Put a constant current regulator on the secondary winding. 230V is a rather high and dangerous voltage to work with. Unless you are testing the transformer its self when it is shorted, and not the circuitry. I don't have any brilliant ideas (as of yet) but I shall endever to ponder on this problem you have presented before me
Some transformers have build-in polyswitch. It limits primary current and protects transformers against overloads.
More info on tis issue here:
**broken link removed**
If you're using it for circuit protection, use a fuse - it's always worthwhile unless it's going to blow a lot - in which case a polyswitch as mentioned or a circuit breaker.
I believe you have an HV switchboard to connect the main line to the transformer and the switchboard should have some protection devices. In my place, my MV switchboard's protection device is fuse.