Comparison of SF6 sensing detection principle- SF6在线监测系统_SF6检漏仪_SF6传感器_SF6密度继电器

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Comparison of SF6 sensing detection principle

发布时间：2016-12-09 来源：ydlcb 浏览次数：39次

1, catalytic combustion technology: electrochemical principle Typical features: combustion, chemical reaction, detection of new substances.

Principle: Through heating, pressurization (500-600℃, 700-800V) to decompose SF6 through the gas sensor, and through the detection of new easily detected substances to achieve SF6 concentration detection.

Weaknesses:

1, heating to 500-600℃, to the environment to produce new toxic gases.

2, 500-600℃ temperature due to the influence of ambient temperature and humidity, the test results drift.

3, the detection is the content of new substances after electrochemical reaction, the quantization accuracy is not high.

4. Because it is a single loop sampling and detection, the detection results are prone to environmental power frequency, harmonics and other disturbances leading to false alarms.

5, electrical breakdown technology: high-voltage electron flow emission and acceptance principle Typical characteristics: emission electron flow, space movement, reception.

Principle: The electrode of the gas sensor emits a high-frequency electron stream at the high pressure and heated anode. When the SF6 gas passes through the detection gap between the anode and the cathode, it will hinder the movement of the electron stream. The strength of the electron stream is sampled through the cathode and the concentration of SF6 is quantified.

Advantages:

High precision of quantization. It can realize quantitative detection, processing and display.

Weaknesses:

1, the need for anode heating conditions, heating causes deformation, affecting the detection gap distance and affect the detection accuracy;

2. Heating is easily affected by ambient temperature and humidity, resulting in data drift;

3, need to add high pressure conditions, easy to adsorb environmental dust material, resulting in a decline in detection accuracy;

4, there are other insulating gases through, can also prevent the flow of electrons, affecting the detection accuracy;

5, so it needs to be verified once every six months, the maintenance cycle is short, only suitable for quantitative leak detection, not suitable for online systems;

3) Thermal cracking technology: polymer thermal cracking principle Typical characteristics: polymer thermal cracking, detection circuit conductance aluminum determines quantization output

Principle: When the leaking SF6 gas contacts the surface of the sensor formed by the high polymer, it reacts with the cracked detection substance, resulting in an increase in the resistivity of the 5 sampling loops located on the surface of the detection layer. The output current changes with the change of resistivity, and the sampling quantization is carried out at the output end to obtain a quantization value that dynamically changes with the concentration.

Advantages:

1, directly change the conductivity of the sampling loop, rapid response;

2, the change of the resistivity of the detection loop, easy sampling and quantization processing, not easy to be disturbed;

3, multi-detection loop sampling, design to take the balanced value, high sampling accuracy;

4, a major current jump in a primary circuit is judged to be caused by harmonic interference, and the alarm is easy to eliminate;

5, dedicated to the detection of SF6 gas detection material, not easily affected by other gases;

Weaknesses:

1, the precision of quantization is not as high as infrared laser technology, but it can be stable at ±5%;

2, infrared technology infrared spectrum absorption principle Typical characteristics: SF6 gas through the detection gap, absorb specific wavelengths of infrared waves.

Advantages: 1, no heating, the materials used are mostly photoelectric materials and projection lenses, the expansion coefficient is small, no deformation, and the detection drift is small.

3, the emission of specific wavelengths, only through SF6 gas caused by large energy loss, so it is not easily affected by other gases.

4, for SF6 detection of specific wavelength modulation, belongs to photoelectric detection, high quantization accuracy, fast speed.

Cons:

1, photoelectric sensing components are greatly affected by ambient temperature, humidity, dust, especially in harsh environments. Therefore, the service life is short, it needs to be calibrated once in half a year, and it must be replaced in 2 years.

2, suitable for quantitative portable testing products, not 24 hours of electrical monitoring, and long-term application in the field environment.

3, chromatographic analysis: a single specific wavelength of gas sampling, and processing and analysis.

Advantages:

1, can accurately and quickly identify gas leaks;

2, can accurately sample, quantify and display SF6;

Cons：

1, is not the relative concentration of sampling and processing, the quantization value given is not the volume ratio indication (ppm);

2, expensive, suitable for quantitative portable testing products, not 24 hours of electrical monitoring and long-term in the field environment.

Weavers test uses the infrared technology based on the infrared spectrum absorption principle of digital quantitative sampling, quantitative analysis, qualitative display of thermal cracking technology principle. At present, it is economical and practical, dedicated to the detection of SF6 leakage gas, and realizes the quantitative detection and quantitative treatment of SF6 gas.