Transmission Detect Non-physical Losses

Units:	Yes/No
Default Value:	False (0)
Validation Rule:	False (0) or True (-1)
Description:	If non-physical losses should be detected (in the piecewise linear loss model) and removed via mixed-integer programming

Transmission toggles on/off an algorithm that detects and eliminates non-physical losses in the piecewise linear loss model.

PLEXOS detects non-physical losses and reports a warning to the screen and log like the following:

           WARNING S20164: Non-physical losses detected on Line "A - B 220kV" in period (9)".

        

The 'standard' approach to dealing with this is a two step procedure:

1. First run the market clearing engine assuming non-physical losses will not occur
2. Check the LP solution for symptoms of non-physical losses
3. In periods and for lines where non-physical losses are detected, introduce an integer variable into the LP formulation that forces the optimizer to chose one flow direction or the other but not both simultaneously
4. Resolve and recheck for non-physical losses - continue to reporting if resolved

This same procedure is built-in to PLEXOS, but is not enabled by default because it involves switching from LP to mixed-integer programming (MIP) to solve. The correction procedure can be turned on using this "Detect Non-physical Losses" option. Non-physical losses are always checked for and warnings issued regardless of the setting of this switch, but the correction procedure is only invoked if this switch is enabled.

In a multi-step or multi-sample simulation, PLEXOS removes the correction each step, starting fresh, which ensures that, at any time only the minimum number of integer elements are present in the formulation.

NOTE: Your optimizer will require a license for mixed integer programming to use this feature.