http://help.sap.com/saphelp_nw73/helpdata/en/b0/078f3b0e8d4762e10000000a11402f/content.htm
Hi Rahul,
PSA data cannot be archived. Data archiving in BW only works for DSO and InfoCubes. Data from PSAs and ChangeLogs have to be deleted.
Please see the link above for details.
Best regards,
Claudia