Inspection, aerial photography and monitoring of state and growth of protective area under power lines is getting more popular and widespread as conventional means are either expensive and risky (using piloted aircraft) or taking lot of time and not having all the necessary angles (inspection from ground).
Lot of companies are now experimenting with UAVs for this purpose as it is versatile platform giving lot of hope for future. Most of time currently it is done by flying UAVs manually. Either flying by camera or visually.
Downside of such approach is that it requires significant skill of UAV operator. Also is limited by range and beyond line of sight operations are dependent on video feed connection to the operator. UAV system for power lines monitoring should operate autonomously and do not require advanced skills from operator to be effective solution on industrial scale and applications
Another aspect is that manual operation is good mainly just for visual inspection. To do reconstructions or mapping of power lines UAV should follow exact route to create material usable for post processing.
As there are differences from general route planning when addressing power line inspection not all mission planning tools in the market are comfortable or suitable for the task.
Here is why. Usually operator on the screen sees satellite image where power line and its support towers are either projected on the ground or only shadow of them is visible. Like in this example circled with red:
Downside is that there are no easy way to check route for errors and visually see how correct it is to ensure safety. If there was some error with height calculations best scenario is that quality of inspection will be low and there will be need to redo it. In not so good scenario UAV can be lost or worst of all cause power line short circuit and outage. Physical damage to power line if using small UAV is not likely. When using large planes for inspecting several tens of kilometers at once the risk increases.
To address these issue UgCS can be used to plan such UAV missions.
First of all using UgCS allows 3D visualization of route and have custom 3D objects such as power lines and transmission towers on your map along with use of custom maps with more precise elevation data. Please make a comparison between previous and following screenshot of UAV route
Here operator can easily see how close to the towers and even lines is the route and visually evaluate its safety and correctness.
As UgCS knows all the parameters of an UAV selected for the mission it will check automatically whether set route, including minimum distance from objects, is safe for execution. In case it is not operator will get warning before even route is uploaded to the vehicle:
Such functionality serves as double check and significantly increases safety.
It is often that low-voltage lines intersects with high voltage ones. UgCS will automatically make route over crossing line. Thus UAV flies over high-voltage line at safe distance.
We are developing special UgCS toolset for creating routes for power line inspection. At the moment during development it exists in form of Excel application.
Provided we have coordinates of power line towers, like these in example below
We can load them in application and with just few clicks for route:
Calculation of the route is done taking into account necessary overlaps and GSD. Shooting interval is taken in account and is set by operator on camera manually. If input date was reliable and had all necessary dimensions of towers there is no need to do corrections later:
Additionally UgCS shows no-flight zones (red cylinders on next screenshot) and during flights can show approaching aircrafts of general aviation or other UAVs equipped with ADS-B technology. For it to work computer running UgCS should be equipped with ADS-B receiver.
Question remains where to get 3D models of power lines and towers?
For this example we used model from 3dwarehouse.sketchup.com, https://3dwarehouse.sketchup.com/model.html?id=b8529f164603520f8ee9b4d22cc47929.
Another option is to use 3D reconstruction of your power lines. Results are not as clean as hand drawn models. Nevertheless they do the job for planning purposes.
As a future update for UgCS for Power Line Inspection there will be repository of schematic 3D models of transmission towers of different standard type. Thus allowing to be placed similar to real towers 3D models on map for better planning and awareness of environment and safety assessment.
Using our Excel Application and UgCS on real life scenario we were able to achieve following 3D reconstruction.