Overlapping between an Outage Event and a Derate Event

In Performance records, the Total Eqv Derate Hrs (N) and Total Eqv Derate MWh (N) fields store the sum of the values in the Total Equivalent Derate Hours w/out Shadowing and Total Equivalent Derate MWh w/out Shadowing fields in all Primary Event records for a given reporting month and year. If an outage event overlaps a derate event, the values in the Total Eqv Derate Hrs (N) and Total Eqv Derate MWh (N) will NOT include derate data for the time during which the outage event was also occurring.

Consider an example of two Primary Event records, Primary Event - Outage and Primary Event - Derate, whose fields are populated as shown in the following table. Assume that both Primary Events records are linked to the GAA Unit record GAA Unit 1, which has a Gross Dependable Capacity of 600 MW and a Net Dependable Capacity of 500 MW.

The date range established by the values in the Event Start Date and Event End Date fields of the two Primary Event records overlap between 11/02/2016 12:00 P.M. and 11/04/2016 12:00 A.M., or 36 hours. So although the derate event lasted 72 hours total, for 36 of those hours, an outage event was also occurring.

In this example, if the entire derate event were included in the Performance calculations, in the Performance record for November 2016 that is linked to GAA Unit 1, the following values would be calculated and stored in the Performance record:

• Total Equivalent Derate Hours (N): 14.4
• Total Equivalent Derate MWh (N): 7200

Because an outage event was occurring during 36 hours of the derate event, however, half of the derate event is not counted, and the values in the Performance record become:

• Total Equivalent Derate Hours (N): 7.2
• Total Equivalent Derate MWh (N): 3600