抄録
This paper proposes a new control method based on the power demand estimation and fuzzy control considering effects of the self-regulation to improve the load frequency control(LFC) characteristics of power system. The proposed control first, to satisfy LFC requirements, estimates power demand variations of the control areas and uses them as the output set-point values of power plants, in-stead of using an integral-type controller. However, when a remarkable change of load occurs, tielines and frequency can not immediately reach the steady state value due to undesirable oscillations appeared in the process. Next, to solve the problem of LFC system using the fore-mentioned output set-point control method, the self-regulation of generators in each area have set an optimal point within the actual range, and to improve stability and robustness in this system, the fuzzy control is implemented.
The fuzzy controller is designed by using the frequency deviation and its change represented in the phase plane, and membership functions of the phase angle and magnitude are determined. The con-trol signal is calculated by means of defuzzification using center of gravity method.
To study the effectiveness of the proposed control, a 3-area longitudinal system which is com-posed of reheat and non-reheat steam power plants is considered as a model system for the computer simulation.
