Optimal Scheduling ofLarge Hydrothermal PowerSystems

In thispaperwe present a new algorithm tofind theoptimal unitcommitment andeconomicdispatch (UC/D) foralarge hydrothermal powersystem. Mathematically, this isa large nonlinear, mixedinteger optimization problem involving over16,800 integer variables fora systemhaving 100thermal units witha 1-weekscheduling horizon. We use a dualprogramming approach tosolve a separate optimal control problem foreachthermal unitandforeachsetof coupled hydro units. Thealgorithm hasbeentested on a 100 thermal unit/6 hydro unitsystem having a 168-hour schedul¬ ingperiod, andwill findsolutions that arewithin 0.1to0.25 percent oftheoptimal dualcost.We report computational results forasystem modeled after theNewYorkPowerPool.