The fixed-point iteration method is widely adopted for short-circuit current calculation in distribution networks integrated with grid-following distributed generation (DG). However

with the increasing DG capacity and penetration level

the convergence performance of the fixed-point iteration method deteriorates. The integration of grid-forming DG further intensifies the nonlinear characteristics of short-circuit current calculation

further degrading the convergence performance of the fixed-point iteration method. To address this challenge

a novel iterative method based on the quasi-Newton rank-two method is proposed for short-circuit current calculation in distribution networks with DG. First

the impact of grid-forming DG integration on the convergence performance of the conventional fixed-point iteration method is analyzed. Second

the Broyden-Fletcher-Shanno (B-F-S) method

a quasi-Newton rank-two method with good convergence performance and convergence robustness

is introduced. The basic principle of the B-F-S method is presented

and its implementation procedure for short-circuit current calculation with DG is provided. Furthermore

the influence of grid-forming DG integration on the numerical stability of the quasi-Newton method is investigated. Finally

the accuracy of the proposed algorithm is validated on the IEEE43-bus distribution network

and comparative analysis against existing methods on the IEEE300-bus power system demonstrates its improved convergence performance and robustness.