Page 322 - Decision Making Applications in Modern Power Systems
P. 322

Decision-making-based optimal generation-side Chapter | 11  283


             should be noted however that the elements of d up ; d down Aℜ NG  may be non-
             positive. In the base case scenario where there are no outages, the power
             mismatch is negative P m , 0, and some elements of d up are also negative. In
             this case the network is congested, hence to relieve it, the generators corre-
             sponding to d up negative should provide down-spinning reserves, while the
             rest of the units would provide up-spinning reserves.


             11.4 Probabilistic security-constrained reserve scheduling

             An optimization horizon N t 5 24 with hourly steps 1 is considered, the sub-
             script t indicate the value of the quantities for a given time instance t 5 1, 2,
             3, .. ., T. For the production cost a quadratic form is considered, and for the
             reserves a linear cost is also considered [38]. Let c 1 ; c 2 ; c up ; c down Aℜ NG  be
             generation and reserve cost vectors and [c 2 ] denotes a diagonal matrix with
             vector c 2 on the diagonal
                For each step t, the vector of decision variables is defined as follows:
                     h    h                      i   i
                                                               ð
                 x t 5 P G;t ; d  i  ; d i  ; R  i  ; R i  Aℜ NG14NG 11 ϒjjÞ  ð11:3Þ
                            up;t  down;t  up;t  down;t
                                                  iAϒ
                where R i up;t ; R i down;t  are the probabilistically worst-case up down spin-
             ning reserves that the system operator needs to purchase for every iAϒ.
             Therefore the optimization problem is written as
                                                                           !
                  T
                 X    i       X     T       T        X    T  i    T   i
              min   P P w Þ 5      c P G;t 1 P ½ŠP G;t 1  c R  1 c down down;t
                                                                     R
                       ð
                                              c 2
                                            G;t
                                    1
                                                          up up;t
                      m
                N t
              χ t fg t51 t51  kAZ w =K i              iAZ
                                                                       ð11:4Þ
             11.4.1 Deterministic constraints
             These are constraints that correspond to a case where the wind power is
             equal to its forecast. Here the reserves are determined based on the
             generation-load mismatch that may occur due to an outage.

                              1 T  C G P G;t 1 C W P f  2 C L P L;t 5 0  ð11:5Þ
                                             w;t
                                    i    i i     f     i
                                 2P f # A P   P                        ð11:6Þ
                                         t inj;t  w;t  # P f
                                                      i
                                             i
                                   i
                                 P # P i G;t  1 R P f w;t  # P  G      ð11:7Þ
                                   G
                                             t

                                            i
                                 2R i    # R P f  # R i                ð11:8Þ
                                    down;t  t  w;t   up;t
                                       i    i
                                      R  ; R    $ 0                    ð11:9Þ
                                       up;t  down;t
   317   318   319   320   321   322   323   324   325   326   327