Overhead Lines

The B2 Study Committee covers the design, construction, operation, and maintenance of overhead lines. This includes the mechanical and electrical design and experimental validation of new line components (e.g., conductors, ground wires, insulators, accessories, structures, and their foundations), the study of line performance in service, assessment of aged line components, line maintenance including robotics, refurbishment and life extension as well as upgrading and uprating of existing overhead lines.

In a world where there is a clear desire to improve access to electricity and to electrify processes that currently use other energy sources, overhead lines play a key role for the electricity system of the future. The activities of SC B2 are fully in line with this important aspect of CIGRE’s mission.

The technical guidelines of SC B2 are:

• Increase the ampacity of existing lines
• Ensure or improve line reliability
• Ensure environmentally compatible lines
• Develop working methods, new tools

SC B2 cooperates with SCs B1 “Insulated Cables” and C3 “Power system environmental performance”. The main objective of this cooperation is to coordinate the work to be done on subjects of common interest.

The main areas of interest of B2 are:

• Route selection
• Optimized line design
• Line maintenance & service
• Refurbishment of existing lines
• Design specifications
• Increase in the power of existing lines
• Asset management guidelines
• Real-time monitoring systems
• New materials
• Sustainability of line components
• Minimizing the environmental impact of lines

Meetings, Sessions

After two years of virtual meetings, an in-person SC B2 meeting took place during CIGRE Paris on September 1, 2022. Being able to interact face to face and exchange ideas again were well appreciated.

The three preferential subjects for SC B2 were:

• PS 1 Challenges and New Solutions in Design and Construction of new OHL
• PS 2 Latest Techniques in Asset Management, Capacity Enhancement, Refurbishment
• Joint PS 3 B2 with C3: Environmental and safety aspects from OHL

The Group Discussion Meeting (GDM) was chaired by the Study Committee Chairman, Herbert Lugschitz (AT), with the Special Reporters Anish Anand (IN) (PS 1), Balint Nemeth (HU) (PS 2), Randy Grass (US) (PS 3/C3) and Stefan Steevens (DE) (PS 3/B2) and Wolfgang Troppauer (AT) as SC B2 Secretary. The chairwomen of SC C3, Mercedes Vázquez (ES), was present at the discussion of JPS 3. The incoming B2 Study Committee Chairman Pierre Van Dyke (CA) was also present (Figure 1).

A total of 68 papers were accepted for the GDM: 22 papers in PS 1, 25 in PS 2, and 21 in PS 3. The prepared contributions came from 15 countries, including 30% from Japan. In total 53 spontaneous contributions from the audience and chat led to a lively session. The most discussed topics were:

• Climate change and determination of loads from ice and snow
• Insulator pollution and test methods
• Cores of composite conductors with new findings about ageing
• Technical aspects of Dynamic Line Rating methods
• Worker´s safety and use of new training methods (virtual reality)
• Bird protection
• Environmentally friendly methods during the erection period for a line

At the end of the B2 annual session in Paris, the B2 chairmanship and secretariat were officially transferred from Herbert Lugschitz and Wolfgang Troppauer to Pierre Van Dyke and Vivek Chari (Figure 2, left picture). The farewell dinner organized for the occasion was an opportunity to bring together four SC B2 chairs: The incoming chair, Pierre Van Dyke (CA), the outgoing chair, Herbert Lugschitz (AT), and the two previous chairs: Konstantin Papailiou (CH) and Rob Stephen (ZA) (Figure 2, right picture).

Structure of SC B2

The organizational chart of B2 is illustrated in Figure 3 with seven Advisory Groups (AG) ensuring the coordination of the work within the study committee, the Working Groups (WG) or Joint Working Groups (JWG) doing the technical work. The AGs of B2 are:

• CAG Customer Advisory, Kjell Halsan (NO)
• PTAG Publication and Tutorial, Wolfgang Troppauer (AT)
• SAG Strategic Advisory, Pierre Van Dyke (CA)
• TAG 04 Electrical Aspects of Overhead Lines, Javier Iglesias (ES)
• TAG 05 Towers, Foundations and Insulators, João da Silva (BR)
• TAG 06 Mechanical Behaviour of Conductors and Fittings, Cécile Rozé (FR)
• TAG 07 Asset Management, Reliability and Availability of Overhead Lines, Balint Nemeth (HU)

B2 is also supported by the National Committees which comprises Regular Members from 24 countries, 6 Regular Additional Members, and Observer Members from 16 countries. Their different provenance allows for different viewpoints, opinions, approaches, solutions, policies, social environment, lessons learned, etc.

