Drones and Robotics have quickly found their places in electricity sector. Their cost effectiveness and ease of use, are expanding their employability in the industry. Use of drones and robotics for power grid inspection brings several advantages such as higher safety and low risks to maintenance technicians, reduction in maintenance equipment downtime, enhanced accuracy in data collection of an asset’s condition, reduced staffing need and associated employment cost, and more accurate asset inventory management.
Use of drones
Drones are being used for many applications in the power and utilities industry to improve or replace inefficient processes. They are being used for mapping (power plant mapping and corridor mapping), inspection, corona detection, collecting real-time data mainly in inaccessible or inhospitable areas. Their up-to-date software, and high-resolution camera, offer detailed insights and results in impressive savings in terms of both monetary and physical efforts. In recent years, with the declining cost and improving technologies of these drones, their use has become widespread. These drones have a built-in system to withstand electromagnetic interference allowing it to operate reliably around high voltage (HV) lines and provide high-definition pictures and thermal imaging of the equipment in real time, so the operator can access the health of insulators and devise steps before a major line failure. Drones equipped with Light Detection and Ranging (LiDAR) can generate accurate three-dimensional (3D) information.
3D model: It can be used to calculate the height of the power line and the ground, the distance from the power line to the nearest obstacle and distance from the tower to another.
3D point cloud: After acquiring the spatial coordinates of each sampled point on the surface of an object, a collection of points is obtained by a LiDAR drone, which is called a ‘point cloud’. Point cloud is obtained by combining laser measurement and photogrammetry principles, including 3D coordinates (XYZ), laser reflection intensity (intensity), and colour information (RGB). It can be used for power line 3D visual management, route planning, and designing.
Thermal map: A thermal drone can be used for measuring the heat emitted from power lines in order to analyse the abnormal voltage and contact resistance. It helps the operation and maintenance personnel to check the defects in time.
Types of drones or unmanned aerial vehicles (UAVs) or in power sector
- Remotely piloted drones
- Autonomous flying drones
The flight of UAVs may operate under remote control by a human operator, as remotely-piloted aircraft (RPA), or with various degrees of autonomy, such as autopilot assistance, up to fully autonomous aircraft that have no provision for human intervention.
In the power sector, drones are currently piloted but have a potential to fly autonomously through global positioning system (GPS). When using GPS, flying near high voltage lines could lead to drone flight errors. Self-position estimation through image processing could solve this issue when the GPS is not available. Drones as well as robots installed for line inspection and maintenance will be supported with sensors, power supply and various maintenance equipment to perform or assist in maintenance work, depending on the nature of the task.
France: Since 2016, French power transmission system operator (TSO), Réseau de Transport d’Électricité (RTE), is an official aeronautic drone operator and has been using drones for various purposes such as substation inspection, diagnostic maintenance, to initiate the leverage of the main aerial cable etc. It has been using long distance remotely operated drone (over 50 km) to survey 400 kV lines. The long-distance drone weights 2 kg, and has a 50 km, 50 minutes range flight at 150-meter height.
Use of robots in power sector
Robots have been part of power network inspection for some years. When the testing units are too heavy or bulky for a drone or the areas are inaccessible, robot inspections are a suitable alternative. They are mainly being used for network inspection, and operation and maintenance. One growth area for robotics in the industry is boiler tube inspection. Tube wall failures can result in forced outages, but manual inspections are not easy and take several days. Robotic tube inspections can accurately predict and prevent wall failures in a fraction of the time. The use of robots to ultrasonically test boiler tube walls results in quickly identifying trouble spots.
They are also used by wind industry, where wind turbines (onshore and offshore) require regular inspection and maintenance. Nuclear power stations also use them to minimise exposure of workers to radiation. For example, robots have inspected the Fukushima nuclear reactors, where high radiation levels make direct inspections impossible. Solar power projects also use robots widespread mainly for cleaning to maintain generation level.
Types of robots used in power sector
- Robotic inspection
- Rolling Robots
- Climbing robots
- Brachiating robots
- Unmanned Ground Vehicles (UGVs)
- Robotic maintenance
- Robotic arms with different equipment
Leading adopters of robotics in the energy sector include the UK’s National Grid, Canada’s Ontario Power Generation (OPG), Canada’s Energie New Brunswick (NB) Power, US-based Talen Energy, US-based Con Edison, UK’s Southern Gas Networks (SGN), Canadian Hydro-Québec, Spanish Iberdrola, and Korea Electric Power Corporation (KEPCO).
Amongst the leading suppliers of robotics in the energy sector are ABB Limited, Sarcos Robotics, ANYbotics, Boston Dynamics, Mobile Industrial Robots (MiR), ULC Technologies, LLC, and PrecisionHawk.
Canada: Hydro Quebec developed LineScout Robot for live transmission line inspection and maintenance. It has been used mainly for the areas inaccessible or risky for line workers, and to remove different obstacles such as dampers, corona rings etc. Highly precise inspections are possible through infrared, high-quality visual inspection and electrical resistance measurement. LineScout is also able to perform different maintenance tasks such as tightening and loosening bolted assemblies, and temporary repair of broken conductor strands. Successful use of this technology helped the company to save money and time through decrease in shutdown time of lines and an increase in flexibility and efficiency during inspection.
The way ahead
The use of drones and robotics is likely to increase with time in the power industry mainly with the rising share of renewables in the grid. With the improving technologies and declining cost, these artificial intelligence (AI)-based solutions are likely to be the future of electricity industry.