Research on the Improved Calculation Method of the Influence of VSC-HVDC on AC Short-Circuit Current

With the increasing number and scale of VSCHVDC connected to the power grid, the impact of VSC-HVDC on the AC short-circuit current level needs to be accurately calculated. Existing studies generally use simplified processing methods, and it is difficult to evaluate the short-circuit current calculation error. This paper summarizes the process and mechanism of VSC-HVDC short-circuit current contribution, establishes a typical VSC-HVDC electromagnetic transient model to analyze the influence on AC short-circuit current, analyzes the error source of the existing VSC-HVDC influence AC short-circuit current calculation method, and puts forward an improved method considering both active and reactive current components - AB coefficient method, which could theoretically improve the calculation accuracy of AC short-circuit current affected by VSC-HVDC. Finally, in order to improve the application range of the AB coefficient method, the fitting AB coefficient method is further proposed to greatly improve the calculation accuracy of the AC short-circuit current affected by VSC-HVDC, and the correctness and applicability of the method are verified through case studies.