Transformers come back to the shop or warehouse from the system for various reasons including failure, changes in loading, and line reconstruction.

The decision whether to return the unit to inventory for reuse depends on many economic factors including the cost of repairs or refurbishment, the expected remaining life, loss levels compared to new units, cost of new units of the same size, installation costs, and utility economic parameters.

Even where the returned unit is undamaged and physically ready to go back into the system, the economics can indicate that it might better be scrapped if its losses or the installation costs do not justify saving it.

DSTAR has developed a Transformer Scrap / Repair Decision Software to help make this decision.

We don’t expect a shop worker to run a computer program for every transformer that comes in, and we don’t expect that anybody in Standards will want to do this for each and every time transformers are returned.

TS/RDS is designed to generate tables of maximum repair costs for transformers in the system which may come back in. Maybe once a year, an engineer or technician will run the program. The table generated might indicate that a Brand X unit with a serial number in a certain range (indicating age, size, and loss parameters) has a maximum justified repair cost of $150. When the shop receives such a unit with only a cracked bushing, and checks the table, the shop would go ahead and repair the unit. If the unit needs a rewind, then it would go to scrap.