Year : 2019  |  Volume : 23  |  Issue : 2  |  Page : 63--67

Electric field exposure assessments and a novel control method for buildings installed nearby high-voltage lines


A Shemshadi, AK Maleki 
 Arak University of Technology, Electrical Engineering Department, Arak, Iran

Correspondence Address:
Dr. A Shemshadi
Arak University of Technology, P. C. 38181- 41167, Arak
Iran

Abstract

This essay presents a review of new methods for electric field value assessment in high-voltage areas. For buildings that are placed near high-voltage transmission line corridor, two main scenarios are modeled using finite element method. A new approach to reduce electric field value is also simulated and the results are discussed in detail. The results are compared to related standards values. In some cases the improvement rate exceeds 65%.



How to cite this article:
Shemshadi A, Maleki A K. Electric field exposure assessments and a novel control method for buildings installed nearby high-voltage lines.Indian J Occup Environ Med 2019;23:63-67


How to cite this URL:
Shemshadi A, Maleki A K. Electric field exposure assessments and a novel control method for buildings installed nearby high-voltage lines. Indian J Occup Environ Med [serial online] 2019 [cited 2020 Sep 28 ];23:63-67
Available from: http://www.ijoem.com/text.asp?2019/23/2/63/267757


Full Text



 Introduction



A lot of high-voltage apparatus which are installed in power networks, such as high-voltage transmission lines, when energized, produce high magnitude electric field that may affect human body.[1],[2],[3],[4] Electric field is calculated by a simple formula.

Electric field may cause and initiate some cancer disease specially leukemia in exposed human body [Figure 1]. Few relatively about static electric field effects on human body are undertaken like ICNIRP 2003 dosimeter aspect report that is usable for limiting exposure to time varying electric and magnetic fields (1-100kHz).furthermore Some studies sponsored by The World Health Organization/International Agency for Research on Cancer (IARC), were published and mostly demonstrate the effect of extremely low frequency fields (like 50 Hz) also.[5],[6],[7],[8],[9],[10] For 3 kHz -300GHz another useful IEEE standard C.95.1 is also provided at 2005.[11]{Figure 1}

 Importance of Electric Field



We have various sources they make fields. Some are natural and some are artificial. Academic and industrial studies of effect of field on health are focused on fields by artificial source like power transmission line, underground cables, induction furnaces, spot welding and home application like refrigerator, television and even some high frequency devices like mobiles and computers because their utilities are grown up every day and their field pollution too.

In recent decade field pollution increased about 100 times. Four-fold due to increased range and twenty-five times due to increased frequency. In first education about effect of field on body Nancy Wertheimer fined children who live near of power line are four times more exposed to leukemia and not just leukemia even every sick that is relate to unusual growth of cells.[1]

Measurement of field have so many positive point in industrial area too, for example we can find deactivation of insulate of wire or find the metal of our plane that have no color because of having better radio communication needs any repairing (we know standard level of field rate around the plane) or non-contact mensuration of charges cells or so much useful usages.

Measurement Orientation

We can calculate field power with two ways. In first the measurement happened in a one time and in single-side measurement like [Figure 2]. This method with a good location give us field in maximum. This is really simple way but just inform from maximum amount and it's trustable only in a correct and accurate locate.{Figure 2}

Second method give us field in three-side measurement. It can calculate with one sensor in three times measurement or by one device that have three sensor perpendicular to each other. The achieved amount is put in Laplace equation and field calculate [Figure 3].{Figure 3}

 Measurement Methods



For measurement we compare three general bench of methods. First methods that use from induction probe second devices use induction probe and a turner field measurement from ac to dc for calculating and finally optic methods.

Induction probe

The basic principle of the operation of measuring the electric field using the probe induction is to allow a conductive sheet or antenna to be balanced with the local field, and then measure the voltage in the plate as showed in [Figure 4] and calculate. Electrometers are very high impedance electrical measurements that can be used to measure the voltage or load on the induction plate. with this knowledge one plate use as a side of capacitor and another for second plate of capacitor.{Figure 4}

Unfortunately, this method is really sensitive against of external field that induct from measurement environment.

Field mills

A common method for measuring electric fields is to create a pseudo-AC field by rotating a shutter near of a capacitor measuring. In another hand this measuring is undoubtedly like induction probe with this different that field source effected on plate is a ac field [Figure 5].{Figure 5}

We have more trust but field mills devices are more complex and expensive and they need periodic repairing because of movement part. They are bulky application and have hardship setup.

