Contamination MitigationMay 8, 2014

Dan Greenwood

Asset Management Consultant

Contamination MitigationAgenda

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

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

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)

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

1.0 Contamination Mitigation Process

Op

era

tio

ns

Sta

rt 1.1 Monitor &

AnalyzeWash or Inspect?

1.2 Inspect

1.4 Wash & Inspect

1.5 Close Out

En

d

Wash?1.3 Wash With

InspectionYes

Stage Number

Stage Name Description

1.1

Monitor & Analyze

The procedure describes the steps taken to: monitor the local conditions make recommendations initiate an inspection and / or wash

1.2

Inspect The procedures describes the steps taken to: initiate the inspection coordinate the inspection perform the inspection

1.3

Wash With Inspection

The procedures describes the steps taken to: initiate the wash coordinate the wash perform the wash

1.4

Wash & Inspect

This procedure describes the steps taken to execute a wash without a prior inspection: initiate the wash and inspection coordinate the wash and inspection perform the wash and inspection

1.5

Close Out This procedure describes the administrative task necessary to formally document the actions taken in the system of record.

Purchased Washing Trailers

Water Tank Size:

535 gallons

Gas Tank Size:

10 gallons

Max PSI:

3500 PSI Gallons per Minute:

8 GPM

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”

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

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

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

Cumulative Wind Vector (CWV) What is It?

Based on Average Daily Wind Speed and Direction

SE

NW

SW

NE

180°

0°

90°135°

270°

45° 225°

315°

CWV Hypothesis TestingBack Cast

Region of Susceptibility

Rita9-24-2005

Ike9-13-2008

CWV Hypothesis TestingTrending Analysis

3/13

/201

2

3/28

/201

2

4/11

/201

2

4/27

/201

2

5/3/

2012

5/24

/201

2

5/30

/201

2

6/11

/201

2

6/27

/201

2

7/23

/201

2

8/3/

2012

8/13

/201

2

8/29

/201

2

9/12

/201

2

9/25

/201

2

11/2

0/20

12

11/3

0/20

12

3/4/

2013

3/15

/201

3

3/21

/201

3

4/15

/201

3

5/1/

2013

5/16

/201

3

5/28

/201

3

6/3/

2013

6/13

/201

3

6/21

/201

3

6/26

/201

3

7/3/

2013

7/11

/201

3

7/29

/201

3

8/21

/201

3

9/3/

2013

9/23

/201

30

20

40

60

80

100

120

140

160

180

200Visual Inspection Vector Value

Vector Reset @ ≥ 0.25" daily rainfall

Visual Inspection turned up nothing as you can see by the low score. This was dueto extremely low humidity levels experienced duringthe use of the corona camera.

Distribution began seeing pole fires in Galveston.

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

Leakage Current Monitoring Sensor Attachment Types

Post Insulators Suspension Insulators

Leakage Current Monitoring Base Station Setup

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?

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

Questions