical structure of that pressure range should be checked in detail.

[0264] 3. After all data acquisition and processing are completed, the ceramic heater is turned off, and the temperature is lowered to ambient temperature via the heat sink. The entire heating, data acquisition, and cooling process takes one hour.

[0265] S107: Output the micro-water density data in ModBus data frame format and match it with preset multi-level early warning rules to issue corresponding early warning actions until the next sampling.

[0266] Specifically, the step of outputting the micro-water density output data in ModBus data frame format and matching it with preset multi-level early warning rules to issue corresponding early warning actions until the next sampling includes:

[0267] Output ModBus data frame format:

[0268] [Device address function code data length data field CRC check];

[0269] The data fields include: current pressure, current temperature, and current... The density, 20°C The volume fraction of gaseous water and the dew point-ambient temperature difference;

[0270] A Level 1 warning is triggered when the dew point-ambient temperature difference is ≤5℃.

[0271] When the 20℃ is A level-two warning is triggered when the volume fraction of gaseous water traces is >300 μL / L;

[0272] A level 3 warning is triggered when data conflicts persist for 60 seconds.

[0273] The implementation of S107 specifically includes:

[0274] 1. Output the measured and calculated data in ModBus data frame format:

[0275] [Device address function code data length data field CRC check];

[0276] The device address is 1 byte long and is a unique identifier for slave devices in the network, used to achieve accurate addressing when multiple devices are networked.

[0277] The function code is 1 byte long and specifies the operation type to distinguish the data read / write request type, ensuring protocol flexibility;

[0278] The data length is 1 byte, which indicates the number of bytes in the subsequent data field and helps the receiver correctly parse the data field boundaries;

[0279] The data fields include: current pressure, current temperature, and current reading. The density, 20°C The volume fraction of gaseous water and the dew point-ambient temperature difference, 12 bytes in length;

[0280] CRC checksums are 2 bytes long and are used to detect transmission errors and ensure data integrity. They perform cyclic redundancy checks on all bytes from the device address to the data field.

[0281] a. Initialize CRC to 0xFFFF;

[0282] b. XOR each byte and then right-shift it. If the shifted-out bit is 1, then XOR it with the polynomial 0xA001.

[0283] c. The final result is in low-byte order.

[0284] 2. Based on the output data, match the preset multi-level early warning rules to issue corresponding early warning actions. The specific matching mechanism is shown in Table 2:

[0285] Table 2

[0286]

[0287] Figure 2 The connection diagram of the micro-water density monitoring system based on multi-sensor fusion compensation provided in this application is as follows: Figure 2 As shown, this embodiment provides a micro-water density monitoring system based on multi-sensor fusion compensation. This system applies... Figure 1 The micro-water density monitoring method based on multi-sensor fusion compensation described in the embodiment includes a monitoring system comprising:

[0288] The sensor selection and installation module is used to select suitable models of the dew point sensor, the pressure sensor, and the temperature sensor to form the micro-water collector and install it on the gas supply valve of the gas-insulated switchgear.

[0289] A signal processing unit assembly module is connected to the sensor selection and installation module. It is used to connect the interface of the 4-layer printed circuit board to the micro water collector and to connect the analog-to-digital converter to the main controller. The 4-layer printed circuit board, the main controller and the analog-to-digital converter are placed in the chassis to assemble the signal processing unit.

[0290] A data acquisition and preprocessing module, which is connected to the signal processing unit assembly module, is used to acquire data using the micro water collector after multiple heating operations, perform the preprocessing and integration operations on the acquired data, and output the integrated data stream.

[0291] A dynamic environment compensation module, which is connected to the data acquisition and preprocessing module, is used to eliminate the influence of the integrated data stream using the dynamic environment compensation method to obtain a data stream after eliminating the ambient temperature.

[0292] The self-calibration and error correction module is connected to the dynamic environment compensation module and is used to perform self-calibration and error correction of the micro-water density monitoring method based on multi-sensor fusion compensation using the built-in facilities of the micro-water collector.

