1Overview of Core Differences

2、 Detailed analysis

1. SF6 ultrasonic sensor

Working Principle:

When SF6 gas leaks from a narrow gap under high pressure, it forms turbulence and generates ultrasonic waves with frequencies above 20kHz (inaudible to the human ear). Ultrasonic sensors capture these specific frequency sound wave signals through built-in piezoelectric microphones and convert them into audible sound or electrical signal intensity indicators for the user. itNot directlyIdentify SF6 gasBut rather identificationThe act of 'leaking'.

Advantages:

Quick positioning：Very suitable for rapid scanning on a wide range of devices to identify the approximate area of the leak point. The operator feels like using a stethoscope, and the location where the ultrasonic sound is heard the most is the leak point.

non-contact：It can be tested at a certain distance (such as several meters to ten meters) without direct contact with the equipment, making it safer for high-voltage equipment.

responsive：Once a leak occurs, ultrasonic waves are immediately generated, and the sensor canfastResponse.

Unrestricted by gas type：In theory, it can detect leaks of any high-pressure gas (such as air, nitrogen), but the equipment is usuallyThe acoustic characteristics of SF6 leakage have been optimized.

Disadvantages:

Unable to quantify：I can only knowThere is a leak here, and it is impossible to know how much ppm of SF6 is leaked.

Vulnerable to interference：Wind noise, rain noise, motor operation, corona discharge, etc. in the environment can all generate ultrasonic waves, causing false alarms or interference with detection.

Not sensitive to micro leaks：The ultrasonic waves generated by low-speed and small leaks are weak and difficult to detect.

Only applicable to ongoing leaks：Unable to detect those that have already stagnated in the airSF6 gas.

2. SF6 infrared sensor

Working Principle:

based onPrinciple of Infrared Spectral Absorption.SF6 gas has a strong absorption effect on infrared light of specific wavelengths (usually in the range of 10-11 micrometers). There is an infrared light source inside the sensor, and the emitted infrared light passes through the measured gas (either ambient air or sampling chamber). The detector measures the intensity of the absorbed infrared light. The more absorption, the higher the concentration of SF6 gas.

Advantages:

High sensitivity and quantitative detection：Can accurately measureThe concentration value of SF6 is usually measured in ppm (parts per million) or% LEL (lower explosive limit percentage). This is crucial for safety monitoring and leak assessment.

Strong ability to detect micro leaks：Even very slow leaks can be detected as long as the gas accumulates to a certain concentration.

Good anti-interference ability：Specially targetingThe absorption peak of SF6 is not easily affected by other environmental noise interference.

Can conduct regional security monitoring：It can be made into a fixed online monitoring system to monitor the switch room in real timeSF6 concentration in GIS rooms and other spaces to prevent personnel from being poisoned by hypoxia.

Disadvantages:

Slow response speed：Gas diffusion or pumping into the sensor is required, with a response time.

Usually requires proximity to the leakage source：For handheld inspection devices, the probe needs to be placed close to the suspected leak point in order to accurately measure. Fixed monitoring is also used to monitor the concentration in a fixed area.

relatively high cost：The core optical components and circuits are usually more expensive than ultrasonic sensors.

Possible cross interference：Although not common, some other gases may cause slight interference if they absorb in the same wavelength band.

3、 Application scenario selection

When you need to quickly locate the leak point (especially high-pressure leaks)：

choice SF6 ultrasonic sensorOperations personnel can carry it alongQuickly scan the sealing surfaces, pipeline joints, and other areas of GIS equipment, like a treasure hunt, to accurately locate leakage points through sound changes.

When you need to know how much leakage is, whether it meets the standards, or conduct regional safety monitoring：

choiceSF6 infrared sensor.

for example：

Quantitatively check whether the leakage rate is qualified after maintenance.

InInstall a fixed SF6 infrared monitoring and alarm system in the GIS room/switch station to ensure personnel safety.

Use a handheld infrared leak detector to quantitatively confirm suspected micro leak points.

4、 Summary and Analogy

A very vivid analogy is:

SF6 ultrasonic sensorJust like a doctor'sStethoscopeIt locates the problem by listening to the leaked sound.

SF6 infrared sensorJust like a doctor'sBlood testIt accurately determines the severity of the "cause" and "condition" by analyzing the sample.

In realityIn SF6 gas leakage detection work, these two technologies are often usedComplementary useFirst use:ultrasonic sensorConduct rapid and large-scale operationsPreliminary screening and localizationAfter finding the suspicious leak point, use it againinfrared sensorconductAccurate quantification and confirmation.