Contamination Mitigation May 8, 2014

1. Contamination MitigationMay 8, 2014 Dan Greenwood Asset Management Consultant

2. Contamination MitigationAgenda • Contamination Events of 2011 • Distribution Mitigation Efforts • Impact Weather Study • Cumulative Wind Vector (CWV) • Leakage Current Monitoring Program

3. 2011 Contamination Event Summary • Unprecedented long term drought condition • contamination related outages began April 25th • Response activities: • Proactive energized and de-energized washing • Elevated patrol response to momentary outages • Accelerated specialized daytime corona inspections • Established washing of generator leads • Contamination mitigation activity tracking • Contamination outage reporting

4. 2011 Contamination Event Review • Operational Opportunities: • Internal Communication (Activity coordination) • Resource availability (Verification of resources) • 3rd Party Facility Access (Notification processes) • Mitigation Activity Tracking (Report consolidation) • Program Initiation (Decision aids) • ImpactWeather Study (Conditional awareness)

5. Contamination Mitigation Process & Procedures • Distribution Contamination Process Document • Detailed process with stage table as well as procedures for washing • Identifies responsible individuals during process • Incorporates checklists for various tasks • Section that lists & defines acronyms for newer personnel

6. Purchased Washing Trailers • Water Tank Size: • 535 gallons • Gas Tank Size: • 10 gallons • Max PSI: • 3500 PSI • Gallons per Minute: 8 GPM

7. CNP Power Washing TrainingPurpose • Why Train? • Support preventative maintenance program • Protect property – CNP and Public • Do the job safely • Learning Objectives: • Operate power washer to clean energized circuit • Inspect that work has been completed • Minimize damage to equipment • All of the above done in accordance to IEEE Standard 957 “Guide for Cleaning Insulators”

8. Additional Contamination Mitigation Tools • Sea Spray Polymer Insulator Program • Polymer insulators carry hydrophobic properties that allows moisture to bead up thus reducing tracking/leakage currents • Program consists of replacing insulators during pole replacement or new pole installation • Infrared Camera Inspection Program • When requested by the service center particular known hot spots/critical locations are scanned • Corona Camera Inspection Program • Inspections performed as necessary during fall/winter and minimally performed bi-weekly during spring/summer • Camera detects ionization of air surrounding an electrical field caused by a mixture of contaminants and water

9. ImpactWeather Study Objectives • Primary focus was on comparing the total monthly contaminated line outages reported in 2011 to a set of environmental variables that included: • Precipitation, temperature, dew point, humidity and wind speed • What contributed to the outages of 2011 • Substantially varying mean & cumulative environmental conditions • Lack of appreciable rainfall • Considerably higher than normal surface wind speeds • Conditions near or at saturation during overnight and early morning hours • Wetting due to high levels of humidity

10. ImpactWeather Study Objectives • Establish correlated–linear relationship between the following: • Line contamination incidents • Frequency and timing of natural line-washing events • Environmental variables: • Wind direction - Southeast most detrimental • Wind speed - Influences rate of deposition • Daily rain fall totals which promote insulator cleaning - Greater than 0.25” per ImpactWeather promotes insulator cleaning • A longer term goal of developing a model to predict probabilities of line-contamination outages

11. Cumulative Wind Vector (CWV) What is It? • Based on Average Daily Wind Speed and Direction NW NE 315° 0° 270° SE SW 45° 225° 90° 180° 135°

12. CWV Hypothesis TestingBack Cast Ike 9-13-2008 Rita 9-24-2005 Region of Susceptibility

13. CWV Hypothesis TestingTrending Analysis

14. Leakage Current MonitoringInitial Pilot • Had to identify 4 sites • One base station per site • 30 sensors per site • Base station & sensors within half a kilometer from each other

15. Leakage Current Monitoring Sensor Attachment Types Post Insulators Suspension Insulators

16. Leakage Current Monitoring Base Station Setup

17. Leakage Current Monitoring Objectives • Short Term • Is there an event underway with a high risk of flashover? • Medium Term • Is Washing Necessary? Can we actively predict it’s necessity? • Long Term • Is there Insulator Degradation?

18. Contamination Mitigation Lesson’s Learned & Next Steps • Program Continuous Improvement • Advanced preparation allows for both internal and external notifications • Well established Roles and Responsibilities Matrix • Ongoing review of Contamination Mitigation Program • Cumulative Wind Vector (CWV) Trending • Model refinement based on visual inspections to lead to decision making across various ops organizations built upon objective data • Notification levels and response training • Localized coastal and industrial contamination • Short-term conditional forecasting based on extended weather outlook

19. Questions