Statistical Analysis of Power System Faults May 99-15 April 30, 1999 Corey Proctor EE Alvina Hendradi EE Chris Dennison EE Greg Bahl EE Advisor/client Dr. James D. McCalley

Agenda Problem Statement Design Objectives End Product Description Assumptions and Limitations Technical Approach Evaluation of Project Success Future Work Lesson Learned Conclusions Questions

Problem Statement How do you balance the RISK with the BENEFIT for loading a conductor in a real power system using real statistical data?

Problem Statement: Background Power Line Heating

Problem Statement: Background Impacts of Thermal Loading Loss of strength due to annealing. Loss of ground clearance due to sagging.

Design Objectives Develop a report that will outline the following items Overview of the research including Description of the data Description of the statistical method Description of the transmission line Description of the process used to determine the associated risk Determine a recommendation for the transmission line Identify areas of further study

End Product Description Risk assessment of a transmission line. Real data Produces a method and a recommendation for a transmission line Analysis of weather Load growth Cost for reinforcement Client takes full ownership of project results

Assumptions and Limitations Statistics Wind and temperature are statistically independent Assumed load duration curve Assumed probability of outages per year Transmission lines 3.5% load growth per year 20 MW used for generation 15% interest rate for capital recovery Limitations Modeled only one load N-1 outage conditions System reduction Limited number of weather sites Risk assessment only for summer all other times risk = 0!

Technical Approach Developed Design Flow Chart Researched Studied Alternatives Compared Solutions Made a Decision

Technical Approach: Research Line Data Location Conductor Load Characteristics Cost of Transmission

Technical Approach: Research Weather Dates needed Cost of data (Benefit analysis) High Plains Climate Center Processing Implementation

Weather Data Collector

Technical Approach: Research Tools Used EPRI Ipflow Research grade software (ISU)

Technical Approach: Study Alternatives Leave power line as is. Restrict future plant load. and/or take the risk. Re-build Add new power line Add onsite generation

Technical Approach: Compare Solutions Cost of Reinforcement Risk Feasibility

Technical Approach: Make a Decision Benefits Ease of implementation

Evaluation of Progress Success Success!: Delivered all objectives Description of: Data Statistical Method Transmission Line Process used to determine the associated risk Determined a recommendation for transmission line Identified further areas of study

Recommendations for Additional Work Promote as a risk tool Use a larger sampling of weather data Study: Conductor characteristics Statistical dependence of wind and temperature Economic value added instead of minimization of cost

Financial and Human Budgets

Lessons Learned Efficient time management Increased understanding of statistical data manipulation. Increased understanding of real-world costs. Evaluating individual strengths and assigning work appropriately.

Conclusion This assessment will provide planners and system operators a better understanding of system loading and financial costs associated with the risk of their actions.

Questions ?