Leica ALS70 LiDAR in powerline profiling projects in Spain presented at European LiDAR Mapping Forum (ELMF) 2011

1. Application of dual output LiDAR scanning
system for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 November 2011
Pedro Llorens(1) – Ron Roth (2) – F. Javier Luque (1) – Alfonso Gómez (1) – Francisco J. Arjonilla (1)
(1) Stereocarto, S.L. – Madrid, Spain, (2) Leica Geosystems
pllorens@stereocarto.com

2. Stereocarto Group
 Group of companies specialized in geoinformation: Capture, process
and exploitation
 Core companies:
• Stereocarto: General geoinformation process and exploitation (orthophoto,
GIS,...)
• HIFSA: Aerial survey flights
• Cartogesa: Feature extraction and edition
• Terra XXI: Consultancy
 Working since 1964
 Belongs to the engineering firm Inypsa (public company in Madrid stock
exchange)
 R & D & Innovation division
 International activity:
• 80% turnover outside Spain
• Subsidiaries in Portugal, Italy, Romania, Ecuador, Brazil and more.
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
2

3. Main resources and projects
 One of Stereocarto strengths is massive data capture:
 5 Digital cameras:
• 3 Z/I DMC
• 1 Leica ADS40
• 1 Leica RCD105
 3 LiDAR systems
• 2 Leica ALS50 II
• 1 Leica ALS60
 5 airplanes
• 3 owned (Beechcraft B200, Cessna 402, 404)
• 2 leased (Cessna 421, Piper Aztec)
 Flight performance in 2009
• 300,000 sq. Km. digital aerial imagery
• 100,000 sq. Km. LiDAR survey
 Current biggest project
• Ecuador (2/3 country – 240,000 sq. Km.): Aerial imagery, LiDAR and 50cm
orthophoto
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
3

4. Powerline geometry studies objectives
 Powerline analysis to detect potential clearance violations (points failing
to keep security distances).
 Powerline design, planning, maintenance, modification and rerating
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
4

5. LiDAR applied to powerlines
 LiDAR is an excellent tool to model powerlines thanks to its unique
features
 Multiple returns capability
 Uniform accuracy
 High level of detail
 High efficiency and productivity (e.g. bigger swath)
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
5

6. Information extracted from LiDAR data
 Overhead cable modelling
• Catenary parameters
 Electricity pylons
 Terrain in the Right-of-Way (ROW) corridor
 Vegetation close to the powerline (inside and outside of the ROW).
 Infrastructure and objects in the powerline surroundings.
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
6

7. Powerline applications of LiDAR
 New lines planning
 Existing lines inventory:
• 3D modelling of high voltage powerlines with catenary extraction
 Lines rerating or repowering
• Thermal capacity analysis of transmission lines
 Environmental:
• Critical distances analysis to vegetation (forest fire prevention)
 Obstacle analysis in the powerline ROW
 Studies include capture at ambient conditions (wind and temperature)
and simulations of extreme weather cases
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
7

8. Red Eléctrica de España (REE)
 REE is the Spanish TSO (Transmission System Operator)
 REE is the unique responsible of electricity transportation or
transmission in Spain (Iberian Peninsule and islands)
 REE manages nearly 40.000 Km of transmission powerlines, mainly
400 KV and 220 KV
 Recently REE is using LiDAR technology to capture powerlines in
maintenance, rerating and ROW vegetation management projects
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
8

9. REE transmission grid
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
9

10. Project objective
 “Data acquisition with laser scanning technology (LiDAR) for
determination of points with critical distances between high voltage
cables belonging to the REE grid and trees or surrounding vegetation”
 Area covered: 837 linear kilometers
• 429 Km 400KV
• 408 Km 220KV
 The project was part of REE vegetation management program
 It should identify areas where field brigades should remove danger
trees and branches
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
10

11. Powerlines covered
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
11

12. Deliverables
 Required data:
•
•
•
•
Listing of critical distance points.
Phase conductor with critical distance.
Cross section to scale of every point with critical distance.
Scale maps of each span containing points with critical distances to
vegetation
• Optionally point clouds
 All data supplied in three different cases (one captured and two
calculated):
1.
2.
3.
Under existing temperature (measured) and wind conditions at the time of
flight (Captured geometry)
Zero wind and max wire load (usually 50ºC temperature) (Calculated
geometry)
120 km/h wind across track and 15ºC. (Calculated geometry)
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
12

