ELECTROMAGNETIC FIELD MEASUREMENTS

121 Pages·2014·12.36 MB·English

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Main activities of ARPA Piemonte in
electromagnetic field protection
• Measurements of electromagnetic fields for
compliance with standard limits (broad band and
narrow band instrumental chains)
• Theoretical evaluation of electromagnetic fields
emitted by sources to be installed on regional areas
(non occupational exposures)
• Managing of a regional register of emf sources by
a data base sources (non occupational exposures)
• Generation of standard fields in metrological
laboratory for calibration of small antennas and
broad band meters (national calibration service
accredited laboratory)
EXPOSURE EVALUATION
Exposure evaluation provides information necessary to perform risk
assessments. Two methods are available:
THEORETICAL ESTIMATION
Theoretical calculation of exposure levels by provisional models
MEASUREMENTS
Inspection on site with instrumental chains
EXPOSURE EVALUATION
THEORETICAL ESTIMATION
Theoretical exposure estimation is necessary:
 before construction of new installations for certifying
compliance with limits;
 to determine georeferred map of field values emitted
from one or more sources all over the investigated area;
 to determine the places where high levels of field
exposure are expected.
ELF ELECTRIC AND MAGNETIC FIELDS
POWER LINE CHARACTERISTICS
t sag
h
g
i
e
h

n
o minimum height
l
y
p
span length
Line conductors approximate the path of a catenary curve (wire strung between two points
 x x 

e  e
k k
 
(x)  k 1
 
2
 
 
k – is the ratio between horizontal mechanical tension [N] and the
weight per unit length [N/m]
Typical magnetic field profile for power lines
with different pylon shapes
V = 380 kV ; I = 1000 A


 dl  r
B  0 I 
3
4  r
Double Circuit Three Phase Power Line
Different phase conductor
arrangments
Magnetic field profile for
different conductor
arrangements
Power line characteristics necessary to calculate magnetic flux
density
• Effective current value
• Span geometry to find catenary curve equation
• Number and position of conductors (pylon shapes)
• Span length
• Phase conductor arrangements in double three phase power lines
Typical electric field profiles for power lines
campo elettrico
6000
5000
380 kV
4000
m)
V/ 3000
(
E
2000 380 kV
1000
0 220 kV
-50 -40 -30 -20 -10 0 10 20 30 40 50
distanza da asse linea (m)
Valutazione del rischio da esposzione a campi elettromagnetici in ambienti di vita e di lavoro e tecniche di misura
ISPRA - Roma 4 - 6 giugno 2013