Semi-submersible Drilling Platform DP3 Closed-loop Power Station Research

Dynamic positioning(DP)system is the core technology of deep-water offshore equipment.It's important technical basis for offshore strategy.The safety and reliability of Dynamic positioning(DP3)is the highest,the electrical part of the dynamic positioning system can be divided into power system and control system.Close ring power system has the advantage of economic,environmental protection,high efficiency.In this paper,the realization of closed ring system under the DP3 system is studied for Semi-Submersible drilling unit.Firstly design close ring power plant system,considering class requirement and working characteristics of close ring power system,Sort out key issues and design points need to be solved;Drawing single line diagram of close ring power system,calculate required load list of each switchboard based on function requirement of drilling unit and load balance requirement,Establish close ring power plant by the designed drawing of High & Middle Voltage Switchboard and selected of generator group;Then setting parameters for load input and output,survey running status of power plant system by software PMS(Power Management System)and AGS(Advanced Generator Supervisor).Then carry out simulation and operation analysis for DP3 close ring power system,,After establish the fame of power plant,Making Models to do power flow analysis by EDSA 4.0;based on the requirement of system pressure drop,To estimate the capacity of switchboard,distributions box,generator,transformer,and load list under Maximum load demand,to present pressure drop of bus-bar by load flow analysis,to determine the adjustment of transformer tap,to verify the capacity of selected transformer and generator;,Make protection selective analysis for close ring system through parameter setting and calculation for switch g-t performance,switch tw-i0-c-b2 performance,switch string04 g-d performance and other switch's performance;Establish simulation model under the environment of Matlab simulation database.To make setting point for parameter of generator,diesel engine,automatic voltage regulator,speed controller,to simulate system failure,fault through etc.,then make transient simulation and analysis for close ring system.Finally,failure mode analysis of DP3 closed loop power plant is carried out.Single point failure in power system shall be mainly considered caused by Fire / water intake in 6.6kW switchboard room or short circuit bus bar;Make failure analysis for 690 v power distribution system under short circuit of Distribution system or Transformer failure caused by a failure of main switchboard,Make failure analysis for 230 v power distribution system to check if have effect to main power system.According to the analysis results,we can see dynamic position function will not be effected by any single failure of this close ring power system,We can come to conclusion from the results of simulation and function test,under the condition of equal power demand,number of operation generator in close ring system more than traditional power system,so close ring power system has the advantage of economic,environmental protection,high efficiency etc.,which meet the function requirements.