Measuring system for fast transients monitoring in gas‐insulated substations

In this paper the results of testing and calibration of measuring systems for very fast transients (VFT) in gas-insulated substation (GIS) are 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 offour measuring probe types adjusted for VFT monitoring in 123 kV SF 6 -insulated substation. The primary construction requirement was the ability to monitor VFT in 123kV SF6-insulated substation containing frequencies ≥ 200 MHz without distortion in both frequency and voltage domains. For the purpose of the measuring system testing and calibration an experimental facility was developed based on the computer experimental modelling technique. The verified experimental facility was then used for testing and calibration of measuring probes type. During the test, various effects on the measuring system response quality were noted with respect to the applied constructional solutions, with different kinds ofdielectric material used for the low-voltage capacitor and different diameters of the sensor probe. The obtained results are explained and the possibilities offurther improvement of SF 6 VFT measuring system characteristics suggested.