13. Schedule
 Project done in summer
 Flight planning and execution 2 weeks
 Trajectory calculation 1 week
 Point cloud and basic LiDAR post processing 2 weeks
 Cable extraction, simulations and deliverables preparation 6 weeks
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
13

14. Technical resources
Technical resources
Model
Manufacturer
Helicopter
Eurocopter Ecureuil AS350 B3
Eurocopter
Laser scanner
ALS 70-HP (Orig. ALS50II)
Leica
IMU
IPAS 20
Leica
Ground reference stations
System 1200
Leica
 Initially planned with our ALS50 II
 Finally used a new ALS70 HP
 Spacing parameters required the use of helicopter instead of fixed wing
aircraft
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
14

15. ALS70-HP
LS70-LP Laser Scanner
SC70 System Controller
LC60 Laser Controller
MM70 Mass Memory
OC50 Pilot Display
GI40 Guidance Indicator
OC52 Operator Display
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
15

16. Sensor mounting
 LiDAR sensor mounted on Dart POD .
ALS with / without
RCD, Dart pod
In cabin
In pod
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
16

17. Sensor parameters
 Main parameters:
• Field of vision (FOV)
• Pulse rate
• Scan rate
 Constraints:
• Point density
• Point spacing
• Fooprint diameter
 Other requirements:
•
•
•
•
•
Detectable object size
Flying height
Aircraft speed
Swath width / Line spacing
Relieve
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
17

18. Sensor parameters
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
18

19. Sensor parameters for cable capture

Cable detection
•

Across track spacing equal to pulse footprint size is used – 12cm for 500 m flying height
Line surrounding objects detection
•
Despite a 2-3m along track spacing would be enough to capture the cable and determine
catenary parameters, ALS70-HP reached <30cm allowing detailed capture of vegetation
and any object in the ROW and surroundings
Flight direction
Pulse footprint
size 0,12cm
Across track
spacing 0,12cm
Cable
Along track spacing
0,27 to 0,90cm
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
19

20. Flight parameters
Flight parameters
Flying heigtht AGL
Ground speed
500
40 (72)
meters
Knots(Km/h)
LiDAR
Parameter
ALS50II
ALS70-HP
150.000
500.000
FOV
28.5
28.5
deg
Average point density
> 28
> 95
pts/m2
> 250
> 250
meters
Max point spacing across track
0,13
0,12
meters
Max point spacing along track
0,90
0,27
meters
Pulse rate
Full swath width
Units
Hertz
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
20

21. Accuracy
 Planned parameters result in:
• Relative accuracy:
• X, Y ~ 6 cm
• Z ~ 7 cm
• Required 0.50 m
• Absolute accuracy:
• X, Y ~ 25 cm
• Z ~ 20 cm
• Required 1 m
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
23

22. Workflow
LiDAR & simulated
data integration
LiDAR flight
planning and
execution
RAW
Data
Process
Critical points
determination
New cable vectors
Weather case
generation
Point cloud
with critical
points
Point
cloud
Cable
parameters
Deliverable generation
Classification
Cable extraction
Classified
point cloud
Catenary definition
Application of dual output LiDAR scanning system
for power transmission line data capture
Plans & cross
sections
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
24

23. LiDAR data process
 Point cloud
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
25

24. LiDAR data process
 Classification
Overhead line
Vegetation & buildings
Application of dual output LiDAR scanning system
for power transmission line data capture
Pylon
Terrain
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
26

25. LiDAR data process
 Cable extraction
• Determination of points belonging to the cable in the point cloud
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
27

26. Captured data
 Critical points identification
• Identification of potencial clearance violations under existing conditions at
the time of flight
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
28

