Dear all
I am facing problem in DCOPF. I need help. In my power grid model i
have fixed the capacity of transmission line in RATE A column by 110% of
initial power flow. Then increase the load by a factor (1.01) and run the
dcopf. But matpower showing infeasible model due to which it is not converging.
I am not able to understand the problem. Here load and generation is also well
balanced. Now which parameter constraint to converging of my test case. I stuck
here for a long time, so please help me
The result shown below is after increasing the load by 1.01.
MATPOWER Version 6.0, 16-Dec-2016 -- DC Optimal Power Flow
Gurobi Version 7.0.2 -- automatic LP solver
Optimize a model with 19515 rows, 4968 columns and 47500 nonzeros
Coefficient statistics:
Matrix range [2e-03, 9e+05]
Objective range [1e+02, 2e+02]
Bounds range [5e-03, 1e+02]
RHS range [3e-17, 4e+02]
Concurrent LP optimizer: dual simplex and barrier
Showing barrier log only...
Presolve removed 2 rows and 17 columns
Presolve time: 0.06s
Solved with dual simplex
Solved in 0 iterations and 0.07 seconds
Infeasible model
>>>>> Did NOT converge (0.17 seconds) <<<<<
Checking connectivity ... single fully connected network
Elapsed time is 0.051284 seconds.
================================================================================
Full
System
Number of: ----------
buses 3989
loads 2227
on 2227
off -
fixed 2227
dispatchable -
on -
off -
generators 979
on 979
off -
shunt elements 247
branches 8096
on 8096
off -
ties (off) -
Load
active (MW)
dispatched 85879.4
fixed 85879.4
dispatchable -
nominal 85879.4
on 85879.4
off -
fixed 85879.4
dispatchable -
on -
off -
reactive (MVAr)
dispatched 23668.6
fixed 23668.6
dispatchable -
nominal 23668.6
on 23668.6
off -
fixed 23668.6
dispatchable -
on -
off -
Generation
active (MW)
dispatched 86451.8
max capacity 213706.7
on 213706.7
off -
min capacity -72665.3
on -72665.3
off -
reactive (MVAr)
dispatched 24069.5
max capacity 69809.7
on 69809.7
off -
min capacity -50352.2
on -50352.2
off -
Shunt Injections
active (MW) -
reactive (MVAr) 10848.8
Branch Losses
active (MW) -
reactive (MVAr) -
DC line
export (MW)
dispatch -
max capacity -
on -
off -
min capacity -
on -
off -
Reference Buses
num of ref buses 1
ref bus numbers 3292
________________________________
From: [email protected]
<[email protected]> on behalf of Ray Zimmerman
<[email protected]>
Sent: Monday, July 3, 2017 9:33:26 PM
To: MATPOWER discussion forum
Subject: Re: DCOPF not converging for large system
If you have a solved AC power flow, that’s a good start. Normally, the first
step I try when faced with an OPF that won’t converge is to eliminate the
branch flow limits by setting the RATE_A column of the branch matrix to zero
(or by increasing the values by some factor). In your case, you can check which
flows in the power flow solution exceed their limits and only relax those to
begin with.
If I were you, I would relax any branch, voltage and generator limits as
required to make the power flow solution you have feasible for the AC OPF
problem. It should solve. If it does, then you can begin to eliminate those
relaxations to find the source of the infeasibility.
Ray
On Jun 23, 2017, at 10:55 AM, Mort D. Webster
<[email protected]<mailto:[email protected]>> wrote:
Dear Matpower Folks:
I have larger network that is a solved load flow case from an ISO.
The AC power flow converges fine, but neither AC nor DC OPF solve.
I supplied my own estimated generator costs, and perturbed them so that none
are identical.
I get the following error:
>> mpc = iso2015sum
mpc =
version: '2'
baseMVA: 100
bus: [7108x13 double]
gen: [720x25 double]
branch: [8930x13 double]
bus_name: {7108x1 cell}
dcline: [4x17 double]
gencost: [720x6 double]
>> results = rundcopf(mpc)
opf_setup: Warning: Multiple reference buses.
For a system with islands, a reference bus in each island
may help convergence, but in a fully connected system such
a situation is probably not reasonable.
MATPOWER Version 6.0b2, 01-Nov-2016 -- DC Optimal Power Flow
The interior-point-legacy algorithm uses a built-in starting point;
ignoring supplied X0.
Exiting: One or more of the residuals, duality gap, or total relative error
has stalled:
the primal appears to be infeasible and the dual unbounded since
the dual objective > 1e+10
and the primal objective > -1e+6.
>>>>> Did NOT converge (7.52 seconds) <<<<<
results =
version: '2'
baseMVA: 100
bus: [7108x17 double]
gen: [720x25 double]
branch: [8930x21 double]
bus_name: {7108x1 cell}
dcline: [4x17 double]
gencost: [720x6 double]
order: [1x1 struct]
om: [1x1 opf_model]
x: [7700x1 double]
mu: [1x1 struct]
f: 2.1192e+06
var: [1x1 struct]
lin: [1x1 struct]
et: 7.5220
success: 0
raw: [1x1 struct]
The system has several complex features:
4 HVDC lines
several storage resources as generators
4 buses as reference/slack bus type
many "isolated" bus types ("4").
Can you suggest where in the results I can look to diagnose the problem?
Thanks so much!
Mort Webster
--
Mort Webster
Associate Professor of Energy Engineering
Dept of Energy and Mineral Engineering
Pennsylvania State University
University Park, PA 16802
(814) 863-1640
[email protected]<mailto:[email protected]>
