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An inertia identification approach has been proposed for diesel generators by using the modified load rejection procedures. Large frequency deviation problems often occur in the Kinmen island power system where many diesel generators are used. In order to avoid erroneous evaluation of frequency deviation caused by generator tripping, one of the critical issues in system planning is to accurately estimate the maximum frequency deviation during system outage events. The main factors that influence the frequency deviation include the generator inertia (H), damping constant (D), and governor controller parameters. In order to improve the accuracy of the transient stability analysis to obtain more actual frequency deviation, it is critical to have more accurate inertia values of these diesel generators. This paper proposes a useful approach to evaluate reasonable inertia values. With the identified inertia values of diesel generators, the frequency responses of the Kinmen power system obtained from PSS/E simulation are more consistent with the field measurement results. [ABSTRACT FROM AUTHOR]

Operation flexibility is a prerequisite to ensure the success of a power market operation. Due to the variable generation mix, generation units that are flexible to meet the challenge of ramping and provide operation reserve are important in today's system operations. Generators participating in frequency regulation and other ancillary services might lose energy market revenue due to reserved margins, thus regulation performance should be evaluated and paid for. The actual value of operation flexibility is dependent on the system characteristics and the market mechanism. Using the information available in energy management system and combined cycle power plants, this study proposes a simple and practical method to estimate the variant fuel cost increase of combined cycle units to provide frequency regulation service in an island power system. Based on actual operation data, analysis results testify the fact that the efficiency of the combined cycle units is reduced at lower loads and the units are subjected to different fuel cost increases at distinct operation configurations. The proposed method is justifiable and applicable for assessing variant costs incurred in providing energy system flexibility. [ABSTRACT FROM AUTHOR]