Application, Functions, and Characteristics of the Leak SF6 Monitor System

Application of SF6 Monitor System

The SF6 monitor system has an important role in the power industry. As a result of its excellent arc-extinguishing properties, SF6 gas can rapidly form an arc flow channel when interrupting high currents and extinguish the arc quickly through diffusion and cooling, ensuring reliable circuit breaking. Additionally, its high insulation properties and resistance to decomposition make sulfur hexafluoride gas widely used in medium and high voltage equipment. This gas not only improves equipment performance but also achieves economic, miniaturized, and low-maintenance designs, significantly saving space by about 90%. This achievement highlights the unique value and importance of SF6 gas in the power industry.

Although pure SF6 gas is non-toxic, it is necessary to prevent the concentration of SF6 gas from rising to oxygen-deficient levels in the workplace. The density of SF6 gas is approximately five times that of air, and if there is a leakage, SF6 gas will settle in low-lying areas, such as cable trenches, posing a risk of asphyxiation at high concentrations. This factor should be considered when designing indoor ventilation systems. The decomposition products of SF6 under arc action, such as SF4, S2F2, SF2, SOF2, SO2F2, SOF4, and HF, are highly corrosive and toxic. Therefore, in workplaces using SF6 in power system GIS, substations, and other applications, monitoring SF6 gas is crucial.

Functions of SF6 Monitor System

• SF6 gas concentration detection and display function: Sensors continuously detect and the main unit reads and displays the SF6 concentration at each monitoring point inside GIS rooms. When the SF6 concentration exceeds the set alarm value (default factory value is 1000 ppm), the system alarms and displays the value.

• Oxygen concentration detection and display function: Sensors continuously detect and the main unit reads and displays the O2 concentration at each monitoring point inside GIS rooms. When the concentration is below the set alarm value (default factory value is 18%), the system alarms and displays the value.

• SF6 monitor and oxygen concentration control function: When the SF6 gas concentration exceeds (≧1000 ppm) or the oxygen concentration is below (≦18%), the system controls the fan to start ventilation until the concentrations of SF6 and O2 return to normal.

• Temperature and humidity detection and display function: Real-time detection by local temperature and humidity sensors and read and displayed by the main unit to show the temperature and humidity values inside GIS rooms.

• Sensor communication status display function: Each sensor continuously detects and the main unit reads and displays the communication status of each sensor inside the GIS room. If there is a communication failure, the fault address will appear as “--” and offline on the interface.

• Timed ventilation function: The SF6 Monitor System can set the fan to start and stop at specified times each day based on the required ventilation of the switchgear room.

• Automatic start-stop ventilation function for concentration exceeding alarm set value: When the SF6, O2 gas concentrations in the GIS room exceed the alarm set value, the fan will automatically start ventilation until the concentrations return to normal, and the fan will stop automatically.

• Forced ventilation function: When the fan is in the stopped state, clicking the fan icon on the right will start the fan. When the fan is running for ventilation, clicking the fan icon on the right will stop the fan.

• Voice prompt function: When the main unit’s voice function is enabled, the SF6 Monitor System will provide voice alarms under specified conditions to alert personnel entering the GIS room.

• Sound and light alarm function: When the SF6, O2 gas concentrations inside the GIS room exceed the limits, a high-frequency alarm sound and flashing red light will be triggered.

• Human infrared sensing function: Before personnel enter the GIS room, the infrared sensor will be triggered, and the main unit will issue a voice prompt.

Characteristics of SF6 Monitor System

• Four-in-one design for temperature, humidity, oxygen, and sulfur hexafluoride;

• Large LCD touch screen display design;

• Online temperature measurement function for switchgear contact points can be included;

• Expandable gas sensors and other functions based on user requirements;

• Programmable for up to 5 independent ventilation systems;

• Voice prompt and forced ventilation can be activated upon entering any door of the GIS room;

• Multiple communication methods including RS485, LoRa, RJ45 network port, and 4G.

Related Article for Reference