Faculty of Electrical Engineering, Technical University of Iasi, Romania
From the multitude of electric and magnetic field sources located in the immediate vicinity of contemporary man (underground power cables, Low and Medium Voltages distribution lines, electric transport, appliances, house wiring), only the source represented by Overhead (very) High Voltage Power Lines (OhHVPL)will be addressed.
In the first part, a synthetic presentation is made of how these extremely low frequency fields interact with the human body.
The main international standards, whether or not transposed into national legislation governing human exposure to these factors, are then reviewed. Emphasis will be placed on electro-physiological and epidemiological considerations that led to the setting of the (covering) limits accepted by these rules, guidelines, norms.
OhHVPL designers adopt solutions that are primarily imposed by energy and economic considerations, in order to increase the line efficiency while decreasing the losses.
For a specific power flows during steady state, the following are just some of the first questions that start the project: what might be the optimal voltage, what type of tower should be used, at what level are they implanted in the ground, what should be the span and the associated sag, a simple, double or even quadruple three-phase configuration should be adopted?
The purpose of our discussion is not to show to what extent parameters of the transmission line influence its performance, but to find out the influence that certain correct solutions in terms of economic efficiency could influence the values of locally generated electric and magnetic fields.
For the selected case studies we mainly used configurations implemented by ”Transelectrica”, the Romanian operator of the National Electric Power Transmission System. The thousands of in-situ measurements, performed with portable, handy spectrum analyzers were enhanced and expanded using simulations developed with several specialized software, which use different numerical methods to solve Maxwell's equations in the ELF field.
Differences between the results provided by these software are interpreted and explained.
The influences of current, voltage, clearance above ground, soil resistivity and balance within (between) circuit(s) are only synthetically presented, both in absolute and relative values.
Particular emphasis is given to phase transposition solutions and especially to the various configurations of bundle conductors. Although these are quite expensive solutions, they are widely used, because their costs are amortized by reducing losses through Joule effect, through corona effect or by minimizing the unbalance due to unequal inductance and capacitance of the phases.
But what would be the effect of these solutions on the values of the magnetic and electric field, measured and simulated at a height of 1 m above the ground, as required by the exposure standards? Detailed answers are required!
The cumulative influence on the fields (within the inner part of the 90 ° angle) that a corner tower configuration of the transmission network can have is also analyzed.
Using either simplified models or extremely detailed anatomical models, the values of the currents induced in the human body are calculated and discussed.
Finally, some solutions to reduce the electric and magnetic field levels of ELF from the perspective of human exposure are addressed.
The presentation concludes with a series of cautious but realistic recommendations, determined by the (objective) lack of indisputable epidemiological studies on the long-term effects and cumulative contributions of several potentially harmful factors on human health.
Alexandru Salceanu (ResearcherID: B-6307-2015) is full professor with the Faculty of Electrical Engineering, Technical University of Iasi, Romania, being doctoral studies supervisor.
His research interests include Electrostatic Discharges, Electromagnetic Compatibility and E&M Fields Influence on Human Beings (measurements, modeling and simulation).
He is IEEE senior member, (EMC and IMS-TC 13), Treasurer of the IMEKO General Council and Chairman of IMEKO Technical Committee nr.4. He is Coordinator of the Research Center "Metrology, Measurement Systems and Innovative Materials-METROS”.
Professor Salceanu is Section Editor and member of the Editorial team of ACTA IMEKO (the e-Journal of the International Measurement Confederation).
He acts since 2010 as chairman of the International Conference on Electrical and Power Engineering EPE, (included in the IEEE meetings database). He was the chairman of the 22-nd IMEKO TC-4 Symposium. For other 3 International Conferences technically sponsored by IEEE (International Symposium on Advanced Topics in Electrical Engineering-ATEE, International Conference on Applied and Theoretical Electricity-ICATE and International Conference SIELMEN) he is currently acting as member of International Program Committee, reviewer and session chair.
He is presently member of 12 scientific and professional societies, member of 10 scientific program committees and reviewer for 16 journals: 15 internationals (10 WoS, 5 BDI) and 1 national.
He is author, co-author or editor of 19 books and 227 data base indexed scientific papers and patents.