Dear Prof. Ray,
Thank you very much for your reply. But I still do not understand why the LMP 
at the node of load curtailed does not reach 100€/MWh. I tried increasing the 
load (both active and reactive with constant power factor) and my results were 
each time the same. The LMPs are the same (82€/MWh) and the objective function 
is the same. May you please explain why the value never reaches 100 €/MWh?

Thank you.

From: [email protected] 
[mailto:[email protected]] On Behalf Of Ray Zimmerman
Sent: lunes, 23 de mayo de 2016 15:50
To: MATPOWER discussion forum
Subject: Re: LMP Calculation during Voltage Congestion

I think what you are seeing is the effect of the constant power factor 
constraint on the curtailable load. This constraint essentially bundles the 
real and reactive power together into a single bundled commodity that is being 
curtailed at 100€/MWh. Some of that due to the nodal price of real power and 
some to the nodal price of reactive power, which is likely to be high in a 
voltage congestion case.

See section 4.1 in the MATPOWER Tech Note 2 on AC Power Flows, Generalized OPF 
Costs and their Derivatives using Complex Matrix 
Notation<http://www.pserc.cornell.edu/matpower/TN2-OPF-Derivatives.pdf> for 
more details on this effect.

   Ray


On May 20, 2016, at 9:30 AM, Ibtihal Abdelmotteleb 
<[email protected]<mailto:[email protected]>> wrote:

Dear Prof. Ray,
I have a question regarding LMP calculation during congestion.
I ran OPF on the 34-node feeder distribution network, feeding from a single 
infinite generator of price 50€/ MWh. It did not converge due to voltage 
congestion, not thermal congestion (there is no line congestion). Then, I 
introduced load curtailment with a price of 100€/MWh. The OPF converged, and at 
the bus of load curtailment the price was 82€/MWh, although I was expecting it 
to be at least 100€/MWh. Do you think I have done something wrong? or is there 
an explanation why thermal congestion is different from voltage congestion?

Thank you very much.

Ibtihal Abdelmotteleb
PhD Student
IIT, Comillias University
Madrid, Spain


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