Effect of System Loading on Exhaust Temperature of CCGT Plant in Isolated and Restructured AGC

Abstract

In recent days, combined cycle gas turbines (CCGTs) contributes to an ever-growing amount of generation capacity on both isolated and interconnected power system. This article studies a single shaft CCGT plant for investigating the effect of temperature deviation in its control output response operating at variant loading. The system is used in combination with a multi-source model to study the impact of CCGT inclusion on a restructured environment. Comparison of integral, proportional-integral, proportional-integral-derivative and integral minus proportional-derivative as secondary, temperature and air-flow controller in a CCGT plant infer the superiority of latter. Results infer that with decrease in system loading during both isolated and interconnected environment, exhaust temperature of gas turbine increases. System responses have an oscillating nature during lightly loaded condition. Simulation results with interconnected system provides a more prominent understanding of frequency and tie-power deviations which infer the limitation of exhaust temperature subjected to system loading.