Another shape [Figure 6] of these field mills have a cylinder rotating shutter that fill all around of capacitor plate and it greatly reduces the environmental error.{Figure 6}

Optical methods

As it was talked about measuring environment specially every mental part around of induct probe has a strong effect on calculation.

Optical sensors work usually on POCKEL effect. POCKEL says dipole properties of a crystal changed under a field and it has a direct effect on passing laser light and with variety of optical system architectures laser speed is detectable. Crystal of Lithium-Nayobat by LiNbO3 chemical formula and Bismuth-Grammates by BiGe3o12 chemical formula are two more useful materials for optic sensor.[2],[3]

Laser light divide to two part. One part for reference that is insulated from field or through from a direction without field and another from the crystal is influenced by the field [Figure 7]. In the end of line by comparing two light speed field power is find.{Figure 7}

 Exposure Restrictions



Except industrial application of knowing intensity of the field and field flux and researching on body effectiveness of field made a massive part of scientists probes and united nation organization have a specific attention on this subject. So a special unit confirm for it and that is specific absorption rate (SAR). SAR represent the amount of radiation per kilogram of every matter will release a joule of energy and it measure with two methods.

At first a probe estimate temperature of matter in field and temperature change can aware us from SAR with equation 1.

[INLINE:1]

C is female tissue coefficient and is temperature altering in centigrade unite and is the time of measurement in seconds.

In another method, the effect of the field on the body is calculate by equation 2 and by a probe that sense electric field and sometimes inter to body.

[INLINE:2]

σ is conductivity coefficient of matter with centimeter per meter (S/m) unit and is mass density in kilogram per square meters (Kg/m2) E is the root mean square(RMS) value of the field in volt per meter(V/m) at [Table 1] the frequent and intensity of the field on different parts are showed.{Table 1}

At [Table 2] measurement field for some home application and some furniture are collected.{Table 2}

In [Table 3], [Table 4], [Table 5] ELM's measured near three base in Tehran state and results are comparable with [Table 1].[4] (Frequent of Iran power lines is 50 Hz).{Table 3}{Table 4}{Table 5}

 High Voltage Effect on Nearby Buildings



With considering these features and by limited component design and using COMSOL Multiphysics software we study in12 scenarios (without protector and with protector in 6 different heights of building and fence) effect of electric field on body in near places that people have their home before constructing power transfer system and they have not any another choice and results comes in [Table 6] but first the best distance of fence select by using result of [Figure 8].{Table 6}{Figure 8}

Rules and distance constraint are get from usual systems and maximum effect in head issue is compared by allowed amount also material of fence is Iron and cables are aluminum conductor steel reinforced (ACSR) The allowed amount for general places from [Table 1] is [INSIDE:1]. Transmit systems followed by Europe standard in 50 Hz and 230 Kilo volt. We study in home and outside of home on a body with three issues, liver with εr=330 head with εr=120 and fat with εr=150 and for home walls cement with εr=150 is opt.

 Discussion



By results of plotting effect of electric field by changing fence distance from home in two situations and on couple body in left and right of home [Figure 9] we find closer fence made better time dependent conditions and comparing these data for example in state 6 made clear that a near fence against an underline installed fence have 28.8 percent more efficient protect from received electric field doze.{Figure 9}

Also analyzing these visualizing in several scenarios [Table 6], confirmed installed fence providing effect and the better choice is a higher fence between home and lines. The percentage of the reduction of the field effect at best was 79.07% and at worst was 17.9% e.g. from a dangerous doze like 12018 vm -1 to a reasonable level like 4000vm -1 that is in unforbidden range.

 Conclusion



These huge effect of field on body resourced by every electrical device in home or occupation area precautious behavior for protecting body health is more pronounced. Insulating electrical devices or using by more distance can be provide safer utilities also for some high frequency devises like mobile receiving signals and processing by mobile and using them by a hands-free against the using microphone and speaker of mobile directly are good advices from United Nations [6] and for neighborhood of high voltage transmit system and for peoples who live by economical compel, a metal protector fence can decrease time dependent effect of electric field [Figure 10] and [Figure 11].{Figure 10}{Figure 11}

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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