It is known that high voltage transmission lines are used for energy transmission to decrease
power losses and increase system efficiency. The energy, which is transmitted at high
voltages for long distances, is distributed at medium voltages through a step-down
transformer near residential areas. Then the energy is introduced to the end users by reducing
the voltage to lower levels. Today, these transformer stations are planted as close as possible
to living areas to enhance system efficiency. These transformer stations placed in urban areas
cause magnetic fields to occur due to the reason of carrying high load currents. Especially due
to the decreasing voltage level at these mentioned transformer substations, the load current
increases significantly. Because of that, magnetic field strength is enhanced near these urban
areas. Additionally, according to the developing technology, characteristic currents of
electrical loads are changed at recent years. High penetration of power electronic loads in
industrial applications cause a significant increase in high frequency components in the
current drawn from electric grid. Similarly, these currents also generate magnetic fields which
consists high frequency components. As known there may be some influences to people who
is exposed to a magnetic field over a threshold value for quite a while. For this reason, some
standards were published to limit the magnetic field strength and exposure time values. In this
study, magnetic field variations around a transformer are analyzed for several loading
conditions with and without harmonics. For this purpose a test system with electronic load
bank, transformer and regulator is built on laboratory and tests are done in several loading
conditions. The gathered results are analyzed for sinusoidal and non-sinusoidal current
conditions considering the standards.
Keywords: Human Health, Transformer, Harmonics, Magnetic Field
[1]
Stephen J. Chapman,et al.
Electric Machinery Fundamentals
,
1991
.
[2]
George A. Kyriacou,et al.
Simplistic numerical methodology for magnetic field prediction in open air type substations
,
2011
.
[3]
Paolo Ravazzani,et al.
Potential health impacts of residential exposures to extremely low frequency magnetic fields in Europe
,
2013
.
[4]
P. Ravazzani,et al.
Potential health impacts of residential exposures to extremely low frequency magnetic fields in Europe.
,
2013,
Environment international.
[5]
Edriss Ali,et al.
Effects of magnetic field of power lines and household appliances on human and animals and its mitigation
,
2010,
IEEE Middle East Conference on Antennas and Propagation (MECAP 2010).
[6]
Leeka Kheifets,et al.
Extremely low frequency magnetic field measurements in buildings with transformer stations in Switzerland.
,
2011,
The Science of the total environment.
[7]
R. Ottoboni,et al.
Low frequency magnetic flux density measurements based on navigation agents
,
2004,
ISA/IEEE Sensors for Industry Conference, 2004. Proceedings the.
[8]
Fabriziomaria Gobba,et al.
Extremely low frequency-magnetic fields (ELF-EMF) occupational exposure and natural killer activity in peripheral blood lymphocytes.
,
2009,
The Science of the total environment.
[9]
H. Brüggemeyer,et al.
Performance of low frequency magnetometers to non-sinusoidal magnetic fields
,
2013
.