ABSTRACT
Growing economic pressure and liberation of the electricity market are forcing utilities to seek new ways of asset management and cost/risk assessment. Transformer reliability depends on a large number of factors and responsibilities both for manufacturers and users. The dry and treat process, the pressing process, and the oil filling and impregnation process are of importance for high reliability. The best design and production quality can be destroyed by means of inadequate transport/erection and commissioning and maintenance processes. Transformer life management, condition assessment, and reliability are highly dependent on the mode of operation, frequency of overloading, and transient condition in respect to dielectric, thermal, and dynamic stresses. Reliability and transformer life are severely influenced by consequent maintenance according to transformer manual and regular service measures as well as by condition assessment—starting from fingerprinting to regular trend analysis by means of off-line diagnostics and online monitoring.
