Ramp Rate Column
Column Type = Text
The Ramp Rate column is used to specify a ramp rate to a unit. The value is expressed as a percent (%), which is divided by 100 and multiplied by the resource capacity to determine the increase in resource capability available in the next hour. If the cell contains zero or NULL, then no ramp rate is applied. A unit will always ramp up to its Minimum Capacity in one hour regardless of this value.
Example:
For a plant with a capacity of 50 MW and a Ramp Rate of 20%:
(20/100) * 50 = 10 MW increase in the resource capability available in the next hour.
Typically, the ramp rate logic will be effective when the project file is set to dispatch for all hours of the study. Some hourly sampling is allowed as long as all days are included in the study, in which case the ramp rates will automatically be converted to match the sampling level. For example, when sampling Every Day, Every 2nd Hour a resource with a ramp rate of 20% per hour would ramp up its generation 40% between dispatch hours. One exception is when running sub-hourly, ramp rates will only be applied when running all hours.
NOTE: Ramp rates are effective only if the Use Ramp Rates switch is selected (located in the Resource folder of Simulation Options).
NOTE: When using ramp rates with the Nodal Capability, the current hour’s constraints (maximum resource capability) will be based on the previous hour’s nodal output for each zonal resource that is mapped to one or more nodal generators.
NOTE: Specify inputs for any time period (annually, monthly, weekly, hourly, or sub-hourly). For information on specifying a variable's time series, see Entering a Time Series.
Ramp Rate Column
