This paper addresses the issue of over- evaluation in short-circuit current (SCC) calculations for grid-following renewable energy grid-connected systems. By developing a network decomposition method and deriving analytical expressions for SCC

this paper reveals the influence of renewable energy’s initial power output on fault currents. Furthermore

it establishes selection criteria for the equivalent voltage source coefficient when calculating the maximum SCC

and proposes a novel method for determining the maximum three-phase SCC at fault locations. The proposed method overcomes the limitations of conventional algorithms

which rely on predefined initial power assumptions

and eliminates deviations caused by amplitude substitution and worst-case voltage scenarios. As a result

it significantly reduces the bias in existing calculation methods. Using the proposed method

this paper theoretically analyzes the impact of renewable energy integration-both direct and replacement-on SCC contributions. The accuracy of the method is validated through electromagnetic transient simulations

while its scalability is demonstrated on a large-scale power system with 110 000 nodes. Additionally

real fault measurements from the North China Power Grid confirm the method’s engineering practicality and superiority over conventional approaches.