Method for determining optimal power transformers exploitation strategy

The paper suggests a procedure for determining an optimal combination of activities and measures to minimize the expected total costs during the planned exploitation period of power transformers.Combinations of different types of preventive maintenance, spare parts keeping and installation of condition monitoring systems of power transformer individual components are taken into consideration. Power transformer is a complex system, consisting of six components (functional parts). It is assumed that each component has two independent, competing failure modes: a wear-out failure mode, modeled by two-parameter Weibull distribution, and a chance failure mode, characterized by an exponential distribution.The superposition of failures and planned maintenance are taken into account in the analysis of some forms of preventive maintenance.The application of the method suggested and the benefits it provides are demonstrated for one transformer station (TS) 110/10 kV/kV with 2 × 31 500 kVA-110 kV Star-10 kV Delta transformers in case of radial supplying of customers as well as in case when outage of one power transformer does not affect the power supply to customers.

► We suggest a method for determining a plan of power transformers optimal exploitation.
► The method provides the lowest costs during the planned exploitation period of power transformers.
► The combinations of preventive maintenance, spare parts keeping and CMS installation are analyzed.
► It is shown that a relatively small investment can bring about large savings.