Ultrasonic Analysis of Lorentz Force for Gas Density Monitoring Using EMAT Sensor

Gas-Insulated Switchgear (GIS) in substations encounters round the clock ppm/ppb level leakages hence increasing the necessity of a robust, reliable, and sensitive device for gas density monitoring. Electromagnetic-acoustic transduction is a novel alternative to piezoelectric transduction for resonator sensors, with unique features and benefits. The paper presents a modeling that defines the electromagnetic-acoustic interaction in the GIS (gas-insulated switchgear) vessel for the detection of SF6 gas leakage. Detection of gas density using an acoustic wave was found to be suitable because of its good electrical properties in gases. It also presents the approach in which the analytical EM (electromagnetic) solvers for Lorentz force density were connected to the ultrasonic simulation. The arrangement is unique as well and helps in finding gas leakage at ppm level because in the substation the live conductors and other electrical components are surrounded by SF6 gas. In this study, the performance and stability of the EMAT sensor for gas leakage were evaluated in the presence of parameters such as its geometry, pressure, temperature, humidity, and molar mass.