Transmission & Distribution Overhead

Line Network Inspections and

Maintenance

• Dr Willie de Beer

• Independent Consultant

• South Africa

Presentation Overview

• Transmission & Distribution Lines in Context

• Overhead Line Planning & Design

• Managing Overhead Lines

– Legal and Regulatory

– Asset Strategy

– Maintenance Philosophy

– Technology Deployment

– Resource Requirement

• Future Perspective

Transmission & Distribution Lines

Context…1

• Globally the Electricity Supply Industry (ESI)

experience changes & challenges.

• Some of the ESI challenges includes, but are not limited to:

– Investor requirements

– Shareholder expectations

– Customer expectations

– Business sustainability

– Capital investment requirements

– Operating costs

– Ageing assets

– Environmental requirements

Transmission & Distribution Lines Context…2

• Transmission and Distribution overhead lines define

the utility footprint & opportunities.

• Overhead lines represent a substantial portion of the

utility asset value.

• The effective performance of the Transmission and

Distribution overhead lines significantly impacts on

the revenue earning capability of an electricity utility.

• The ESI is at risk where the focus is dominated by a

generation capacity concern without a holistic ESI

view.

• New market entrants are shaping tomorrow.

ESI Challenges

The “Five Big” Utility Challenges

Overhead Line Planning and Design

Transmission & Distribution

Interdependency

Source: Aurecon

Performance, Capacity & Ageing

Overhead Line Planning and Design…1

• Resource selection

– Relevant experience

– Understanding of the environment

• Future perspective

• Current asset performance

• Topography

• Line profiling & routing

• Structure design

• Foundation design

• Etc.

Overhead Line Planning and Design…2

• Infrastructure requirement

– New Infrastructure

– Planning for Renewal/Upgrading

– Replacement

• Asset life-cycle costs.

Overhead line indicative cost ratio

• While there are many factors such as the operating voltage, structure selection, foundation requirements, terrain, etc influencing the cost of an overhead line, the following reflects an indicative ratio:

– Foundation 25%

– Structure 30%

– Conductor 25%

– Hardware 10%

– Design, etc. 10%

Dominant Faults Fault Transmission Distribution

Lightning related

Insulator related

Veld fires

Vegetation

Conductor

“clashing”

Connections

Pollution

Vandalism

Wildlife Related Willie de Beer & Associates

Managing Overhead Lines…1

• Overhead lines form an integral part of the utility asset base and must be managed as such.

• Procurement “errors,” ineffective line design and bad construction cannot be corrected through maintenance.

• Critical indicators:

– Line availability

– Line reliability

– Capacity/load transfer capability

– Technical losses

– Customer satisfaction

– Technical support

– Operating cost

Managing Overhead Lines…2

• Legal & Regulatory compliance

– Regulated business

– Health, Safety & Environmental compliance

• Asset management strategy

– Asset life cycle

• Design

• Specification

• Procurement

• Construction

• Commission

• Operate

• Retire

– Maintenance philosophy

• Frequency based vs predictive reliability/ performance based/etc.

Managing Overhead Lines…3

• Line working procedures.

• Performance monitoring, benchmarking &

reporting.

Basic Inspection Requirements

• Defined line inspection plan.

• Sound knowledge of the relevant overhead

lines, structures, components and route.

• Correct equipment to:

– Access

– Inspect

– Evaluate/Assess

– Communicate

– Record

• Knowledge of the relevant servitude/way leave

conditions.

Basic Maintenance Requirements…1

• Asset register.

• Network/plant location.

• Defined asset management strategy.

• Supporting line management & maintenance

plan.

• Emergency/restoration plan.

• Supporting budget.

• Pre-job assessment.

• Critical task assessment and procedures.

Basic Maintenance Requirements…2

• Line/structure specific task breakdown.

• Defined specialist tasks.

• Material, equipment, tools and skilled

resources to maintain what was

constructed.

• Sound understanding of the application of

project management principles.

Basic Maintenance Requirements…3

• Maintenance planning & execution must

be informed by:

– Legal, regulatory, health, safety and

environmental requirements

– Network performance statistics/reports

– Line inspection reports

– Selection of maintenance execution approach

• Effective recording.

Maintenance Prioritisation

• Legal and regulatory non-compliance.

• Probability of failure.

• Consequences of failure.

• Environmental, health and safety.

• Worst served customers/section/plant.

• Interruptions/100 customers.

• Faults/100 km.

• Customer hours lost.

Maintenance Recording

• It is essential to record factors such as:

– Reliability.

– Failure rates.

– Specific problems.

– Generic problems.

– Design issues.

– Environmental factors etc.

– Recommended next steps/corrective action.

• Date of maintenance.

• Maintenance executed.

Managing Overhead Lines through

Technology Deployment

• In most jurisdictions the demand for electricity is

creating an expansion of the transmission and

distribution footprint.

• Considering the complexity and cost to manage the

lines, technology deployment becomes a logic

choice.

• The benefits to be derived through technology

deployment includes:

– Real time information

– Ability to facilitate proactive asset management

– Optimised resource deployment

– Higher network availability

Subsidence Monitoring

Source: CSIR

Drone Inspection

Return on Asset

Source: SANEDI

Future Perspective…1

• Overhead Lines are here to stay.

• The assets are ageing and this aspect must be

taken into account in defining the asset

management strategy.

• Advanced technology deployment is required to

manage the overhead lines effectively.

• It is essential that overhead networks must

provide open access to IPP’s and prosumers.

• The future will dictate the need for unbundling of

the wires and energy component of the tariffs.

Future Perspective…2

• Considering the network loading, customer

expectations and revenue requirements; it is to be

expected that live/hot work will become the name

of the game.

• Advanced training and development of resources

will be required to satisfy the future skill set

requirements.

• Acquiring servitudes and way leaves will become

even more challenging.

Future Perspective…3

• The historic approach to the management of

transmission and distribution entities is at risk.

• Opportunity to leverage the overhead line

footprint to generate alternative revenue

streams.

• Leverage your overhead line knowledge in the

rate cases submission.

THANK YOU

Acknowledgement

• Aurecon

• Africoast

• Hawk 62

• CSIR

• SANEDI

• Willie de Beer and Associates