PLEXOS 6.302 Release Notes

  1. Upgrade Compatibility
  2. Changes
    1. Piecewise Linear Loss Model
    2. CPLEX and Gurobi
    3. Purchaser (Interruptible Load) Reserves
    4. Storage Initial Volume Optimized
    5. Blocks
    6. Enforce Limit Flag
    7. Generator Heat Rate Default
  3. Features
    1. Gas Basin Class and Gas Market
    2. Hub Class and Transmission Rights
    3. Variable Temporal Resolution
    4. Hanging Branches in Scenario Tree
    5. GLPK Solver
    6. Wildcard Nodes* Collection
  4. User Interface
  5. New Inputs
  6. New Outputs
Released
March 31, 2014
Previous Version
6.301
Next Version
6.4

1. Upgrade Compatibility

This version will automatically upgrade any previous Version 5 or Version 6 database. You may need to check the upgrade notes of earlier releases for any compatibility issues.

Databases in 6.302 format will retro-grade to 6.301 however you may need to check the following properties whose meaning or default values has changed between versions:

2. Changes

The following are the changes to existing functionality between this version and 6.301:

2.1. Piecewise Linear Loss Model

The piecewise linear loss model has been refactored with a new formulation that is more closely compatible with the loss function formulation used in most LP-based market clearing engines. The new formulation is only different in its solutions when the line import and export limits are different magnitudes. In addition the parameter Transmission Max Loss Tranches now sets the total number of tranches used across the entire flow of the line, rather than the number used in the forward or back direction. The default value has been changed from 5 to 100.

The property Loss Incr Back was previously expected to be a non-negative number, but this is inconsistent with its description it the help and original design. From this version forward the property is expected to be non-positive i.e. the negative incremental loss multiplies the notionally negative flow to produce a non-negative loss.

2.2. CPLEX and Gurobi

Both solver versions have been updated. In particular the 12.6 version of CPLEX has improved performance and may produce different results on some models.

2.3. Purchaser (interruptible Load) Reserves

It is now required that both reserve purchasers offer quantity and offer price be set to define an interruptible load reserve bid. Previously only the quantity was required.

2.4. Storage Initial Volume Optimized

The functionality has been restored whereby the storage initial volume will be optimized if it is not defined and the storage is recycled.

2.5. Blocks

The settings LT Plan blocks and MT Schedule blocks are renamed to block count.

2.6. Enforce Limit Flag

The line and transformer settings enforce limits have new options. See the help topic for details.

2.7. Generator Heat Rate Default

The default value for the property generator heat rate is changed from one to zero. You should ensure that you set the heat rate rather than relying on the old default value.

3. Features

3.1. Gas Basin Class and Gas Market

The new Gas Basin class models a collection of Gas Field objects and allows aggregate reporting and constraints to be modelled.

The Market class now supports gas markets.

3.2. Hub Class and Transmission Rights

The new Hub class represents a collection of node objects and is used in pricing as well as in the enhanced version of the transmission right class.

3.3. Variable Temporal Resolution

The new settings LT Plan Last Block Count and MT Schedule Last Block Count allow you to reduce (or increase) the resolution of the simulation over the course of the simulation horizon. This applies when LT Plan Chronology or MT Schedule Chronology is "Partial" (load duration curves) or "Fitted" (chronological).

Example

In the following example the horizon starts with 20 blocks in the first week and reduces to one block by the end of the horizon. The blocks reduce according to a power function.

Property Value
Chronology "Partial"
Block Count 20
Last Block Count 1

3.4. Hanging Branches in Scenario Tree

When running a multi-stage stochastic optimization, the Scenario Tree construction now supports the concept of "hanging" branches. These are branches that spawn from tree nodes at a given stage and then never spawn sub-branches, but instead continue to the end of the horizon. This technique greatly reduces the number of scenarios required. See the topic Global Tree Stages Hanging Branches for details.

3.5. GLPK Solver

The open-source GLPK solver is now supported. See Performance SOLVER.

3.6. Wildcard Nodes* Collection

The Generator and Purchaser classes now support a wild card membership called Nodes*. Populating this collection causes the object to be copied and placed at each of the listed Node locations. This is a convenient shortcut for modelling a generic new build candidate in LT Plan or modelling distributed generation or storage such as batteries, where it would be time consuming to copy the object manually to 100s or 1000s of nodes. The copying of the object to the nodes is done at run time and reflected in the simulation and solution. Therefore you need only to maintain the data on the original objects in the input database.

