Linear asset networks in the Australian energy sector
Nearly 650,000km of above ground high voltage power lines make up the United States electrical grid. In Australia, Victoria alone has over 30,000km of single wire transmission lines spread across the state. "Tedious", "time consuming", and "expensive" are terms used most often used by those people tasked with the inspection and maintenance of those vast networks.
"Vital" and "necessary" are the terms we commonly use that best reflects the work they do.
The continuous and safe operation of the Australia's power grid is rightly a non-negotiable enterprise, so its reliability and safety are paramount. Modern life as we know it grinds to halt whenever the power flow is interrupted. Sparks from faulty, or damaged, power lines are one of the most common ignition sources for bushfires. Despite the critical role of our power distribution network, and the priority given to its care and maintenance, inspection and monitoring methods are almost as old as the industry itself.
Updating a timeless ritual
Each day inspectors are routinely dispatched across the network to manually inspect assets. They physically climb the poles, inspect the vegetation, and log the many miles required. For smaller networks in more densely populated areas this is a practical, if time consuming and expensive, method. For larger grids that extend across remote, and more severe terrain, a literal army of inspectors is needed, and that's when things get prohibitively expensive. Through necessity methods have been devised to offset cost.
With limited manpower and time constraints paramount, optimisation is a major factor in how inspections are undertaken, after all, some inspection is better than none, so prioritisation is essential. Areas with aggressive vegetation growth, areas judged as marginal during the last inspection, traditional trouble spots, and the more important operational nodes on the network are prioritised for attention. Inevitably this leads to subjective decision making based on the skills and knowledge of each individual inspector which is not ideal. It can lead to an over reliance on certain skills and knowledge that are difficult to replicate once an inspector leaves the job.
Taking to the air
Augmentation by helicopter has increased the amount of ground that can be covered. Inspectors can point out any areas of interest and relay the info to ground teams for further inspection. High end cameras mounted on the helicopter can also capture images for later study. While being a definite improvement in time spent, and kilometres covered, it is still a prohibitively expensive undertaking, which precludes coverage of the entire grid. Concerns have also been raised about safety - that, in practice, asset inspection officers routinely lean out of helicopter windows with GoPros to capture imagery!
One way of getting more "bang for your buck" out of helicopter inspections is by augmenting the onboard remote sensing capabilities. In addition to standard UHD cameras, newer technologies such as thermal imaging identifies hotspots, LiDAR (light distancing and radar) helps to build 3D maps, and hyperspectral imagery assists with identifying plant species.
The drawback of these technologies has always been their size and weight. Helicopters would have to do several flyovers of an area, changing the payload and setup each time so as to be able to gather all of the required data, which means more expense, and more time taken. If only this extremely useful technology could be miniaturised.
Drones are taking off
The most recent advancement in power line inspection is the adaptation of UAV's (Unmanned Aerial Vehicles), to assist in asset inspection and management. UAV's are more commonly known as drones and may turn out have the most far-reaching impact of all methods. Drones can provide the advantages of helicopters, but at only a fraction of the cost, time, and manpower.
The application of drones is still relatively new, but they have already shown huge potential. If the routine inspection of power lines and 'energy corridors' (where powerlines go through the Australian bush) can be augmented via drones then the task of inspecting power lines will change from "tedious", "time consuming", and "expensive" to "efficient", "cheap", and "effective". Perhaps even "fun".
Because of recent advances in AI, MI (machine learning), and miniaturisation, drones can now execute many of the same mapping and sensing functions as a helicopter. The big advantage, of course, is that they are smaller, more manoeuvrable, can stay in the air longer, and can easily be transported in the field. Currently they are being used to enhance the range and productivity of inspection crews by boosting the size of the area being covered, as well as the volume, and quality of the data being captured.
It's all in the data
The quality of the data being is the vital aspect here. This includes the same information that has traditionally been obtained by an inspector clambering up a pole or beating back bush around a pylon, but he drone can provide more. The drone provides layers of data (from UHD, LIDAR) that can be combined. Drones provide the aerial platform to record the data that allows for a new and exciting technique called "twinning".
Twinning uses multiple layers of information to create a digital model. Simply put, LiDAR, hyperspectral, and thermal imagery are digitally combined. The various data streams are cross referenced using time and location stamps and a representative model is created. For example, LiDAR data detects a branch encroaching into a danger area around power line. Hyperspectral imagery identifies the type of tree, and that it has a high probability of falling on top of the powerline in high winds. High-definition imagery confirms the diagnosis. Inspectors can "virtually" tour the grid, review any "hot spots", create precise work orders, and then dispatch the appropriate team to deal with the threat.
The future is automation
Like any nascent technology, the functionality of drones, the types of data being captured, and the associated uses of that data is in a constant state of flux. It is a rapidly advancing technology so any company moving into it needs expert advice.
Measure Australia is a drone services company that provides the resources and expertise required to set up and assist in power line asset inspection. Asseti is the associated data management platform that can create and run the multi-layered twinning technology described above.
As drone-based inspection becomes more entrenched within the industry, twinning will move from being an innovative solution, to a new baseline from which decisions are made. From here new programs and apps will be developed to efficiently process the data being produced by hardware being simultaneously developed for drones.
Once regulations that currently limit drone operations to line-of-sight are relaxed, drones will be able to cover more ground. Advances in AI and ML will enable drones to be able to operate autonomously. Advances in battery technology, solar power tech, and in-the-field charging pads will allow near continuous operations. Without the limitations of human control, continuous inspection of the entire grid, which is currently impractical, becomes a possibility.
There may also be other applications for the data being gathered. Enriched data utility provides operators with information that can be combined with other energy technologies, such as grid current, voltage monitoring, and fault management.
Complementary solutions may exist. For example, asset management data could provide context to an extant fault, or persistent faults could point out a priority area to be inspected more frequently in the future for potential fire prevention.
Whatever the future may hold for drone technology and power line inspection, the seeds for that future are being planted today, so get in early for a head start.