CATASTROPHIC FAILURE OF AN ASEA TYPE IMBE-170 A4 CURRENT TRANSFORMER
This month’s Featured Technical Paper is from the Proceedings of the 2025 International Conference of Doble Clients. The paper is titled: Catastrophic Failure of an ASEA Type IMBE-170 A4 Current Transformer.
Abstract
An explosion of a current transformer (CT) was observed in a 161kV electrical substation. The failure projected pieces of porcelain more than 250 feet and caused a fire on the equipment. The CT was built in 1988 and operated and tested without any issue until failure. This CT was installed in a substation supplying industrial loads, including aluminum potlines that generated harmonic currents. The harmonic filter had been taken out of service for seven days before this failure. An autopsy was performed on the failed CT and two adjacent CTs installed in the other phases. The source of the defect was identified but the fundamental cause was still unknown. Insulation measurement and oil samples were carried out on all similar models in all our stations. A replacement program was implemented and prioritized based on the measurement campaign.
Doble Service Agreement Clients
This and other technical papers and presentations are available in the MyDoble Resource Center - one of the many benefits available to you as a Doble Service Agreement Client. To get to the MyDoble Resource Center login click here. Not a member? Follow the sign-up process.