Improved Time-Domain Distance Protection Scheme Based on RLC Model for Wind Farm Transmission Line

The long-distance transmission lines of large-scale wind farms have significant capacitance currents distributed to the ground, which significantly impacts the adaptability of existing time-domain distance protection based on the RL models. This paper studies a time-domain distance protection scheme based on the RLC model. Firstly, the applicable frequency band differences of RL, RLC, and distributed parameter models under different line lengths are analyzed. The results indicate that with an increase in line length of 100km, the frequency used by the RLC model decreases by 300Hz, while the RL model remains approximately 100Hz. Further, the characteristic differences between internal and external faults based on the RLC model are analyzed: When there is an internal fault, the line resistance and inductance parameters are both positive; When there is an external fault, the line resistance or inductance parameters are negative. Based on the feature differences of this model, a time-domain distance protection scheme considering the physical characteristics of line parameters is constructed. Taking the grounding fault of A typical wind farm output line as an example, the simulation results indicate that the time-domain distance protection scheme based on the RLC model has a shorter fault identification time compared to the RL model, which is more conducive to the rapid implementation of faults.