Penalty when the return filed u/s 148 is a refund.

Assessee has not filed the return of Income for AY 2018-19 against which he had received notice under section 148.

On Filing the return of income u/s 148 the assessee is claiming a refund.

We wanted to know the penalty which can be levied by the AO if there is a refund.

Thanking you.