Maintenance Management of Maintenance Management of

Transmission LinesTransmission Linesusingusing

Condition Assessment Condition Assessment andand

Computer Data AnalysisComputer Data Analysis

The New Zealand ExperienceThe New Zealand Experience____________________________________________________________

Wal Marshall : Director, LineTech ConsultingWal Marshall : Director, LineTech Consulting

22

Introducing MyselfIntroducing Myself

��Wal (Walter) MarshallWal (Walter) Marshall

��38 years in the power transmission 38 years in the power transmission

industryindustry

��28 years with NZ National Grid company 28 years with NZ National Grid company

Transpower.Transpower.

��10 years as head of Transmission Line 10 years as head of Transmission Line

engineering section at Transpower. engineering section at Transpower.

��10 years as Director and Principal 10 years as Director and Principal

consultant with LineTech Consulting >consultant with LineTech Consulting >

33

Presentation OverviewPresentation Overview��Part 1: Part 1: BackgroundBackground: LineTech,: LineTech, New Zealand, Transpower New Zealand, Transpower

��Part 2: Part 2: Problems we face inc Problems we face inc Line DiversityLine Diversity

��Part 3: Part 3: Condition assessmentCondition assessment / condition coding / condition coding

------------------

��Part 4: Part 4: Predictive modellingPredictive modelling: The basic concepts : The basic concepts

��Part 5: Part 5: EnvironmentEnvironment, and component life , and component life datadata

��Part 6Part 6:: Putting it all togetherPutting it all together

��Part 7:Part 7: Linetech SoftwareLinetech Software: Some output examples : Some output examples

��Part 8:Part 8: Summary >Summary >

44

Part 1: BackgroundPart 1: Background��LineTech Consulting.. LineTech Consulting..

�� A bit about usA bit about us…… and TLMand TLM

��New ZealandNew Zealand

�� How does it compare with Norway/Iceland?How does it compare with Norway/Iceland?

��Transpower (NZ National grid operator)Transpower (NZ National grid operator)

�� OverviewOverview

�� Terrain, line assets, problems etcTerrain, line assets, problems etc

The purpose is to set the scene for why the The purpose is to set the scene for why the

systems developed.>systems developed.>

55

LineTech Consulting LtdLineTech Consulting Ltd

�� In business for 15 years. In business for 15 years.

��LineTech are part of LineTech are part of TLMTLM Group joint ventureGroup joint venture

�� TTesla (Protection, comms , substations)esla (Protection, comms , substations)

�� LLinetech (Overhead lines)inetech (Overhead lines)

�� MMitton (Earthing specialists, substations)itton (Earthing specialists, substations)

�� Approx 60 engineers in total for Approx 60 engineers in total for TLMTLM Group.Group.

��Preferred Consultant to Transpower via Preferred Consultant to Transpower via TLMTLM

��Work throughout New Zealand, Australia and Work throughout New Zealand, Australia and

South East Asia. South East Asia.

��Specialise in HV Transmission Lines >Specialise in HV Transmission Lines >

66

New Zealand Key FeaturesNew Zealand Key Features

�� Extensive coastline = Salt pollutionExtensive coastline = Salt pollution

�� High wind run = Salt blown inlandHigh wind run = Salt blown inland

�� Much rugged mountainous terrainMuch rugged mountainous terrain

�� Geothermal areas = Localised corrosionGeothermal areas = Localised corrosion

�� Highly diverse with extreme climatic Highly diverse with extreme climatic

changes over short distances. changes over short distances.

�� Temperate climate (warm / wet = rapid Temperate climate (warm / wet = rapid

corrosion). >corrosion). >

77

NZ Transmission NZ Transmission

GridGrid350 kV HVDC Transmission

Link incl 3 Submarine

cables between Islands(1965)

��12,000 route km of lines 12,000 route km of lines

(17,000 cct km)(17,000 cct km)

��110 kV, 220kV, and 110 kV, 220kV, and

350kVDC lines.350kVDC lines.

��24,000 lattice towers, 24,000 lattice towers,

11,000 poles.11,000 poles.

��Average line asset age Average line asset age

approx 50 years.approx 50 years.

88

General Grid picturesGeneral Grid pictures220kV single circuit: 50 yrs old.2 km from coast.

Painted towers, reconductored, reinsulated (twice).

99

350kV DC. 45 yrs old.

Extensively rebuilt, twice reinsulated.

110 kV double Circuit, 35 yrs old

Towers Painted, Reinsulated twice, Reconductored.

High Wind Coastal Area: Wellington

1010

Heavy ice loadings in

mountainous areas

+350 KVDC line

Helicopters : New Zealand = 650 Norway = 120 ????

1111

220 kV towers in mountainous terrain. 40 yrs old. Painted and reinsulated.

