Maintenance and production constraints

The production at a given plant in Prodrisk is constrained by the last point on the plant’s PQ curve. This is not a time-dependent attribute, hence the reference PQ-curve given as input is constant in time throughout the simulation period. Since the PQ-curve is scaled internally in the model according to the head coefficient, maximum production depends on upstream and downstream reservoir levels. In order to achieve time-dependent or state-independent maximum production limits, additional attributes are needed.

Maintenance

The maintenance and maintenance_hourly attributes are used to mimic planned maintenance on a generator. Since Prodrisk uses an aggregated plant object, where multiple generators are represented by one common PQ-curve, this is done by reducing the maximum production of the reference PQ-curve such that it equals the maximum production of the remaining active generators. The resulting PQ-curve will still scale according to the head coefficient, and the maximum production will depend on upstream and downstream reservoir levels.

The maintenance attributes specify the reduction in maximum production, given in MW. Note that even though maintenance_hourly is given with hourly resolution, it will be converted to weekly resolution within the Prodrisk core.

The pmax attribute

In order to achieve a firm upper production limit for a plant, independent of the head coefficient, the pmax attribute is used. Contrary to maintenance, the model reduces the maximum production of the PQ-curve after the head coefficient scaling. The maximum production will therefore be independent of upstream and downstream reservoir levels.

The pmax attribute specifies the new maximum production limit in MW. The attribute is given with hourly resolution, but is converted to price period resolution within the Prodrisk core.