27. Captured data
 Deliverable
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
29

28. Captured data
 Deliverable
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
30

29. Captured data
 Cross section
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
31

30. Weather case simulation
 Catenary parameters and cable position determination under alternative
scenarios or weather cases.
• Maximum load condition
• Conductor temperature increases and suffers dilatation so it gets closer to the
ground. Case temperature defined by the customer, usually 50º.
• Extreme across track wind situation.
• At 15ºC, a 120 Km/h across track wind is considered, resulting in a deviation of the
cable from the vertical plane. In nearly 1Km spans this means several meters.
 Simulation done with PLSCADD and propietary software from Inypsa
 Data had to be captured in a wide area around the powerline in order to
take into account the new position of the overhead cable in the weather
cases
 The existing temperature conditions at the time of flight had to be
registered to calculate the derived weather cases
• This was done lowering the helicopter next to the powerline every 10-15 Km
• Temperature was registered with a helicopter probe
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
32

31. Inypsa simulation application
LiDAR data
Overhead line
modeling
engine
Conductors
properties
database
Ambient Temp
Insulators
database
Power line info
catenary @
max T / max
E. load
Application of dual output LiDAR scanning system
for power transmission line data capture
catenary @
max crosswind
pressure
load
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
33

32. Simulated data
 Point cloud
Simulated cable
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
34

33. Simulated data
 Point cloud cross section
Cable simulation
Wind case
Cables
Cable simulation
Max load
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
35

34. Extreme wind case
 Deliverable
Simulated cable
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
36

35. Extreme wind case
 Deliverable
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
37

36. Extreme wind case
 Cross section
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
38

37. Alphanumeric deliverables
 Critical points:
• Data grouped by spans between pylons.
• Cable parameter listings (captured and simulated).
• Coordinate listings of critical points.
 LiDAR data:
• Point clouds (optional)
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
39

38. Critical distances
Pylon
Distance to pylon
Cable clearance
Object class
East
North
Elevation
1
16,1
4,99
vegetation
333871,86
4215925,71
669,77
2
22,29
0,12
vegetation
334137,93
4216678,86
720,61
2
22,3
0,18
vegetation
334137,98
4216678,85
720,66
2
22,3
0,22
vegetation
334138,05
4216678,83
720,63
3
22,3
3,79
vegetation
334137,98
4216678,85
720,66
3
22,3
3,82
vegetation
334138,05
4216678,83
720,63
3
22,3
3,83
vegetation
334137,93
4216678,86
720,61
2
9,99
3,16
vegetation
334169,98
4216834,57
692,72
2
9,99
3,21
vegetation
334170,06
4216834,55
692,68
2
9,99
3,24
vegetation
334170,13
4216834,53
692,67
2
9,98
3,58
vegetation
334170,39
4216834,45
692,38
2
9,98
3,59
vegetation
334170,32
4216834,47
692,36
2
9,97
3,6
vegetation
334170,46
4216834,43
692,38
2
9,99
3,8
vegetation
334170,00
4216834,54
692,09
2
9,97
3,84
vegetation
334170,57
4216834,4
692,17
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
40

39. Buildings clearance
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
41

40. Terrain clearance
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
42

41. Vegetation clearance
 Growing vegetation
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
43

42. Vegetation clearance
 Falling trees danger
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
44

43. High level of detail – pylon 1
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
45

44. High level of detail – pylon 2
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
46

45. High level of detail – pylon 3
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
47

46. Weather case visualization
 Maximum load cable modelling in Google Earth
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
48

47. Weather case visualization
 Extreme across track wind (120 Km/h) cable modelling in Google Earth
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
49

48. Conclusions
 ALS70-HP allows doubling flight speed over 80 knots without
compromising spacing
 Finally speed is only limited by helicopter maneuverability
• Speed at bends
• Terrain following with hight slopes
 Point density and accuracy do not limit flight specification
 Some consistency issues with input data
• Pylon numbering
• Pylon position
 LiDAR data editing software considers catenaries contained in a
vertical plane so it is not able to model the 120Km/h wind case as the
catenary gets out of that plane. This forced the development of an
specific sowtware tool to determine distance from cables in any position
to obstacles, trees and ground.
Application of dual output LiDAR scanning system
for power transmission line data capture
European LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
50

49. OFICINAS:
STEREOCARTO, S.L.
OFICINA CENTRAL:
General Díaz Porlier, 49
28001 Madrid, España.
Telf. +34 911211800
Fax: +34 914021609
España
Portugal
Italia
Rumania
Brasil
Colombia
Ecuador
http://www.stereocarto.com
European
STEREOCARTO, S.L. LiDAR Mapping Forum
Salzburg Congress Austria 29-30 Nov 2011
51