Fix #256, make opf.use_vg compatible with gens at PQ buses.

Author: rdzman

CHANGES.md

@@ -13,6 +13,10 @@ For change history for [MOST][3], see [most/CHANGES.md](most/CHANGES.md).
 since 8.0
 ---------
 
+#### 2/17/25
+  - Fix [bug #256][38] to make `opf.use_vg` option compatible with generators
+    at PQ buses.
+
 #### 8/30/24
   - Incorporate major [MP-Opt-Model][27] refactor of `mp_idx_manager` and
     `opt_model` to use the new classes `mp.set_manager`,
@@ -3453,3 +3457,4 @@ First Public Release – *Jun 25, 1997*
 [35]: https://github.com/MATPOWER/mx-simulink_matpower
 [36]: https://github.com/MATPOWER/matpower/issues/210
 [37]: https://github.com/MATPOWER/matpower/issues/223
+[38]: https://github.com/MATPOWER/matpower/issues/256

docs/src/MATPOWER-manual/MATPOWER-manual.tex

@@ -8691,7 +8691,7 @@ \subsubsection*{Other Improvements}
 \subsubsection*{Bugs Fixed}
 \begin{itemize}
 \item  Optional \codeq{soln\_fname} input to \code{run\_mp()}, hence also to \code{run\_pf()}, \code{run\_cpf()}, and \code{run\_opf()}, was being ignored.
-
+\item Fix bug \#256 to make \code{opf.use\_vg} option compatible with generators at PQ buses.
 \end{itemize}
 
 \subsubsection*{Incompatible Changes}

lib/+mp/data_model.m

@@ -736,9 +736,10 @@ function display(obj)
 
             %% gen connection matrix, element i, j is 1 if, generator j at bus i is ON
             Cg = sparse(gbus, (1:ng)', 1, nb, ng);
+            Cg(:, bus_dme.type(gbus) == mp.NODE_TYPE.PQ) = 0;   %% exclude PQ buses
             Vbg = Cg * sparse(1:ng, 1:ng, gen_dme.vm_setpoint, ng, ng);
             vm_ub = max(Vbg, [], 2);    %% zero for non-gen buses, else max vm_setpoint of gens @ bus
-            ib = find(vm_ub);               %% buses with online gens
+            ib = find(vm_ub);               %% non-PQ buses with online gens
             vm_lb = max(2*Cg - Vbg, [], 2); %% same as vm_ub, except min vm_setpoint of gens @ bus
             vm_lb(ib) = 2 - vm_lb(ib);
 

lib/mpver.m

@@ -36,7 +36,7 @@
 v{1} = struct(  'Name',     'MATPOWER', ... 
                 'Version',  '8.0.1-dev', ...
                 'Release',  '', ...
-                'Date',     '30-Aug-2024' );
+                'Date',     '17-Feb-2025' );
 if nargout > 0
     if nargin > 0
         rv = v{1};

lib/opf_setup.m

@@ -110,6 +110,7 @@
   if use_vg     %% adjust bus voltage limits based on generator Vg setpoint
     %% gen connection matrix, element i, j is 1 if, generator j at bus i is ON
     Cg = sparse(mpc.gen(:, GEN_BUS), (1:ng)', mpc.gen(:, GEN_STATUS) > 0, nb, ng);
+    Cg(:, mpc.bus(mpc.gen(:, GEN_BUS), BUS_TYPE) == PQ) = 0;    %% exclude PQ buses
     Vbg = Cg * sparse(1:ng, 1:ng, mpc.gen(:, VG), ng, ng);
     Vmax = max(Vbg, [], 2); %% zero for non-gen buses, else max Vg of gens @ bus
     ib = find(Vmax);                %% buses with online gens