1212

NZ Transmission Line IssuesNZ Transmission Line Issues�� High wind run =High wind run =

�� Rapid wear of insulator fittingsRapid wear of insulator fittings

�� Sea salt blown long distances inland = corrosionSea salt blown long distances inland = corrosion

�� Conductor aeolian vibration damageConductor aeolian vibration damage

�� Sea salt exposure = rapid corrosion ofSea salt exposure = rapid corrosion of�� Galvanised steel fittingsGalvanised steel fittings

�� Tower steelTower steel

�� ACSR ConductorACSR Conductor

�� High rainfall & warm climate =High rainfall & warm climate =�� Increased corrosion ratesIncreased corrosion rates

�� Geothermal areas = Geothermal areas = �� Areas of extreme localised corrosion >Areas of extreme localised corrosion >

1313

Part 2: Line Aging ProblemsPart 2: Line Aging Problems

�� Rapid line deteriorationRapid line deterioration

�� Wind, Rain, Salt, GeothermalWind, Rain, Salt, Geothermal

�� Line DiversityLine Diversity

�� Increasing condition diversity with ageIncreasing condition diversity with age

�� Other issuesOther issues

�� Poor records / asset knowledgePoor records / asset knowledge

�� Loss of skillsLoss of skills

1414

High Wind Run = Rapid wear High Wind Run = Rapid wear

1515

Wind run = Rapid wearWind run = Rapid wear

1616

Wind Blown Salt = Severe CorrosionWind Blown Salt = Severe Corrosion

1717

Severe Salt CorrosionSevere Salt Corrosion

1818

Sea salt tower steel corrosionSea salt tower steel corrosion

1919

Line Condition Diversity: A Growing IssueLine Condition Diversity: A Growing Issue

�� Line networks are no longer new: Line networks are no longer new:

�� New Zealand average age 51 yrs.New Zealand average age 51 yrs.

�� The key drivers on ageing are mostly The key drivers on ageing are mostly

environmental. environmental.

�� Environments can change drastically along a Environments can change drastically along a

single line route: coastal, industrial, geothermal, as single line route: coastal, industrial, geothermal, as

well as well as ““clean inlandclean inland””. .

�� Different components age at differing rates.Different components age at differing rates.

�� Maintenance is often piecemeal. Maintenance is often piecemeal.

�� Upgrades/deviations/storm repairs, all change bits Upgrades/deviations/storm repairs, all change bits

of lines. >of lines. >

As lines age,As lines age,

they develop ever growing they develop ever growing

component condition diversitycomponent condition diversity..

Here are some NZ examples:Here are some NZ examples:

2121

Environmental diversity: GeothermalEnvironmental diversity: Geothermal

2222

Geothermal Geothermal

Corrosion:Corrosion:

10 yrs10 yrs

2323

Environmental Diversity: CoastalEnvironmental Diversity: Coastal

Sea salt is a major problem in many areas. This section of line needed to be totally replaced after 19 years

2424

Environmental Diversity: Environmental Diversity:

Inland, Cold, Low Rainfall, Low CorrosionInland, Cold, Low Rainfall, Low Corrosion..

2525

Environmental Diversity: Environmental Diversity: High Rainfall, Geothermal drift, High CorrosionHigh Rainfall, Geothermal drift, High Corrosion

2626

Line Diversity Study:Line Diversity Study:

HVDC Line, WellingtonHVDC Line, Wellington

1

10

96

89

25

OTBHAY

1 -10 Very severe coastal. Severe wind exposure. Totally replaced with new line 1981.

All new insulation, spacers and dampers fitted in 1990 and again 2006

10-25 Moderate coastal. Reinsulated, new spacers, dampers, 1990. 4 new towers various

ages, Some duplex, triplex and Quad sections of line. Now needs reconductoring.

Original line commissioned 1965

25-45 Moderate Coastal. Several new towers various ages.

45-61 Moderate coastal: New deviation built 1990. New and 2nd hand towers.

New and 2nd-hand conductor. New insulation and dampers.

61-89 Moderately severe coastal: Approx half of towers replaced between 1980 and 1997.

Insulation, dampers and spacers replaced 1990. Now needs reconductoring.

89-96 Light Coastal: All original towers and conductor. New insulation, dampers and

spacers in 1990.

45 61

2727

Tower Condition Diversity: Actual ExampleTower Condition Diversity: Actual Example

2828

Other (Typical) IssuesOther (Typical) Issues

�� Poor records Poor records

�� Missing / poor drawingsMissing / poor drawings

�� Asset records incomplete / out of dateAsset records incomplete / out of date

�� Poor maintenance recordsPoor maintenance records

�� Very pieceVery piece--meal past maintenancemeal past maintenance

�� Very poor or inaccurate recordsVery poor or inaccurate records

�� Loss of skills and asset knowledgeLoss of skills and asset knowledge

�� Contracting out Contracting out

�� Aging workforce >Aging workforce >

2929

Ageing Diversity: SummaryAgeing Diversity: Summary

��No line ages uniformly.No line ages uniformly.

��No structure ages uniformly.No structure ages uniformly.

��Component conditions become ever more Component conditions become ever more

diverse with increasing age.diverse with increasing age.

��Ongoing maintenance changes conditionsOngoing maintenance changes conditions

��Every component on every tower can be in a Every component on every tower can be in a

different condition to those at other structures. > different condition to those at other structures. >

So why is all this importantSo why is all this important……??

3030

Future MaintenanceFuture Maintenance

��Any line is only as reliable as the weakest Any line is only as reliable as the weakest

component.component.

��The inevitable process of increasing The inevitable process of increasing

diversity, is a threat to our ability to keep diversity, is a threat to our ability to keep

lines maintained properly in the future.lines maintained properly in the future.

��Maintenance planning processes therefore Maintenance planning processes therefore

MUST MUST be able to manage extreme be able to manage extreme

diversitydiversity. >. >

3131

Part 3: Condition Assessment and Part 3: Condition Assessment and

Condition CodingCondition Coding

��Condition Assessment: IntroductionCondition Assessment: Introduction

��Condition Coding: Basic approachCondition Coding: Basic approach

��Data collection methodsData collection methods

��Condition assessment of key componentsCondition assessment of key components

�� Towers and polesTowers and poles

�� Insulation and fittingsInsulation and fittings

�� Conductor and fittingsConductor and fittings

��Accuracy and Quality: Auditing >Accuracy and Quality: Auditing >

3232

Defect vs. Condition Based MaintenanceDefect vs. Condition Based Maintenance

�� Defect based maintenance : (traditional approach)Defect based maintenance : (traditional approach)

�� Patrols/inspections concentrate on Patrols/inspections concentrate on finding defects onlyfinding defects only..

