Analysis of Electrical Distribution System for Offshore Oil and Gas Platform

The electrical power system of a medium size offshore oil and gas platform is studied by using a power system simulator software, namely ETAP. The load flow and short circuit analyses under various operating conditions are carried out, including normal, service, emergency and black start operation. The operations that generate maximum and minimum fault current magnitudes at the main switchboard and electric submersible pump are calculated, respectively. The protective device coordination is achieved by using the time-current curve tool of ETAP. The component ratings, voltage drop, and protection device setting are evaluated based on the results obtained from these analyses. A modern multifunctional transformer relay is proposed on a 2240kVA 6.6/0.415 kV transformer to provide a comprehensive protection and control. The overcurrent tripping time is reduced by using the combination of instantaneous and time-delay protection functions of the multifunctional transformer relay, hence mitigate the arc flash damages to the system and improve safety for personal. The relay is assessed in the laboratory by using a secondary current injection tester. The result shows that the correctness of the relay setting. The future work includes transformer internal fault studies and testing, and integration of protection systems with plant automation.