Dolev company with a unique method for lowering the magnetic field (radiation) around populated areas is an active shielding method,
With this method it is possible to limit the magnetic field of the source wave by using the creation of another magnetic field which is the same in magnitude as the original magnetic field but opposite in direction.
These inverted fields are usually created by electric currents that flow to active coils, these coils create the magnetic field in the opposite direction to the direction of the source wave.
The active shielding is effective in limiting radiation (magnetic fields) in the vicinity of overhead / high voltage lines, since these power lines are a uniform source of radiation that only changes according to the current flow by the electric company.
What is the active protection system?
An active protection system, a square loop that conducts a current must be produced and thus will actually cause the development of a magnetic field in the conducting loop,
The active shielding system depends on the characteristics of the offending field and the ability of the system that produces the opposite field to meet these characteristics so that a significant attenuation of the field is obtained.
From the simulation result, it can be seen that the maximum magnetic field strength in the high voltage line is 12.185uT, at a calculated distance of about 10 meters from the power line, the simulation results are 9.55uT, and at a calculated distance of about 20 meters from the power line, the simulation result is 4.62uT.
The installation of the system requires preliminary preparations, Dolev Electromechanika Company performs all the theoretical engineering preparations, among other things, performing the analysis of the area designated for shielding against magnetic radiation and performing measurements in order to know where the measurement sensors should be placed in order to give the system maximum efficiency in lowering the field to the accepted values. As well as all the constructive planning of the system components while emphasizing the electricity law and municipal bylaws.
Measurements before and after the application of the active protection:
The measurements presented were performed before the implementation of the active system and after its implementation, the measurements were performed using equipment for direct measurement of magnetic and electric fields for low frequency when the measurement was performed under conditions of maximum current consumption in order to estimate the radiation intensity and the effectiveness of the shielding for the worst case.
Measuring equipment:
Radiation risk meter made by PMM company model EHP50C, for the frequency range 5Hz – 100kH.
The measurements shown are calculated measurements that were performed using the active shielding system where the magnetic flux levels before the application of the shielding are the actual levels and the magnetic flux levels after the application are the levels that the system will be able to reach given the nature of the system’s calibration.
The first calculated measurement that is shown was performed in the northern part of the building in front of the center of the high voltage line at a height of 1 meter above the ground.
The Dolev company is the only company in Israel that can provide an active protection system
For radiation from high voltage lines of an electricity company
In Israel, 10 active protection systems have been established since 2007.