�� defects/failures recorded, trends analysed, and defects/failures recorded, trends analysed, and

�� maintenance effort directed to locations with unacceptable ratesmaintenance effort directed to locations with unacceptable rates

of failures/defects.of failures/defects.

�� Condition based maintenance: (Current approach)Condition based maintenance: (Current approach)

�� Data collected on condition of Data collected on condition of allall line components.line components.

�� Analysis of condition of total asset possible. Analysis of condition of total asset possible.

�� maintenance work can be optimized to achieve any performance maintenance work can be optimized to achieve any performance

outcome desired.outcome desired.

�� maintenance work can be optimized to minimise overall long maintenance work can be optimized to minimise overall long

term cost or use of resources. >term cost or use of resources. >

Condition Driven Maintenance Condition Driven Maintenance

means that you canmeans that you can

Plan what will happenPlan what will happen(Proactive; No surprises, Low cost, High Reliability )

rather thanrather than

React to what did happenReact to what did happen(Reactive; Frequent call outs, High cost,(Reactive; Frequent call outs, High cost,

Low reliability)Low reliability)

3434

Its worth putting time and effort Its worth putting time and effort

into getting good condition datainto getting good condition data

CONDITION

DATA

Current and

Impending Work

Medium Term

Work Identification

Long-term Work

Load (Predictive

trending)

Secure Asset

Valuation

System

Planning

Purchase and

Warehousing

Planning

Manpower

Planning

3535

Condition Assessment: Basic ApproachCondition Assessment: Basic Approach

��Done 3Done 3--8 yearly. Frequency depends on 8 yearly. Frequency depends on --�� Condition (if poor done more frequently) alsoCondition (if poor done more frequently) also

�� Type, age and system ImportanceType, age and system Importance

��Only dedicated teams usedOnly dedicated teams used�� Specialist trained contractorsSpecialist trained contractors

�� NOT regular linemenNOT regular linemen

�� Asset Data accuracy is checked on siteAsset Data accuracy is checked on site�� Correct tower, insulation, spacers, etc. Errors corrected.Correct tower, insulation, spacers, etc. Errors corrected.

��Aim is to maximise the productivity of a single Aim is to maximise the productivity of a single visit to site. visit to site.

��Overall cost similar to traditional climbing Overall cost similar to traditional climbing inspection, butinspection, but

��Vastly more data is gathered. >Vastly more data is gathered. >

3636

Condition Assessment: Basic ApproachCondition Assessment: Basic Approach

��All key components coded individuallyAll key components coded individually�� E.g. Tower top, tower bottom, foundation ea, E.g. Tower top, tower bottom, foundation ea,

��Smaller components grouped e.g.Smaller components grouped e.g.�� All insulators string in stringAll insulators string in string

�� All conductors in a spanAll conductors in a span

�� All spacers in a span, all dampers in a span etcAll spacers in a span, all dampers in a span etc

��Worst component in any group drives overall Worst component in any group drives overall

codingcoding

�� All condition codes are dated >All condition codes are dated >

3737

Condition Coding: Basic ApproachCondition Coding: Basic Approach

�� Coding based on % of deterioration.Coding based on % of deterioration.

�� 100% = new100% = new

�� 60% = half of service life60% = half of service life

�� 20% = normal last replacement point20% = normal last replacement point

�� 10% = no safely factor left10% = no safely factor left

�� 0 % = imminent failure under 0 % = imminent failure under ““every dayevery day””

loads. >loads. >

3838

Condition Coding ConceptCondition Coding Concept

Field

Condition

Code

%

Years from new

100

0

20

60

40

80

Replacement Criteria

Halfway through

service life

New Component

Imminent

FailureIncreasing risk of failure

10No safety factor left

0

Slope of this line depends on the environment;

(Steeper for more aggressive environments)

Tr

>>>> Service life >>>>

3939

Data Collection MethodsData Collection Methods

�� Transpower sets Coding Criteria to ensure Transpower sets Coding Criteria to ensure uniformity across networkuniformity across network

�� Contractors use mixture of electronic data Contractors use mixture of electronic data recorders, and paper .recorders, and paper .

��Early problems with data recordersEarly problems with data recorders�� Hardware reliabilityHardware reliability

�� Crude interface and programmingCrude interface and programming

�� User resistance, but User resistance, but …………

�� Increasing trend towards data recorders due to Increasing trend towards data recorders due to cost savings in data uploading, and reduction in cost savings in data uploading, and reduction in loading errors. >loading errors. >

4040

Example: Condition coding of tower steelExample: Condition coding of tower steel

We use a mixture of text

and pictures to set coding

criteria for inspectors,

backed up by training.

4141

Tower steelTower steel

�� Top usually Top usually

worse than bottomworse than bottom

�� Zinc thickness Zinc thickness

measurement measurement

problematicproblematic

�� Corrosion layers Corrosion layers

vary with climatevary with climate

��Visual inspection Visual inspection

mostly usedmostly used

4242

Tower FoundationsTower Foundations��GrillagesGrillages

�� Sample excavationsSample excavations

�� Corrosion current testing tried, and discarded Corrosion current testing tried, and discarded –– to to unreliable.unreliable.

