The FDA shield (drawings 12004-200-00, 12004-200-00-02) is a part of power supply devices for relay automatic interlocks and GAC and provides:

• connection and switching of two feeders of external power supply and one feeder of DGA;
• automatic switching of feeders in modes without feeder predominance, with predominance of the first and with predominance of the second feeder;
• connection of UBP of a third-party manufacturer or UBP on the DC bus - PSHPT shield, as well as automatic or manual switching of power supply bypassing the UBP in case of their failure;
• power supply of guaranteed loads, as well as connection and power supply of one or more boards: PRM, PP-25/75M.

The PVM board houses: a diagnostic system computer with a touch monitor, controllers of the UEP-U self-diagnosis system, a GSM-informing device about emergency events (UEP-U) EC.