Návrh a nastavní elektrických ochran pro rozvodnu 110/22 kV Kojetín

Abstract

This thesis is focused on electric protections in distribution of medium voltage power. There is a general description of protections in theoretical part of thesis at first. There is a description of choice of new protections and its properties according to the most frequent faults. The aim of the second chapter is an explanation of principal functions of various kinds of protections. The last theoretical chapter deals with short-circuit current calculation. This is necessary for setting of new protections. The practical part begins in fourth chapter. There is a description of the present state of distributing substation Kojetin and its devices. The chapter continues with enumeration of imperfections in actual protection system. The important part is a proposal of new protection system which eliminates old imperfections. The main aim is correct setting of new protection. For this purpose it is necessary to calculate the short-circuit currents at output of the distributing substation. The main contribution of thesis is the table with setting values for new protections. It’s very important for substation to be protected well. In conclusion of the thesis I bring my own idea how the protection system of distributing substation Kojetin could be improved in the future.