[0293] The data frame output and early warning module is connected to the self-calibration and error correction module. It is used to output the micro-water density output data in ModBus data frame format and match it with preset multi-level early warning rules to make corresponding early warning actions.

[0294] The sensor selection and installation module specifically includes:

[0295] Select appropriate models of dew point sensor, pressure sensor and temperature sensor;

[0296] The selected dew point sensor, pressure sensor, and temperature sensor are installed on the gas supply valve of the gas-insulated switchgear in a fixed manner.

[0297] The signal processing unit assembly module specifically includes:

[0298] Select a suitable signal processing unit component;

[0299] Design a 4-layer circuit board;

[0300] Configure the circuitry at each sensor interface;

[0301] Configure the analog-to-digital converter;

[0302] The actual analog-to-digital converter current value is calculated using a linear conversion formula.

[0303] The components are installed in the chassis in a specific manner.

[0304] The data acquisition and preprocessing module specifically includes:

[0305] The ceramic heater is controlled by the main controller to heat the ceramic to 15°C above room temperature.

[0306] Configuration is sampled synchronously via the main controller;

[0307] Different digital filtering algorithms are used to process the data collected by different types of sensors;

[0308] Use sensor cross-validation logic.

[0309] The dynamic environment compensation module specifically includes:

[0310] The gas-solid interface adsorption effect compensation method is used to eliminate the influence of ambient temperature on the integrated data stream.

[0311] The influence of ambient temperature on the integrated data stream is eliminated by using pressure-dew point nonlinear mapping and normalization.

[0312] Obtain the data stream after removing ambient temperature.

[0313] The self-calibration and error correction module specifically includes:

[0314] Compensation is performed using the temperature compensation function built into the dew point sensor;

[0315] Calibrate using the zero-point calibration function built into the pressure sensor;

[0316] Obtain micro-water density output data;

[0317] The ceramic heater was turned off and allowed to cool down until room temperature.

[0318] The data frame output and early warning module specifically includes:

[0319] The micro-water density output data is output in ModBus data frame format;

[0320] Based on the output data, match the preset multi-level early warning rules to issue corresponding early warning actions.

Claims

1. A method for monitoring micro-water density based on multi-sensor fusion compensation, characterized in that, include: A micro-water collector is constructed using a dew point sensor, a pressure sensor, a ceramic heater, a humidity-sensitive capacitor, and a temperature sensor, and is installed on the gas supply valve of a gas-insulated switchgear. A four-layer printed circuit board is connected to the interface of the micro water collector, and an analog-to-digital converter is connected to the main controller. The four-layer printed circuit board, the main controller, and the analog-to-digital converter are placed in a chassis and assembled into a signal processing unit. The ceramic heater is triggered by the timer in the main controller to heat the micro water collector multiple times until the temperature collected by the micro water collector reaches a stable state. The micro water collector is used to synchronously sample during the heating process and the sampling frequency is specified. Different types of signals collected by the micro water collector are digitally filtered and logically cross-validated to output an integrated data stream. The cross-validation includes: dew point-temperature physical logic check and pressure-density dynamic verification. The dew point-temperature physical logic check includes: triggering a level 3 response when the dew point temperature is greater than or equal to the ambient temperature. a. Activate the self-heating calibration function of the dew point sensor; b. An event log consisting of a timestamp and the temperature difference between the dew point temperature and the ambient temperature; c. Send the pre-set warning code to the host computer; The pressure-density dynamic verification includes: according to The state equation calculation The density was used to verify the reasonableness of the pressure value: in, Representing the The density; Represents absolute pressure; Representing the The gas constant; Represents thermodynamic temperature; if three consecutive abnormal readings occur, the micro-water collector is determined to have malfunctioned and the self-test mode of the micro-water density monitoring method based on multi-sensor fusion compensation is triggered. A dynamic environmental compensation method is composed of a gas-solid interface adsorption effect compensation method and a pressure-dew point nonlinear mapping and standardization method. The dynamic environmental compensation method is used to eliminate the influence of ambient temperature on the integrated data stream to obtain a data stream after eliminating ambient temperature. The gas-solid interface adsorption effect compensation method includes: generating a calibration data table by simulating the micro-water content under different temperatures and pressures in the laboratory; and dynamically checking the calibration data table to correct the measured values ​​based on the temperature collected by the temperature sensor and the pressure collected by the pressure sensor. The data stream after eliminating ambient temperature is self-calibrated and error-corrected using the self-calibration of the dew point sensor and the zero-point calibration of the pressure sensor to obtain micro-water density output data. The ceramic heater is then turned off and cooled to ambient temperature through the heat sink. The micro-water density output data is output in ModBus data frame format and matched with preset multi-level early warning rules to issue corresponding early warning actions until the next sampling.

