1.
Transmission & Distribution Overhead
Line Network Inspections and
Maintenance
• Dr Willie de Beer
• Independent Consultant
• South Africa

2.
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

3.
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

4.
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.

5.
ESI Challenges

6.
The “Five Big” Utility Challenges

7.
Overhead Line Planning and Design

8.
Transmission & Distribution
Interdependency
Source: Aurecon

9.
Performance, Capacity & Ageing

10.
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.

11.
Overhead Line Planning and Design…2
• Infrastructure requirement
– New Infrastructure
– Planning for Renewal/Upgrading
– Replacement
• Asset life-cycle costs.

12.
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%

13.
Dominant Faults
Fault Transmission Distribution
Lightning related
Insulator related
Veld fires
Vegetation
Conductor
“clashing”
Connections
Pollution
Vandalism
Wildlife Related
Willie de Beer & Associates

14.
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

15.
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.

16.
Managing Overhead Lines…3
• Line working procedures.
• Performance monitoring, benchmarking &
reporting.

17.
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.

18.
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.

19.
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.

20.
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.

21.
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.

22.
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.

23.
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

24.
Subsidence Monitoring
Source: CSIR

25.
Drone Inspection

26.
Return on Asset
Source: SANEDI

27.
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.

28.
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.

29.
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.

30.
THANK YOU

31.
Acknowledgement
• Aurecon
• Africoast
• Hawk 62
• CSIR
• SANEDI
• Willie de Beer and Associates