Research On Shipping Combined Power Station And Electrical Network Power Quality

Along with the rising of the traditional energy crisis and carbon emission,environmental protection is the direction of the ship in the future.Now the new energy technology is in constantly developing and its application in shipbuilding industry has been paid more attention,and researchers and scholars from different countries are actively exploring new energy application technology in ship industry to save energy and reduce environmental pollution of the ship.The development of new energy technology used in the ship,expanding types of energy in the shipping power station,to make it multimodal.According to the specific situation of ship,reasonably planning the composition of different kinds of energy would enhance energy utilization and efficient besides the liability of ship power station.The application of new energy for shipping can be referred to new energy technology on the land,but the Marine environment and ship factors must be given full consideration to,and we should also pay attention to the technical differences between both new energy technology.We shall never transplant the land new energy technology simply and directly to ships.Micro-grids technology ensure grid-connected generation system safe and efficient.It can not only improve the quality of the new energy utilization and energy,but also adjust effective operation control and energy management according to different demand.Reference to microgrids on the land,building the micro-grids with characteristics of ship power system to ensure the distributed energy systems efficiently and safely into shipping power station.Electricity network power quality impacts the shipping equipment,navigation safety,and energy saving effects of the vessel,so high quality electricity can ensure the safety,efficient and economical operation of ship electric power system.The main works are summarized as follows:Firstly,this paper takes ‘Shipping combined power station' as an object and research on all kinds of distributed power supply and key components of it,which includes PV power generation system,hybrid energy storage system(HESS),ship shaft generator system,diesel power generation system,Dynamic and static load in the ship,The models of them are built based on the theory proved by Matlab/Simulink.Secondly,research on the problems caused by new energy into the ship power system,increasing the brittle sources and decreasing the system inertia,which make the system unstable,power coordination among a variety of distributed generation.Proposed control strategy of grid inverter based on the principle of virtual synchronous generator used in the ship.Which applies to the autonomous power system like ship electric power system,because of large inertia and output impedance,power distribution according to droop characteristic as similar with the synchronous generator.Considering the problems of ship electric network quality have effect on the performance of equipment and load in the ship,reduce its life,reduce its efficiency,will also seriously threaten the safety.Meanwhile it can reduce the economy operation of ship,lower power factor and harmonic can increase the system's line loss.If the harmonic beyond a certain range,the speed shall be slowed down or the capacity of ship power station shall be reduce to ensure the safe operation of ship,which reduce the energy efficiency.Three important factors of the electric network quality would be analyzed in the paper: harmonic,fluctuations of voltage and frequency caused by distributed generation;the influence of the working condition and the load of ship;the faults of electric network in the ship.Finally,on the basis of modified method of instantaneous power,the multi-functional grid connected inverter is presented.The multi-objective control method makes full use of the residual capacity of the inverter,can not only deliver the power,but also provide reactive power compensation and harmonic suppression.It greatly reduces the investment cost of the ship and the system volume,improves the use efficiency of inverter,and saves valuable space,whch is suitable for ship electrical power system.