1Why do we need monitoring?SF6

SF6Gas has good insulation and arc extinguishing performance, and has been fully utilized in the field of high-voltage electrical switchgear in substations. However, due to the manufacturing and installation of high-voltage electrical switchgear has a certain difference, and the use of time is too long after the product material aging phenomenon, soSF6There is a gas leakage phenomenon in the production and operation of high-voltage electrical switchgear, which will affect the normal operation of the equipment and bring certain safety hazards to the personal safety of the staff.

The State Grid Corporation of China Electric Power Safety Work Regulations stipulate that oxygen and oxygen must be installed in relevant places.SF6Detect alarm devices and install necessary ventilation devices. Therefore, it is of great significance to realize the on-line monitoring, real-time alarm and ventilation control of the indoor environment of the switch.

Sulfur hexafluoride gas90%The left and right are used for power industry equipment insulation and arc extinguishing. Once the leakage of sulfur hexafluoride in this occasion, the arc generated during the switching process of the equipment will lead to the generation of many fluorides and sulfides in the cavity of the closed high-voltage power equipment. Most of these fluorides and sulfides are toxic or even highly toxic. Although they will be rapidly synthesized and reduced back to the original gas after arc extinguishing, there are still a considerable proportion of chemical mixed toxic gases. Occasional such as engineering installation contact with these leaked gas mixture, no impact on the human body. However, if you have long-term contact with workers such as power maintenance and patrol inspection, you must pay attention to exhaust air in advance or install an online monitoring and alarm system for sulfur hexafluoride leakage when entering the room equipped with sulfur hexafluoride electrical equipment to absolutely ensure the safety of personnel.

2How to monitorSF6

The reaction equation of sulfur hexafluoride and oxygen is:2SF6 O2→2SOF2 8F. When in the environmentSF6If the gas content exceeds the standard or lacks oxygen, it can give an alarm in real time, and at the same time automatically turn on the ventilator for ventilation. It has many rich functions such as temperature and humidity detection, working status voice prompt, remote alarm, historical data query, etc.

3MonitoringSF6The technical parameters

PureSF6Although the gas is non-toxic, it should be prevented in the workplace.SF6The concentration of the gas rises to the level of oxygen deficiency. Our country stipulates that the allowable concentration of sulfur hexafluoride gas in the air between operations is not greater6g/m3Or the oxygen content in the air should be greater18%; short-term contact, the allowable concentration of sulfur hexafluoride gas in the air is not greater7.5g／m3。

Here, to recommend you a detection of oxygen sensorSO-D0-250This sensor is Austria.SensorLimiting current oxygen sensor specially developed for detecting oxygen.

1. oxygen sensorSO-D0-250Working principle

Because the carrier of the current in the zirconia electrolyte is oxygen ions, when a voltage is applied to the zirconia cell, oxygen is drawn through the zirconia disk to the anode. If a perforated cover is added to the cell cathode, the rate of oxygen flow to the cathode is limited. Limited by this rate, the current in the cell will reach saturation as the applied voltage is gradually increased. This saturation current is called the limiting current and is proportional to the oxygen concentration in the ambient environment.

2. oxygen sensorSO-D0-250The relevant parameters

1Wide measurement range,0.1%~25%Oxygen

2High accuracy, ±0.25% O2

3Wide temperature range,-20℃~+350℃

4The sensor signal has a small dependence on temperature,0.034 %Measurement signal /°CAmbient temperature

5High flexibility, output100 UA - 200 U.S., can be self-built amplifier circuit, can also be used with the board

62. Easy to install, with threaded structure, after installation, the sensor is firm and reliable

7Long service life,20000Hours

8Low cross sensitivity

3.Oxygen sensorSO-D0-250matching board

1、GSBBoard

Input:

12Vdc (Possible range6-25Vdc)

Power consumption:

Standard power consumption200mA @ 12Vdc

Output:

① Simulation0-5V (Vout)

② Simulation4-20mA (Iout)

③ ThroughRS232Generate Digital Output

2、EDABBoard

Input:

7-30 VDCor6 VDC(Optional)

Power consumption:

Power consumption is approximately2.5 – 3.0Watt

Output:

① Linear output signal0–5 V DC (Adjustable lower output voltage with optional software)

②4Programmable alarm thresholds (Programmable with optional software)