A High Precision Cost-effective Ultrasonic Sensor for Detection of Gas Leakage in Gas Insulated Switchgear

Abstract

This paper presents modelling and testing of an ultrasonic sensor for detection of SF6 gas leakage from vessels of gas insulated switchgears (GISs) with less than 0.5% margin. As per industry standard and practices, the desired level of gas leakage is to be kept below 0.5% per annum per in the SF6 gas vessel. Detection of gas density using acoustic signals was found suitable due to its good electrical properties in ideal gases. This unique arrangement helps in detection of gas leakage at ppmlevel where the live conductors and other electrical equipment inside the GIS are surrounded by Sulphur hexafluoride SF6 gas. Performances and stability of the ultrasonic sensor have been evaluated in presence of some influencing parameters such as pressure, temperature, molar mass, humidity. The cost effectiveness of the sensor is ensured because of its simple modelling and robust design.