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.
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)              -

  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                 -

  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

<> on behalf of Ray Zimmerman 
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.


On Jun 23, 2017, at 10:55 AM, Mort D. Webster 
<<>> 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<>

Reply via email to