Answer to Question #226501 in Electrical Engineering for Alock kumar

Question

What is the significance of sub-transient reactance and transient reactance in short circuit studies?

Answer 1

Transient reactance Xd’ is the apparent initial reactance of the stator winding, if the effect of all amortisseur windings is ignored and only the field winding considered. This reactance determines the current following the period when subtransient reactance is the controlling value.

Sub transient reactance Xd” is the apparent reactance of the stator winding at the instant short circuit occurs, and it determines the current flow during the first few cycles of a short circuit