Load-frequency control and inadvertent interchange evaluation in restructured power systems

The subject of load-frequency control (LFC) from the point of view of the restructuring process of the electrical industry is addressed. LFC is treated as an ancillary service essential for maintaining the electrical system reliability at an adequate level. Reference is made to the guidelines suggested by the Union for the Co-ordination of Transmission of Electricity. Specific autonomy conditions, involving particular constraints on regulator parameters, are analytically derived and implemented for two control schemes: the pluralistic and hierarchical LFC. The results of simulations performed on a power system based on an IEEE Reliability Test System arranged into a three-control-area configuration are reported for the different LFC schemes. Evaluation of inadvertent interchanges is performed and suggestions on their accounting are proposed.