Failure Analysis and Detection Technology Considerations for a Dry-Type Air-Core Reactor in an Ultra-high Voltage Substation

Dry-type air-core reactors are crucial equipment for inductive reactive power regulation in ultra/extra-high voltage substations. In recent years, multiple incidents of equipment failure and fire faults have occurred, posing significant challenges to grid stability. Focusing on a 2024 fire fault involving a 35 kV dry-type air-core reactor in an ultra-high voltage substation, this study conducted a disassembly analysis of both the faulted phase and a reference phase, performed comprehensive diagnostic testing and verification, and carried out failure analysis. By combining these findings with existing detection methods for dry-type air-core reactors, the study identifies limitations in current detection approaches. This work offers valuable insights for the industry regarding fault diagnosis, analysis, and the advancement of detection technologies for dry-type air-core reactors.