F.  Duke Energy Carolinas’s ATC Calculation

The SERC NTSG OASIS studies are performed quarterly for the next five quarters/seasons.  When first completed, the SERC NTSG OASIS studies will cover an 18 month period.  Before the next study is produced, that period will have decreased to 15 months.  The SERC NTSG OASIS studies can be used for calculating the TTC.  The SERC NTSG OASIS studies calculate the FCTTC for each of Duke’s interface based on the following formulas:

      FCTTC= FCITC + base transfer modeled in the OASIS study for that season

            TTC     = lesser of {Contract Path or FCTTC)

Where,

FCITC = First Contingency Incremental Transfer Capability as calculated using DC MUST in the OASIS study.

Using the TTC as calculated above, the calculation of Firm Available Transfer Capability (Firm ATC) and Non-Firm Available Transfer Capability (Non-firm ATC) are as follow:

 

Firm ATC = TTC – Firm Pt-Pt Reservations – Firm Network Reservations – CBM – TRM

Non-Firm ATC = TTC – Non -Firm Pt-Pt Reservations – Secondary Network Reservations – Firm Pt-Pt Schedules –Firm Network Schedules – CBM - TRM (after 10AM the day before)

Non-Firm ATC = TTC – Non-Firm Pt-Pt Reservations – Secondary Network Reservations – Firm Pt-Pt Reservations – Firm Network Reservations – CBM - TRM (before 10AM the day before)

As stated above, the seasonal TTC is based on the corresponding OASIS study.  However, as a minimum, Duke Energy Carolinas also re-calculates TTC on a daily basis for the next day up until November 2006 when MISO as the Independent began to perform that task.  The load flow model for the appropriate SERC NTSG study is modified to consider near real-time operating data such as units availability, transmission outages and load forecast.  The TTC for each interface is calculated using the modified load flow model.

For OASIS posting beyond the time period covered by OASIS studies, the posted TTC is the contract path.  The formulas for calculating Firm ATC and Non-Firm ATC in this period remain the same as shown above. The table below is the formulation of the calculation done by the software used by Duke Energy which is provided by OATI Inc. These calculations reflect the items shown in the above formulas with reference to reservations and tags as seen by the OATI system.

Parameter Scheduling
Committed
Initialize
Firm
Scheduling
Committed
Intialize
Non
Firm
Operating
Committed
Intialize
Firm
Operating
Committed
Intialize
Non
Firm
Planning
Committed
Initialize
Firm
Planning
Committed
Intialize
Non
Firm
Scheduling
Pending
Intialize
Firm
Scheduling
Pending
Intialize
Non
Firm
Operating
Pending
Intialize
Firm
Operating
Pending
Intialize
Non
Firm
Planning
Pending
Intialize
Firm
Planning
Pending
Initialize
Non
Firm
Scheduling
Committed
Firm
Scheduling
Committed
Non
Firm
Operating
Committed
Firm
Operating
Committed
Non
Firm
Planning
Committed
Firm
Planning
Committed
Non
Firm
Scheduling
Pending
Firm
Scheduling
Pending
Non
Firm
Operating
Pending
Firm
Operating
Pending
Non
Firm
Planning
Pending
Firm
Planning
Pending
Non
Firm
CUFirm N N N N N N N N N N N N N N N N N N N N N N N N
CUNonFirm N N N N N N N N N N N N N N N N N N N N N N N N
ComFirm_DS N N N N N N N N N N N N N N N N N N N N N N N N
ComNonFirm_DS N N N N N N N N N N N N N N N N N N N N N N N N
ComResFirm Y N Y N Y Y Y N Y N Y Y Y N Y N Y Y Y N Y N Y Y
ComResFirm_CS N N N N N N N N N N N N N N N N N N N N N N N N
ComResFirm_DS N N N N N N N N N N N N N N N N N N N N N N N N
ComResNonFirm N Y N Y N Y N Y N Y N Y N Y N Y N Y N Y N Y N Y
ComResNonFirm_CS N N N N N N N N N N N N N N N N N N N N N N N N
ComResNonFirm_DS N N N N N N N N N N N N N N N N N N N N N N N N
ComTagFirm N Y N Y N N N Y N Y N N N Y N Y N N N Y N Y N N
ComTagFirm_CS N N N N N N N N N N N N N N N N N N N N N N N N
ComTagFirm_DS N N N N N N N N N N N N N N N N N N N N N N N N
ComTagNonFirm N N N N N N N N N N N N N N N N N N N N N N N N
ComTagNonFirm_CS N N N N N N N N N N N N N N N N N N N N N N N N
ComTagNonFirm_DS N N N N N N N N N N N N N N N N N N N N N N N N
MiscFirm N N N N N N N N N N N N N N N N N N N N N N N N
MiscNonFirm N N N N N N N N N N N N N N N N N N N N N N N N
NWComFirmRes_Firm Y N Y N Y N Y N Y N Y N Y N Y N Y N Y N Y N Y N
NWComFirmRes_NF N N N N N Y N N N N N Y N N N N N Y N N N N N Y
NWPendFirmRes_Firm N N N N N N Y N Y N Y N N N N N N N Y N Y N Y N
NWPendFirmRes_NF N N N N N N N N N N N Y N N N N N N N N N N N Y
NewComResFirm Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y
NewComResNonFirm N Y N Y N Y N Y N Y N Y N Y N Y N Y N Y N Y N Y
NewPendResFirm N N N N N N Y Y Y Y Y Y N N N N N N Y Y Y Y Y Y
NewPendResNonFirm N N N N N N N Y N Y N Y N N N N N N N Y N Y N Y
OffsetFirm N N N N N N N N N N N N N N N N N N N N N N N N
OffsetNonFirm N N N N N N N N N N N N N N N N N N N N N N N N
PendFirm_DS N N N N N N N N N N N N N N N N N N N N N N N N
PendNonFirm_DS N N N N N N N N N N N N N N N N N N N N N N N N
PendResFirm N N N N N N Y N Y N Y N N N N N N N Y N Y N Y N
PendResFirm_CS N N N N N N N N N N N N N N N N N N N N N N N N
PendResFirm_DS N N N N N N N N N N N N N N N N N N N N N N N N
PendResNonFirm N N N N N N N Y N Y N Y N N N N N N N Y N Y N Y
PendResNonFirm_CS N N N N N N N N N N N N N N N N N N N N N N N N
PendResNonFirm_DS N N N N N N N N N N N N N N N N N N N N N N N N
SAS1_Firm N N N N N N N N N N N N N N N N N N N N N N N N
SAS1_NF N N N N N N N N N N N N N N N N N N N N N N N N
SAS2_Firm N N N N N N N N N N N N N N N N N N N N N N N N
SAS2_NF N N N N N N N N N N N N N N N N N N N N N N N N
ScheduleFirm N N N N N N N N N N N N N N N N N N N N N N N N
ScheduleFirm_CS N N N N N N N N N N N N N N N N N N N N N N N N
ScheduleNonFirm N N N N N N N N N N N N N N N N N N N N N N N N
ScheduleNonFirm_CS N N N N N N N N N N N N N N N N N N N N N N N N
SetasideFirm N N N N N N N N N N N N N N N N N N N N N N N N
SetasideNonFirm N N N N N N N N N N N N N N N N N N N N N N N N