Research On Common Cause Failure And Fault Reconstruction Technology Of Ship Integrated Electric Propulsion System

The ship's medium voltage direct current(MVDC)integrated electric propulsion system has become the key development direction of China's navy's next-generation equipment.The electric propulsion system using medium voltage DC power distribution has put forward higher requirements for system reliability.In this paper,the problems of common cause failure of ship MVDC integrated electric propulsion system and fault extraction modeling,voltage stability evaluation index and network reconstruction optimization algorithm in distribution network fault reconstruction are studied in depth.The common cause failure mode of the ship MVDC integrated electric propulsion system is analyzed,and the main stress causing the failure of each module in the system is studied.Through the load-strength interference analysis method,the relationship between the reliability of distribution network components and the environmental load/intensity distribution characteristics is analyzed,and the common cause failure probability model which can reflect the failure correlation is established,and the model is discretized.Can be applied to actual data tests.According to the failure probability model analysis and evaluation results,the distribution network operation environment is adjusted accordingly to avoid the common cause failure failure and improve the reliability of the fault reconstruction technology.Applying the breadth search method and the branch-node correlation matrix to extract the branch faults,and establishing the corresponding mathematical model for the DC-DC converter and inverter in the distribution network of the ship's medium voltage DC power system,and obtain the equivalent.Admittance.The node admittance matrix of the entire distribution network is established by using the branch-node correlation matrix.According to the structural characteristics of the AC/DC distribution network,an improved node potential method is designed to solve the steady-state parameters of the distribution network.The program simulation proves that the method satisfies the weight.The requirements of technology for power flow calculation.The voltage stability of the medium voltage DC power system distribution network is studied,and the system load margin calculation model is established.The static voltage stability index is set by the key branch method.The dynamic state of the motor is analyzed to establish its dynamics.The stability index model;the static and dynamic voltage stability indicators are weighted and normalized as the voltage stability index of the distribution network.Taking load recovery,voltage stability and switching action as the objective function optimization index,generator power and line capacity limitation as constraints,the fault reconstruction model of ship medium voltage DC distribution network is established;combined with adaptive weight method and hybridization The pool algorithm and the design of the "directional variation method" improve the particle swarm optimization algorithm,enhance its optimization speed and global search ability,and apply it to the fault reconstruction model of the distribution network.The simulation results show that the algorithm can obtain a more complete reconstruction scheme more quickly and ensure maximum fault recovery.