4. User Interface

No significant changes.

5. New Inputs

New inputs are:

Collection Property Relates To
Diagnostic Scenario Tree Write Diagnostics for the scenario tree
Diagnostic Sample Weights Write diagnostics for the sample weights
Generator Min Down Time Mode Controls how [Min Down Time] is applied after outages
Fuel FO&M Charge Annual fixed operation and maintenance charge
Storage Target Level Storage target
Storage Target Level Hour End of hour storage target
Storage Target Level Day End of day storage target
Storage Target Level Week End of week storage target
Storage Target Level Month End of month storage target
Storage Target Level Year End of year storage target
Gas Basin Max Production Maximum production of gas from the basin
Gas Basin Max Production Hour Maximum daily production of gas from the basin
Gas Basin Max Production Day Maximum daily production of gas from the basin
Gas Basin Max Production Week Maximum weekly production of gas from the basin
Gas Basin Max Production Month Maximum monthly production of gas from the basin
Gas Basin Max Production Year Maximum annual production of gas from the basin
Gas Basin Min Production Minimum production of gas from the basin
Gas Basin Min Production Hour Minimum daily production of gas from the basin
Gas Basin Min Production Day Minimum daily production of gas from the basin
Gas Basin Min Production Week Minimum weekly production of gas from the basin
Gas Basin Min Production Month Minimum monthly production of gas from the basin
Gas Basin Min Production Year Minimum annual production of gas from the basin
Gas Basin x Value to pass-through to solution
Gas Basin y Value to pass-through to solution
Gas Basin Max Production Maximum production of gas from the basin
Gas Basin Max Production Hour Maximum daily production of gas from the basin
Gas Basin Max Production Hour Maximum daily production of gas from the basin
Gas Basin Max Production Day Maximum daily production of gas from the basin
Gas Basin Max Production Week Maximum weekly production of gas from the basin
Gas Basin Max Production Month Maximum monthly production of gas from the basin
Gas Basin Max Production Year Maximum annual production of gas from the basin
Gas Basin Min Production Minimum production of gas from the basin
Gas Basin Min Production Hour Minimum daily production of gas from the basin
Gas Basin Min Production Day Minimum daily production of gas from the basin
Gas Basin Min Production Week Minimum weekly production of gas from the basin
Gas Basin Min Production Month Minimum monthly production of gas from the basin
Gas Basin Min Production Year Minimum annual production of gas from the basin
Gas Basin x Value to pass-through to solution
Gas Basin y Value to pass-through to solution
Gas Basin z Value to pass-through to solution
Gas Pipeline Volume Imbalance Absolute value of the difference between delivery volume into the pipeline and the redelivered volume off the pipeline
Gas Pipeline Imbalance Charge The charge applicable to the volume imbalance
Gas Demand Bid Quantity Quantity bid in band
Gas Demand Bid Price Value of gas in band
Region Transmission Constraints Enabled If transmission line constraints are enabled in this region
Region Transmission Constraint Voltage Threshold Voltage level at which thermal limits are modelled in this region
Region Transmission Interface Constraints Enabled If interface constraints are enabled in this region
Region Enforce Transmission Limits on Lines in Interface If lines in interfaces should have their limits enforced regardless of voltage in this region
Region Transmission Report Enabled If transmission reporting is enabled in this region
Region Transmission Report Voltage Threshold Voltage level at which transmission reporting begins in this region
Region Transmission Report Lines in Interfaces If all flows on lines selected interfaces are reported in this region
Region Transmission Report Injection and Load Nodes If all injection and load buses (nodes) are reported on (regardless of voltage) in this region
Hub Pricing Method Method used to calculate the hub price
Hub x Value to pass-through to solution
Hub y Value to pass-through to solution
Hub z Value to pass-through to solution
Transmission Right Type Type of transmission right
Transmission Right Settlement Model Direction of settlement
Transmission Right Price Scheduled price
Constraint Wildcard Mode Controls whether or not the constraint is copied when it is associated with a wildcard membership
Global Tree Stages Hanging Branches Scenario Tree: Number of hanging branches in each stage
Generator Nodes Loading Participation Factor Proportion of pump load at the node
Node Hubs Pricing Weight Contribution of nodal price to hub price
Constraint Storages End Level Coefficient Coefficient of storage end level
Constraint Storages Hours Full Coefficient Coefficient of the number of hours the waterway is flowing
Constraint Gas Basins Production Coefficient Coefficient of gas basin production
Constraint Gas Basins Units Built Coefficient Coefficient of number of gas field units built
Gas Basins Units Built in Year Coefficient Coefficient of number of gas field units built in the year
Constraint Gas Storages End Volume Coefficient Coefficient of storage end volume
Constraint Hubs Load Coefficient Coefficient of hub load
Constraint Hubs Generation Coefficient Coefficient of hub generation

