For small turbine starts generating power 12.6 kph (3.5 m/s) is the typical cut-in speed. At 36–54 kph (10–15 m/s) produces maximum generation power. At 90 kph (25 m/s) maximum, the turbine is stopped or braked.
For the given circuit shown in figure, D1 is forward bias mode - On state D2 is in reverse bias mode - off state D3 is in reverse bias mode - off state.
Intern turn winding fault can be easily detect by differential protection relay. Also detect by buchholz relay (gas operated relay), cause buchholz relay is used to detect the internal fault of transformer.