Combined aerial LiDAR and photogrammetry survey of 220 kV and 110 kV overhead power lines for a solar farm planning application. Every pole, span, sag point, and ground clearance mapped remotely.
A solar farm developer was preparing a planning application for a large-scale PV installation in the Irish Midlands. The site was located in close proximity to two high-voltage overhead transmission lines – a 220 kV line and a 110 kV line – that crossed the proposed development area and surrounding land over a combined corridor of approximately 15km.
EirGrid and the planning authority required accurate as-built data for both lines: pole/tower positions, span lengths, conductor sag profiles, and minimum ground clearance measurements at every span. This data was needed to assess safe separation distances for the solar panels and access roads, and to demonstrate compliance with OHTL (Overhead Transmission Line) clearance standards.
Surveying 15km of live high-voltage infrastructure on mixed private land using traditional methods would have required access agreements with dozens of individual landowners, an extended fieldwork programme, and significant safety management overhead. Several land parcels were inaccessible without crossing crops or gated private land.
The client needed a fast, accurate, non-intrusive solution that could capture all the required data without requiring ground access to every span.
The 15km corridor was divided into flight blocks following the line routes, with a 150m capture width on each side to provide full context data beyond the line easement. We identified any controlled airspace segments along the routes and coordinated flight permissions in advance. The entire corridor was captured over three mobilisation days using the DJI Matrice 300 RTK with the Zenmuse L2 LiDAR sensor.
LiDAR was the primary capture method because the laser pulse return could resolve individual conductors – including fine wires – and also penetrate through low vegetation to give a bare-earth terrain model beneath the line. This is critical for ground clearance calculations, where the conductor height above true ground (not above vegetation) is what matters for OHTL compliance reporting.
A simultaneous photogrammetric run with the P1 camera provided the orthomosaic corridor strip, giving the client a visual reference layer to sit alongside the LiDAR data. The orthomosaic was used to identify and attribute structures, access tracks, watercourses, and land boundaries along the corridor, which the LiDAR point cloud alone does not easily convey.
The point cloud was classified in post-processing: ground, low vegetation, medium vegetation, high vegetation, building, and power line classes. Conductor geometry was extracted for each span, and minimum ground clearance values were calculated and tabulated for the planning report. All data was delivered in ITM with Malin Head vertical datum, compatible with the engineer’s existing project model.
The entire 15km corridor was surveyed without requiring access agreements from any of the private landowners along the route. We operated within airspace from public access points only.
Every span on both the 220 kV and 110 kV lines was captured with usable conductor geometry. Ground clearance values were tabulated for each span and provided in a format ready for the planning submission.
The LiDAR clearance report was submitted as a technical appendix to the planning application. The planning authority accepted the data without requesting additional physical survey.
Traditional survey of this corridor – requiring access agreements, extended fieldwork, and safety management for live HV infrastructure – would have taken an estimated three to four weeks. We captured everything in three mobilisation days.
Airborne LiDAR scanning for bare-earth terrain, vegetation penetration, and infrastructure mapping.
Survey-grade photogrammetric mapping for corridor and linear infrastructure projects.
Linear drone surveys for pipeline routes, power lines, rail corridors, and road alignments.
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