How can we rapidly trace the BF in siemens VFD simovert drives(12 pulses)?

Follow siemens manual for details.

On siemens, BF(Bus fault) would be on the BMS communication side that uses profibus. When there is no profibus used in your connected BMS system, this fault appears. Go to product support on Siemens website or follow the steps to deactivate the BF in the VFD manual so that this fault disappears. After deactivating the BF in your VFD, the BF fault disappears. Hope this brief answer helps.