A modified optimal load‐frequency controller for interconnected power systems

This paper presents a modified optimal load‐frequency controller for interconnected hydrothermal power systems. The weighting matrix of the optimal controller is sequentially modified to let the dominant energy open‐loop poles or poles in a conventional optimal feedback system be located in the desired region. The poles selected to be shifted are determined using the concept of dominant energy modes rather than those located closer to the imaginary axis. Improper pole placement can be avoided and very good system frequency and tie‐line power dynamic responses can be achieved by the proposed controller.