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Frequency drops and the high ambient temperature cause a decrease in airflow and an increase in the exhaust gas temperature of a gas turbine (GT). These two conditions significantly reduce the maximum continuous power output of GTs. Correct modeling of these conditions under heavily loaded conditions, such as in hot summer, is very important. Otherwise, the simulated maximum output of GT may be significantly higher than the real one and estimation of frequency responsive reserve and spinning reserve may be gravely erroneous. This paper describes the modeling and simulation of a heavy-duty GT operating under temperature control to study its impact on power system stability. For the practical simulation, a simple logic was added to the temperature reference parameter to represent the GT under the temperature control mode under steady-state conditions in the popular Rowen GT model, and the bumpless tracking logic was considered in the proportional-integral temperature controller. For three widely used GT models, GAST, GAST2A, and GGOV1, the effect of the temperature control loop on the transient stability is reviewed in a simple manner by applying the three-phase fault. Finally, the impact of GT under temperature control operation on frequency stability was analyzed using the proposed GT model with the determined model parameters of a practical GT system with 341 MVA during frequency drop against a six-machine, 23-bus system. [ABSTRACT FROM AUTHOR]

This paper proposes a new simplified model of a doubly fed induction generator (DFIG) that is integrated with a rotor-side converter for studies of large-scale transient stability. This model accurately considers the rotor field dynamics of an induction generator to yield simulation results that are more accurate in terms of voltage stability, as well as angle stability. The purpose of this paper is to provide a simple but effective DFIG model for the study of large-scale transient stability, and to examine the important aspects of rotor voltage and rotor slip power. This new simplified DFIG model with an electric/turbine control system was tested against a six-machine and 23-bus system, and the responses obtained in case studies of transient stability were compared with those of a PSS/E program. Finally, the proposed DFIG model was also validated by comparing the simulation results for a single-machine and infinite-bus system with those of PSCAD/EMTDC. [ABSTRACT FROM AUTHOR]

Highlights: [•] We model a hybrid SFCL which solves a late recovery time after quenching. [•] We examine the hybrid SFCL to the Dangjin multi-unit power plant in Korea. [•] The hybrid SFCL decreases the acceleration power of the generators during a fault. [•] Reducing tripped generators is verified that transient stability will be improved. [ABSTRACT FROM AUTHOR]