What are the technical reasons for soaking transformers for
various times before allowing them to pick load after a
fault ?

Answer Posted / al kafaah

I think the transformers are soaked with normal operating
voltage level as testing with HV of the transformer
insulation, winding at site is impractical as well not
economical. Besides soaking allows the transformer
insulation to be tested for operating voltage such as oil
(so that oil inside is not breaking down) or winding
insulations, short circuits, inter-turn faults (though
these items are individually tested for its correctness at
site test, but not as a whole unit at Normal operating
voltage). Whereas the Switchgears and Cables which are
other Primary circuit components are tested with High
voltage even at site

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