The single line diagram of a balanced power system is shown in the figure. The voltage magnitude at the generator internal bus is constant and $1.0$ p.u. The p.u. reactances of different components in the system are also shown in the figure. The infinite bus voltage magnitude is $1.0$ p.u. A three phase fault occurs at the middle of line $2$.
The ratio of the maximum real power that can be transferred during the pre-fault condition to the maximum real power that can be transferred under the faulted condition is _________.