Apr 2018
Electricity Transmission
EPRI Research Collaboration on Overhead Lines (P35) 2018-2021
Apr 2018
Apr 2021
National Grid Electricity Transmission
Ben Muncey
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Network Innovation Allowance
ET - New technologies and commercial evolution
Asset Management, Condition Monitoring, Conductors, Maintenance & Inspection, Overhead Lines and Electricity Transmission Networks
National Grid recognises that the challenges faced by the electricity industry can be more efficiently and cost-effectively addressed when approached through international collaboration initiatives. It is particularly useful when addressing challenges where the solutions require statistically diverse data sets and/or significant trialling and testing in different environments, under various conditions and/or diverse ways.

The Electric Power Research Institute (EPRI), with its wide international membership, is one of the routes through which these initiatives can be delivered, thereby maximising stakeholder value. The approach of managing collaborative projects within an internationally driven research and development initiative is beneficial to National Grid and consumers alike, because it provides valuable information, learning and knowledge that would be considerably more expensive if approached on an individual basis.

As an owner of overhead lines, National Grid faces challenges around optimisation, asset life, development of innovative and fit for purpose monitoring, maintenance practices and understanding what novel technologies could be applied to improve efficiencies. The EPRI Overhead Transmission Lines Programme 35 (P35) aims to develop this work via five supported project work-streams.

Following an assessment of our internal Overhead Line strategy and an internal review, National Grid determined that within EPRIs Overhead Transmission programme, the largest leverage for the UK consumer can be achieved through involvement in the following five projects during the period 2018-2021:

P35.001 - Inspection, assessment and asset management of overhead transmission lines

P35.002 - Conductor, earth wire and hardware corrosion management

P35.003 - Structure and Sub-Grade Corrosion Management

P35.011 - Polymer and composite overhead transmission insulators

P35.013 - Overhead line ratings and increased power flow

P35.015 - Qualification, selection and maintenance of advanced conductors

The work areas have outputs that span across multiple years, consequently,  this project will benefit National Grid and our stakeholders by committing to deliver the research activities of P35 over three years.
The objectives for the 2018-2021 period include the continuation of National Grid’s membership with EPRI P35 and the delivery of a selection of reports and guidance documents associated with the five work-streams by undertaking the following tasks:

P35.001 - Inspection, assessment and asset management of overhead transmission lines

Overhead Transmission Line Inspection, Assessment and Asset Management Reference Guide (Yellow Book):
Yellow Book Browser Application (Software)
Overhead Transmission Line Inspection – Online Training (OTLOT) Version 2018
Overhead Transmission Inspection and Sensing Information Tool (OTIS) Version 2018
Practical Inspection and Assessment Workshop
Overhead Transmission Line Field Guides
P35.002 - Conductor, earthwire and hardware corrosion management

Assess and evaluate new and emerging inspection technologies including non-contact and ground based inspection
understanding the potential of using near infra-red (NIR) spectroscopy to determine degradation rates and remaining conductor life
Develop corrosivity models using algorithms for aging and atmospheric exposure of conductors and hardware and correlate results though lab and field testing
continued development of NIR spectroscopy technology application for condition assessment of degraded hardware or component surfaces
P35.003 - Structure and Sub-Grade Corrosion Management

Corrosion probe inspection tool for sub-grade corrosion evaluations
Coating system selection and application guidelines
Corrosion education
Fleet management
Failure database
Concrete foundation mitigation and remediation methods
P35.011 - Polymer and composite overhead transmission insulators

multi-stress ageing tests to understand various modes of degradation and performance of polymer components National Grid has commissioned EPRI to carry out accelerated aging tests on a range of polymer insulators at various stages over the last 15 years. These tests are planned to continue for several years more to provide reliable information on long term performance alongside some ongoing field trials on the NG network. In addition to this National Grid are also able to receive benchmark data across a broader field of suppliers
continued development of the failure database to help identify trends and attributes to failures
developing short duration, small scale tests that are representative of in-service stresses. The tests may be included in utility specifications
inspecting service-aged insulators to aid in understanding how insulators age and the factors of aging which in turn helps improve applications and improve reliability and performance
development of E-field modelling software to help model the electric field on new or existing insulator designs.
P35.013 - Overhead line ratings and increased power flow

Development of software tools
Development of rating methodologies
Development of guidebooks, reports, and training materials for implementing increased power flow strategies, and for training engineers on increased power flow technologies.
Comparison of economic benefits of increased power flow technologies, enabling utilities to make informed decisions when choosing options for their specific applications.
P35.015 - Qualification, selection and maintenance of advanced conductors

Developing an HTLS conductor application guide.
Developing a test protocol to compare different carbon fiber composite core conductors
Provide information on comparing and selecting suitable HTLS conductors for specific applications.
Developing maintenance procedures and recommend that can be incorporated into utility’s maintenance manuals.
Testing the thermal and mechanical performance of these HTLS conductors.