Archiver
User
Posts: 7876
Joined: 1 year ago

Hello!

I am trying to do a simple example and I am New to GAMS.
I want to do a simple Power flow example in order to expand it later, i want GAMS to minimize the cost by choosing the cheapest generators.
My problem is that I want the load to change for every hour for my system, here is a 3 hour example and the error is marked in red.

HERE IS MY CODE:

\$TITLE pflow

Set t hours per day / t1, t2, t3 / ;
parameters
/t1 3
t2 5
t3 8/ ;
Scalar
Cost_diesel in â‚¬ per kWh / 2 /
Cost_pv in â‚¬ / 1.1 /

VARIABLES
*L(t),
X_g Diesel generator,
X_pv Domestic PV generation ,
Z Total cost of grid operation in â‚¬ per kWh for on hour;

EQUATIONS
OBJ Objective equation total cost of grid operation in â‚¬ per kWh ;

Load_balance.. X_g + X_pv -L(t) =E= 0 ;
149 Uncontrolled set entered as constant
OBJ.. Z =E= (X_g*Cost_diesel) + (X_pv*Cost_pv);

* Upper bounds
X_g.UP = 10 ;
X_pv.UP = 2 ;
* Lower bounds
X_g.lo = 0 ;
X_pv.lo = 0 ;
* Initial point
X_g.l = 0 ;
X_pv.l = 0 ;

MODEL pflow / ALL / ;
OPTION LIMROW = 100;
OPTION LIMCOL = 100;

loop(t, SOLVE pflow USING LP MINIMIZING Z) ;

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Archiver
User
Posts: 7876
Joined: 1 year ago

Hi,

the programming problem was very basic, see new equation definition
and alias for the loop.

Still the problem as defined is unfeasible, you might want to check
its rational definition.

\$TITLE pflow

Set t hours per day / t1, t2, t3 / ;
parameters
/t1 3
t2 5
t3 8/ ;
Scalar
Cost_diesel in â‚¬ per kWh / 2 /
Cost_pv in â‚¬ / 1.1 /

alias(t,tt);
VARIABLES
*L(t),
X_g Diesel generator,
X_pv Domestic PV generation ,
Z Total cost of grid operation in â‚¬ per kWh for on hour;

EQUATIONS
OBJ Objective equation total cost of grid operation in â‚¬ per kWh ;

Load_balance(t).. X_g + X_pv -L(t) =E= 0 ;
*149 Uncontrolled set entered as constant
OBJ.. Z =E= (X_g*Cost_diesel) + (X_pv*Cost_pv);

* Upper bounds
X_g.UP = 10 ;
X_pv.UP = 2 ;
* Lower bounds
X_g.lo = 0 ;
X_pv.lo = 0 ;
* Initial point
X_g.l = 0 ;
X_pv.l = 0 ;

MODEL pflow / ALL / ;
OPTION LIMROW = 100;
OPTION LIMCOL = 100;

loop(tt, SOLVE pflow USING LP MINIMIZING Z) ;

hope this helps,
Roger
http://fnu.zmaw.de/index.php?id=7179&L=3

2014-10-16 12:44 GMT+02:00 Ivan Nordnes Dahlberg :
> > Hello!
> >
> > I am trying to do a simple example and I am New to GAMS.
> > I want to do a simple Power flow example in order to expand it later, i want
> > GAMS to minimize the cost by choosing the cheapest generators.
> > My problem is that I want the load to change for every hour for my system,
> > here is a 3 hour example and the error is marked in red.
> >
> >
> > HERE IS MY CODE:
> >
> > \$TITLE pflow
> >
> > Set t hours per day / t1, t2, t3 / ;
> > parameters
> > L(t) Load for each
> > /t1 3
> > t2 5
> > t3 8/ ;
> > Scalar
> > Cost_diesel in â‚¬ per kWh / 2 /
> > Cost_pv in â‚¬ / 1.1 /
> >
> > VARIABLES
> > *L(t),
> > X_g Diesel generator,
> > X_pv Domestic PV generation ,
> > Z Total cost of grid operation in â‚¬ per kWh for on hour;
> >
> > EQUATIONS
> > Load_Balance Maintane a stable grid,
> > OBJ Objective equation total cost of grid operation in â‚¬ per kWh ;
> >
> > Load_balance.. X_g + X_pv -L(t) =E= 0 ;
> > 149 Uncontrolled set entered as constant
> > OBJ.. Z =E= (X_g*Cost_diesel) + (X_pv*Cost_pv);
> >
> > * Upper bounds
> > X_g.UP = 10 ;
> > X_pv.UP = 2 ;
> > * Lower bounds
> > X_g.lo = 0 ;
> > X_pv.lo = 0 ;
> > * Initial point
> > X_g.l = 0 ;
> > X_pv.l = 0 ;
> > * Load(s).l = 0 ;
> >
> > MODEL pflow / ALL / ;
> > OPTION LIMROW = 100;
> > OPTION LIMCOL = 100;
> >
> > loop(t, SOLVE pflow USING LP MINIMIZING Z) ;
> >
> > --
> > "gamsworld" group.
> > To unsubscribe from this group and stop receiving emails from it, send an
> > To post to this group, send email to gamsworld@googlegroups.com.
> > Visit this group at http://groups.google.com/group/gamsworld.
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Rofice
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Posts: 16
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