This paper deals with the various aspects of AGC of interconnected multi-area hydrothermal systems.

Thermal area is considered with reheat turbine and hydro area is considered either with an electric governor or a

mechanical governor. Optimization of conventional integral controllers in all the areas has been carried out using

integral square error (ISE) criterion. Sensitivity analysis is done on the system which means the study of effect of

various parameter variations on system’s dynamic performance. The effect of changing sampling time period on

dynamic responses has also been investigated with conventional integral controller considering small step

perturbations in different areas. - This　paper　deals　with　the　various　aspects　of　AGC　of　interconnected　multi-area　hydrothermal　systems.

Thermal area is considered with reheat turbine and hydro area is considered either with an electric governor or a

mechanical governor. Optimization of conventional integral controllers in all the areas has been carried out using

integral square error (ISE) criterion. Sensitivity analysis is done on the system which means the study　of effect of

various　parameter　variations　on　system’s　dynamic　performance.　The　effect　of　changing　sampling　time　period　on

dynamic　responses　has　also　been　investigated　with　conventional　integral　controller　considering　small　step

perturbations in different areas.