Environmental and life cycle considerations for distribution and small power transformer selection and specification

A superficial review of power transformer options frequently leads to the conclusion that a standard dry-type transformer is more environmentally responsible alternative than a liquid transformer. However the differences in lifetime losses represent real differences in environmental costs as well as energy costs. This paper equates the losses to various environmental costs, and presents a life cycle economic model to help evaluate total lifetime owning costs in monetary terms. The cost components include the initial costs of the transformer itself, directly related equipment and installation costs, operating costs including power losses and maintenance and end of life costs related to decommissioning, salvage value or disposal cost. Less quantifiable factors such as audible noise, physical size and reliability are also be compared for dry-type transformers and their liquid counterparts. Finally, electrical insulating fluids commonly used in these transformers are compared in terms of economic, environmental and safety factors. Economic factors include the initial fluid cost, maintenance and disposal cost or salvage value. Environmental properties such as biodegradation, BOD, fate and effects and environmental regulations are discussed. Safety aspects, including transportation and workplace exposure regulations, are compared, and fire properties including ignition resistance, heat loading, smoke generation and combustion toxicity are detailed.