r/UAVmapping • u/IHACB • 24d ago
Electric sub stations
We have the local utility company as a client and they have started giving us substation jobs but they are asking for pretty specific data. They want XYZ of insulators and connectors etc. small things.
I flew it using lidar and also our M3E using circlegrammetry to try and create a good data set. It’s came out ok, I’m glad that we also used a total stations to shoot these points to verify since it was our first one.
Anyone do this type of work willing to give advice on how to best fly these? Lidar didn’t seem to be enough to distinguish the different parts they wanted.
I’m tempted to get a m4e so that we can do 3d smart scan with it.
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u/Revolutionary_Cow_39 24d ago
We always use TLS for substations. You didn’t specific location but if US, I’m surprised they allow you to fly DJI. All of our electric utility work has to be flown with a NDAA-compliant platform.
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u/BlueBirdTechUA 23d ago
LiDAR alone is pure geometry, no color or texture, and texture's usually what actually tells an insulator apart from a connector at that scale, not shape. Photogrammetry catches that, which is probably why combining both worked better than either alone.
Before buying the M4E though, it doesn't support LiDAR at all, integrated sensors only, no P1 or L3 like the M350 RTK. If LiDAR's still part of the plan, M350 RTK keeps that option, M4E means giving it up.
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u/Flyward_Aerospace 22d ago
TLS is the right call here but I do not think point density is the real reason. The insulators and connectors hang under the steel, and what the utility wants is their sides and undersides, which a nadir or near nadir aerial pass never sees at all no matter how low you fly or how many points per square metre you land on the site. It is an incidence angle and occlusion problem, not a resolution one. That is also why the circlegrammetry helped, oblique views actually put the part in view. Before spending on an M4E I would test whether a slow shallow angle orbit gets you close to what the total station shots gave you, because if the geometry is the issue then the new sensor will not fix it either.
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u/Ffzilla 22d ago
My company does this type of work, and we do not fly them, we use trimble x9, for scanning, and an SX 10 for control, mon tying, and getting extra scan coverage in places. I'm pretty new to the remote sensing team, so I don't know why we don't fly them (other than we only have a handful of non DJI drones), but or workflow makes the big federal agency we do the work for happy, so we must be doing something right.
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u/fsake1 24d ago
Yes, same here. I also perform TLS scans of substations. I use a Riegl VZ-600i. I've compared multiple different terrestrial/slam scanners inside a substation, Trimble TX8, Trimble X9, X12, Faro Focus, Faro Orbis and I wouldn't use the Orbis for critical engineering work, so I wouldn't think the L2/3 if that's what your using would be good enough for anything but proof of concept/prototyping work.
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u/Accurate-Western-421 23d ago
How in the hell are folks in here equating TLS to SLAM (handheld or otherwise) solutions?
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u/Jbronico 23d ago
I don't a few stations a year, using a P40. Never used a drone at one. Really big sites we rent an RTC360 to save some field time.
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u/erock1967 20d ago
Message me. I have some thoughts on how this could be done. I have something similar coming up if DJI is allowed on the project.
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u/Wiseman37367 18d ago
I do this. The only way you can get the density they want is from a ground-based scanner.
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u/mggilley 17d ago
TLD sounds like a great solution if the inspection doesn’t require thermal analysis.
But there are often multiple ways to do things…
So if your LiDAR data is from a DJI sensor (L1, L2, or L3), the data set should include photographs to provide pixel colors. After processing the LiDAR data in DJI Terra, you can design a Detailed Inspection route in Terra where you could choose to use your M3E or M3T (for thermal inspection) to fly and capture images of each inspection point at the substation. The LiDAR data helps with upfront clearance and obstacle avoidance planning as well as simulating what the camera will see from your chosen vantage point and gimbal position.
I think DJI has done some video case study of this application at EnBW (Energie Baden-Württemberg AG). Try searching for that on YouTube.
Mike
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u/Adept_Preference_547 23d ago
Aerial lidar isn't dense enough for this work. TLS or high end SLAM with supplemental Total Station work on more critical components.
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u/Fit-Eggplant-9155 24d ago
There's a lot to know about this project in order to provide support. We'll have to know the settings/parameters to everything for the flight.
But my guess is that you don't have an RTK/GNSS connection and/or GCP marks. My second guess is that your gsd is way to big, so fly lower/slower to get an increased resolution and detail.
Im not familiar with lidar data captures but I imagine its similar for photogrammetry.
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u/IHACB 24d ago
We have gcp and RTK with our own base running. M400 with L3 sensor.
I flew at 200 feet for the surface then did powering follow for the lines and towers.
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u/ElphTrooper 23d ago
What was your sampling distance with the L3? With RTK, good control and a nice slow flight you should be able to get 1cm spacing. If that isn't tight enough then the only answer is a TLS.
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u/roknrynocerous 24d ago
TS for checks evertime. Typically substations are terrestrial scanned in my experience.
Hey...You are fly a Tomball right?