0 2 4 6 8 10 12
A B C D E F G 05
1015 2025 3035 4045 5055
-20 -15 -10 -5 0 5 10 15 20
Height (m)
Distance to center line (m) Max ground projection
In this work an investigation method to assess the exposure to electric and magnetic field generated by power lines was described, based both on measurements and simulations.
Method for Monitoring the Electromagnetic Impacts due to High Voltage Overheads Lines in Aosta Valley
Claudia Desandré, Marzia Mathiou, Valeria Bottura, Marco Cappio Borlino, Leo Cerise, Erik Imperial
ARPA Valle d’Aosta
Saint Christophe (AO), Italy
Abstract—The aim of this paper is to show the methodology used by the Environment Protection Agency (ARPA) of the Aosta Valley for evaluating the electromagnetic impact due to high voltage overhead lines which cross the region, with regards to public exposure. At first, by simulation and inspections, buildings potentially exposed to electromagnetic field due to their proximity to the lines were identified, then field measurements, performed for some day time, permitted to verify if exposure limits were exceeded and to set a method to evaluate the population exposure level at any
time and on any time lapse provided current data are known. So far, two important line branches were examined with the purpose to extend the controls to all lines in Aosta Valley.
Framework
Legend:
Line 40-150 kV Line 220 kV Line 380 kV Primary station
Fr ance
Switzerland
Moreover, due to
orography and water supplies of the
region, many local hydroelectric power plants produce and introduce energy into the national
transmission network.
Methodology
A. Inspections and measurements
1. Line identification Two 220 KV lines were chosen due to proximity to buildings
Villeneuve – Chatillon (single line T209) Valpelline – Leinì (composed line)
Primary station Valpelline
Primary station Châtillon
Primary station Montjovet
Primary station Leinì
Line T210 Line T207Line T211Line T215
2. Preliminary EMF simulation along lines paths
Aim: define restricted areas (buffer zone) on both sides of conductors where
magnetic field can exceed an established value and identify the buildings witin these areas
Data required:
shape and
coordinates of the pylons,
geometry of
conductors and current rating in normal
service
3. Inspections and screening selection of buildings for thorough measurements
4. Measurements electric field istantaneous outside the buildings and magnetic field istantaneous and long-term (acquirement every 30 seconds for one week).
B. Indirect assessment to evaluate magnetic field from current data
Correlation (C) between magnetic field data series and current values was calculated.
If C>0.9 average of the ratio between field measured values and current data in the same time was used as a multiplication factor to
evaluate magnetic field in any time period in witch current data were known
Single lines
Composed line when line phases are known:
First step (WinELF software by Vector)
• Reconstruction of 3D geometrical configuration
• Identification of the exact point of long term measurement
Second step (MoE software by CESI)
1. Data required: output of previous step,
magnetic field measurements, current data (amplitude and phase)
2. Simulation of the magnetic field and comparison with measurements in time period were
measured and calculated data are both available 3. Simulation at any time provided that current
data are available
Composed line when line phases are not known
Simulation algorithmis can’t help, it is necessary to repeat measurements over time
Results
A. Inspections and measurements
Data Statistical analysis
B. Indirect assessment Elaboration since 2005
Single lines Composed line when line phases are known
Conclusions
1. Knowing pylons position and shape and line electrical characteristics, a 2D buffer can be drawn on the map to locate buildings to be investigated in the aim of estimate population exposure to magnetic and electric field.
2. Electric and magnetic field measurements are carried out. The first don’t vary in time so the exposure can be immediately evaluated. The latter varies according to current flow: to
evaluate exposure single measurement aren’t comprehensive and some more analysis has to be accomplished.
3. If values of current flowing in the lines during the field measurements and line phases are known, and correlation between current and field data is higher than 0.9, mathematical
methods can be used, both for single or double lines, to evaluate magnetic field values from current data series at any time.
4. If steps from 1 to 4 are verified, the method can be used to investigate exposure limit
overrun and evaluate average exposure on a long period or field values on a specified time, provided that the current data are available.
Aosta Valley is an Italian alpine region crossed by many high overhead voltage lines (220 kV or 380 kV) which
transport electric power from France and Switzerland to Italy.
Only one
point exceeds the exposure limit provided by the Italian law for the electric field.
All magnetic field values were lower than
exposure limit.
Maximum daily median Annual average 0
50 100 150 200 250 300 350
0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8
Current (A)
Magnetic field (µT) Magnetic field Current
Time
0 1 2 3 4
A B C D E F G Buildings
20052006 20072008 20092010 Years
Maximum daily median Annual average
0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 5
Magnetic field (µT)
Time Magnetic field MoE
Hourly average of the measures
0 1 2 3 4
G1G2 G3 G4 A1 A2 0
2 4 6 8 10 12
G1G2G3G4 A1 A2
Magnetic Field (µT)
Buildings
0 2 4 6 8 10 12
a b c d e f g h i j k l m n o p q r s t u v w x y z aabb
Magnetic Field (µT)
Sites
Max value outdoor Max value indoor Max median indoor Italian limit
0 1.000 2.000 3.000 4.000 5.000 6.000 7.000 8.000
a b c d e f g h i j k l m n o p q r s t u v w x y z aabb
Electric Field (V/m) Max value outdoor Limit
0%
5%
10%
15%
20%
25%
30%
35%
40%
0.0-0.5 0.5-
1.0 1.0-
1.5 1.5-
2.0 2.0-
2.5 2.5-
3.0 3.0-
4.0 4.0-
5.0 5.0- 6.0
Frequency (%)
Classes (µT)
Max value outdoor Max value indoor Max median indoor
0%
5%
10%
15%
20%
25%
30%
35%
40%
0-0.2 0.2-0.5 0.5-1.0 1.0-2.0 2.0-3.0 3.0-4.0 4.0-5.0 5.0-6.0
Frequency (%)
Classes (kV/m)
Max value outdoor
