ABSTRACT
On-line monitoring of transformers and associated accessories by measuring certain parameters or conditions while energized is an important consideration in their operation and maintenance. e justi–cation for on-line monitoring is driven by the need to increase the availability of transformers, to facilitate the transition from time-based and/or operational-based maintenance to condition-based maintenance, to improve asset and life management, and to enhance failure-cause analysis. ere are four major accessories in a transformer where solutions exist for on-line monitoring. ey include the insulation system including the transformer insulating «uid and oil preservation system, the coil and core assembly, bushings, and, if so equipped, its load tap changing equipment. Historically, it has been found that issues that evolve into failures occur in one of these four accessories and therefore are good candidates for on-line monitoring.
