Research on Self Diagnostic Method of Digital SF6 Meter

Sulfur hexafluoride (SF6) is widely used in modern power equipment due to its excellent insulation and electrical properties. Accurately measuring the density of SF6 gas plays a certain role in the reliable operation of equipment. However, due to the difference between the ambient temperature of the SF6 density meter and the temperature of the equipment itself, measurement errors may occur. Therefore, studying the impact of this temperature difference is of certain significance for identifying abnormal data in SF6 density meters and determining the actual status of GIS. This article designs an SF6 gas density detection experimental platform that can simulate different temperature difference conditions. By controlling the heating and cooling processes, the influence of temperature difference on density measurement under operating conditions is studied. The experimental results indicate that as the ambient temperature decreases, the measured density values show an upward trend, and the relationship between temperature difference and density difference is as follows: at 5 °C, the density difference is 0.0074MPa; 10°C is 0.018MPa; 15°C is 0.029MPa; 20°C is 0.038MPa. When the ambient temperature increases, the density value shows a downward trend, and the relationship between temperature difference and density difference is: at 5 °C, the difference is 0.0094MPa; 10°C is 0.021MPa; 15°C is 0.029MPa; 20°C is 0.038MPa. Under constant air pressure, density measurement values show a significant negative correlation with changes in ambient temperature, and there is a strong linear correlation between measurement errors and temperature differences. Based on this, this article proposes a diagnostic method using SF6 density table time series data to determine whether density changes are caused by environmental temperature differences, which helps identify abnormal data and provides support for the safe operation of power equipment.