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A "precise" value of the inrush peak current depends on exact transformer data (rating plate information, impedance, etc.).
In attached pages, tabulated data given for liquid-filled & dry type transformers by France-Transfo (including Trihal which is dry type).
Example (for 500kVA Trihal transformer):
Peak inrush current = 10 times the transformer r.m.s rated current;
For 500kVA MV/LV transformer fed at MV side with 11kV, rated current = approximately 26.25A
The peak inrush current to be 262.5A with a decay time constant of approximately 0.25s.
In attached pages, tabulated data given for liquid-filled & dry type transformers by France-Transfo (including Trihal which is dry type).
Example (for 500kVA Trihal transformer):
Peak inrush current = 10 times the transformer r.m.s rated current;
For 500kVA MV/LV transformer fed at MV side with 11kV, rated current = approximately 26.25A
The peak inrush current to be 262.5A with a decay time constant of approximately 0.25s.