How to design Surge Protection Device?

I want to design a Surge Protection Device according to IEC61643-11 Standard. Any can support on the design. Voltage protection level up to 2.5kv

Why do you want to make a suge protector when its already available in the market. Its like reinventing the wheel. You can buy surge protectors depending on your application. Is their any specific use case of make one??

Yes, but there’s an cost is high. For that I am thinking to design our Surge Protection Device with minimum cost