Power system automatic generation control revised from the open trading perspective

The paper describes the significant changes expected in power system operation and management required by the restructuring process of electric industry. The problem of automatic generation control (AGC) is addressed under the open trading perspective. The fundamental concepts of AGC are recalled and the possible modifications are presented. The co-existence of a primary service predominantly based on long-term bilateral contracts and of secondary services (or ancillary services) such as load-following and secondary frequency control is highlighted. Different AGC solutions are theoretically reported and supported by simulations on a CIGRE test system.