Abstract
According to Italian Legislative Framework on EMF, existing HV lines, in case of long
human presence (2: 4 hours a day), have to respect quality objective of 3 μT with reference to
new constructions and attention value of 10 μT regarding existing buildings; limits of 100 μT
and 5 kV /m must be guaranteed in any other condition of exposure.
With regard to Overhead Lines, compliance with these standards requires first of all detection
of accurate localization of existing grid (poles and conductors). In order to reach this scope
Terna, the Italian TSO, between 2009 and 2010 run a survey for master data acquisition of the
whole national aerial transmission grid (more than 60.000 km) through LiDAR technology.
This survey, investigating for each line a corridor 100 m wide, was carried out by helicopter
equipped with laser, Inertial Measurement Unit (IMU), digital photo camera, temperature
sensors and coupled with ground point OPS, in order to guarantee accuracy.
Result of detection is a classified cloud point which describes in 3D and with an accuracy of
50 cm the exact position of poles and conductors, as well as buildings, trees, roads, railways
and any other thing inside the corridor surveyed. In the meantime also conductors'
temperature and orthophotos are acquired.
All the classified laser points are well managed by a customized software that allows several
types of analysis, specially related to distances between interferences (buildings, roads, trees,
etc.) and catenaries that software itself is able to draw, starting from original measured values,
for every condition of temperature.
Software includes as well special tools for data export in main standard formats (* .dxf, * .shp,
etc.). 3D data acquired, together with additional info related to current loads, allow both
simplified and detailed EMF computations and modelling. Main platforms used for simplified
automatic calculations are the customized sw and EMF tools, developed by CESI, while
detailed 3D analysis are provided through WinEDT developed by Vector. Export in CAD and
GIS allows at the same time immediate visual analysis.
Data collected and software analysis give Terna the chance to identify all possible EMF risky
situations, to produce respect width of 3 μ T required for city planning and to have necessary
info available for project of new HV lines.
Of course this amount of data is used not only for EMF analysis, but also for other Operation
and Maintenance needs.
Periodical update of laser data is foreseen in order to take under control the evolution of grid
and environment
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