An industrial plant is to be supplied by three identical transformers. A decision must be made whether to purchased afourth transformer to build a sparing transformer system oralternatively, to configure the source as a secondary selective system. If the secondary selective option is chosen,
a. how much larger must each transformer be to be able to supply the full plant load in the event that one transformerfails?
b. how many additional circuit breakers must be purchased to provide the necessary bus tie capability?