��ConcreteConcrete�� BaseBase--plates plates –– Visual + chip out mortar on samplesVisual + chip out mortar on samples

�� StubStub--legs legs -- VisualVisual

��Piled (river crossings)Piled (river crossings)�� Concrete and steel VisualConcrete and steel Visual

�� Timber with concrete caps. Partial excavate 10 yrly Timber with concrete caps. Partial excavate 10 yrly Preservative Injection systems installed. >Preservative Injection systems installed. >

4343

Tower Foundations: Ground LevelTower Foundations: Ground Level

�� Visual Visual

InspectionsInspections

�� Rusting / Metal Rusting / Metal

loss measuredloss measured

��Below ground Below ground

concrete not concrete not

evaluated >evaluated >

4444

Timber Piled FoundationsTimber Piled Foundations

(Preservative Injection systems)(Preservative Injection systems)

4545

Grillage FoundationsGrillage Foundations

�� Ages from 30 years to Ages from 30 years to over 80 yearsover 80 years

��Worst corrosion usually Worst corrosion usually at ground levelat ground level

�� Sample excavations to Sample excavations to establish conditionestablish condition

4646

Timber Poles and ArmsTimber Poles and Arms

��Wide variety of testing optionsWide variety of testing options

��Mostly still use excavate 600 mm Mostly still use excavate 600 mm and drill + visual/probe.and drill + visual/probe.

��Some use of ultra sound devices.Some use of ultra sound devices.

�� Excellent Australian study on Excellent Australian study on hardwood poles showed older hardwood poles showed older poles without observable defects poles without observable defects were 50% weaker than calc were 50% weaker than calc strength. strength.

��Timber poles being replaced with Timber poles being replaced with concrete and steel.concrete and steel.

��Timber arms being replaced with Timber arms being replaced with RHS steel. >RHS steel. >

4747

Concrete Poles Concrete Poles -- PrestressedPrestressed��Long lifeLong life

��Visual inspection only Visual inspection only

��External signs of deterioration External signs of deterioration only appear towards the end of only appear towards the end of lifelife

��Life limited by spalling usually Life limited by spalling usually above groundabove ground

��Hairline cracks Hairline cracks ��chunks chunks broken out.broken out.

��New technologies available to New technologies available to measure corrosion of measure corrosion of embedded reinforcing and/or embedded reinforcing and/or concrete stress. >concrete stress. >

4848

Insulation: CeramicInsulation: Ceramic

��50% Porcelain, 50% glass 50% Porcelain, 50% glass

��Visual inspection Visual inspection

��Replacement driven mainly Replacement driven mainly

by fitting corrosion.by fitting corrosion.

��Very little problems with Very little problems with

porcelain punctures or porcelain punctures or

cracking. >cracking. >

4949

Insulation: CompositeInsulation: Composite

��Mostly Silicone RubberMostly Silicone Rubber

��Visual inspection only.Visual inspection only.

��Multiple potential failure modes. Multiple potential failure modes.

(Some visible, some are not).(Some visible, some are not).

��Spray droplet test also used for Spray droplet test also used for

hydrophobicity to check shed aginghydrophobicity to check shed aging

��No serious problems encountered No serious problems encountered

to date, but to date, but …….. ..

��All first generation units have been All first generation units have been

removed.removed.

5050

Insulator FittingsInsulator Fittings�� Two Failure mechanisms Two Failure mechanisms --

1.1. CorrosionCorrosion

�� Replaced when seizedReplaced when seized

�� Or loss of cross sectionOr loss of cross section

2.2. Wear (moving joints)Wear (moving joints)

�� Top and bottom of suspension Top and bottom of suspension

stringsstrings

�� Wind run drivenWind run driven

3.3. Joints assessed by visual Joints assessed by visual

inspection + sample removal inspection + sample removal

and disassembly. >and disassembly. >

5151

Conductor Conductor �� CopperCopper

�� Visual + Samples removed for testing for annealingVisual + Samples removed for testing for annealing

�� ACSR: GZ (Mostly Greased)ACSR: GZ (Mostly Greased)

�� Lots of problems with corrosion.Lots of problems with corrosion.

�� Visual inspection for bulgesVisual inspection for bulges

�� Cormon corrosion detector (selected sites)Cormon corrosion detector (selected sites)

�� Removal of samples for internal inspectionRemoval of samples for internal inspection

�� Recent problems with grease Recent problems with grease ““holidaysholidays””..

�� Vibration damage at some sites.Vibration damage at some sites.

�� ACSR AC (Greased)ACSR AC (Greased)

�� Very long life even in extreme environmentsVery long life even in extreme environments

�� Only vibration damage found. Only vibration damage found.

�� Steel conductors: Visual inspection onlySteel conductors: Visual inspection only

�� No AAAC (Yet) No AAAC (Yet)

5252

ACSR CorrosionACSR Corrosion……�� Lots of problems and 1000Lots of problems and 1000’’s of km of conductor s of km of conductor

replaced.replaced.

