This paper analyzes the rotor angle stability of a typical infinity bar system for a power generation plant using the Phillips-Heffron model. Subsequently, a power system stabilizer is incorporated to obtain mechanical and electrical damping to maintain synchronism in its operation and control of the rotor angle. With these models,we can better understand itsoperation and establish the conditions to minimize disturbances and improve response instability.The simulations were carried out in the computer tool Matlab.