I'm an intern at an electrical utility and I've been tasked with doing a proposal/cost analysis to evaluate whether or not starting a pilot with a company specializing in robotic inspections is worth it. The pilot, if it goes through, would consist of a tethered drone conducting an infrared/thermography scan and a LiDAR point-cloud (light detection and ranging) scan, in addition to a high-resolution RGB scan of the manhole, with permitting and de-watering as rather significant additional costs. The economics are not favorable, and there are some questionable aspects of the entire process, mainly
- The permitting, de-watering of the manhole, 4-gas monitor air sampling, and lid removal/re-installation is still necessary procedure for the process, even if a tethered drone as opposed to human personnel will make entry (thus an additional cost requiring two teams; the crew that removes the lid will still have to wait around for the drone inspection crew to finish, all the while still charging for the time spent doing nothing. The drone inspection company claims they have a solution to this by going to other manholes while one is being de-watered, but I don't know how this will actually work in practice.)
- Union arguments/conversations about a future where they aren't in the picture or something of the sort
- The fact that the data must be analyzed off-site, so a problem can't be remediated until the data is analyzed and then a return to the manhole structure is made.
What I'm wondering is: How effective is LiDAR in practice? Does it enable inspections to be done faster? If so, how much faster? I know that underground inspections are prone to human error and missed information, but there is some information on LiDAR effectiveness that I can't seem to find when looking at research. Say if one has a manhole structure where a vault exists. Resolution of photos and ability to see 2nd or 3rd cable deep on a rack in the back office is critical to evaluate defects – particularly cables with cracks and no active oil leak. I don't see how a tethered vehicle is going to be able to position itself to find these defects. It makes it even more difficult to give an honest analysis because I haven't ever been inside a manhole myself.
If anyone could speak towards their experience with IR/thermography and LiDAR point-cloud scan effectiveness in manhole structures, your advice will be greatly appreciated.