Source Code for Module pypower.uopf

  1  # Copyright (C) 1996-2011 Power System Engineering Research Center (PSERC) 
  2  # Copyright (C) 2011 Richard Lincoln 
  3  # 
  4  # PYPOWER is free software: you can redistribute it and/or modify 
  5  # it under the terms of the GNU General Public License as published 
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  7  # or (at your option) any later version. 
  8  # 
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 11  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 
 12  # GNU General Public License for more details. 
 13  # 
 14  # You should have received a copy of the GNU General Public License 
 15  # along with PYPOWER. If not, see <http://www.gnu.org/licenses/>. 
 16   
 17  """Solves combined unit decommitment / optimal power flow. 
 18  """ 
 19   
 20  from time import time 
 21   
 22  from copy import deepcopy 
 23   
 24  from numpy import flatnonzero as find 
 25   
 26  from opf_args import opf_args2 
 27  from ppoption import ppoption 
 28  from isload import isload 
 29  from totcost import totcost 
 30  from fairmax import fairmax 
 31  from opf import opf 
 32   
 33  from idx_bus import PD 
 34  from idx_gen import GEN_STATUS, PG, QG, PMIN, MU_PMIN 
 35   
 36   
 37 -def uopf(*args): 
 38      """Solves combined unit decommitment / optimal power flow. 
 39   
 40      Solves a combined unit decommitment and optimal power flow for a single 
 41      time period. Uses an algorithm similar to dynamic programming. It proceeds 
 42      through a sequence of stages, where stage C{N} has C{N} generators shut 
 43      down, starting with C{N=0}. In each stage, it forms a list of candidates 
 44      (gens at their C{Pmin} limits) and computes the cost with each one of them 
 45      shut down. It selects the least cost case as the starting point for the 
 46      next stage, continuing until there are no more candidates to be shut down 
 47      or no more improvement can be gained by shutting something down. 
 48      If C{verbose} in ppopt (see L{ppoption} is C{true}, it prints progress 
 49      info, if it is > 1 it prints the output of each individual opf. 
 50   
 51      @see: L{opf}, L{runuopf} 
 52   
 53      @author: Ray Zimmerman (PSERC Cornell) 
 54      @author: Richard Lincoln 
 55      """ 
 56      ##----- initialization ----- 
 57      t0 = time()                                 ## start timer 
 58   
 59      ## process input arguments 
 60      ppc, ppopt = opf_args2(*args) 
 61   
 62      ## options 
 63      verbose = ppopt["VERBOSE"] 
 64      if verbose:      ## turn down verbosity one level for calls to opf 
 65          ppopt = ppoption(ppopt, VERBOSE=verbose - 1) 
 66   
 67      ##-----  do combined unit commitment/optimal power flow  ----- 
 68   
 69      ## check for sum(Pmin) > total load, decommit as necessary 
 70      on   = find( (ppc["gen"][:, GEN_STATUS] > 0) & ~isload(ppc["gen"]) )   ## gens in service 
 71      onld = find( (ppc["gen"][:, GEN_STATUS] > 0) &  isload(ppc["gen"]) )   ## disp loads in serv 
 72      load_capacity = sum(ppc["bus"][:, PD]) - sum(ppc["gen"][onld, PMIN])   ## total load capacity 
 73      Pmin = ppc["gen"][on, PMIN] 
 74      while sum(Pmin) > load_capacity: 
 75          ## shut down most expensive unit 
 76          avgPmincost = totcost(ppc["gencost"][on, :], Pmin) / Pmin 
 77          _, i = fairmax(avgPmincost)   ## pick one with max avg cost at Pmin 
 78          i = on[i]                     ## convert to generator index 
 79   
 80          if verbose: 
 81              print 'Shutting down generator %d so all Pmin limits can be satisfied.\n' % i 
 82   
 83          ## set generation to zero 
 84          ppc["gen"][i, [PG, QG, GEN_STATUS]] = 0 
 85   
 86          ## update minimum gen capacity 
 87          on  = find( (ppc["gen"][:, GEN_STATUS] > 0) & ~isload(ppc["gen"]) )   ## gens in service 
 88          Pmin = ppc["gen"][on, PMIN] 
 89   
 90      ## run initial opf 
 91      results = opf(ppc, ppopt) 
 92   
 93      ## best case so far 
 94      results1 = deepcopy(results) 
 95   
 96      ## best case for this stage (ie. with n gens shut down, n=0,1,2 ...) 
 97      results0 = deepcopy(results1) 
 98      ppc["bus"] = results0["bus"].copy()     ## use these V as starting point for OPF 
 99   
100      while True: 
101          ## get candidates for shutdown 
102          candidates = find((results0["gen"][:, MU_PMIN] > 0) & (results0["gen"][:, PMIN] > 0)) 
103          if len(candidates) == 0: 
104              break 
105   
106          ## do not check for further decommitment unless we 
107          ##  see something better during this stage 
108          done = True 
109   
110          for k in candidates: 
111              ## start with best for this stage 
112              ppc["gen"] = results0["gen"].copy() 
113   
114              ## shut down gen k 
115              ppc["gen"][k, [PG, QG, GEN_STATUS]] = 0 
116   
117              ## run opf 
118              results = opf(ppc, ppopt) 
119   
120              ## something better? 
121              if results['success'] and (results["f"] < results1["f"]): 
122                  results1 = deepcopy(results) 
123                  k1 = k 
124                  done = False   ## make sure we check for further decommitment 
125   
126          if done: 
127              ## decommits at this stage did not help, so let's quit 
128              break 
129          else: 
130              ## shutting something else down helps, so let's keep going 
131              if verbose: 
132                  print 'Shutting down generator %d.\n' % k1 
133   
134              results0 = deepcopy(results1) 
135              ppc["bus"] = results0["bus"].copy()     ## use these V as starting point for OPF 
136   
137      ## compute elapsed time 
138      et = time() - t0 
139   
140      ## finish preparing output 
141      results0['et'] = et 
142   
143      return results0 
144