SF6 gas is an insulating gas widely used in high voltage switches. However, SF6 gas is a gas banned under the Kyoto protocol and severely damages the atmosphere. Of course, if there is a leak in the high voltage switch, its insulation capacity will be reduced. Therefore, SF6 gas leak detection is very important. At present, there are many common methods for SF6 gas leak detection, and each method has its own advantages and disadvantages. 

At present, the conventional SF6 leakage detection methods include soapy liquid leakage detection, local dressing method leakage detection, leakage detection by leakage detector, infrared imaging method leakage detection, etc.

1. Foam leakage measurement method: choose to apply soap solution in the leakage measurement position to see whether there are bubbles. A basic understanding of the leak location is required before it can be determined. At the same time, it is not possible to check the charged position whose spacing does not meet the requirements, which leads to heavy workload and poor applicability.

2. Qualitative leakage measurement method: move the leakage probe along the interface surface of the circuit breaker and the surface of the aluminum casting, and judge the gas leakage according to the reading of the leakage probe. This method is heavy workload and purposeless. If the probe moves too fast, it can easily miss a leak; The leakage measurement is affected by the wind speed, and the leakage gas is easily blown away by the wind, which affects the leakage measurement. The live equipment whose spacing does not meet the requirements cannot be checked.

3. Bandaging and leakage detection method: bandaging the inflatable equipment, after a period of time, use the leakage detector to conduct leakage detection in the bandaging body, and check the leakage situation at the bandaging position. The workload is heavy, some locations are difficult to bandage or cannot be bandaged, and the live locations whose spacing does not meet the requirements cannot be checked. At the same time, this method is a local inspection, it is not easy to quickly find the leakage point.

4. Infrared imaging method: it is a new technology leakage measurement method that has emerged in recent years, but it will also have certain limitations in practical use. Due to the low detection accuracy of infrared imaging, a small amount of leakage cannot be detected at all, and the leakage position also needs to adjust the focal length for many times to find leakage; In addition, indoor GIS equipment is compact to install and internal leakage measurement is difficult. For outdoor HGIS equipment, due to the high installation height, it is difficult to measure the leakage at the top, edge or hidden part of the system, and due to the influence of environmental factors such as outdoor wind speed, temperature and humidity, some HGIS equipment with slight leakage is more difficult to detect by optical imaging method.