Neutral Grounding Resistor - for Star-Broken delta transformer with resistor

[NickParker]

I list below the procedure to select the neutral grounding resistor
1. Find the stator damage curve current.
2. Check that current limited via resistor is below the stator damage current.
3. Check the capacitive charging current of the system(3Ic)
4. Select the resistor such that the current through resistor is higher the capacitive charging current of the system (3Ic).

Q1. what if the capacitive charging current 3Ic is higher than the stator damage curve current? In this case, resistor cannot be selected higher than capacitive charging current.

 

[RRaghunath]

You are right. You cannot go for resistive current that is lower than the total capacitive current. This is to safeguard the system against over voltages and associated damages.
This means accepting the possibility of stator core lamination damage (though very remote) in case of an earth fault.
Using a Unit transformer and a bus duct to connect generator to the unit transformer are popular ways to reduce the generator system capacitance and is followed widely in power stations.