1SF6The core function of gas monitoring sensors

SF6Gas monitoring sensors are key tools for detecting the status of power equipment, and their core functions revolve aroundSF6The physical and electrical properties of gases are explored, and multidimensional data acquisition and analysis are achieved through high-precision sensing technology.

1. Real time monitoring of concentration

Using non dispersive infrared spectroscopy（NDIR）Or electrochemical sensing principle, which can accurately measureSF6Gas volume fraction（0-2000ppmRange), accuracy up to±1%FSFor example, inGISIn gas insulated switchgear, sensors can continuously trackSF6Leakage situation, when the concentration drops to the threshold (such as80%Trigger an alarm when the rated concentration is reached.

Application case: A certain500kVThe substation successfully captured the circuit breaker chamber by deploying sensors0.5%/Minor leakage of the year, ahead of schedule3Complete maintenance within a month to avoid unplanned shutdowns.

2. Humidity and temperature compensation

Integrate temperature and humidity sensors to correct the impact of environmental factors on measurement results through algorithms. Humidity measurement range0-100%RHTemperature compensation range-40℃~+80℃Ensure that in-20℃~+50℃The data stability at working temperature is better than±2%RH.

Technical advantage: In humid areas of the south, the humidity compensation function enables the sensor to85%RHCan still maintain in the environment±3%RHThe measurement accuracy effectively prevents false alarms caused by condensation.

3. Abnormal pressure warning

Monitor chamber pressure（0-1.2MPa）When the pressure is lower than0.3MPaOr higher than1.0MPaTriggering Level 3 Alarm (Warning)/alarm/Urgent). The pressure sensor adopts the piezoresistive principle and has a response time<1sRepetitive error<0.5%FS.

Application value: In high-altitude areas of the Qinghai Tibet Plateau (atmospheric pressure)0.6MPa）Sensors accurately reflect the actual state of the chamber through pressure compensation algorithms, avoiding misjudgments caused by changes in environmental pressure.

4. Analysis of decomposition products

Some models are equipped with electrochemical sensor arrays that can detectSF6Decomposition products（SO2TheH2STheCF4The detection limit is as low as0.1ppmBy analyzing the concentration changes of decomposition products, it is possible to predict in advance3-6Monthly warning equipment internal malfunction.

Fault diagnosis: A certain220kVTransformer malfunction detected by sensorSO2Concentration from0.2ppmSudden increase5ppmCombined with partial discharge monitoring, it was diagnosed as insulation discharge to avoid catastrophic accidents.

2、 Typical application scenario analysis

1. High voltage switchgear status monitoring

Application scenario: InGISTheHGISIn hybrid gas insulated switchgear, the sensor passes through485Bus or wirelessLoraNetworking enables real-time monitoring of chamber pressure, humidity, and concentration. Statistics from a provincial power grid show that after deploying sensors, the annual failure rate of equipment has decreased42%Improve maintenance efficiency35%.

Technical configuration: Adopting a three parameter integrated sensor (concentration)+humidity+Pressure, protection levelIP67Adapt to the outdoors-40℃~+70℃The environment and data upload cycle can be set to1minute/Next time.

2. Evaluation of Transformer Insulation Performance

Application scenario: In oil immersed transformers,SF6Used as a buffer gas. Sensors evaluate the degree of aging of insulation paper by detecting changes in gas purity. Research shows that whenSF6The concentration decreases to95%At that time, the polymerization degree of the insulation paper may have decreased to500(Initial value)1000）Immediate maintenance needs to be arranged.

Innovative Applications: CombiningDGAUsing dissolved gas analysis technology to construct a multidimensional fault diagnosis model, the accuracy of transformer fault identification is improved78%upgrade to92%.

3. Cable terminal sealing detection

Application scenario: In high-voltage cable terminals, sensors detect through detectionSF6Leakage rate（<0.1%/Evaluate the reliability of the sealing structure. In a pilot project of a certain city's power grid, sensors successfully identified3Minor leakage at the terminal head to avoid insulation breakdown caused by moisture intrusion.

Technological breakthrough: Micro sensors using laser scattering principle, with a volume of onlyΦ30mm×80mmIt can be embedded inside the cable terminal head to achieve zero leakage detection.

4. Construction of Smart Grid and Internet of Things

Application scenario: In IoT platforms, sensors useNB-IoT/4GThe module realizes remote data transmission and supports cloud analysis. The construction of a power grid in a certain citySF6Monitoring the Internet of Things, covering2000More than one gas chamber, with an annual processing capacity exceeding10Billion items, achieving visual control of device status.

System architecture: edge computing+Cloud analysis mode, with edge nodes completing data preprocessing and big data mining in the cloud, shortens the fault prediction cycle from monthly to weekly.

3、 Technological development trends

1. Multi parameter fusion detection

New generation sensor integrationSF6The four parameter detection functions of concentration, humidity, pressure, and decomposition products are achieved throughAIAlgorithm implementation for automatic identification of fault types. For example, a smart sensor developed by a certain enterprise can distinguish three fault modes: leakage (concentration decrease), moisture (humidity increase), and discharge (decomposition product increase), with an accuracy of95%.

2. ad hoc

adoptLoraWANorZigbeeProtocol construction for wireless monitoring network, supporting100+Node self-organizing network reduces deployment costs60%In mountainous power grid applications, wireless sensors achieve relay hopping transmission to achieve20kmReliable transmission of data within the scope.

3. Miniaturization and Low Power Design

MEMSMicro Electro Mechanical Systems (MEMS) technology reduces the size of sensors toΦ20mm×50mmReduce power consumption to0.1W(Continuous work). A certain micro sensor can be embedded inside the contact box of a switch device to achieve local integrationSF6Direct environmental monitoring.

4. Digital twin application

combineBIMBuilding Information Modeling (BIM) technology, constructing digital twins of equipment, achievingSF6Dynamic mapping of status and device physical parameters. In the digital twin system, sensor data drives the operation of virtual devices, which can simulate the aging process of devices in advance and optimize maintenance strategies.

4、 Selection and Deployment Guide

1. Selection of core parameters

Measurement range: Select according to equipment type（GISsuggestion0-1000ppmSuggestions for Transformers0-2000ppm）

Accuracy level: Selection of key equipment±1%FS, optional for general equipment±2%FS

Output method:485Bus (wired)Lora(Wireless)4G(Remote)

Protection level: Outdoor equipment requiresIP67Indoor equipmentIP65just

2. Key deployment points

Installation location: The concentration sensor should be installed at the bottom of the chamber（SF6The humidity sensor is installed at the top of the air chamber, with a density greater than that of air

Calibration cycle: It is recommended to calibrate every2Calibrate once a year, and calibrate annually in high humidity areas

Data collection frequency: Set the fault prone area as1minute/Next, set the stable operation area as10minute/time