MAINTENANCE approaches of high voltage transformers in the field have been developed over recent years. There are several traditional approaches employed for transformers, either corrective or time based preventive maintenance strategies have been generally implemented. The corrective strategy involves implementation of maintenance once the power station or substation has failed to operate. The advantage of this type of maintenance is that it
does not require any decision tools. However, using this approach will cost the operator a significant amount to replace
the asset once it has failed. Meanwhile, time-based preventive maintenance can be implemented and has advantages over
corrective strategies due to the fact that assessment of