PALANIUK O. Methods and means of diagnosing windings of power transformers of distribution electric networks.

In the dissertation, the task of creating methods and tools for diagnosing the windings of power transformers in the task of assessing the residual resource of the insulation of the windings of power transformers is solved. As a result of the dissertation research, the following results were obtained. So, in particular, based on the laws of heat transfer, a mathematical model has been developed to estimate the degree of aging of the insulation of the windings of a power transformer according to the thermal state, which allows, unlike known models, to estimate the influence of short-term loads and overloads on the insulation state of the transformer and, as a result, to predict the moment of exhaustion of the working resource insulation of windings at the highest temperature. Mathematical models based on the theory of fuzzy sets have been developed to estimate the thermal aging of the insulation of the windings of power oil and dry transformers, taking into account the influence of external environmental factors. Parametric optimization of the fuzzy model was carried out for its adjustment under operating conditions. With the use of a neural network, a mathematical model was developed to estimate the allowable period of operation of a power dry transformer in the overload mode. In order to assess the adequacy of the synthesized models, simulation simulations of various operating modes of the power transformer at various load spikes, both short-term and long-term, were carried out. The analysis of the obtained results of computer modeling confirms the theoretical statements and the effectiveness of the synthesized mathematical models for assessing the thermal aging of the insulation of the power transformer under different operating conditions. On the basis of synthesized mathematical models and developed algorithms, a variant of the implementation of a microprocessor tool for diagnosing and forecasting the consumption of the remaining resource of the insulation of a power transformer is proposed. Implementation of the developed methods and means will improve the operation of power transformers, as well as increase the reliability of the electric power system as a whole.