Generator Cost Data Format (*.gcd)

See Also

 

These files are outdated for Simulator version 8.0 and later. Their descriptions are still maintained here as they can still be read into Simulator. However, they can no longer be saved. These records are now stored in Auxiliary Script/Data Files.

The generator cost data file contains the parameters used to model the generator operating costs. Each record in the generator cost data file specifies the operating cost model for a single generator. The cost model may be either a cubic polynomial or a piecewise linear curve. When reading a file of generator cost data records, Simulator will open the Cost Curve Data Options Dialog below. This dialog gives you additional control over the input and process of generator cost information.

 

Each generator cost data record begins with the fields

num or name, ID,

where

num/name  the generator’s bus number or the bus’ name in single quotes,

ID  the generator’s single character id,

Following the ID field is an optional single-character field CostModel that specifies the type of cost model. If CostModel is ‘CUBIC’ or is not specified, the record describes a cubic cost model and thus concludes with the following fields:

 ai, bi, ci, di, FuelCost ParFac

where

ai, bi, ci, di input-output curve coefficients; see Generator Cost Information for details,

fuelcost fuel cost, expressed in price per Mbtu,

ParFac generator participation factor.

If, on the other hand, CostModel is ‘PLIN’, the record describes a piecewise linear cost model. The remainder of the record specifies pairs of generator output and corresponding generator cost:

 FixedCost MW1 IncCost1 MW2 IncCost2 … MWn IncCostn MWneg ParFac

where

FixedCost Operation cost independent of the generator’s MW output; expressed in $/Hr,

MWi, IncCosti  Output/incremental cost data point pairs that define the incremental cost model for the generator (note IncCosti has the units $/MWhr),

MWneg An arbitrary negative value used to terminate the record,

ParFac generator participation factor.

 

Cost Curve Data Options Dialog

The Cost Curve Data Options Dialog gives you additional control over the input and processing of generator cost information. It appears when you try to read generator cost information from an auxiliary data file (either .aux or .gcd). 

To command Simulator to turn all units onto automatic generation control (AGC) for which it reads a cost data record, check the first checkbox. This box has the rather lengthy label "If a unit for which a cost curve is read is not on AGC, Simulator should set it on AGC." In other words, if a cost curve is read for a particular generator, that generator will be set on AGC if this box is checked.

Cross-compound is a generator architecture sporting a single boiler and two turbines, one operating at high pressure and the other operating at low pressure. The existence of cross-compound units may complicate the modeling of generator cost characteristics, because sources for this information tend to describe the cost associated with the tandem, whereas Simulator’s economic dispatch will try to dispatch the two parts of the cross-compound unit as two separate units. To address this problem, Simulator gives you the option to lump the properties of the high- and low-pressure turbines into a single unit. It consolidates the two components by adding together their maximum MW outputs, minimum MW outputs, and present output levels, assigning these quantities to one of the units, and setting the other unit off AGC and at 0 MW of output. To have Simulator perform this function for you, check the box in the Cross Compound Units panel.

To tell Simulator how to identify units that belong to the same cross-compound generator, click the box labeled "How To Identify…". This will open the How to Identify Cross-Compound Dialog described next.

 

How to Identify Cross-Compound Dialog

Simulator regards cross-compound units as those that are connected to the same bus and that have generator id’s that match any of a number of specified pairs. You must define for Simulator the pairs of generator id’s that should be used to identify cross-compound units. Use the "How to identify cross-compound units" dialog to do this. 

Specify the pair of generator id’s in the small text boxes below the text labeled "Specify a new pair of id’s that identify two units that belong to the same cross-compound set." Then, click the Add button to include the pair of id’s you just entered in Simulator’s cross-compound identification procedure. The box on the right lists all the pairs of identifiers Simulator will use to identify parts of a cross-compound set. To remove a pair of identifiers from this list, select it from the box and click the Delete key.

The list of cross-compound identifier pairs is stored in the pwrworld.ini file, so there is no need to specify these pairs each time you load in a new case.