X-ray Testing of High Voltage Oil-filled Electrical Equipment: Physical Background and Technical Requirements L.A. Darian, P.V. Golubev and R.M. Obraztsov JSC “Technical Inspection UES” 7 Kitajgorodskij proezd, Moscow, 109074 Russia E.P. Grabchak Ministry of Energy of Russian Federation 42 Shepkina Street, Moscow, 107996 Russia R.R. Gimaev National Research Center “Kurchatov Institute” 1 Akademika Kurchatova Square, Moscow, 123182 Russia O.V. Ozerov, R.V. Kovalev-Serebryakov and V.I. Zverev Dukhov Research Institute of Automatics 22 Sushchevskaya Street, Moscow, 127055 Russia ABSTRACT In this study the capability of X-ray technology to examine the internal elements of high-voltage equipment is reported for the first time. Samples of high-voltage minimum oil and SF6 circuit breakers were designed and tested to evaluate the X-ray images and compare with known artificial defects. The assessment of the influence of X-ray spectral energy characteristics on information obtained by X-ray imaging of objects having spread equivalent radiation thickness determined the technical requirements for this analysis. Index Terms — high-voltage circuit breakers, non-destructive testing, oil-filled electrical equipment, X-ray imaging, radiation 1 INTRODUCTION THE radioactive method of non-destructive testing is widely used in engineering. This method is based on registration and analysis of ionizing radiation after interaction with a controlled object and transformation of radiation passed through the object into an X-ray image [1]. To date, there is some experience of using this method for electric power equipment diagnostics. Known X-ray systems for heterogeneous objects of large geometric dimensions are used to control the internal content of passenger luggage, vehicles and freight containers [2–4]. For X-ray analysis of these objects whose internal contents are not known in advance, a “Z back-scatter technology” is primarily used. This technology is rather expensive and complicated to implement. In case of equipment control, the X-ray diffraction of objects with known internal content is carried out; for quality control, it is necessary to have drawings of structural elements of the equipment for comparison with its radiographs. However, with regard to electric power equipment, there is little experience with X-ray control of line insulators, cable boxes, SF 6 dead tank circuit breakers and gas-insulated switchgears (GIS). Moreover, in scientific and technical literature there is a lack of information on the use of radiography to monitor the technical condition of high-voltage oil-filled equipment. However, X-ray based non-destructive testing is of great interest for examining a large-size engineering equipment containing heterogeneous structures. It should be noted that the existing methods of monitoring the technical condition, such as high-voltage circuit breakers, based on the measurement of electrical, mechanical, physical and chemical indicators, can only indirectly identify the defects in structural elements of this equipment. The X-ray diffraction allows visualization of defects in the internal volume of equipment in various operating positions (“on”, “off” or in the intermediate position of the moving contact). Manuscript received on 10 June 2019, in final form 23 September 2019, accepted 10 October 2019. Corresponding author: V. Zverev. 172 L. A. Darian et al.: X-ray Testing of High Voltage Oil-filled Electrical Equipment: Physical Background and Technical Requirements DOI: 10.1109/TDEI.2019.008363 Authorized licensed use limited to: Lomonosov Moscow State University. Downloaded on February 15,2020 at 07:58:02 UTC from IEEE Xplore. Restrictions apply.