Question

why power factor is low in no load condition?

Answer 1

Ans) Under no load ,if you consider transformer ,it draws majorly magnetising current which is required to setup flux in the core ,hence if you see the equivalent circuit of transformer ,a huge magnetising reactance kept in parallel and resistance of windings is negligible ,hence majority of the load is inductive magnetising reactance ,hence power factor is low in no load condition ,if you increase the load the resistance comes in parallel causes power factor to improve

Fo transmission line also reactance caused due to line inductance is greater than line resistance cause powerfactor to be low under no load