idx_brch

idx_brch()
idx_brch() - Defines constants for named column indices to branch matrix.
Example:

[F_BUS, T_BUS, BR_R, BR_X, BR_B, RATE_A, RATE_B, RATE_C, ...
TAP, SHIFT, BR_STATUS, PF, QF, PT, QT, MU_SF, MU_ST, ...
ANGMIN, ANGMAX, MU_ANGMIN, MU_ANGMAX] = idx_brch;

Some examples of usage, after defining the constants using the line above,
are:

 branch(4, BR_STATUS) = 0;              % take branch 4 out of service
 Ploss = branch(:, PF) + branch(:, PT); % compute real power loss vector

The index, name and meaning of each column of the branch matrix is given
below:

columns 1-11 must be included in input matrix (in case file)
 1  F_BUS       f, from bus number
 2  T_BUS       t, to bus number
 3  BR_R        r, resistance (p.u.)
 4  BR_X        x, reactance (p.u.)
 5  BR_B        b, total line charging susceptance (p.u.)
 6  RATE_A      rateA, MVA rating A (long term rating)
 7  RATE_B      rateB, MVA rating B (short term rating)
 8  RATE_C      rateC, MVA rating C (emergency rating)
 9  TAP         ratio, transformer off nominal turns ratio
 10 SHIFT       angle, transformer phase shift angle (degrees)
 11 BR_STATUS   initial branch status, 1 - in service, 0 - out of service
 12 ANGMIN      minimum angle difference, angle(Vf) - angle(Vt) (degrees)
 13 ANGMAX      maximum angle difference, angle(Vf) - angle(Vt) (degrees)
                (The voltage angle difference is taken to be unbounded below
                 if ANGMIN < -360 and unbounded above if ANGMAX > 360.
                 If both parameters are zero, it is unconstrained.)

columns 14-17 are added to matrix after power flow or OPF solution
they are typically not present in the input matrix
 14 PF          real power injected into "from" end of branch (MW)
 15 QF          reactive power injected into "from" end of branch (MVAr)
 16 PT          real power injected into "to" end of branch (MW)
 17 QT          reactive power injected into "to" end of branch (MVAr)

columns 18-21 are added to matrix after OPF solution
they are typically not present in the input matrix
                (assume OPF objective function has units, u)
 18 MU_SF       Kuhn-Tucker multiplier on MVA limit at "from" bus (u/MVA)
 19 MU_ST       Kuhn-Tucker multiplier on MVA limit at "to" bus (u/MVA)
 20 MU_ANGMIN   Kuhn-Tucker multiplier lower angle difference limit (u/degree)
 21 MU_ANGMAX   Kuhn-Tucker multiplier upper angle difference limit (u/degree)