I have digital readout which has a ac supply of 220v, I get incoming voltage around 245 volts, because of more voltage fuse are getting blown when there is a power flickered, I want to reduce the voltage from 245v to 220v. What is option, which value reisiter should I use, or any other option to reduce the voltage

I need additional information:
1) What amperage or load level in watts does you digital readout system require?
2) Is the supply 50 or 60 hertz (cycles per second)?

A dropping resistor may work but it is very dependent on the amperage your system draws from the supply.

My suggestion would be to use an autotransformer connection with a 250 volt to 25 volt transformer capable of supplying the load current you need.

Hope this helps.