Page 45 - Energize June 2021

TECHNICAL

The use of robots in the

maintenance of overhead lines

Information from Cigré

Strategic assets, such as electricity transmission grids, must be operated in a safe, predictable and
reliable way. Live-line work is of paramount importance for most maintenance operations, and the
need to maintain system availability is a key factor in the introduction of robotics in this field.

n

n order to maintain or increase Transmission line robotics
the reliability of ageing overhead Four robot classifications are identified here:
Itransmission lines (OHTLs), new • Line-suspended robots
maintenance techniques are becoming • Unmanned aerial vehicles (UAVs)
available to assess and diagnose the • Ground based robots
condition of various OHTL components. • Other types of robots
Line inspection and maintenance already
benefit from developments in mobile Line-suspended robots
robotics, which can reduce the potential Line-suspended robots are designed to serve as the extended eyes and arms of the
risk to maintenance crews (including live transmission lineman. Their basic design function is to perform visual inspection in
work), reach hardly accessible spans transmission lines which cross difficult rights of way, such as large rivers or mountainous
(such as river crossings), perform tedious areas. Also, they may perform a condition assessment of steel core wires of aged ACSR
tasks faster, and decrease costs. conductors, detect and locate broken wires and measure the remaining cross-section of steel
wires as well as temporary repair of components. Such robots or moving platforms are able
State-of-the-art of robotic technologies to travel over the live or ground conductor of transmission lines and many of them are able to
Although some robotic technologies pass through or cross over different obstacles.
aimed at the assessment and
maintenance of OHTLs were developed Unmanned aerial vehicles
in the 1990s, most of them were Routine inspections and asset condition assessment in many cases are usually carried out
developed after 2000. This article will using helicopters with trained personnel to capture information for an intended purpose.
define and classify robots and robotic Currently, electric power utilities are interested in investigating the technology of unmanned
technologies with regard to the Cigré aerial vehicles (UAVs) as they give clear images and unique inspection views when they fly
working group (WG) B2.S2’s terms of close to the transmission lines.
reference which are to review the existing Robots of this type have achieved autonomous operation as they have been able to verify
and developing robotic technologies for their own position as they fly and wirelessly transmit images to operators on the ground.
effective implementation, assessment Development of this type of robot is very active as more and more prototypes are being built
and maintenance of OHTLs, in order to and more players are expected to enter the market as service providers of technology users.
assist overhead line engineers to improve
line reliability and restore integrity and to Ground-based robots
aid asset managers in investing in further Ground-based robots are designed to remotely capture and control energised conductors
development and implementation of and execute tasks which are far beyond human capability, from a mechanical and electrical
these technologies. stress perspective. They represent a mature technology, which has been used for more than
Many definitions and classifications 15 years, and could be used for transmission structure repair and replacement, insulator
of robots and robotics technologies replacement, etc. Much of the development has focussed on robotic arms for the manipulation
already exist. Agreement on these and control of energised conductors.
definitions and classifications within the
robotics community has not yet reached a Other types of robots
consensus. In an effort to clarify important In spite of the recent developments in robots for inspection and maintenance of OHTLs, there
ideas that will establish a baseline of are still some components which remain mostly off-limits to robots. Towers, insulators, and
further discussions, this section aims jumper lines are some of the key components of the OHTL infrastructure that may require the
at specifying reference terminologies use of specialised robots for inspection and maintenance, when not easily accessible from
relevant to robotics related to the ground-based or UAV systems. Therefore, other types of robots have been developed for less-
assessment and maintenance of OHTLs. conventional work, such as tower/pole climbing, insulator inspection and insulator cleaning.

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