Optimisation of discrete-type load-frequency regulators considering generation-rate constraints

In the paper a method of designing discrete-type load-frequency regulators of a two-area reheat-type thermal system with generation-rate constraints is presented. The construction of the regulators is based on the conventional tie-line bias control. The regulator parameters are optimised by minimisirig a discrete-type quadratic performance index with a term for presenting a generation-rate constraint. The optimisation of the parameters is achieved by using a Newton-Raphson iterative algorithm. The control effects by the proposed regulators are examined by digital simulations of the system. Furthermore, a suitable means for preventing excessive and unnecessary control action is also proposed considering the constraint.