Research On The Short-circuit Fault And Stability Of Ship Power System

The power system of ship includes DC system and AC system,now most ships are AC power systems.Compared to the AC power system of ship,the DC power system of ship has many advantages,for example,control method of DC power system is simple,power distribution does not need to consider the distribution of reactive power.In addition,the ship's energy storage equipment and modern battleship catapult installations are inseparable from the DC power system.Therefore,the ship's DC power system is highly valued by experts and scholars around the world.Failure of the ship's DC power system will affect the stable operation of the ship's power system.One of the most serious faults is the short circuit.Improving the stability of the ship's power system in the event of a short-circuit failure is a prerequisite for the stable operation of the ship.There are few studies on the research of short-circuit protection for shipboard DC power systems,therefore,it is necessary to study the short-circuit fault and stability of the ship's DC power system.First,determine the topology of the ship's DC system based on the background of the project.Established a simulation model of a ship's DC power system,realizes the simulation of no-load voltage build-up,grid-connected operation,sudden increase of load and short-circuit,lay the foundation for follow-up research.Second,this paper designed a hybrid DC circuit breaker and a new solid-state DC fault current limiter and conducted in-depth research on their topological structure,working principle and logic control under a variety of operating conditions.Built simulation model in MATLAB/Simulink and verifie simulation model.Third,based on the topology of the ship power system,draw up 19 representative short-circuit fault points,and complete the short-circuit current calculation and simulation verification for each short-circuit point.Based on the working principle of the selective protection device designed in this paper and the specification of the ship power system,the design of the selective protection scheme of the ship's DC current system is realized,and the setting value of each protection system component is calculated.Fourth,based on the fault diagnosis method combined with expert system and BP neural network,using the working status of each hybrid DC shunt as the sampling data of the expert system,using the current signal of the circuit breaker operating point at each short circuit point as the sample input data of the BP neural network,the short-circuit fault diagnosis and topology reconstruction are realized.Finally,for the requirement of on-line adjustment,real-time monitoring,and diagnostic verification,comprehensive using the interface technologies of LabVIEW,MATLAB,and Veristand software achieves the construction of dual-machine integrated real-time simulation platform and simulates the ship power system in real time.