6. New Outputs

New outputs are:

Collection Property Relates To
Generator Min Generation Minimum Generation in the period
Generator Max Generation Maximum Generation in the period
Generator Cleared Reserve Offer Cost Area cleared under reserve offer curve
Fuel FO&M Cost Fixed operation and maintenance cost
Storage Initial Level Storage level at the start of the period
Storage Hours Full Number of hours the storage is full
Storage Potential Energy Potential energy of water in storage
Waterway Hours Flowing Number of hours the waterway is flowing
Purchaser Cleared Bid Price Price of marginal bid band
Purchaser Cleared Bid Value Area cleared under demand curve
Purchaser Cleared Reserve Offer Cost Area cleared under reserve offer curve
Reserve Cleared Offer Price Price of marginal offer band
Reserve Cleared Offer Cost Cost of cleared offer bands.
Reserve Generators Cleared Offer Price Price of marginal offer band.
Reserve Generators Cleared Offer Cost Cost of cleared offer bands.
Reserve Purchasers Cleared Offer Price Price of marginal offer band.
Reserve Purchasers Cleared Offer Cost Cost of cleared offer bands.
Market Gas Nodes Sales Gas sold into the market.
Market Gas Nodes Purchases Gas bought from the market.
Market Gas Nodes Net Sales Net gas sold into the market.
Market Gas Nodes Net Purchases Net gas bought from the market.
Market Gas Nodes Revenue Revenue from gas sales in the market.
Market Gas Nodes Cost Cost of gas purchases from the market.
Market Gas Nodes Net Revenue Net revenue from gas sales in the market.
Market Gas Nodes Net Cost Net cost of gas purchases from the market.
Gas Basin Initial Volume Volume of gas in the basin at the start of the period.
Gas Basin End Volume Volume of gas in the basin at the end of the period.
Gas Basin Production Quantity of gas produced from the basin.
Gas Basin Production Cost Cost of extracting gas from the basin.
Gas Basin FO&M Cost Fixed operation and maintenance cost.
Gas Basin Fixed Costs Total fixed costs including amortized build costs.
Gas Basin Shadow Price Shadow price of gas in the basin.
Gas Basin Units Number of gas fields in the basin.
Gas Basin Units Built Number of gas fields built in the basin.
Gas Basin Build Cost Cost of building gas fields in the basin.
Gas Basin x Pass-through value (summed in summary).
Gas Basin y Pass-through value (summed in summary).
Gas Basin z Pass-through value (averaged in summary).
Gas Pipeline Volume Imbalance Volume imbalance.
Gas Pipeline Imbalance Cost Cost of imbalances.
Region Cleared Reserve Offer Cost Area cleared under reserve offer curve.
Zone Cleared Reserve Offer Cost Area cleared under reserve offer curve.
Node Flow Flow through the node.
Node Voltage Voltage at the node.
Transformer Voltage Voltage of the transformer.
Company Gas Market Revenue Revenue from gas markets.
Hub Price Price at the hub.
Hub Customer Load Load net of generator auxiliaries and losses.
Hub Net Generation Generation net of pump load.
Hub Cost to Load Cost to load of their energy purchases.
Hub Generator Pool Revenue Total generator pool revenue.
Hub Load-weighted Price Load-weighted average price.
Hub Generation-weighted Price Generation-weighted average price.
Hub x Pass-through value (summed in summary).
Hub y Pass-through value (summed in summary).
Hub z Pass-through value (averaged in summary).
Transmission Right Net Profit Settlement net of scheduled Price.