Sir,
As I see it, this is no problem to worry about.
Opening an inductive circuit can rise the voltages, but if you have connected 415 V (to the 220 kV), this will result in a 20,75 V !!! at the 11 kV-side (= 11 kV / 220 kV x 415 V). Maybe the voltage will rise when opening the circuit, but not...