Interconnected system frequency response

Frequency management is a primary goal in the control of an electric power system. Traditionally, this has been accomplished via tie-line bias control within a well defined control area. However, the control area´s frequency bias characteristic, which is an important component in the tie-line bias control equation, is a difficult term to quantify. This is due to the fact that this term represents the combined droop characteristics of all the generators serving the load plus the frequency dependency of the load. However, since most load frequency controllers use integral controllers, this inability to accurately quantify the control area´s frequency response characteristic has not caused unacceptable control errors. But, as the power industry moves into a new era, the control schemes must be re-examined in the light of the new system operating rules. This paper introduces some new ideas on frequency management that utilize what is referred to in this paper as the interconnected system frequency response characteristic, β_sys. It explains the problems associated with the present approach and why this new method offers improvements for large control areas, especially in the new competitive environment