Generator Max Ramp Down

Units:	MW/min
Mode:	Input/Output
Multi-band:	True
Default Value:	1E+30
Validation Rule:	≥0
Key Property:	No
Description:	Maximum ramp down rate that applies at the given load point

Generator Max Ramp Down sets a limit on the rate at which the generator can decrease production and is expressed in megawatts per minute. This property is multi-band which allows for different ramp limits depending on the generation level. If a single band is defined, then this limit applies for Generation ranges between Min Stable Level and Max Capacity, unless Run Down Rate or Shutdown Profile are defined in which case this ramping limit applies before shutdown begins.

To define different ramp limits depending on generation level, pair bands of the Max Ramp Down with Ramp Down Point.

For multi-unit generating stations the available ramp down is defined as:

Units Generating

When modelling Reserve the amount of available ramping down capability may be reduced by the provision of lower ancillary services. See the Response Ratio property for more details.

By default the ramping limit is a hard constraint meaning that no violation is allowed. To create soft constraints with a penalty price use the Max Ramp Down Penalty property.

Table 1: Max Ramp Down Example
Property	Value	Units
Units	1	-
Max Capacity	100	MW
Min Stable Level	40	MW
Max Ramp Up	0.5	MW/min.
Max Ramp Up Penalty	100	$/MW
Max Ramp Down	0.5	MW/min.
Max Ramp Down Penalty	100	$/MW

To model the running down period where Generation is between Min Stable Level and zero use either the Shutdown Profile or Run Down Rate properties.

Related reporting properties: