Stepura O. Detecting and evaluating the sources of power quality distortion in electrical distribution networks

This dissertation focuses on finding practical solution to the problem of increasing sensitivity to detect the sources of power quality distortion in electrical distribution networks. The object of the study was the process of detecting and evaluating the impact of nonlinear and asymmetric consumers on the deterioration of electricity quality. The subject of the study is methods of increasing the sensitivity of detection and evaluation of the influence of nonlinear and asymmetric consumers on the deterioration of electricity quality. During the dissertation work, research methods were used, which were based on: the theory of electrical engineering - in obtaining analytical expressions of methods of detecting and evaluating the influence of nonlinear and asymmetric consumers on the deterioration of electricity quality in networks; on the theory of mathematical statistics - when conducting statistical processing of the results of experimental studies. Scientific novelty of the research is grounded in the fact that the process of detecting and evaluating the sources of power quality distortion in electrical distribution networks has been improved by using conditional capacities of reverse and zero sequences. The findings of the research are as follows: 1. Informative values to evaluate the impact of nonlinear and asymmetric consumers on distortion the quality of electric powers in distribution networks by using generalized instant symmetrical capacities of reverse and zero sequences which provides separation of distortions caused by canonical harmonics and harmonics multiple of three have been justified. 2. Method of detecting and evaluating the impact of nonlinear and asymmetric consumers on distortion the quality of electric powers based on usage of conditional capacities of reverse and zero sequences which provides increasing sensitivity to detect and evaluate the impact of nonlinear and asymmetric consumers on distortion the quality of electric powers has been improved. 3. Method of detection sensitivity analysis of impact of nonlinear and asymmetric consumers on distortion the quality of power in isolated and grounded networks subject to harmonics that takes into account the ration between conditional capacities of reverse and zero sequences and capacities of harmonic component that causes this type of distortion has received further development. This made it possible to evaluate the possibility of detecting nonlinear consumers in the presence of third-party harmonic distortions. ASCAE (automated system of commercial accounting of electricity) with the function to detect and evaluate the impact of nonlinear and asymmetric consumers on distortion the quality of electric power has been developed and practically implemented. The results obtained in the course of the research, in particular, software and hardware complex for a system of commercial accounting of electricity (ASCAE) with the function to detect and evaluate the impact of nonlinear and asymmetric consumers on distortion the quality of electric power have been successfully implemented in private enterprise "Promavtomatika" confirmed by the act of implementation from 07.02.2019. The results of the research are also used at Vinnytsia National Technical University at the department of electrical engineering systems of power consumption and energy management to provide professional training of specialists to get the specialty 141 – “Electricity, electrical engineering and electromechanics”, certificate about implementation issued from 17.06.2019.