A New Short-Circuit Current Calculation and Fault Analysis Method Suitable for Doubly Fed Wind Farm Groups

Area of Science:

• Electrical Engineering
• Renewable Energy Systems
• Power Systems Analysis

Background:

• Wind farm groups exhibit complex transient characteristics and strong grid coupling, complicating fault analysis.
• Existing methods struggle to accurately model the impact of doubly-fed wind turbines (DFIGs) and their control strategies during grid faults.
• Accurate fault current calculation is crucial for grid stability and protection with increasing wind power integration.

Purpose of the Study:

• To develop a novel short-circuit current calculation method for doubly-fed wind farm groups.
• To analyze the influence of low-voltage ride-through (LVRT) control on fault currents in DFIGs.
• To provide a foundation for improved power grid fault analysis post-wind farm group integration.

Main Methods:

• Established a mathematical model for converter input-output characteristics.
• Developed a transient DFIG model incorporating LVRT control effects on short-circuit current.
• Proposed a short-circuit current calculation method for DFIG groups, analyzing inter-farm interactions during faults.
• Verified the method using Real-Time Digital Simulation (RTDS).

Main Results:

• A validated short-circuit current calculation model for DFIG groups with LVRT control was established.
• The interaction mechanisms between wind farms during faults were analyzed.
• RTDS simulations confirmed the accuracy of the proposed calculation method.
• The study provides insights into power grid fault analysis after DFIG group access.

Conclusions:

• The developed method accurately calculates short-circuit currents in DFIG groups, considering LVRT.
• This research enhances the understanding of fault behavior in grids with significant wind power penetration.
• The findings support more reliable grid protection and stability analysis for power systems with integrated wind farms.