3-Dimensional modelling in evaluating ELF fields exposure

In the last years the Regional Environment Protection Agency of Tuscany (ARPAT) has made an evaluation of the ELF (Extremely Low Frequencies) exposure of population trough the means of an integrated system which includes the implementation of the Regional Power Lines Archive (CERT)1 as a data source for the calculation software. The storage of 380 and 220 kV lines has been possible entering the lines routes, the profiles and the technical diagrams of high and very high-tension power lines -- obtained from the lines operators after an agreement with Tuscany Region -- in the CERT archive. Differently from the 380 and the 220 lines, the storage of 132 kV is still in progress. The PLEIA calculation software -- developed in a IFAC-ARPAT agreement -- allows the 3-dimensional calculation of magnetic field values in proximity of power lines. A control procedure has been developed to guarantee the quality of theoretical valuations obtained by using the data of the CERT archive. The controls concerned the geometrical features of pylons and buildings got from the numeric cartography. DGPS (Differential GPS) measures have allowed to improve the precision of the pylons coordinates; all the geometric features stored in the archive have been verified (straddles amplitude, lower wire height, span catenary constant) for each pylon using a laser telemeter. The same tool has been used to measure the distances of closest buildings to power lines and their height. In conclusion, some 3-dimensional visualization environments (ESRI ArcScene and GoogleEarth) have been tested as further support by the technicians involved in the controls.