Pilot Protection of Low-Frequency Transmission Lines for Offshore Wind Power Based on JS Divergence

Flexible low-frequency transmission is a crucial technical approach for large-scale wind power transmission in mid- and high-sea regions. When a fault occurs in the offshore low-frequency transmission line, the short-circuit current on both sides of the line is supplied by the power electronic converter. This alters the system’s fault characteristics, leading to a decline in the performance of traditional phasor differential protection. This paper introduces the structure of the offshore wind power low-frequency transmission system and the control strategy for converter faults. It analyzes the adaptability of traditional phasor differential protection to the changed fault characteristics in low-frequency lines and proposes a line pilot protection principle based on JS(Jensen-Shannon) divergence. Specifically, rapid fault identification and isolation are achieved by calculating the similarity of the probability distributions of the current sampling points on both sides of the line at the same moment. The reliability and speed of the proposed protection method are validated through electromagnetic transient simulations of various fault types both within and outside the low-frequency line area.