Перегляд за Автор "Shutenko, O. V."
Зараз показуємо 1 - 3 з 3
Результатів на сторінці
Налаштування сортування
Документ Analysis of distribution laws of insulation indicators of high-voltage oil-fillled bushings of hermetic and non-hermetic execution(РC Tесhnology сеntеr, 2018) Shutenko, O. V.; Zagaynova, A. A.; Serdyukova, G. N.The object of research is the distribution laws of capacitor-type insulation values that were obtained during preventive tests for both serviceable and defective high-voltage bushings of 110 kV of hermetic and non-hermetic execution. One of the most problematic areas is insufficient knowledge and lack of justification of the laws for distributing these preventive tests of insulation of bushings. In the course of the research, a comprehensive approach to the solution of the problems was used, including probability theory and statistical analysis, analysis of world experience and a logical approach. In the long term, the results are expected to be extended to the bushing of other types having similar problems in the diagnosis of the condition. The method of statistical processing of the results of periodic tests of high-voltage bushings is proposed, which allows to form arrays with homogeneous values of indicators in conditions of limited measurement information. It is established that for the bushings of hermetic and non-hermetic execution, the insulation values for both the serviceable and faulty state can be described by the Weibull distribution. It is established that the distribution densities for serviceable and faulty state of high-voltage bushings intersect, and therefore it is impossible to select the maximum permissible values of insulation parameters that would not give erroneous solutions. The maximum permissible values of the insulation indices of high-voltage oil-filled bushings are proposed using statistical methods and taking into account the most significant operational factors. It is shown that for high-voltage bushings of the same execution there is a shift in mathematical expectations, which is due to the difference in operating time and different load factors of transformers. This circumstance must be taken into account when adjusting the maximum permissible values of the insulation indices of high-voltage bushings. The use of the developed algorithms and procedures of mathematical statistics in the problems of diagnosing high-voltage bushings contribute to improving expert judgment and decision-making.Документ Comparative analysis of existing standards and methodologies for interpreting DGA results(Typography Madrid, 2021) Shutenko, O. V.; Kulyk, O. S.; Ponomarenko, S. G.The study guide is intended for performing individual computational tasks in the course "Mathematical Bases of Technical Diagnostics". The guide contains a systematised analysis of methods and criteria used to recognise the type of defects in oil-filled equipment based on the results of analysis of gases dissolved in oil. The contents of the problem, an example of its performance and variants for calculation are given. It is intended for full-time and extramural international Masters and learners in English of specialisation No. 141 "Electric power engineering, electrical engineering and electromechanics" with specialisation in "Electrical systems and networks", as well as for applicants, postgraduate students and researchers working in the field of diagnostics of high-voltage electric power equipment state.Документ Determining the maximally permissible values for the indicators of insulation of sealed entrance bushings with a voltage of 110 kV using the method of minimal risk(PC тесhnology сеntеr, 2018) Shutenko, O. V.; Zagaynova, A. A.; Serdyukova, G. N.A method for determining the maximally permissible values for the indicators of insulation of high-voltage oilfilled entrance bushings that ensure the minimal risk value has been proposed. The proposed method differs in that the maximally permissible values for indicators are determined by minimizing the function of average risk, using the Newton’s method, taking into consideration the actual operating conditions of equipment, which makes it possible to improve the operational reliability of entrance bushings. We have derived an expression to determine the average risk with respect to the distribution law of indicators for the insulation of high-voltage entrance bushings (by Weibull), the minimization of which makes it possible to determine the maximally permissible values for the indicators, taking into consideration the duration of their operation, the values of load currents, the grade of a transformer oil, and other factors. A comparative analysis was performed for risk values, which are accompanied by applying the maximally permissible values for indicators that are regulated in Ukraine, with the maximally permissible values for indicators, which were obtained by using different methods. The analysis revealed that the minimal risk value is ensured by the maximally permissible values for indicators, which are obtained by applying the method of minimal risk, taking into consideration the operating conditions for entrance bushings. We have performed an analysis of impact of the values for probabilities of the proper-functioning and faulty state of entrance bushings, the cost of incorrect decisions, as well as the value for a scale parameter and a shape parameter in the Weibull distribution, on the maximally permissible values for the indicators of insulation of high-voltage oil-filled entrance bushings in an airtight structure. It was established that an increase in the probability of a defect and its conditional cost, as well as prolonging the operation duration of entrance bushings and their loading, leads to a decrease in the maximally permissible values for the indicators. It has been proven that the maximally permissible values for the indicators of insulation of high-voltage entrance bushings, which ensure the minimal economic loss, are not constant. In order to practically implement the method of minimal risk during operation, it has been proposed to apply the likelihood ratios, which make it possible to diagnose the state of high-voltage entrance bushings at a minimal risk, but without determining the maximally permissible values for the indicators.