In the insulation system of power equipment,SF6Gas is widely used in high-voltage switchgear due to its excellent arc extinguishing and insulation properties. However, equipment leakage causedSF6The decrease in gas concentration poses a serious threat to operational safety.SF6The online monitoring system for gas concentration provides critical data support for equipment operation and maintenance by sensing gas status in real-time. This article systematically elaborates on the functional characteristics and technical advantages of such systems.

1、 Core monitoring function system

1. Multi parameter synchronous monitoring

The system integrates a high-precision sensor array, which can measure simultaneouslySF6Gas concentration（0-2000μL/LRange), environmental temperature and humidity（±0.5℃/±3%RHAccuracy), pressure parameters（±1%FS）. At ultra-high voltageGISIn the device application, the system successfully captured the daily concentration decay rate of a certain interval caused by the aging of the sealing ring0.8μL/LThe abnormal situation.

2. Leakage location technology

A positioning scheme that combines laser scattering and ultrasonic detection technology:

Laser positioning: using tunable diode laser absorption spectroscopy（TDLAS）Technology to achieve spatial positioning accuracy of leakage points±5cm

Acoustic positioning: utilizing20-100kHzUltrasonic sensor for locating small leaks (leakage rate)0.1g/h）
at some point500kVIn the actual measurement of the substation, the system accurately identified the diameter0.3mmThe sand hole leakage point.

3. Intelligent alarm mechanism

Establish a three-level warning system:

Attention value: Concentration drops to1000μL/LTriggering a yellow warning

Outlier: concentration below800μL/LStart an orange warning when activated

Fault value: concentration breakthrough600μL/LWhen a red alert is issued
The system supports SMS, sound and lightAPPMulti channel alarm to ensure timely response by operation and maintenance personnel.

2、 Key technical features

1. Anti interference design

Electromagnetic compatibility: throughIEC 61000-4-5Standard surge test（4kV/2kA）

Cross sensitivity suppression: using neural network algorithms to eliminateCO2Influence of interference factors such as moisture

Temperature compensation: built-inPT1000Temperature sensor,-20℃~+70℃Measurement error of concentration within the range is less than3%

2. Long life sensor

Electrochemical sensor: with a lifespan of up to5Year, annual drift<2%

NDIRInfrared sensor: lifespan10Year, maintenance cycle extended3times

Self diagnostic function: Real time monitoring of sensor health status, in advance30Sky warning replacement requirement

3. Data management platform

Trend analysis: Automatically generate concentration change curves, supporting30Tracing historical data

Report generation: compliantDL/T 596-2021One click export of standard testing reports

Remote Access: Supports5G/4G/Ethernet multi-mode communication, data upload delay<1s

3、 Typical application effectiveness

In a certain ultra-high voltage direct current project in East China, the system achieves88TaiwanGISCluster monitoring of devices. By constructing a concentration attenuation model, the optimization rate of annual maintenance plans can be improved40%，SF6Reduced gas replenishment volume65%The data shows that after adopting online monitoring, the equipmentSF6The failure rate caused by insufficient concentration0.3%/Annual decrease0.05%/Year.

The system is implemented through'perception-analyze-decision'The closed-loop architecture willSF6The transformation of gas state assessment from offline sampling to online continuous monitoring provides strong technical support for the safe operation of power grid equipment. With the deep integration of IoT technology, future systems will achieve more accurate leak prediction and intelligent air supply control, promoting the evolution of high-voltage equipment operation and maintenance towards intelligence.