�� Average life to replacement in coastal areas only Average life to replacement in coastal areas only 2020--25 yrs25 yrs

�� Note: All new and replacement conductor is ACSR AC Note: All new and replacement conductor is ACSR AC (Greased.) >(Greased.) >

5353

ACSR Grease HolidaysACSR Grease Holidays

�� Gaps in grease coating on core wireGaps in grease coating on core wire

�� Caused by manufacturing quality controlCaused by manufacturing quality control

�� Results in unpredictable early corrosion Results in unpredictable early corrosion

failuresfailures

�� Cormon being used to find them >Cormon being used to find them >

5454

Cormon Corrosion Cormon Corrosion

TesterTester

�� Used to find grease Used to find grease

holidaysholidays

��Used on older ACSR Used on older ACSR

to confirm sampling to confirm sampling

results. >results. >

5555

Cormon Sample Test ResultCormon Sample Test Result

Result of a scan on 101 m span, showing a 3 m Result of a scan on 101 m span, showing a 3 m ““grease holidaygrease holiday”” at start .at start .

5656

DampersDampers

�� Life varies widely (10Life varies widely (10--30 yrs)30 yrs)

�� Life limited by corrosion of messenger wire orLife limited by corrosion of messenger wire or

�� Fatigue of Messenger wire (as below)Fatigue of Messenger wire (as below)

�� Drooping = damper is past end of useful life >Drooping = damper is past end of useful life >

Fatigue Crack

5757

JointsJoints

��Multiple joint deterioration Multiple joint deterioration

processes.processes.

�� Internal corrosion, thermal Internal corrosion, thermal

cycling, ice jacking etccycling, ice jacking etc

��Resistance measurements Resistance measurements

used. Good results.used. Good results.

��Resistances measured live.Resistances measured live.

��Random sampling + every joint Random sampling + every joint

on highly loaded circuits.on highly loaded circuits.

�� Thermal imaging not used Thermal imaging not used

much. much. (End of life detection only)(End of life detection only)

�� Problems encountered >Problems encountered >

5858

Live Line Joint Resistance Measurement. Live Line Joint Resistance Measurement.

220 kV: (Ohmstick)220 kV: (Ohmstick)

5959

Improving Condition Data QualityImproving Condition Data Quality

�� Dedicated inspectorsDedicated inspectors

�� Good Training Good Training

�� Good coding guidesGood coding guides

�� Electronic data collectionElectronic data collection

�� Top down reviews of the dataTop down reviews of the data

�� On site audits of data qualityOn site audits of data quality

�� Feedback to inspectors. >Feedback to inspectors. >

6060

Part 4: Predictive Modeling Part 4: Predictive Modeling

�� What is it ? What is it ?

�� Why do it ?Why do it ?

�� What are the basic concepts?What are the basic concepts?

�� What data is required?What data is required?

�� What can you get out? >What can you get out? >

6161

Predictive Modeling : What is it?Predictive Modeling : What is it?

�� A method of looking forward in a A method of looking forward in a

structured waystructured way using the best combined knowledge we have today

to

�� PredictPredict what the pattern of future what the pattern of future

maintenance will look like, and maintenance will look like, and

�� Get feel for future costs & resourcing Get feel for future costs & resourcing

�� Value the assets >Value the assets >

6262

Why? : The big ask!Why? : The big ask!

Management want the following :Management want the following :

1.1. A 10 year maintenance plan, (+20 yr outlook?)A 10 year maintenance plan, (+20 yr outlook?)

2.2. Detailed line by line. Detailed line by line.

3.3. Detailed by Detailed by twrstwrs, , fndsfnds, insulation, conductor etc, insulation, conductor etc

4.4. Costed yr by yr by line & component group.Costed yr by yr by line & component group.

5.5. Costs broken by components and labour.Costs broken by components and labour.

6.6. Plan must stand up to external audit.Plan must stand up to external audit.

7.7. State the condition of each line and allocate an State the condition of each line and allocate an

asset value and effective remaining life based asset value and effective remaining life based

on condition. >on condition. >

EasyEasy……...????........NOT!...????........NOT!

6363

Why .. isnWhy .. isn’’t it easy?t it easy?

��Huge volume of assets. (17,000 structures NZ) Huge volume of assets. (17,000 structures NZ)

��Lines from new to over 80 years old. (NZ)Lines from new to over 80 years old. (NZ)

��Piecemeal past maintenance Piecemeal past maintenance

��Poor or no records of past maintenance.Poor or no records of past maintenance.

��Poor / unreliable (or no) condition information.Poor / unreliable (or no) condition information.

��Lines / component conditions vary widely.Lines / component conditions vary widely.

��Aging process driven by environment not age.Aging process driven by environment not age.

��Very diverse environmentsVery diverse environments

��Component types aging at different ratesComponent types aging at different rates

��Loss of asset skills and knowledge. >Loss of asset skills and knowledge. >

6464

Basic ConceptsBasic Concepts

�� If we know what we have now, and If we know what we have now, and

�� We know what condition its in now, andWe know what condition its in now, and

�� We know how it agesWe know how it ages……

�� And what it costs to repair..And what it costs to repair..

then a computer programme can -

�� Predict how fast each part will agePredict how fast each part will age

�� Tell us when it is likely to need repair, andTell us when it is likely to need repair, and

�� What it will cost to repair.What it will cost to repair.

�� And it can tell us a lot more as well! >And it can tell us a lot more as well! >

6565

Big PictureBig Picture

1. ASSET DATA Per Line Fixed.

2. CONDITION DATA Per Line Live.

3. ENVIRONMENT DATA Per Line Fixed.

4. COMPONENT LIFE DATA System wide Fixed.

6. COST DATA System wide Fixed.

5. DECISION TREES System wide Fixed.

PREDICTIVE REPORTING

6666

Output InformationOutput Information

�� Maintenance can be predicted as far into Maintenance can be predicted as far into the future as you want. (e.g. 50 yrs!)the future as you want. (e.g. 50 yrs!)

