With the intelligent development of rail transit and the promotion of the "double carbon" goal, artificial intelligence technology has been preliminarily explored in the traction power supply system. This report discusses the application of artificial intelligence in fault diagnosis of traction power supply system, and focuses on three key technologies: 1) the application of artificial intelligence in fault diagnosis of high voltage circuit breaker; 2) the application of artificial intelligence in the isolation switch fault diagnosis; 3) application of artificial intelligence in the identification and localization of high impedance ground faults in traction electric network.