Hi everybody!
I am completely newby in Gams and never did any programming before… I have to make a model to complete my thesis and I am encountering difficulties in solving some errors.
Please, I really need your help and I already apologize as I am pretty sure the solution to my problem must be straightforward to most of you, but still, i can’t see it…
Here is the thing:
set
n countries /E, P, A, F, B/
t technologies /PFC, SPP/
h hours /1*24/;
alias (n,m);
Table
C1(t,n) Generation costs
E P A F B
PFC 27 47 34 29 25
SPP -96 0 0 0 0
;
Table
K(t,n) Generation capacities (MW)
E P A F B
PFC 9 15 39 0 12
SPP 471 1 3 14 0
;
Table
kd(t,n) generation coeff
E P A F B
PFC 0.85 0.85 0.85 0.85 0.85
SPP 0.3 0.3 0.3 0.3 0.3
;
Parameter
RR_C(t) Ramp rate Committed capacity in % of capacity
/PFC 50
SPP 0 /
;
Table
Cap(n,m) Interconnexion capacities
E P A F B
E 1400
P 3000 468
A 3850 1000
F 1400 900 1300
B 468 400
;
Table
D(n,h) Consumption level / hour
1 2 etc until 24
E 26229 24935
P 10591 9961
A 62403 60023
F 72078 72017
B 11001 10541
variables
x1(t,n,h) production of technology t in country n to country n in hour h
x2(t,n,m,h) production of technology t in country n to country m in hour h
TotCost total cost to minimize
;
equations
k1 Function to minimize
k2(t,n,h) production capacity contraint
k3(n,m,h) line capacity constraint
k4(h) equilibrium constraint
k5E(n,h) national equilibrium in country E
k5A(n,h) national equilibrium in country A
k5F(n,h) national equilibrium in country F
k5P(n,h) national equilibrium in country P
k5B(n,h) national equilibrium in country B
k6(t,n,h) positive production
k7(t,n,m,h) positive export
h1 (t,n,h) production in h1
h2 (t,n,h) production in h2
;
k1 … TotCost =e= Sum(n,Sum(h,Sum(t,x1(t,n,h)*C1(t,n)))) + Sum(m,Sum(h,Sum(n,Sum(t,x2(t,n,m,h)*C1(t,n)))))
;
k2(t,n,h) … kd(t,n)*K(t,n) - x1(t,n,h) - Sum(m,x2(t,n,m,h))=g=0
;
k3(n,m,h) … Cap(n,m) - Sum(t,x2(t,n,m,h)) =g=0
;
k4 (h) … Sum(n,D(n,h)) - Sum(n,Sum(t,x1(t,n,h))) - Sum(m,Sum(n,Sum(t,x2(t,n,m,h)))) =e=0
;
k5E(“E”,h) … D(“E”,h) - Sum(t,x1(t,“E”,h))- Sum(n,Sum(t,x2(t,n,“E”,h))) =e=0
;
k5A(“A”,h) … D(“A”,h) - Sum(t,x1(t,“A”,h))- Sum(n,Sum(t,x2(t,n,“A”,h))) =e=0
;
k5F(“F”,h) … D(“F”,h) - Sum(t,x1(t,“F”,h))- Sum(n,Sum(t,x2(t,n,“F”,h))) =e=0
;
k5P(“P”,h) … D(“P”,h) - Sum(t,x1(t,“P”,h))- Sum(n,Sum(t,x2(t,n,“P”,h))) =e=0
;
k5B(“B”,h) … D(“B”,h) - Sum(t,x1(t,“B”,h))- Sum(n,Sum(t,x2(t,n,“B”,h))) =e=0
;
k6(t,n,h)… x1(t,n,h) =g=0
;
k7(t,n,m,h) … x2(t,n,m,h) =g=0
;
h1 (t,n,“1”) … kd(t,n)K(t,n) - x1(t,n,“1”) - Sum(m,x2(t,n,m,“1”))=g=0
;
h2 (t,n,“2”) … x1(t,n,“2”) + sum(m,x2(t,n,m,“2”)) =l= x1.l(t,n,“1”) + sum(m,x2.l(t,n,m,“1”))+ RR_C(t)(((k(t,n)*kd(t,n) - x1.l(t,n,“1”) - sum(m,x2.l (t,n,m,“1”)))))
;
model test / all /
;
solve test minimizing TotCost using lp
;
ERROR MESSAGE :
489 model test / all /
490 ;
491 solve test minimizing TotCost using lp
492 ;
**** $66,256
**** The following LP errors were detected in model test:
**** 66 equation h2… symbol “x1” has no values assigned
**** 66 equation h2… symbol “x2” has no values assigned
What did I do wrong with those x1&2 ?
notes:
Here, h1 must represent the generation capacities that equalizes the Demand in the 1st hour.
then I try to constrain the ramping capacities called next hour according to their ramping flexibility.
I must add, the problem occures when I am running the model including h2 in the equations. The step before, the programme seems to run normally.
THANK YOU SO MUCH IF YOU CAN HELP ME !
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