The system shown in figure shows an existing plant consisting of a generator of 100 MVA, 30 kV, with 20 percent sub transient reactance and a generator of 100 MVA, 30 kV with 20 percent sub transient reactance and a generator of 50 MVA, 30 kV with 15 percent sub transient reactance, connected in parallel to a 30-kV bus bar. The 30 kV bus bar feeds a transmission line via the circuit breaker C which is rated at 1250 MVA. A grid supply is connected to the station bus bar through a 500 MVA, 400/30-kV transformer with 20 percent reactance. The reactance of a current limiting reactor in ohm to be connected between the grid system and the existing bus bar such that the short-circuit MVA of the breaker does not exceed is ______