1. Compare and Contrast Reliability Assumptions
Bob Pierce
May 12, 2006

2. Education Process
Shared and discussed transmission planning practices among Participants
Identified similarities and differences in the reliability assumptions used by PEC and Duke in their transmission planning processes
DRAFT

3. Primary Differences Planning Process Calendar Case Development
Assessment Practices
DRAFT

4. Planning Process Calendar
PEC divides screening into two sets of studies:
near-term (1-5 yrs) performed during the 1st quarter
long-term (6-10 yrs) performed in the 3rd quarter
Duke does not divide the screening process into near-term and long-term
DRAFT

5. Case Development: Rollover and Future DNRs
Duke includes Designated Network Resource (“DNR”) projections provided by the Load Serving Entities (“LSEs”) in the base cases
PEC assumes roll-over of existing DNRs, but does not include changes to existing DNRs or new DNRs in base cases until the Open Access Transmission Tariff (“OATT”) requirements, initiated by Open Access Same-time Information System (“OASIS”) requests, are completed
DRAFT

6. Case Development: Dispatch Priority
Duke’s base cases assume a dispatch priority of LSE resources provided by the LSEs
PEC’s base cases include all LSE imports flow and owned generation
PEC on system resources are backed down to accommodate full use of LSE resources
DRAFT

7. Case Development: Future “Dummy” Generation
Duke locates dummy generation at buses based on knowledge gained from the generator interconnection queue regarding feasible locations
PEC locates dummy generation at a 500 kV bus to reduce the impact it may have on the system
There are sufficient resources to serve the load in the control areas in the 2011 case, therefore location of dummy generation is not an issue
DRAFT

8. Case Development: Transmission Reliability Margin (“TRM”)
Both Duke and PEC reserve VACAR Reserve Sharing on respective interfaces
In addition, PEC:
Includes a parallel path component
Uses a system inrush response on non-VACAR interfaces
DRAFT

9. Assessment: Ratings Used for Analysis
Duke uses 12-hour and long term emergency (seasonal) ratings for contingency analysis
PEC uses the continuous rating for all contingency analysis
Minor differences between Duke and PEC in the assumptions made in determining the continuous ratings of lines and transformers
DRAFT

10. Assessment: Import Assumptions
Duke does not import for the loss of one generator
For the outage of two generators, Duke’s assessment imports the amount of the 2nd generator outage
PEC assesses with all import obligations, including TRM
DRAFT

11. Assessment: Contingency Assumptions
Duke assesses a generator maintenance case plus an additional generator outage
PEC assesses a generator contingency plus unit derations replaced by TRM imports
DRAFT

12. Assessment: Phase Angle
Due to the impact on phase angle from significant 500 kV flow, PEC monitors the Richmond-Newport 500 kV line phase angle
Duke does not currently monitor phase angle
DRAFT

13. Conclusions
The comparison of Duke’s and PEC’s reliability planning practices includes many similarities; but there are some differences
The consequences associated with resolving some of these differences are complex
For the first Collaborative Plan, the PWG will not change planning practices for the 2006 plan, except to adjust the planning process calendar
The PWG will assess impacts of the differences and may recommend changes as the joint studies proceed
DRAFT