Long-term optimization of hydro-thermal power systems by generalized Conjugate-Gradient Methods

The optimal management of hydro storage reservoirs is considered. The objective is to minimize thermal power station fuel costs, over a horizon of one or more years, in a mixed hydro-thermal power system. A model of the New Zealand system is developed that is simple enough for computational purposes but nevertheless accounts for all major factors including load diversity and transmission losses. A version of Powell's generalized conjugate-gradient algorithm with Beale restarts is used for the optimization. State and control constraints are enforced by penalty functions and transformations, respectively. Results are presented for a reduced-order model of the New Zealand system.