Protection relay setting of the 6,6kV motor feeder at LNG carrier

Abstract

Due to the large number of motors in marine vessels, proper calculation of short-circuit currents and setting up a motor protection are vital tasks of engineering design in order to ensure safety of vessel itself, personnel, cargo and equipment; and prevent from abnormal operations of onboard installations. The main regulatory documents for that are standard IEC 61363 and ABS rules. The main purpose of this thesis is to calculate maximum and minimum short-circuit currents at 6,6 kV switchboards of LNG carrier with specific configuration, propose necessary protection functions and its settings for chosen motors based on applicable marine standards and selectivity in the whole MV system, and also represent all tripping curves.