Long-term optimal operation of a power system

An algorithm for the most economic operation of a hydrothermal power system, over a one year time span, is described. The algorithm handles hydro storage reservoirs, thermal power stations, AC transmission system losses, and major operating constraints, including a DC Link. A nonlinear programming solution technique, involving a conjugate-gradients method, is used. As an example, a solution is obtained for the New Zealand power system, modelling eight large storage reservoirs, six thermal power stations and all major operating constraints. A schedule for 13 intervals of 4 weeks each is computed. Part of the strategy obtained is given, along with details regarding implementation as an aid to hydro reservoir management.