What Is FAT vs SAT in Transformer Procurement?
Quick answer — FAT (Factory Acceptance Test) happens at the manufacturer to prove the unit meets the spec before shipment; SAT (Site Acceptance Test) happens after installation to confirm it is set up correctly and ready to energise. FAT covers routine/type tests and inspection; SAT covers commissioning checks, protection, connections and a successful energisation.
Contents
What is a FAT and a SAT for a transformer?
FAT
Run at the factory, it verifies the design and the unit against the specification — tests, losses, quality, documentation — and any changes are made before it leaves.
SAT
Run on site after installation, it confirms correct erection, connections, protection settings, auxiliary/cooling operation and that the unit passes the pre-commissioning checks before energisation.
Witnessing
FAT is often witnessed by the customer (or an inspector) for the agreed tests; SAT is witnessed on site and may include a period of supervised energisation.
References & standards
- IEC 60076-1
- IEEE C57.12.90
Related
Related manufacturers
Prolec GE (GE Vernova) · Prolec GE Waukesha · Hitachi Energy USA · Siemens Energy · Eaton · Virginia Transformer Corp
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Technical content is prepared from engineering references, standards frameworks, manufacturer documentation and industry sources. Contractual or compliance decisions should refer to current official standards. TransformerPath Technical Editorial.
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