Three-level agc for large-scale PV power plant with string inverters

For Automatic Generation Control System (AGC) in a large-scale photovoltaic power plant with numerous string PV inverters, calculating capability, storage volume, and communication turn into bottlenecks. To deal with these issues, a new three-level AGC topology is proposed in this paper. An AGC subsystem module will be integrated in the string PV array with a group of inverters to serve as the intermediate AGC execution device between the plant AGC system and individual inverters. The AGC function at array level, the relationship and control strategy between the plant AGC system and the array AGC system will be discussed, followed by some power allocation result, error analysis and time response of the above AGC technology in application, which shows that the technology can affectively solve above AGC problems in large-scale PV plant with string PV inverters.