Electric Power Systems Research 90 (2012) 42–54 Contents lists available at SciVerse ScienceDirect Electric Power Systems Research jou rn al h om epa ge: www.elsevier.com/locate/epsr Experimental measurement, analysis and prediction of electric and magnetic fields in open type air substations Charalambos P. Nicolaou a , Antonis P. Papadakis b,∗ , Panos A. Razis a , George A. Kyriacou c , John N. Sahalos d a Department of Physics, High Energy Physics Group (HEP), University of Cyprus, PO Box 20537, 1678 Nicosia, Cyprus b Department of Electrical Engineering, Frederick University, Pallouriotissa, 1036 Nicosia, Cyprus c Department of Electrical and Computer Engineering, Democritus University of Thrace, 12, Vasilissis Sofias, 67100 Xanthi, Thrace, Greece d Department of Electrical and Computer Engineering, University of Nicosia, 46 Makedonitissas Avenue, PO Box 24005, 1700 Nicosia, Cyprus a r t i c l e i n f o Article history: Received 19 October 2011 Received in revised form 16 March 2012 Accepted 26 March 2012 Available online 3 May 2012 Keywords: Electric and magnetic field measurements Experimental modeling Open type air substations International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines a b s t r a c t In this paper, the electric and magnetic flux density values in open type air substations are analyzed. For this reason, an extensive measurement survey was conducted to identify potential large sources of electric and magnetic fields within seven 132/11 kV open type air substations always having them compared with the International Commission Non Ionizing Radiation Protection (ICNIRP) safety guidelines published in 1998. The maximum electric and magnetic flux density values obtained in the open air circuitry units are found to be 7696 and 7306.5 V m −1 and 45.89, 38.11, 35.30 T, which are 1.30, 1.37, and 10.9, 11.3, 14.1 times below the safety guidelines of the ICNIRP. In one of the coil rooms, the magnetic flux density was found to be 6.26 times above the safety guidelines, constituting an immediate threat to working personnel of the substation. Furthermore, a simplistic theoretical methodology based on experimental measurements is proposed that establishes a linear correlation between the transformer current and the maximum magnetic flux density based on Biot–Savart law, provided that the distance from the source remains constant, to predict the magnetic flux density by extrapolation to the permitted and nominal currents and compare them to the safety guidelines of the ICNIRP. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Electrical energy is generated, transmitted and distributed via generation, transmission and distribution networks. The transition of electricity from the transmission to the distribution network is achieved via substations. These substations reduce the operating voltage, and forward the increased current to the distribution net- work of the electric grid. There are three types of substations, the open, closed and underground type substations. The location and cost will ultimately determine what type of substation should be used. At areas where there is very limited space, such as in urban areas, closed type substations are preferred, where most of the equipment is kept in a building. Open type substations tend to occupy more space than closed type substations, and since they are cheaper to build, they are preferably used at the country side, where there is plenty of space available. In cases that substations must ∗ Corresponding author. Tel.: +357 99 334791; fax: +357 22 108532. E-mail addresses: ncharal@ucy.ac.cy (C.P. Nicolaou), eng.ap@frederick.ac.cy (A.P. Papadakis), razis@ucy.ac.cy (P.A. Razis), gkyriac@ee.duth.gr (G.A. Kyriacou), sahalos.j@unic.ac.cy (J.N. Sahalos). have minimum environmental impact, underground substations are preferred. In open air type substations, the very high voltages and currents generate high electric and magnetic fields that may pose a threat to working personnel and general public. There is a general concern from the public for any possible health effects that these fields may cause due to the ever increasing cancer incidents in the Republic of Cyprus the last few years. This concern has also been shared worldwide for many years, thereby a series of phenomenological and epidemiological studies have been performed in an attempt to clarify whether electric and magnetic fields are harmful to human beings [1–5]. These studies have shown that the ionizing radiation at the very high frequency range is harmful [6–10]. For the low frequency radiation, which is also defined as non- ionizing radiation, excitation of the molecules occurs instead of ionization, inevitably reducing the possibility of alternation of the molecular structure of the human DNA. Nevertheless, it has not been proven beyond any doubt that this is the case, especially in the long run, even though numerous extensive studies have been per- formed throughout the years [11–15]. Due to the general concern of the consequences of electric and magnetic field exposure, most of the counties of the European Union have adopted the safety guide- lines of the ICNIRP published in 1998 [16], which state the amount 0378-7796/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.epsr.2012.03.014