�� Cost detailed by year, line, tower and Cost detailed by year, line, tower and component.component.

�� Costs broken by labour and materials.Costs broken by labour and materials.

�� An effective remaining An effective remaining ““engineering lifeengineering life””for each line asset.for each line asset.

�� An engineering valuation based on An engineering valuation based on overall line condition.overall line condition.

��And moreAnd more……. >. >

6767

What ValueWhat Value…….?.?

��All output is based on set criteria that can be All output is based on set criteria that can be

auditedaudited

��Whole network evaluated on a single set of Whole network evaluated on a single set of

assumptions that can be easily changed if assumptions that can be easily changed if

required.required.

��All opinions and input data are visible All opinions and input data are visible

�� Future materials and manpower resourcing trends Future materials and manpower resourcing trends

become visible become visible

��Powerful Powerful ““what ifwhat if”” tool. (e.g. this route or that)tool. (e.g. this route or that)

��Entire network can summated into a single page. Entire network can summated into a single page.

>>

6868

50 yr Network Wide Prediction..50 yr Network Wide Prediction..

6969

Presentation Road MapPresentation Road Map��Part 1: Part 1: Background onBackground on New Zealand, Transpower New Zealand, Transpower

��Part 2: Part 2: Problems we facedProblems we faced

��Part 3: Part 3: Condition assessment / condition codingCondition assessment / condition coding

��Part 4: Part 4: Predictive modeling: The basic concepts Predictive modeling: The basic concepts

��Part 5: Part 5: Environment and component dataEnvironment and component data

��Part 6Part 6:: Putting it all togetherPutting it all together

��Part 7:Part 7: Linetech Software: Some output examples Linetech Software: Some output examples

��Part 8:Part 8: SummarySummary

7070

Part 5: Environment & Component Part 5: Environment & Component

DataData

�� Defining and collecting environment dataDefining and collecting environment data

�� Defining component livesDefining component lives

�� Component replacement tablesComponent replacement tables

�� Repairs & replacements Repairs & replacements

�� Costs: Costs:

�� Labour and Labour and

�� Materials >Materials >

7171

Environment data : What types?Environment data : What types?

�� CorrosivityCorrosivity–– (Zinc loss rates):(Zinc loss rates):

�� Towers, fittings, ACSRTowers, fittings, ACSR

�� Rainfall : Rainfall :

�� Towers, wood poles and arms, Towers, wood poles and arms,

�� Wind run : Wind run :

�� Suspension hot and cold ends, dampers. Suspension hot and cold ends, dampers.

�� Soil resistivity/acidity :Soil resistivity/acidity :

�� Grillage foundations >Grillage foundations >

7272

Defining EnvironmentsDefining Environments

�� Precision not necessary, or possible !Precision not necessary, or possible !

�� Environments change from year to year Environments change from year to year

(more so recently (more so recently -- global warming?)global warming?)

�� Even at a single tower site environment Even at a single tower site environment

will change with tower height .will change with tower height .

�� Reasonable to define general Reasonable to define general

environment from tower site to tower site environment from tower site to tower site

7373

Environment data: Where from?Environment data: Where from?

��National corrosion mapsNational corrosion maps

��National rainfall mapsNational rainfall maps

��National wind run, speed & direction dataNational wind run, speed & direction data

��National soil type mapsNational soil type maps

��Physical observations on sitePhysical observations on site

��Distance from coast / geothermal ventsDistance from coast / geothermal vents

��Observation of actual component aging at Observation of actual component aging at

each site. each site. (Very useful) >(Very useful) >

7474

Corrosion Corrosion

MapsMaps

�� Useful as a Useful as a general guide general guide onlyonly

�� Individual Individual tower sites tower sites can vary can vary greatly.greatly.

��Adjacient Adjacient sites can be sites can be markedly markedly different >different >

7575

Rainfall Rainfall

Maps Maps

�� Some Some correlation correlation with with corrosion corrosion mapsmaps

�� Useful to Useful to know the know the likely likely number of number of wet/dry wet/dry cycles.cycles.

7676

On site aging observationsOn site aging observations

�� If we knowIf we know

�� When any component was installed new, When any component was installed new,

�� andand

�� We can measure its current condition (say We can measure its current condition (say

after 10 years) after 10 years)

�� Then we can define the environment quite Then we can define the environment quite

accuratelyaccurately

�� Corrosion factor is determined this way. >Corrosion factor is determined this way. >

7777

Environment data coding.Environment data coding.

�� Basic environment coding approach similar to condition data ie

� Benign environment = 100 (1) (CF > 100)

� Moderate environment = 50 (.5) (CF = 60)

� Severe environment = 10 (.1) (CF < 30)

� “Corrosion factor” used only for Zinc loss corrosion. >. >

7878

Environmental Coding for Zinc LossEnvironmental Coding for Zinc Loss

Y e a rs to g a lv a n is in g

fa ilu re

(F ro m 6 0 0 g m s/m 2 )

Z in c lo ss ra tes

p er y ea r

(g m s/m 2 /y r )

E n v iro n m en t

C o d e

1 0 0 6 1 .0

8 0 7 .5 0 .8

6 0 1 0 0 .6

4 0 1 5 0 .4

2 0 3 0 0 .2

1 0 6 0 0 .1

5 1 2 0 0 .0 5

7979

How long do line components last ??How long do line components last ??

�� Accountants: 40 years for everything!!Accountants: 40 years for everything!!

