| Abstract [eng] |
This paper investigates such characteristic of low-voltage automatic switches as selectivity. The core of the research is based on providing evidence about the necessity of improvement of a widely used time-current technique. The recommendation for choosing a proper protection coordination scheme was proposed. Protection coordination of two circuit breakers connected in series is observed. The proposed improvements are evaluated based on theoretical and empirical backgrounds. Firstly, circuit breakers with time-current based on thermal-magnetic release and current selectivity are tested in order to obtain selectivity. Then, the simulations are conducted in order to check the eligibility of specialized software program for investigation of protection coordination among low voltage automatic switches. Finally, conclusions and recommendations are presented. Structure: introduction, literature review, experiment, simulation, conclusions and recommendations, references. The thesis consists of 72 p. text without appendixes, 29 pictures, 48 bibliographical entries. |
