Short Circuit Analysis on AHTS Ship Due To Use of Closed Circuit Electrical System

Abstract

Dynamic Positioning (DP) enables a ship to automatically maintain a vessel’s position and heading by using its own propellers and thrusters. The position can be kept optimally when the ship leans on the harbour with the assistance of the anchoring and mooring process. Under particular circumstances, when the ship is in the middle of the sea, both of the processes can’t be done optimally. To ensure the ships absolute position, the ship must have zero six degrees of motion: heave, sway, surge, roll, pitch and yaw, in which the vessel must be in absolute idle despite the wave effect. The DP is used to articulate wave force and against it by a work of mechanism and sensor in which prevents the ship’s standpoint deviates. The computer will proceed with the information, articulate a levelised thruster work, and avoid any degrees of motion from becoming non-zero. Ship equipped with this DP system generally uses split bus configuration in the electricity system, by allowing one load supplied by one independent generator to improve its reliability. However, this configuration was deficient with the efficient aspect and high emissions caused by the power supply. With the application of closed bus configuration electricity system, there is a high potential of excess current influx, which causes short circuit current. The analysis of how much short circuit current happened on the electricity system of AHTS ship is to revolve the short circuit current, and thus resulting in electrical system failure. Based on the analysis that has been done, the configuration electricity system with 1 generator supply power thruster and two diesel generator, also the load that used is two bow thruster and 60% shipload having short circuit based of the standard short circuit for low voltage electricity.