Experimental Studies of Operating Modes of Electric Drive in Bow Thruster as a Part of the Ship Electrical System

Abstract

Autonomous electrical power systems using parallel operation of diesel generator sets are widely used in various scope of human activities. Ensuring the proper quality of electricity and an uninterruptible power supply to autonomous electrical power systems is a complicated and important task because the safety of people and goods depends on their successful implementation. The operation of powerful AC electric drives, comparable to power of asynchronous motors creates the most complicated operating modes and requires carrying out a research. The "Yeisk" sea ferry was chosen for scientific research. It has a thruster with a variable-pitch propeller and an induction motor with a power of 135 kW, which is the most powerful AC electric drive onboard the ship. Oscillograms of currents, voltages and active power of parallely operated generators were obtained in all the operating modes of the bow thruster as a result of the experimental studies. They provide comprehensive information about the parameters of electromechanical processes during the operation of an electric drive comparable to the power of an electrical power system. Power exchange oscillations were recorded between the parallel operated synchronous generators of the marine power plant in all the operating modes of the thruster. The results of the study confirm the need to apply methods and means of eliminating power exchange oscillations. It seems very useful and necessary to get acquainted with the time and amplitude characteristics of the electromechanical processes by the maintenance personnel of ship’s electrical power system. It is recommended to carry out similar studies for all the autonomous electrical power systems including powerful electric drives.