SF6 gas leak monitoring and alarm system

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应用案例

SF6安全保障专家

专注于SF6气体检测的专业化

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Application of SF6 gas leakage monitoring and alar

SF6 gas leakage monitoring and alarm system is an online monitoring and alarm system for SF6 insulated gas leakage of SF6 combined electrical equipment in new unmanned substation. It is mainly used in 35kV SF6 switch room and GIS room above 110kV to carry out real-time monitoring of SF6 gas leakage and air oxygen content in SF6 combined electrical equipment room environment.

SF6 gas is widely used in power system because of its excellent insulation and arc extinguishing performance. However, the leakage of SF6 gas will pollute the indoor environment, so that the health and even life of the operators and inspection personnel entering the room are seriously threatened. Therefore, good SF6 leakage gas monitoring technology has been valued and pursued by power industry practitioners.

"DL408-1991 Electrical industry safety Regulations (Electrical Parts of Power plants and substations)" Chapter 8, "DLT 639-1997 sulfur hexafluoride Electrical Equipment Operation, testing and maintenance personnel safety protection Rules" chapter 4 requirements and "JBT 10893-2008. Requirements of sulfur hexafluoride environmental monitoring system for high voltage combined electrical distribution room. Among them, in the "Electrical industry safety Work Regulations" (power plant and substation part), the distribution unit room equipped with SF6 equipment must ensure that the SF6 gas concentration is less than 1000ppm, in addition to the installation of strong ventilation devices must also be installed can alarm oxygen meters and SF6 gas concentration monitoring and alarm meters.

Main technical specifications of SF6 gas detection device in switch room

1SF6 concentration exceeding limit alarm point: 1000ppm (national standard value), accuracy ≤ 10%FS; Detection range: 1-2000ppm.

2 Oxygen content detection range: 1 ~ 25%, hypoxia alarm point: 18% (national standard value), accuracy ≤ 3%FS and below.

3 Temperature detection range: -55 ~ +99℃.

4 Humidity detection range: 1 to 99%RH.

5 Working power supply: AC 165 ~ 260V/ 50HZ.

6 Fan output power contact: AC220V/10A; Normally open (active)3 pairs.

7 Alarm contact capacity: AC220V/1A; Normally open/normally closed (passive).

8 Monitoring data storage capacity: 5 years of historical data.

9 Display size: 10.4 inches.

10 Installation mode of the host and monitoring unit: wall-mounted.

11 Fan starting conditions:

① Oxygen content; 19.6%, automatically start the fan until the oxygen level returns to the safe state.

② SF6 concentration ≥ At 1000ppm, the fan is automatically started until SF6 concentration returns to normal.

③ The user can customize the start and stop time of the fan (up to 8 periods).

④ Manually start the fan

12 Infrared sensing distance of the human body: within 5M radius in front of the host.

13 Communication interface: 2 485 bus interface; Baud rate: 4800bps.

14 Power consumption: host < 25VA; Probe < 6VA.

15 The fan works for at least 15 minutes at irregular intervals.

16 Electrical strength (between the metal part of the shell and the power supply) : > 2000V.

17 Electrical fast transient pulse group immunity: meet GB/T17626.4 requirements.

18 Power supply: 2KV 5/50ns 5kHz; I/O, communication port: 1KV 5/50ns 5kHz.

19 Surge immunity: 2KV 1.2/50us according to GB/T17626.5 requirements.

20 Electrostatic discharge immunity: meet GB/T17626.2 requirements 6KV contact discharge 8KV air discharge.

21 Continuous interference voltage: conforming to GB4343 requirements 0.15~0.50 MHz, 66~56 dBV quasi-peak, 0.50~5.00 56 dBV quasi-peak 5.00~30.0 MHz, 60 dBV quasi-peak.

Main function of system

1 Detection and display of excessive SF6 gas concentration

The detection signal is triggered in real time, and the onsite host dynamically displays the SF6 concentration status at each gas probe in the GIS room. When the concentration exceeds 1000 PPM (users can set the alarm threshold between 100 and 1000 PPM), the SF6 concentration under the exceeded state is displayed in red font; otherwise, the SF6 concentration under the normal state is displayed in green font.

2 Oxygen content detection and display

The detection signal is triggered in real time, and the on-site host dynamically displays the oxygen content value at each gas probe in the GIS room. When the oxygen value is 18.0%, the red font indicates the oxygen value, otherwise the green font shows the actual value.

3 SF6 concentration and oxygen content control function

SF6 gas concentration exceeded 1000ppm (national standard value) or oxygen content ≤ At 19.6% (national standard value), the system automatically controls and starts ventilation until SF6 concentration and oxygen content return to normal.

4 Monitoring unit communication status display

The field host takes turns to detect and display the communication status between the monitoring unit and the host in the GIS room. If any monitoring unit fails to communicate, the field host will prompt the monitoring unit to communicate the fault in real time.

5 Ventilation at regular intervals

The system can set multiple periods of time (users can define up to 8 periods) for the fan to start and stop regularly every day to ensure that the GIS room can be ventilated as needed every day. Continuous ventilation time of 23 hours and 59 minutes; To short sustained ventilation time 1 minute.

6 Abnormal SF6 concentration and oxygen content are automatically ventilated

If there is no forced ventilation or set ventilation period, the system starts the fan for ventilation when detecting abnormal SF6 concentration and oxygen content. If the monitoring unit detects an abnormal SF6 concentration or oxygen content within 15 minutes from the start, the time starts from the newly detected time, and the system automatically shuts down the fan after 15 minutes.

7 Forced Ventilation

When the fan is stopped, press the host touch screen interface “ Manual/automatic ” Ventilation switch button, the system can be forced ventilation; When the fan is running, press the host touch screen interface “ Manual/automatic ” Ventilation switch button, the system will forcibly shut down the fan. You can view the current fan running status in the upper right corner of the display.

8 Temperature detection and display function

The system detects and dynamically displays the current GIS indoor temperature through the temperature and humidity monitoring unit.

9 Humidity detection and display function

The system detects and dynamically displays the humidity in the GIS room through the temperature and humidity monitoring unit in real time.

10 Voice prompt function

When the onsite host detects an environment exception, it prompts the alarm by voice to remind the staff to leave the site and query the leakage situation. Under normal circumstances, when the staff is close to the host area within 5M, the host automatically prompts the current environment status. Real-time voice on/off status is displayed in the upper right corner of the display. And has voice on/off voice function.

11 Optical alarm function

When the host detects that the ambient SF6 concentration or oxygen content exceeds the limit, the alarm device on the control host blinks to remind the staff that the indoor environment is in a dangerous state and they can enter the room only after the safety is restored.

12 Human body infrared sensing function

When the staff in and out of the GIS room, through the human body infrared sensor detection, the system automatically prompts the safety of the environment. And switch the host display from the low power screen saver state to the normal display state. .13 Historical monitoring data storage function

32M large-capacity data storage space, used to store historical data, and in the case of power failure, the data can be stored for more than 5 years.

14 Query historical data

You can query historical data in any time period by going to the Query historical data page on the menu item of the onsite host.

15 System self-check function

A separate self-check module is designed on the internal hardware structure. When detecting the abnormal or abnormal operation of the main system program, it automatically resets and imports the backup program, so that the system can restore the normal working state in time.

16 Remote alarm function

The onsite host provides two sets of passive hard contacts, normally open and normally closed, which operate when the SF6 concentration or oxygen content is abnormal. Users can connect the remote communication devices (such as the Nanrui RTU) in the main control room to realize remote alarm of the scheduling center. To prompt the staff to go to the site inspection or to carry out leak detection work.