A short-circuit current calculation method for direct-driven wind farms based on voltage iteration

Abstract

Short-circuit current calculations for wind farms typically employ equivalent models that neglect internal lines， transformers， and other critical factors， leading to reduced accuracy. Methods that account for these factors often rely on simultaneous voltage and current iteration， which complicates the intuitive verification of convergence. To address such issues， this paper proposes a short-circuit current calculation method that incorporates the internal structural parameters of wind farms. Based on the current characteristics of direct-driven permanent magnet synchronous generators （D-PMSG） under current-limiting conditions and the equations for the maximum node voltage of wind farm， a calculation model for short-circuit current in a wind farm is built. Then， Norton equivalence is applied to eliminate unknown current parameters， and the modified node voltage equation based on varying operating conditions is established. Finally， by implementing voltage iteration， a modified short-circuit current calculation method based on the modified model and the characteristics of the wind farm is obtained. Simulation comparisons demonstrate that the proposed method offers enhanced accuracy and improved convergence.

Keywords

• large-scale wind farm
• short-circuit current
• d-pmsg
• iterative calculation
• limiting effect