On the Issue of Evaluating the Resonance Properties of External and Internal Oscillatory Circuits of Power Autotransformers

When operating high-voltage equipment, it is necessary to take into account the presence of eigenfrequencies of its structural elements. This is due to the appearance of undesirable electromagnetic processes both in the transformer itself and when taking into account its interaction with external electrical equipment. Studies show that the appearance and development of resonance phenomena can be used not only to assess overvoltage, diagnose mechanical deformation of windings, but also to obtain diagnostic information about the state of structural elements of a transformer. This is possible by analyzing the spectra of signals corresponding to vibrational systems. The paper considers the issues of theoretical and experimental evaluation of the resonant frequencies of external and internal structural elements of a 500 kV power autotransformer. It is shown that the resonant frequencies of the external and internal structural elements of transformers are located in the megahertz range and can be determined both by calculation and experimental methods. The article evaluates both the resonant frequencies and the bandwidths of the oscillatory circuits. The results obtained can be used to identify informative frequency bands for assessing the technical condition of the autotransformer by the method of electromagnetic control based on the analysis of the spectra of its own electromagnetic radiation.