opf_consfcn.m

function [h, g, dh, dg] = opf_consfcn(x, om, Ybus, Yf, Yt, mpopt, il, varargin)
%OPF_CONSFCN  Evaluates nonlinear constraints and their Jacobian for OPF.
%   [H, G, DH, DG] = OPF_CONSFCN(X, OM, YBUS, YF, YT, MPOPT, IL)
%
%   Constraint evaluation function for AC optimal power flow, suitable
%   for use with MIPS or FMINCON. Computes constraint vectors and their
%   gradients.
%
%   Inputs:
%     X : optimization vector
%     OM : OPF model object
%     YBUS : bus admittance matrix
%     YF : admittance matrix for "from" end of constrained branches
%     YT : admittance matrix for "to" end of constrained branches
%     MPOPT : MATPOWER options struct
%     IL : (optional) vector of branch indices corresponding to
%          branches with flow limits (all others are assumed to be
%          unconstrained). The default is [1:nl] (all branches).
%          YF and YT contain only the rows corresponding to IL.
%
%   Outputs:
%     H  : vector of inequality constraint values (flow limits)
%          where the flow can be apparent power, real power, or
%          current, depending on the value of opf.flow_lim in MPOPT
%          (only for constrained lines), normally expressed as
%          (limit^2 - flow^2), except when opf.flow_lim == 'P',
%          in which case it is simply (limit - flow).
%     G  : vector of equality constraint values (power balances)
%     DH : (optional) inequality constraint gradients, column j is
%          gradient of H(j)
%     DG : (optional) equality constraint gradients
%
%   Examples:
%       [h, g] = opf_consfcn(x, om, Ybus, Yf, Yt, mpopt);
%       [h, g, dh, dg] = opf_consfcn(x, om, Ybus, Yf, Yt, mpopt);
%       [h, g, dh, dg] = opf_consfcn(x, om, Ybus, Yf, Yt, mpopt, il);
%
%   See also OPF_COSTFCN, OPF_HESSFCN.

%   MATPOWER
%   Copyright (c) 1996-2017, Power Systems Engineering Research Center (PSERC)
%   by Carlos E. Murillo-Sanchez, PSERC Cornell & Universidad Nacional de Colombia
%   and Ray Zimmerman, PSERC Cornell
%
%   This file is part of MATPOWER.
%   Covered by the 3-clause BSD License (see LICENSE file for details).
%   See http://www.pserc.cornell.edu/matpower/ for more info.

if nargout == 2     %% contraints only
    g = om.eval_nln_constraint(x, 1);       %% equalities (power flow)
    h = om.eval_nln_constraint(x, 0);       %% inequalities (branch flow limits)
else                %% constraints and derivatives
    [g, dg] = om.eval_nln_constraint(x, 1); %% equalities (power flow)
    [h, dh] = om.eval_nln_constraint(x, 0); %% inequalities (branch flow limits)
    dg = dg';
    dh = dh';
end