MEASURING SYSTEM FOR FAST TRANSIENTS MONITORING IN GAS-INSULATED SUBSTATIONS

In this paper the results of testing and calibration of measuring syst ems for very fast transients (VFT) in gas-insulated substation (GIS) a re presented. The general principles for the construction of measuring systems for recording and transmission of VFT are also discussed. The paper describes in detail the constructions of four measuring probe t ypes adjusted for VFT monitoring in 123 kV SF6-insulated substation. T he primary construction requirement was the ability to monitor VFT in 123 kV SF6-insulated substation containing frequencies greater than or equal to 200 MHz without distortion in both frequency and voltage dom ains. For the purpose of the measuring system testing and calibration an experimental facility was developed based on the computer experimen tal modelling technique. The verified experimental facility was then u sed for testing and calibration of measuring probes type. During the t est, various effects on the measuring system response quality were not ed with respect to the applied constructional solutions, with differen t kinds of dielectric material used for the low-voltage capacitor and different diameters of the sensor probe. The obtained results are expl ained and the possibilities of further improvement of SF6 VFT measurin g system characteristics suggested.