2. The micro-water density monitoring method based on multi-sensor fusion compensation according to claim 1, characterized in that, The micro-water collector, composed of a dew point sensor, a pressure sensor, a ceramic heater, a humidity-sensitive capacitive sensing element, and a temperature sensor, is installed on the gas supply valve of the gas-insulated switchgear. It includes: The dew point sensor is vertically mounted on the gas supply valve, and the sealing surface between the dew point sensor and the gas supply valve is sealed with a fluororubber O-ring. The pressure sensor and the dew point sensor share a flange interface, and the bellows of the pressure sensor faces downward. Insert the probe of the temperature sensor directly. The air chamber and the temperature sensor use shielded twisted-pair cable as the lead wire; The ceramic heater is fixed to the inside of the metal housing by laser welding, and the power pin is led out through an insulating ceramic sleeve. The humidity-sensitive capacitor is bonded to the surface of the ceramic heater using conductive silver paste to ensure full contact.

3. The micro-water density monitoring method based on multi-sensor fusion compensation according to claim 1, characterized in that, The four-layer printed circuit board is connected to the interface of the micro water collector, and the analog-to-digital converter is connected to the main controller. The four-layer printed circuit board, the main controller, and the analog-to-digital converter are placed in a chassis to assemble a signal processing unit, including: The four-layer printed circuit board includes: a top layer consisting of the interface of the micro water collector and analog signal traces, a first inner layer consisting of a fully copper-clad ground plane, a second inner layer consisting of power planes partitioned into 5V and 3.3V zones, and a bottom layer consisting of digital circuit traces. The interface circuit of the micro water collector is adjusted by using a Pt100 three-wire connection and a 4-20mA signal processing method. The analog-to-digital converter is connected to the main controller via SPI interface wiring; The four-layer printed circuit board is installed at the bottom of the chassis. The interface of the micro water collector is connected to the chassis and silicone rubber is applied to the interface for waterproofing. The analog-to-digital converter is installed near the interface of the micro water collector. The main controller is installed on the left side of the chassis and the power supply is installed on the right side of the chassis. The whole assembly constitutes the signal processing unit.

4. The micro-water density monitoring method based on multi-sensor fusion compensation according to claim 1, characterized in that, The step of using a timer in the main controller to trigger the ceramic heater to heat the micro water collector multiple times until the temperature collected by the micro water collector reaches a stable state includes: An STM32 is used as the main controller, and the timer of the STM32 is used to trigger the ceramic heater to heat the micro water collector multiple times. The heating time of each heating is ≤2 minutes and the heating automatically stops when the temperature exceeds the ambient temperature by 15°C. The stable state is reached when the temperature fluctuation collected by the micro water collector is less than ±0.1℃ for 10 consecutive times.

