Improving SF6 Leakage Detection in Switchgear by Reducing the Influence of Solar Radiation on Density Measurement

Solar radiation onto gas-insulated switchgear has a major impact to the SF₆ density distribution. The resulting fluctuations in the sensor signal hinder the detection of small gas leakages. The authors propose a model-based filtering algorithm. This model, based on physical principles of conservation of energy, momentum and mass, was developed and tested. The tests were performed by comparison with data from an experimental test setup. The model proposed here reduces the fluctuations in the sensor signal and allows detecting small leakage rates at an early state. This can help to reduce the total emissions of SF₆ gas to the atmosphere and increase the reliability and availability of the substation.