This chapter proposes a security solution with value-based data governance tailored for large-scale flexible loads’ data. Our approach introduces a real-time data value assessment model within a comprehensive framework that employs a fine-grained hierarchical management and protection strategy. This strategy dynamically adjusts governance and security measures based on the data value of large-scale flexible loads, addressing all stages of its life cycle. Numerical analysis demonstrates that the solution enhances data protection and system performance while reducing security costs. It also promotes data circulation and value generation, outperforms traditional methods in both security and efficiency, and supports a sustainable and intelligent power system transition.