�� Managers : As long as they are in the job Managers : As long as they are in the job --

(and if they don(and if they don’’t it will be your fault!)t it will be your fault!)

�� Engineers however know that Engineers however know that --

Line component life is entirely dependent on the environment! >

8080

Defining Component livesDefining Component lives

�� To look ahead we need to know how long To look ahead we need to know how long

each component will last in various each component will last in various

environmentsenvironments

��Benchmark data usually available from Benchmark data usually available from

actual field experience.actual field experience.

��Gaps filled in from common sense, best Gaps filled in from common sense, best

guess until better info available. >guess until better info available. >

8181

Age Age vsvs Environment TableEnvironment Table

�� To define how long items are expected to To define how long items are expected to

last in service, a table was used last in service, a table was used

�� For each component type the table For each component type the table

related age, and environment to the related age, and environment to the

maximum life to replacement point.maximum life to replacement point.

�� Relationships are sometimes complex Relationships are sometimes complex

and often non linear. >and often non linear. >

8282

Component Life to Replacement Component Life to Replacement

Point Point vsvs EnvironmentEnvironment

100806550372720151063Galv Steel Earthwire:

2201601309980655040353025ACSR AC Greased

8875605040322520151210ACSR GZ Greased

60504035302520151286ACSR GZ Ungreased

756555453530231814945Hot & cold hardware: Galv

70605040332620151284Insulator : Glass/porcelain

12010080655038282015105Tower steel bare

1009080706050403020105Environment Code %

BenignModerateSevere

Environmental Driver : CorrosivityAGE (YRS) AT

REPLACEMENT CRITERIA

8383

Component Life Component Life vsvs Environment Environment

Relationship is usually non linear.Relationship is usually non linear.

8484

Replacement tablesReplacement tables

When an item needs replacing or maintaining, When an item needs replacing or maintaining, we define what happens in a table we define what happens in a table

OPGW 40%GZ Earthwire

ACSR AC Conductor30%ACSR GZ Conductor

Concrete Pole25%Wood Pole

Steel RHS crossarm30%Wooden Crossarm

Composite Insulator30%Glass Insulator String

Damper20%Damper

Replacement ItematOriginal Item

8585

When a component needs to be When a component needs to be

maintainedmaintained (not replaced)(not replaced)

�� Maintenance action can be set to any point in Maintenance action can be set to any point in

aging cycle (Condition code) e.g.aging cycle (Condition code) e.g.

�� Tower at 60% = Painted tower.Tower at 60% = Painted tower.

�� Grillage Foundation at 40% = Blast and zinc Sprayed Grillage Foundation at 40% = Blast and zinc Sprayed

foundation.foundation.

�� Stub Leg foundation at 50% = Blast and painted stub.Stub Leg foundation at 50% = Blast and painted stub.

�� Maintenance action is treated just like a Maintenance action is treated just like a

replacement. The maintained item has new replacement. The maintained item has new

defined remaining life. >defined remaining life. >

8686

Decision TreesDecision TreesDecision trees set correct maintenance actions:

Example below is for tower painting

8787

Maintenance CostsMaintenance Costs

�� Costs are defined in a table for all Costs are defined in a table for all

maintenance actions; replacement and maintenance actions; replacement and

maintenancemaintenance

�� Costs are allocated against each item as Costs are allocated against each item as

�� Labour (Lineman hours + Engineering hours)Labour (Lineman hours + Engineering hours)

�� Materials (Imported from stock system)Materials (Imported from stock system)

�� Labour costs / hr are set centrally so Labour costs / hr are set centrally so

regular changes can be applied globally. >regular changes can be applied globally. >

8888

Summary: What data do we need?Summary: What data do we need?1.1. Comprehensive asset data. Comprehensive asset data.

�� What is at each tower site and in each spanWhat is at each tower site and in each span

2.2. Condition data on all Condition data on all ““key componentskey components””�� Condition data must be date codedCondition data must be date coded

3.3. Environment data Environment data �� For every tower siteFor every tower site

4.4. Component life data tablesComponent life data tables�� How long each item lasts in each environmentHow long each item lasts in each environment

5.5. Replacement tables. Replacement tables. �� What each item is replaced with/repaired with each time it What each item is replaced with/repaired with each time it

needs work.needs work.

�� At what point in the component life it is replaced/repaired. At what point in the component life it is replaced/repaired.

6.6. Cost data for each componentCost data for each component�� Labour and materials per Labour and materials per ““changechange””. .

Note: Mostly static data except item 2 . >

8989

Storing Lines Data.Storing Lines Data.

9090

Conceptual Data FlowsConceptual Data Flows

Central database

to hold all lines

related data:

(Asset data &

Condition data.)

Field based

data

collection

&

validation

system

Software to

build

management

reports

9191

Data flows: More detailData flows: More detail

Condition

data from

Field

Assessment.

3-8 yearly

rolling

update.

Environment

coding

from each

structure

site

Line and

Structure

Asset data

Component

condition

data

Tables of

Standard

components

and costs

Structure

environment

codes

Frozen data

“Snapshot”

containing

all required

modeling

data

Data

Record

Archived

Defined output

parameters: e.g. time

span to be modeled,

components covered,

report format etc.

