It is difficult to identify a fault on a direct-driven wind farm collection line. Thus a protection of the line based on transient high-frequency energy is proposed. First, considering the converter control strategy, the electrical parameters and component transient characteristics in the high-frequency section, a wind farm collection line transient high-frequency model composed of inductive impedance is established. Then a transient high-frequency network of internal or external faults is established. According to the matching degree of different fault cases and transient high frequency energy at the protection installation site, a protection criterion is constructed using the difference of transient high-frequency energy direction. Finally, an RT-LAB simulation platform verifies that this method can correctly identify the internal or external faults under various fault conditions. The fault identification is not affected by synchronization error, and has strong resistance to transition resistance.

This work is supported by the National Natural Science Foundation of China (No. 51822703).