The optimal decentralized control of a large power system: Load and frequency control

The load and frequency control of a three-area interconnected power system consisting of 9 synchronous machines (described by a 98th order system) is studied. In this problem, the system is assumed to be subject to unknown constant disturbances, and it is desired to obtain if possible, robust decentralized controllers so that the frequency and tie-line power flow of the power system are regulated. The problem is solved by using some structural results recently obtained in decentralized control, in conjunction with a parameter optimization method which minimizes the dominant eigenvalue of the closed loop system. A minimum order robust decentralized controller which solves this problem, and also the general multi-area load and frequency control problem, is obtained.