Table of standard

replacement

components, and

costing data

Table of component

lives in each defined

environment

Field

data

“Main”

databaseLine Model Database and Software

Output

File or

report

Live data

LINE

MODEL

SOFT-

WARE

Modeling data

9292

Example: End of life calculation Example: End of life calculation

�� Replacement date = Assessment date + Remaining LifeReplacement date = Assessment date + Remaining Life

�� Remaining Life = Max life x Environment code x Condition Remaining Life = Max life x Environment code x Condition

code code

�� Example:Example:

��An insulator string was last inspected in An insulator string was last inspected in 19931993

�� It was assessed as being slightly more than halfway through its It was assessed as being slightly more than halfway through its life; life;

equivalent to a condition code of 50% or equivalent to a condition code of 50% or 0.5.0.5.

��When new, the string is capable of lasting When new, the string is capable of lasting 5555 years in a benign years in a benign

environment (i.e. with a code of 1.0)environment (i.e. with a code of 1.0)

��The actual environment code is more aggressive = The actual environment code is more aggressive = 0.750.75

Therefore:Therefore:

��Replacement date = Replacement date = 1993 + (55 x 0.75 x 0.5 = 21) = 2014.1993 + (55 x 0.75 x 0.5 = 21) = 2014.

�� Note that the Note that the ““new installnew install”” date is not required. date is not required. >>

9393

Some Reporting ExamplesSome Reporting Examples�� Line / component condition (now) Line / component condition (now)

�� Line / component future replacement and cost profile Line / component future replacement and cost profile

�� Line or whole of Network future cost prediction over any Line or whole of Network future cost prediction over any future time frame.future time frame.

�� Material requirement prediction by component type / line / Material requirement prediction by component type / line / across network over any future time frameacross network over any future time frame

�� Manpower requirement prediction by lineman & engineer by Manpower requirement prediction by lineman & engineer by line or across network, over any future time frame.line or across network, over any future time frame.

�� What if studies: If we build that line on route A What if studies: If we build that line on route A vsvs Route B Route B what will the long term maintenance costs be?what will the long term maintenance costs be?

�� What is the remaining life of a line? (Calc value weighted What is the remaining life of a line? (Calc value weighted average remaining life of all components)average remaining life of all components)

�� What is the remaining What is the remaining ““valuevalue”” of a line ? (Sum all of a line ? (Sum all components depreciated in proportion to remaining age)>components depreciated in proportion to remaining age)>

9494

Hot end fitting condition by tower.Hot end fitting condition by tower.

0

10

20

30

40

50

60

70

80

90

100

1 3 5 7 9 11 13 15 17 18 20 22 24 26 28 30

% Remaininglife.

Tower Number

New

Failure

%

Worn

9595

Actual Condition ReportActual Condition Report

9696

1 0 0 % 7 0 % 4 0 % 1 0 %

T o w e r s

F o u n d a t i o n s

I n s u l a t i o n

H a r d w a r e

C o n d u c t o r

D a m p e r s

S p a c e r s

E a r t h w i r e

0

2 0

4 0

6 0

8 0

1 0 0 % 7 0 % 4 0 % 1 0 %

T o w e r s

F o u n d a t i o n s

I n s u l a t i o n

H a r d w a r e

C o n d u c t o r

D a m p e r s

S p a c e r s

E a r t h w i r e

T o w e r s

F o u n d a t i o n s

In s u l a t i o n

H a r d w a r e

C o n d u c t o r

D a m p e r s

S p a c e r s

E a r t h w i r e

Bunnythorpe -

H enderson Line A

Line condition

Sum m ary

M ay 96

Component Condition

Condition of a whole LineCondition of a whole Line

9797

50 Year Network Wide Cost Prediction50 Year Network Wide Cost Prediction

9898

Line by Line Work PlanLine by Line Work Plan

��Detailed list of work required on either the Detailed list of work required on either the

total line or structure by structure.total line or structure by structure.

��Numbers of components requiring work. Numbers of components requiring work.

Where and when.Where and when.

��Estimated first order costs for the workEstimated first order costs for the work

��Year by year prediction to any future time Year by year prediction to any future time

period. >period. >

9999

Future Maintenance Cost Future Maintenance Cost

ComparisonComparison

Inland vs Coastal Route Maint Cost Comparison

0

500

1000

1500

2000

2500

3000

3500

5 30 55 80 105

Years

Cu

mu

lati

ve

Co

st Route 1

Coastal

Route 2

Inland

100100

Predictive Modeller SoftwarePredictive Modeller Software

�� This is a stripped down demo version. The original runs This is a stripped down demo version. The original runs on a mainframe system. on a mainframe system.

�� This was compiled to run on a laptop under Windows This was compiled to run on a laptop under Windows with a small database of one line. (Normally data would with a small database of one line. (Normally data would be pulled off a server on a network. be pulled off a server on a network.

101101

Presentation SummaryPresentation Summary�� As lines age they will not only deteriorate but become As lines age they will not only deteriorate but become

increasingly diverse in condition and construction.increasingly diverse in condition and construction.

�� The task of managing maintenance will become The task of managing maintenance will become evermore more complex.evermore more complex.

�� Maintenance bust be able to manage diversity Maintenance bust be able to manage diversity

�� Detailed condition assessment data is essential to enable Detailed condition assessment data is essential to enable sound forward planning in diverse systems without loss sound forward planning in diverse systems without loss of reliability.of reliability.

�� A computerised line model can give you A computerised line model can give you --�� a view of where you are going, and the costsa view of where you are going, and the costs

�� allow you to optimize your maintenance management toallow you to optimize your maintenance management to

�� achieve the reliability and cost targets you wantachieve the reliability and cost targets you want

�� allow you to value your assets consistently. allow you to value your assets consistently.

�� Plan future resourcing Plan future resourcing

�� You can see where you are going! >You can see where you are going! >