'Bulletins' Category

Synopsis

PLEXOS 6.202 R11 introduces a number of new features including new input properties, algorithm enhancements and solution properties.

Details

New input properties:

• Data File [Shape Distortion]: A new controlling parameters for the quadratic growth method that allows the user to finely control the level of distortion in the ordered load curve shape when the rate of growth of the maximum and energy are different.
• Diagnostic [Random Number Seed]: Reports all random number seeds generated in the program, which allows the user to use these later to repeat the outage patterns of Generators and Lines.
• Generator [Load Subtracter]: Defines a profile of values that will be subtracted from the system-wide load duration curve prior to slicing the curve into blocks. For systems with significant amount of renewable generation defining this property on the renewable generators means the slicing of the LDC will be done on the “net load” curve and is potentially more accurate than slicing the raw load curve.
• Region [Is Strategic]: Toggles on/off gaming algorithms for the Region.
• Region [Elasticity]: For the Nash-Cournot game this overrides the Competition [Default Elasticity] setting for the Region.
• Region/Zone [Min Native Capacity Reserves/Min Native Capacity Reserve Margin]: Capacity reserve requirements that must be sourced from capacity inside the Region/Zone without recourse to capacity sharing.
• Line [Max/Min Capacity Reserves]: Limits for capacity sharing on lines independent of the thermal limits.
• Financial Contract [Is Physical]: Turns a financial contract into a physical requirement for generation.
• Emission Generators [Shadow Price Scalar]: A multiplier on the effect of emissions on the incremental cost of generation. Specifically this parameter can be set to zero for generators operating in regions where emissions costs are not reflected in generation cost.
• Constraint Generators [Ramp * Coefficient]: A number of new Constraint properties that allow ramping and ramp violation terms in generic constraints.
• Condition Reserves: Reserve terms can now appear in the definition of a Condition.

New solution properties:

• Fuel [Generation], [Average Heat Rate]: The generation associated with the Fuel and the average heat rate of generation using the Fuel.
• Emission, Emission Generators, Emission Fuels, Region Emissions [Generation], [Intensity]: The generation associated with the Emission and the average intensity.
• Region [Shadow Load], [Shadow Generation], Company [Shadow Generation], Company Regions [Shadow Generation]: Additional values from the shadow solution i.e. the solution prior to gaming and uplift.
• Company Regions [Marginal Cost]: Marginal cost of generation for the Company in the Region.

Algorithmic changes:

• Nash-Cournot: The Nash-Cournot algorithm is completely revised. The equilibrium is calculated on each block of the LDC in MT Schedule and demand response and mark-ups are fed back into the simulation. Please refer to the Help for more details.
• Improvements to multi-step LT Plan models.

Graphical User Interface:

• Property tree now supports multi-select through use of check boxes on the nodes.
• The Report settings now allow the user to select which properties are written to flat (text) files.

Solvers:

• Xpress-MP is updated to Version 7.2
• Gurobi is updated to Version 4.6 see their release news.

Please refer to the updated product help for more details.

Synopsis

A serious issue has been identified in the application of Variable data to the simulation in the second and subsequent simulation steps of MT Schedule and LT Plan.  Users of the affected versions should update immediately to avoid the issue.

Affected Versions

The following versions of PLEXOS for Power System software are affected:

• PLEXOS 5 up to and including 5.201 R27
• PLEXOS 6.201 up to and including 6.201 R27
• PLEXOS 6.202 up to and including 6.202 R04
• PLEXOS Version 4.x is not affected by this bulletin.

Details

By default LT Plan solves the entire horizon in a single optimization step. For this case the bulletin does not apply. But if LT Plan is configured to run in two or more steps then the problem described below can occur. MT Schedule by default will solve the simulation horizon into yearly steps. This bulletin applies to MT Schedule when running  with two or more steps.
The first simulation step of LT Plan or MT Schedule is unaffected by the issue. But in the second and subsequent simulation steps the values of Variable objects is applied incorrectly to the formulation. Specifically the Variable values from step one are applied in step two, three, etc rather than the values for the appropriate step. The Variable object reporting is correct i.e. Variable [Value], [Error], [Raw Value] all report correctly, but the formulation and reporting of properties derived from the Variable values are shown with incorrect values e.g. if you were to apply a Variable to a Region [Price] then the Region [Price] in the solution would show the incorrect values.

Workarounds

No workarounds are available for this issue.

Resolution

Install the latest version of the software from the Downloads page.
The updated versions are:

• For PLEXOS 5.x users: 5.201 R28
• For PLEXOS 6.201 users: 6.201 R28
• For PLEXOS 6.202 users: 6.202 R05

For more information contact your support representative.