which IEC standard used for electrical clearance 2

The only one I can think of is 60071-1 (Annex A) which provides "Clearances in air to assure a specified impulse withstand voltage installation"

Hope it can help.

Regards.

k0412d.

28021984,
Please refer IEC61936-Part 1-Common Rules for most of the clearences.

i don't have these IEC61936-Part 1.

If possible can u please send the copy of that perticular page.

See Chapter 4 of the ABB switchgear manual.
Regards
Marmite

28021984,
If you are involved in a layout of a 220/ 66 kV substation, you must be definitely working for a engineering consulting company and the company must be paid by a client. So I cannot understand why your company cannot allocate some funds to buy all the relevant standards/ guides at the first place. Then they are available for your ready reference and also it will be a valuable investment for the future work too.