To address the issue of performance degradation in traditional protection during faults on outgoing transmission lines from renewable energy plants caused by limited short-circuit current and frequency deviation, a new pilot protection criterion is proposed. The criterion is based on empirical mode decomposition (EMD) to extract multimodal components, i.e., intrinsic mode functions (IMFs), and employs the Kendall’s correlation coefficient for fault identification. First, the limitations of traditional protection and existing similarity algorithms are analyzed. On this basis, fault currents from line terminals are decomposed via EMD, and the similarity of the components is analyzed by using the Kendall coefficients to reveal fault characteristics. The differences in Kendall coefficients among IMFs of different orders during internal and external faults are examined to assess their fault representation capability. Finally, a comprehensive similarity-based protection criterion integrating current amplitude, phase, and polarity features is developed by adaptively weighting IMFs. Simulation results show that the proposed method is immune to the specific fault current characteristics of renewable energy sources and can accurately discriminate between internal and external short-circuit faults under various fault scenarios in renewable energy plants, featuring fast operation, high accuracy, and strong adaptability.