Návrh a nastavení elektrických ochran lodních rozvodných systémů

Abstract

This diploma thesis deals with design and setting of electric protection relays in ship power distribution systems. First part contents basic theory and philosophy to design in marine industry and its brief differences to land based installations. After that there is description of air insulated high voltage switchgear ABB ZS1 and installed electric protection relays REFx. In second part of this thesis there is description of high voltage power distribution network of LNG vessel GASLOG followed by calculation in accordance with PNE 33 3042 which is based on IEC 60909-4, where the short circuit current is calculated. The results of this manual calculation are compared with results provided by software SKM Power Tools, where the network has been simulated. There are two different sets of results for far-from generator short circuit, in accordance with IEC 60909 and near-to generator short circuit in accordance with IEC 61363. After that there is selectivity study for three different power transformers which leads to design and setting of particular over current protections in particular power stream. In the end there is proposed setting of earth fault and undervoltage protections.