Calculation of Transient Current of Rectifier Generator With DC Grid Faults

In the DC grid, DC short-circuit fault is the main fault type. When calculating the electromechanical transient state of the AC/DC hybrid power grid, the AC power grid and the DC power grid are solved separately, which will lead to the problem of inaccurate short-circuit current calculation when the DC power grid is short-circuited. After combing the AC/DC hybrid power grid, DC microgrid structure and marine DC power grid structure, the transient short-circuits current of the rectifier generator feeds to the short-circuit fault of the DC grid is calculated. After obtaining the expression of the transient current, the analytical expression of transient current is acquired through analogy to the calculation of short-circuit current of synchronous generator. Finally, the validity of the analytical expression is verified by simulation, and it can be used for DC fault diagnosis and protection mode determination.