Overview of the Working Groups

At present B2 has 27 active Working Groups including three Joint Working Groups with other SCs. 552 experts contribute in WGs (excluding multiple memberships in different WGs), from 45 countries. B2 has 11% women members in the WGs and 7% “young members”, both showing an interesting upward trend over the years. The current WGs are:

• B2.50 Safe handling of fittings and conductors
• B2.57 Survey of operational composite insulators: Experience & applications
• B2.59 Forecasting dynamic line ratings
• B2.60 Affordable overhead transmission lines for Sub-Saharan countries
• B2.65 Detection, prevention and repair of sub surface corrosion in overhead line supports, anchors and foundations
• B2.66 Safe handling and installation guide for high temperature low sag (HTLS) conductors
• B2.67 Assessment and testing of wood and alternative material type poles
• B2.68 Sustainability of OHL conductors and fittings – Conductor condition assessment and life extension
• B2.70 Aircraft warning markers and bird flight diverters for overhead lines – Experience and recommendations
• B2.71 Recommendations for interphase spacers of overhead lines
• JWG B2/D2.72 Condition monitoring and remote sensing of overhead lines (lead B2)
• B2.73 Guide for prevention of vegetation fires caused by overhead line systems
• B2.74 Use of unmanned aerial vehicles (UAVs) for assistance with inspection of overhead power lines
• B2.75 Application guide for insulated and un-insulated conductors used on medium and low voltage overhead lines
• JWG B2/C4.76 Lightning & grounding considerations for overhead line rebuilding and refurbishing projects, AC and DC (lead B2)
• B2.77 Risk management of overhead line networks: A model for identification, evaluation and mitigation of operational risks
• B2.78 Use of high temperature conductors in new overhead line design
• B2.79 Enhancing overhead line rating prediction by improving weather parameters measurements
• B2.80 Numerical simulation of electrical fields on AC and DC overhead line insulator strings
• B2.81 Increasing the strength capacity of existing overhead transmission line structures
• B2.82 Overhead line foundations for difficult soil and geological Conditions
• B2.83 Mitigation of induced noises by corona activity in overhead AC and DC lines
• B2.84 Assessment of the methodologies to analyse wind induced overhead line conductor’s motion: applications and limitations.
• B2.85 Emergency restoration systems for overhead lines - Guide for design, planning and installation
• JWG B2/C1.86 Approach for asset management of overhead transmission lines
• B2.87 Live line and vicinity working on overhead lines: Safe management guidelines
• B2.88 Guidelines for safety of overhead line construction, maintenance & operations

B2.88 started in early 2023 and its scope of work is explained hereafter:

B2.88 Guidelines for Safety of Overhead Line Construction, Maintenance & Operations

Safety will continue to be a key focus for construction and maintenance of OHL and there is an increasing expectation of ensuring a safe work environment to the workers; driven by both economic benefits, legislative compliance, and community values. Design of new transmission line assets are typically required to account for safe work methods that may be adopted over asset whole-of-life (construction, maintenance and even demolition). On the other hand, existing assets may lack the same measures and require modification to make-safe prior to undertaking routine or corrective maintenance. The objective is not to develop design/construction engineer or work supervisor into safety specialists, but rather ensure these front-line persons have the awareness, tools and understanding to ensure risks are minimised.

The scope of the work shall include:

• Review social/industry acceptable levels of risk of injury in the construction industry.
• Identify types/frequency of occurrence of incidents related to OHL work and contributing factors.
• Define meaning of hazard and risk.
• Ensuring that baseline risk assessment is developed in relation to the specific scope of work; Identify hazards that expose line workers to harm during construction, commissioning, inspection & maintenance.
• Evaluate processes to manage hazards, application of the hierarchy of control (elimination, substitution, personal protective equipment, administration).
• Evaluate safety-in-design endeavours to identify and eliminate/substitute hazards to improve safety. Engaging safety practitioners during the design change for their inputs.
• Evaluate a selected range of safety manuals/training & site safety management practice including effectiveness of engagement with line workers.
• Review safety culture within the industry at both organisational and tool-box level for compliance with documented work methods, company, legal and statutory compliance.
• Recommend processes for introduction of new technology to identify & manage hazard, and risk assessment in the workplace.
• Post review session for the identification of areas from improvement.

The work will be undertaken in two stages (i.e., two reports): - Part 1: Identification of Construction/maintenance work hazards/risks - Part 2: Evaluation of current safety control management practices & recommended guidelines for improved practice.

Publications

The CIGRE Green books are the leading reference publication in the field of electrical network. They provide knowledge from experts in the field. So far, B2 has published four GBs including the first one in 2017 as well as a joint Green Book:

• Overhead lines, 2017
• Modelling of vibrations of overhead line conductors, 2018
• Electricity supply systems of the future (joint Green Book where all 16 Study Committees have contributed, authors of the ‘Overhead Lines’ chapter are from B2), 2020
• Techniques for protecting overhead lines in Winter conditions, 2022

Green books can be purchased in print or digital format. The ‘Overhead lines’ Green Book reached an important milestone in 2022 by reaching 50 000 downloads, which is a great success.

