Hi Mohammad,
Remember that LMP is the sensitivity of the total objective function value to
changes in load at the node of interest. So, I think your expectation that LMP
is high when power is low and low when power is high is a bit too simplistic.
Certainly, in an uncongested system with a range of generation costs, the LMP
will rise as the total generation (and total load) increases. Here the LMP is
going to be governed mostly by the cost of the most expensive unit required to
meet the load (with small variations in location due to differences in
sensitivity to losses).
However, when you have congestion in the system (binding line flow limits or
binding lower voltage limits), then LMP values can vary widely depending on
where the congestion is relative to the expensive vs. inexpensive generators,
and how sensitive the flow in the congested line is relative to generator
redispatch.
So there is an intuitive explanation for the LMP, namely, the change in system
cost required to supply another unit of load at the bus, but the actual value
of that change in cost depends on many different factors for a system with
binding constraints.
Ray
> On Jul 26, 2016, at 8:42 AM, Haroon Malik <[email protected]> wrote:
>
> Hello Dr. Zimmerman,
>
>
> I would like to resolve an issue with the LMP and Power generation
> relationship, I am plotting both LMP and Power Generated to see the
> difference when taking out lines and generators one by one. From my
> understanding the LMP is high when power is low, LMP is low when power is
> high.
>
> I have 8 cases in which, the first 5 cases I am taking the transmission lines
> out one by one. Example 1st case one line is out, 2nd case two lines out and
> so on.
>
> The final 3 cases, are for generators to be turned off one by one. Example
> one generator is out, then two generators out etc.
>
> However for my final 3 cases it is giving me a good waveform plot where, when
> the power starts to decrease as the LMP increases.
>
> Could you tell me why, when the LMP is changing for the first 5 cases (due to
> the lines being taken out one by one) either increasing or decreasing in
> value, the power generation remains almost constant which does not reflect
> any change with the LMP values.
>
>
> I appreciate your time and response,
>
> Mohammad Haroon Malik
