Automatic voltage control system of power plant substation

The invention provides an automatic voltage control system of a power plant substation, which comprises a plurality of lower computers, a master upper computer, a standby upper computer, a background computer, a movable communication unit, a power plant decentralized control system (DCS), a plant unit automatic voltage regulator (AVR), a controller area network (CAN), a network communication channel and a power data network, wherein the upper computer and the lower computer intercommunicate in the controller area network (CAN); the upper computer and the background computer communicate through the network communication channel; and the upper computer and the master station communicate in the power data network. The scheme of the invention fully considers the actual field situation of the power plant and has the characteristic of strong applicability.