1. Reliability Analysis Sample Study October 2000 Jahan Alamzad 1250 Aviation Avenue Suite 200M San Jose, CA 95110 Tel: 408-295-7730 Fax: 408-280-5700 Email: jahan.alamzad@ca-advisors.com CA Advisors

2. Objectives  Present a sample study for reliability analysis applicable in the electric power utility industry  Provide a general framework for reliability analysis  Suggest the structure of a detailed project

3. CA Advisors Introduction  Reliability analysis approaches have been successfully applied in the airline industry with impressive results –optimizing maintenance program –forecasting for maintenance events –planning resources for maintenance requirement  A decision was made to explore the possibility in apply similar techniques in the electric power utility industry  To investigate applicability, this pilot study was conducted to understand various issues –data –analytical models –outputs

4. CA Advisors Collected data  Extract of maintenance records, dating 1990 -1999, for one part, provided by a utility company –Breakers –Model: 15VHK500 –Key data:  Workorder Class  Type  Mode  Serial No.  Date  Workorder No.

5. CA Advisors General framework Probability of failure before t = p one-parameter approachtwo-parameter approach Slope: beta parameter t f(p) ln-ln scale Slope: failure rate t f(p) ln scale Characteristic Life  Analysis process: –identify Scheduled vs Unscheduled events –determine inter-event time –build probability distribution function (pdf) –transform data points –do regression analysis –determine parameters

6. CA Advisors Results  Application –Input:  next scheduled maintenance: 400 days  time since last maintenance: 120 days –Output:  probability of failure before scheduled maintenance  expected time until next failure (days)  One-parameter –Failure rate: 0.00149 –R-Squared: 95.9%  Two-parameter –Beta: 1.06067 –Characteristic life: 703.30 –R-Squared: 98.0% one-parametertwo-parameter 0.4488 0.4360 301306

7. CA Advisors Considerations  Maintenance records –availability –content –quality  Maintenance event identification –scheduled –unscheduled  Influencing factors –analysis unit –unit relationships

8. CA Advisors Applications  Similar to the airline industry, using reliability-based maintenance planning yields substantial benefits –understand the inherent reliability of parts –forecast maintenance events –anticipate maintenance activities –determine maintenance workload and material requirements during a specific period of time –strategic assessment of maintenance needs –identify support resources –optimize inventory requirements  repairable parts  expendable parts –design optimal maintenance program

9. CA Advisors Motivations  Reliability-based maintenance planning reduces the unit cost of production and delivery  Needed resources can be scientifically justified and decisions can be analytically supported OverageShortage Unit Cost Resource Level

10. CA Advisors Project: reliability-based maintenance planning Scoping Framing Structuring input Beta version Production version Implementation 6 months