Current Through Neutral Earthing Resistor

We have an 11kv/6.6kv , 4.5MVA , Impedence 9.73, Dyn11 transformer. Resistance neutral earthed through a 4.7ohms earthing resistor. How do I calculate the earth fault current that would be sensed by the current transformer ( for earth fault protection ) installed on the secondry side. I assumed 38% of 3 Phase fault which is a single phase to earth fault but the result I got was too high to be realistic.