SF6 gas online monitoring

1SF6 gas online monitoringOverview

With the continuous development of the power system, SF6 electrical equipment is becoming more and more widely used, especially GIS composite appliances, which are widely used due to their advantages of greatly reducing the footprint and spatial volume of electrical equipment, easy installation, safe and reliable operation, and convenient maintenance.

Pure SF6 gas is colorless, odorless, non-toxic, and non flammable, with a specific gravity five times that of air. When the distribution equipment room equipped with SF6 equipment, such as GIS, leaks, SF6 gas accumulates to a certain concentration in the lower space. If workers enter the room, serious personal safety accidents such as cerebral hypoxia and even rapid suffocation may occur. In addition, under the influence of arc, partial discharge, high temperature and other factors, SF6 gas will produce highly toxic decomposition products such as SF4, S2F2, SOF2, and some decomposition products will produce corrosive electrolytes when they come into contact with water. These not only pose a serious threat to personal safety, but also endanger the normal operation of electrical equipment. The "Electricity Safety Work Regulations" (for power plants and substations) specifically stipulate that the distribution equipment room equipped with SF6 equipment must ensure that the SF6 concentration is less than 1000ppm. In addition to installing strong ventilation devices, monitoring devices such as oxygen meters and SF6 gas concentration detection alarms that can sound an alarm must also be installed.

This system is an intelligent online monitoring system designed and developed to provide personal health and safety protection for workers in distribution equipment rooms equipped with SF6 equipment, based on the current emphasis on safety production in the power system.

IISF6 gas online monitoringMain functions

1. Real time monitoring and display: The detection signal is triggered in real time, and the host dynamically displays the SF6 concentration value and oxygen content value of each gas transmitter. When the SF6 concentration exceeds 1000ppm or the oxygen content is below 18.0%, a red data color display will be prompted, otherwise the actual value will be displayed in normal color;

2. Automatic linkage control function: When the SF6 gas concentration exceeds 1000ppm or the oxygen content is below 18.0%, the system automatically controls the start of ventilation until the SF6 concentration and oxygen content return to normal;

3. Screen display: The host adopts a 7-inch touch color screen with screensaver function;

4. Timed ventilation function: The system can set 8 time periods for the fan to start and stop at regular intervals every day to ensure that indoor ventilation can be carried out as needed. The duration of fan start can be set;

5. Forced ventilation: When the fan is in a stopped state, press the main unit (start fan) button, and the system can perform forced ventilation; When the fan is in operation, pressing the host (stop fan) button will force the fan to shut down. The current fan operation status can be viewed in the bottom left corner of the screen;

6. Fire linkage function: The system has linkage with the fire protection system, and when it receives a fire alarm signal, it forcibly stops the fan from starting;

7. Display the latest start and stop time of the fan: If the fan has experienced a start/stop action, the detailed record of the fan start/stop action and action type (such as manual start, timed start, alarm linkage) will be recorded in the system host event log. The staff can determine whether forced ventilation is needed before entering the switch room based on this information.

8. Human body infrared sensing voice prompt alarm function: When the on-site host detects environmental abnormalities, it will give a voice prompt alarm to remind the staff to evacuate the scene and check the leakage situation. Under normal circumstances, when personnel approach the host area within 8-12 meters, the host will automatically provide voice prompts for the current environmental status; And it has voice on/off function;

9. Remote control and alarm function: The on-site host provides four sets of alarm output nodes (one set of normally open passive dry contacts, one set of normally open pulse signals, one set of normally closed pulse signals, and one set of magnetic hold normally open signals), which act when SF6 concentration or oxygen content is abnormal, for users to use as needed;

10. Historical data query function: You can enter the historical data query interface in the menu items of the on-site host to query the alarm historical data of any time period;

11. System self-test function: A separate self-test module is designed on the internal hardware structure. When abnormal or non normal operation of the main system program is detected, it will automatically reset and import backup programs to restore the system to normal working state in a timely manner.

3、 Technical parameters

1. Working voltage: AC/DC 220V ± 10%, 50Hz

2. Power consumption:<10W at rated voltage

3. Accuracy level: 2.5 level

4. SF6 gas concentration measurement range: 0-3000ppm

5. SF6 concentration over limit alarm point: 1000ppm (standard value), accuracy<5% FS

6. Oxygen content detection range: 0-25%

7. Hypoxia alarm point: 18% (standard value), accuracy<1% FS

8. Temperature detection range: -40 to+120 ℃ (accuracy ± 0.5 ℃)

9. Humidity detection range: 10-99% RH: accuracy ± 0.5% RH

10. Fan output power contact: 6A

11. Remote communication method: RS485

12. On site host dimensions (mm): L330 × W250 × H65

13. SF6 and oxygen detection unit size (mm): L162 × W150 × H38

14. Size of temperature and humidity detection unit (mm): L162 × W150 × H38

15. Monitoring historical data storage capacity: 5 million records;

16. Touch screen size: 7 inches

17. Installation method of host and detection unit: wall mounted

18. Working environment temperature: -25 ℃~70 ℃

19. Working environment humidity: ≤ 95%

20. Test the electromagnetic compatibility performance indicators of this device according to the provisions and methods of GB/T 17626:

① Electrostatic discharge, level 4

② Radio frequency electromagnetic field radiation immunity, level 3

③ Electrical fast transient burst immunity, level 4

④ Surge (impact) immunity, level 4

⑤ Conducted disturbance immunity induced by radio frequency field, level 3

⑥ Power frequency magnetic field immunity, level 5

⑦ Pulse magnetic field immunity, level 5

⑧ Damping oscillation magnetic field immunity, level 5

⑨ Voltage sag and short-term interruption immunity, 60% UT, lasting for 10 cycles;

21. Test the mechanical performance indicators of this device according to the provisions and methods of GB/T 11287 and GB/T 14573:

① Vibration response, level 1

② Vibration durability, level 1

③ Shock response, Level 1

④ Impact durability, Level 1

⑤ Collision, Level 1

4SF6 gas online monitoringImage display