576
CHAPTER 13 ECONOMIC OPERATION OF POWER SYSTEMS
or set of decisions (in the sense of minimum cost) over the rst
(
N
- 1) stages
of the daily load cycle; this is equivalent to assuming that we know how to
choose the best combination of units for each of the rst (N - 1) intervals. If
we agree that combination Xi" is the best combination for stage (N - 1), then
by
searching among all the feasible combinations x j of
the