TABLE OF CONTENTS Power systems generally consist of a large number of fossil-fired power stations, able to maintain their output indefinitely at specified levels, to follow defined loading/unloading schedules, or to vary their output in accordance with system demand. The introduction of significant wind generation presents an energy source not amenable to central control, and which may not be available to generate when required due to lack of wind. It is important therefore to consider the variability of wind generation over various time scales, and to consider the behaviour of distributed wind farms from a system perspective. The load-following implications for the remaining generation and the response to generation loss incidents can then be examined.
In the normal operation of thermal power systems, generating units are scheduled to meet the predicted load demand profile and spinning reserve requirements at minimum operating cost, given a specified reliability criterion. Units committed to the system must be capable of changing their output to match changes in system demand over the scheduling period. This should include the ability to follow normal daily load changes (particularly the morning rise and evening fall), participate in frequency regulation and supply replacement power following a loss of generation event, or other major contingency. Those units required to load follow are capable of meeting normal load fluctuations as well as sudden, unexpected changes in demand.
Increasing concern about global warming has, however, led to greater interest...
