A methodology for management of spinning reserve requirements

This paper describes a methodology for management of spinning reserves involving, on the one hand, determination of system reserve requirements, and, on the other, determination of the availability of such reserves at any dispatch condition. Three types of reserves are maintained: primary reserves, intended to arrest the initial fall in frequencies; secondary reserves, intended to quickly bring frequencies back to acceptable levels following their initial drop; and 10-minute reserves, with the purpose of returning area control error (ACE) to zero within this time frame. Primary and secondary response capabilities are determined by subjecting the unit to a test whereby measured frequency is altered to elicit the governor's response to marginally acceptable frequency excursions. Examples of simulations of such responses for typical steam, hydro and combined-cycle units are provided. Reserve requirements are calculated from basic principles, taking into account the largest unit dispatch, the frequency sensitivity of loads, and, when applicable, expected contributions from neighboring systems.