3D shielding modelling and design of three phase current limiting reactances

Current limiting reactors are commonly employed in power systems to limit the flow of large currents during faults. Due to their dimensions and the high currents flowing through the coils under normal operating conditions, a magnetic induction in the order of thousands and hundreds of µT appears in the surrounding space, even at several meters, overcoming frequently the limits established by the international guidelines concerning the short-term exposure of both workers and the general public. Furthermore, some countries have also their own regulations for limiting the exposure of the population in areas with permanence. Consequently, reactors designers and customers must take this problem into account, selecting the most suitable position where to install the inductors to respect the limits of exposure to magnetic fields. To deal with this issue, in this work different solutions based on passive shielding systems are proposed for the mitigation of the magnetic fields caused by current limiting reactors. Different shielding configurations are analysed consisting of different shapes, thicknesses and shielding materials. Their mitigating efficiency is evaluated by means of 2D and 3D simulations solved numerically by the finite element method, highlighting the key strengths of the proposed solutions.