Magnetic fields caused by electrical equipment typically have to be reduced in order to comply with the legal limits in “places of sensitive use”. Two reference projects are described below.
On the ground floor of the property in Zurich West, a former industrial space is being converted / converted into office space with permanent workstations. Next to the rooms, which are considered “places of sensitive use” (OMEN) according to the NISV, there is an existing transformer station.
Systron was commissioned to map the actual situation with a magnetic field calculation and to develop a customer-specific shielding solution. Subsequently, we were allowed to carry out the complete installation including proof of measurement.
The following picture shows the actual situation as an isoline picture simulated with software EFC-400.
The simulation results showed that the 1µT system limit is clearly exceeded at the OMEN.
Based on the results, a suitable shielding solution with Systron PowerShield® was developed and verified by simulation.
The developed solution, with a shielding area of about 225m2, was installed as planned.
In order to demonstrate the effectiveness of the developed solution in practice, measurements of the “actual situation” were carried out before and after installation of the Systron PowerShield® shielding. The effectiveness of the shielding at the measuring point with the highest magnetic flux density is shown below.
The results show that the maximum value of the measured 50 Hz fields (green curve) has decreased from 30’082 nT to 234.5 nT at this measuring point. Thus, the fields at this point were reduced by a factor of 128 or by 99.2%. Systron’s measurements were verified by an engineering firm.
The measurements also showed that the NISV limits were clearly complied with after installation of the shielding.
On behalf of the Canton of Zurich, ewz planned the transformer stations Y13, Y18, Y34 and Y38 for the University of Zurich at the Irchel campus. Above all stations are locations with sensitive use (OMEN).
Systron was commissioned to calculate the magnetic flux density for all stations and to implement the proposed shielding measures to comply with the NISV.
A total of 520 m2 of Systron PowerShield® area shielding was installed as part of these projects.