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Dedicated AC Power Flow Solver #590
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This is a good question and there are quite a few details to get the most out of a warm start in PowerModels. At a high level these are the key points,
I hope that helps. I'll also note that PowerModels was originally designed for solving OPF without a good guess for a starting point. Due to that focus, doing very fast PF solves is not super easy in PowerModels. In the future I plan to add some dedicated AC-PF solvers that assume a good starting point and are much faster and simpler to use for that use case. |
@jchen975, can we close this issue? |
Thank you for your answer and sorry for taking so long to get back to you, I was on vacation and didn't have access to internet until now. If you don't mind, I'll take some time tomorrow to figure out how to do warm-start ACPF properly and close the issue then. One last thing and please correct me if I'm wrong, currently |
No problem. The equations implemented by PowerModels are identical to Matpower when reading matpower case files (as of Matpower v6), so for an identical problem specification they should be the same. You can try the |
Thanks again for your time! I took a look at the Ipopt documentation and adjusted those parameters, but I couldn't really find anything on |
So far there is no documentation on setting the starting point in PowerModels. I am still exploring how to best initialize Ipopt. You can have a look in this file to see the names of the parameter you need to add in the network data to specify the starting value for each variable. |
Hi Dr. Coffrin, regarding your previous comment on your plan to add an ACPF solver that accommodates warm-start conditions, has there been any updates? If that's not a short-term priority, I was actually thinking about creating a new package that only solves the PF problem, by rewriting the Matpower |
@jchen975 there are not updates per-se, it is still possible to warm-start Ipopt with the current version of PowerModels, although it is not well documented. Please feel free you write your own power flow solver, I hope to implement something similar in PowerModels in the next 6-12 months, so I might draw some inspiration from your implementation. |
a native DC power flow solver is not available. The |
Hi @jchen975, is this still an open issue? I'd be interested in a dedicated power flow solver in Julia that uses Any thoughts? |
FYI, @jd-lara as I know you have an interest in this. |
Sweet! Perhaps there is room for collaboration @jchen975? Perhaps we can talk about details via e-mail? You can find mine on my github profile. |
@timueh we have implemented something similar as what your objective is in PowerSystems.jl where we use Julia's solvers to solve the Non-linear system of equations. The intention for us is to initialize the system with a PowerFlow solution when needed. https://github.com/NREL/PowerSystems.jl/tree/master/src/utils/power_flow The tests show examples of how to use it. https://github.com/NREL/PowerSystems.jl/blob/master/test/test_powerflow.jl |
Thanks. That looks like what I was looking for. Just a quick question---which I could answer myself with playing with the code, but you might know the answer immediately---what's the number of decision variables in the power flow problem? Is it |
The number of decision variables is always |
* add NLSolve to deps * add complex admittance matrix computation * add julia native ac power flow solver, closes #590 * add tests for native ac pf solver
A prototype version of this feature is now available in the |
After a long wait, I am happy to report that this has been implemented. Documentation is available here, https://lanl-ansi.github.io/PowerModels.jl/stable/power-flow/ |
Hi, I just realized this problem, but when I run a solved Matpower case, it takes the same number of iterations as it would with default values. In Matpower,
should result in
iterations: 1
in the end. When running with default/solved values for case118, and case300, it takes 4 and 5 iterations respectively. I tried both with the case saved from Matpower and with manually updating thevm
,va
fields of all buses from the solutions dict, and got the same results.Any idea why this is happening? I know Matpower uses NR for acpf by default, so I'm assuming it has something to do with Ipopt. I'd appreciate any clarifications on this.
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