Power frequency magnetic fields of medium voltage switchgear. A concept for evaluating the field strengths under an exposure limit point of view

Power frequency magnetic fields caused by medium voltage switchgear might disturb sensitive equipment such as video display units or might even conflict with exposure limits concerning people living or working near such installations. In order to prevent possible influences or adverse effects the knowledge of the magnetic field levels produced by the switchgear is necessary. A suitable concept to get magnetic field distributions around substations is described. This concept considers the emissions of switchgear from a general point of view and avoids investigating actual substations in detail. Rather it allows derivation of the field strength levels from the data of the switchgear type.