Since 1980 EMI (electromagnetic interference) Diagnostics has provided information on the electrical and mechanical condition of several hundred electric generators. This on-line technique has been applied to many sizes and designs of 2-pole and 4-pole steam and combustion turbines, air cooled and hydrogen cooled generators. This paper provides several case studies of electrical and mechanical deterioration identified with EMI Diagnostics for air cooled machines. Several methods that enhance analysis of EMI Diagnostics are presented, such as trending, data comparison at different loads as well as data comparison on-line and off-line but energized.
Power transformer mechanical condition assessment with a vibration-based diagnostic method
