Short Circuit Calculation Method For Ship AC Power Electrical System

With the dramatically increasing of the power system capacity of the ship, thenetwork structure is more complicated, and the application of medium voltage ACsystem has become an inevitable trend. The traditional method of AC short-circuitcurrent calculation is difficultly to meet the requirements for ignoring more content,especially the emergence of the more complex structure like the ring and grid powernetwork also presents a new challenge for the short-circuit current calculation.Firstly, the article analysis the current short-circuit current calculation methodof AC ship power system，such as GJB173, GB3321, Japanese precision calculations,CCS2009and so on. Comparing with other methods, the accuracy of CCS2009ishigher. Secondly，take generators and motor into the unified transient network, andbe combined with the transfer impedance method to calculate the short-circuitcurrent of any power network structure. Then integrating the amended CCS2009power equivalent process into stratification equivalent method to calculate theshort-circuit current of tree network, which has strict mathematical derivation anditerative process, wherefore greatly improve the calculation accuracy and speedcompared with the traditional method. A practical case and SIMULINK simulationhas been used to verify the validity and accuracy of the proposed method.In order to facilitate the application, the article has developed the software onthe platform of MATLAB/SIMULINK to achieve the transfer impedance methodwhich based on the amended source model of CCS2009. The software has set up theelectrical module, and we can set up any power system of ship on the platform, andcalculate the short-circuit current of any point.