Surge protection for systems <66kV

[kaspor]

hello

I have read in some literature that switching surges in systems <66kV do not typically exceed equipment BIL ratings.

Is this true? If so, have you come across this conclusion in a standard or any other literature? Looking for some further references.

Thanks

 

[RRaghunath]

Switching impulse test is specified for transformers rated 220kV and above. For lower voltage ratings, lightning impulse test is adequate. You can refer IEC 60076.