Peak margin penalty query

If I sold my holdings, say 1000 quantities of Reliance. Then again I did intraday in Reliance ( Buying and selling 1200 quantity ). Will there be any peak margin penalty?

If you had other cash in your account ( to re purchase additional 400 Qty) , then no.
You will be able to use only procceds of 800 qty as 20% will be blocked as delivery margin.