Objective With the large-scale application of compressed air energy storage (CAES) technology, the fault diagnosis of its main equipment, compressors and expanders, has become critical for ensuring system safety and reliability. This paper aims to systematically review the common faults of CAES main equipment and its corresponding diagnostic techniques, providing a reference for related research and engineering practices.

Method This paper first outlined the fundamental operating principles of CAES systems and the typical fault modes of their main equipment. Subsequently, it provided a comprehensive review of the current status in fault diagnosis technologies from four perspectives: model-based, signal processing-based, data-driven, and knowledge-driven. By comparatively analyzing the core ideas, advantages, disadvantages, and application cases of each technique, the main challenges in current research were identified.

Result The review finds that although existing fault diagnosis technologies for CAES main equipment have made significant progress, there is a clear trade-off among different methods in terms of diagnostic accuracy, real-time performance, and robustness, with each having limitations in practical applications. Furthermore, intelligent diagnostics, predictive maintenance, and the fusion of multiple technologies are identified as the definitive future trends in this field.

Conclusion Fault diagnosis of CAES main equipment is fundamental to ensuring stable system operation. The core challenge in current research lies in developing hybrid diagnostic strategies that can integrate the advantages of multiple technologies. Future breakthroughs will focus on constructing more intelligent and predictive comprehensive diagnostic systems, thereby providing a solid technical foundation for the widespread adoption of CAES technology and the stable and efficient operation of future power systems.