Didushok O. Methods and means of diagnosing the technical condition of the vacuum circuit breakers

This dissertation focuses on finding practical solution to the problem of increasing of reliability of work of vacuum switches and electric networks as a whole by perfection of methods and means of diagnostics of the electromagnetic drive and contact system of the vacuum switch. The object of research is the processes of changing the technical condition of vacuum circuit breakers during their operation. The subject of research is methods and means of determining the technical condition of the electric drive system of vacuum switches and their diagnostic features during operation. To solve the problems and analyze the circuit and algorithmic solutions used methods: theories of general electrical engineering to describe electrical processes during switching, the theory of magnetism to describe magnetic processes in an electromagnet, the finite element method to build a computer model of an electromagnet, the theory of thermogas to describe arc processes in a vacuum chamber, computer simulation methods to study the transients occurring in the switching process and to confirm the adequacy of the developed mathematical models, probability theory for finding errors of the first and second kind, analytical capabilities of computer algebra for implementation calculations of mathematical models. The scientific novelty of the obtained results is that: for the first time a mathematical model of diagnosing the technical condition of the electromagnetic drive of a vacuum switch based on comparing the reference weber-ampere characteristic with the current and determining the deviation coefficient, which allows to estimate the current technical condition of the switch electromagnet; for the first time a mathematical model was developed to determine the wear of the contact system caused by arc processes and mechanical overvoltages when turning on and off the vacuum switch, which allows to assess the approximation of the technical condition of the contact system of the switch to the emergency; improved mathematical model for evaluating the synchronous operation of the switch contact system, which, in contrast to existing ones, allows to calculate deviations from the allowable value of the switch-on time and generate control signals for operational personnel to adjust the moving contacts of the switch poles. For each pole, an informative signal is generated to bring its moving contacts closer or further away from the fixed ones to ensure synchronous operation of the switch contact system. The use of the obtained results made it possible to develop and implement an approach and mathematical model for diagnosing the electromagnetic drive of a vacuum circuit breaker based on the analysis of weber-ampere characteristics and a mathematical model for evaluating the synchronous operation of the contact system of a vacuum circuit breaker. , which in turn increases the reliability of the vacuum switching apparatus. The results obtained in the dissertation are implemented in the JSC “Vinnytsiaoblenergo” (implementation act from 19.05.2020) and in the educational process of Vinnytsia National Technical University (implementation act from 12.05.2020).