Three B2 Green Books are in preparation on the following topics:

• Compact overhead line design, AC & DC, expected date of publication: early 2024
• Dynamic loadings on towers and foundations, expected date of publication: 2024
• Innovative solutions for overhead line supports, expected date of publication: 2025

B2 has published 96 Technical Brochures since 1994. No new Technical Brochures have been published since the last annual report, but two are expected to be published in early 2023 by the WG B2.50 Safe handling of fittings and conductors and B2.68 Sustainability of OHL conductors and fittings – Conductor condition assessment and life extension.

B2 papers in CIGRE Science and Engineering (CSE) is an open electronic Journal, free to download for all, and has three issues per year. It provides high-quality articles that are rigorously peer-reviewed. Three CSE papers were published on B2 topics in 2022:

Workshops, tutorials, and webinars

• CIGRE Paris, August 2022
  • Workshop Extra-long transnational transmission lines - Study Committees B1, B2, B4 & C1
  • Tutorial WG B2.64 Inspection and testing of tools, equipment and training for live-line work on overhead lines (Figure 4 and Figure 5)

• CIGRE 2022 AORC (Asia-Oceania Regional Council of CIGRE) SCB2 Panel Meeting was successfully held online on December 2nd with 12 technical presenters, 3 commemorative lecturers, 3 guest speakers, and 79 participants, for a total of 97 people

• SEERC (South-East European Regional Council of CIGRE)
  • May 2022, Colloquium, Vienna, Austria, 150 participants
  • January 26-27, 2023, Workshop - Resilience of Electrical Grid: Events and Solutions, Roma, Italy, 20 presentations

• CIGRE Muscat International Symposium, Oman, March 6-8, 2023
  • Short course: High voltage overhead lines
  • Tutorial: Overhead conductor motion phenomena and control methods (Aeolian vibrations and subspan oscillations) (Figure 6)

CIGRE Awards

During the CIGRE Paris session, the outstanding contribution of six B2 members (Figure 7) was recognized with the following CIGRE awards:

• The Next Generation Network Significant Contribution Award 2022 went to Ms. Ana Lovrenčić (SI), Secretary of JWG B2/C1.86 and Chair of CIGRE NGN Slovenia for her outstanding contributions.
• The CIGRE Technical Council Award 2022 went to Dr. Balint Nemeth (HU), national representative of Hungary in B2, Convener of WG B2.87, member of CAG, SAG and Working Groups, contributor to several TBs and recently nominated convenor of TAG B2.07.
• The CIGRE Fellow Award 2022 went to Mr. Joao Nolasco (BR) in recognition of his active participation in the activities of the Association, as Special Reporter of the Study Committee B2 "Overhead lines" during the Paris Sessions, as Convener of the Joint Working Group B2/B4/C1.17 "Impacts of HDVC lines on the Economics of HDVC projects", and as co-author of the CIGRE Green Book on "Overhead Lines".
• The CIGRE Honorary Member Award 2022 was given to Herbert Lugschitz (AT) in recognition of his outstanding contribution to the activities of the Association, as Chairman of the Study Committee B2 "Overhead Lines" from 2016 to 2022.

The work of two exceptional SC B2 members was also recognized during the session where Dr. Rob Stephen (ZA), former CIGRE President, former Chair of Study Committee 22 ‘Overhead lines’ former Chair of the South African National Committee, and Editor-in-chief of CIGRE Science & Engineering, received the 2022 CIGRE Award Medal. The 2020 CIGRE Award Medal was given during the pandemic to Dr. Konstantin Papailiou (CH), former Chair of SC B2 ‘Overhead lines’, founder and former Chief Editor of CSE, and he received it during the same ceremony.

Coming B2 events

29^th Sept – 6^th Oct 2023 in Sendai, Japan: B2 Annual meeting and Colloquium “Recent Overhead Transmission Line Technology and Environmental Measures” with the participation of Study Committees B2, C3 and C4. A total of 113 abstracts have been accepted and the resulting papers will be presented and/or shown as posters. The preferential subjects for B2 are as follows and will certainly bring up interesting discussions:

• PS1: Sustainable OHL, Environment and Planning (joint PS with C3)
• PS2: Reliability of OHL, Advanced Construction and Maintenance (joint PS with C4)
• PS3: Resilience of OHL, Recent Technologies for Disaster Recovery

The colloquium will also be the recipient of a SC B2 meeting, WG meetings, 3 Tutorials and a Technical tour.

2024 August Paris Session. The call for papers is already open and the preferential subjects for B2 are:

• Challenges from renewables integration and influences of energy transition on OHL
• Asset management, strategies, technologies and methods for OHL
• Impacts from climate change on OHL

Contact

• Contact of the Chair and/or the Secretary of the Study Committee