5. The micro-water density monitoring method based on multi-sensor fusion compensation according to claim 1, characterized in that, The process involves using the micro-water collector to synchronously sample water during the heating process at a specified sampling frequency. Different types of signals collected by the micro-water collector are digitally filtered and logically cross-validated. The resulting integrated data stream is then output, including: The cutoff frequency for synchronous sampling is 1Hz, and the resolution of the analog-to-digital converter is ≥16 bits. The digital filtering process includes: The dew point signal collected by the dew point sensor is processed using median filtering; The pressure signal acquired by the pressure sensor is processed using a moving average filter; The temperature signal acquired by the temperature sensor is processed using a first-order low-pass filter with a cutoff frequency of 0.1Hz; The data stream is integrated and output using time-aligned data packets and a real-time communication protocol.

6. The micro-water density monitoring method based on multi-sensor fusion compensation according to claim 1, characterized in that, The dynamic environmental compensation method, which combines the gas-solid interface adsorption effect compensation method with the pressure-dew point nonlinear mapping and standardization method, is used to eliminate the influence of ambient temperature on the integrated data stream, thereby obtaining a data stream after eliminating ambient temperature. This includes: The pressure-dew point nonlinear mapping and normalization method includes: The pressure-corrected micro-water value is calculated in real time using the volume fraction conversion formula in GB / T5832.2 standard; Electricity standards are based on 20°C.

7. The micro-water density monitoring method based on multi-sensor fusion compensation according to claim 1, characterized in that, The process of using the self-calibration of the dew point sensor and the zero-point calibration of the pressure sensor to perform self-calibration and error correction on the data stream after eliminating ambient temperature to obtain micro-water density output data, and then turning off the ceramic heater and cooling it to ambient temperature through heat sinks includes: Compensation is performed using the temperature compensation function built into the dew point sensor; Calibrate using the zero-point calibration function built into the pressure sensor; The ceramic heater is turned off, and the micro-water collector is cooled to ambient temperature via the heat sink.

8. The micro-water density monitoring method based on multi-sensor fusion compensation according to claim 1, characterized in that, The step of outputting the micro-water density output data in ModBus data frame format and matching it with preset multi-level early warning rules to issue corresponding early warning actions until the next sampling includes: Output ModBus data frame format: [Device Address Function Code Data Length Data Field CRC Check] The data fields include: current pressure, current temperature, current SF6 density, and 20°C. The volume fraction of gaseous water and the dew point-ambient temperature difference; A Level 1 warning is triggered when the dew point-ambient temperature difference is ≤5℃. When the 20℃ is A level-two warning is triggered when the volume fraction of gaseous water traces is >300 μL / L; A level 3 warning is triggered when data conflicts persist for 60 seconds.

9. A micro-water density monitoring system based on multi-sensor fusion compensation, characterized in that, The monitoring system employs the monitoring method according to any one of claims 1 to 8, and the monitoring system comprises: The sensor selection and installation module is used to select suitable models of the dew point sensor, the pressure sensor, and the temperature sensor to form the micro-water collector and install it on the gas supply valve of the gas-insulated switchgear. A signal processing unit assembly module is connected to the sensor selection and installation module. It is used to connect the interface of the 4-layer printed circuit board to the micro water collector and to connect the analog-to-digital converter to the main controller. The 4-layer printed circuit board, the main controller and the analog-to-digital converter are placed in the chassis to assemble the signal processing unit. A data acquisition and preprocessing module, which is connected to the signal processing unit assembly module, is used to acquire data using the micro water collector after multiple heating operations, perform the preprocessing and integration operations on the acquired data, and output the integrated data stream. A dynamic environment compensation module, which is connected to the data acquisition and preprocessing module, is used to eliminate the influence of the integrated data stream using the dynamic environment compensation method to obtain a data stream after eliminating the ambient temperature. The self-calibration and error correction module is connected to the dynamic environment compensation module and is used to perform self-calibration and error correction of the micro-water density monitoring method based on multi-sensor fusion compensation using the built-in facilities of the micro-water collector. The data frame output and early warning module is connected to the self-calibration and error correction module. It is used to output the micro-water density output data in ModBus data frame format and match it with preset multi-level early warning rules to make corresponding early warning actions.

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