Optimum passive shields for mitigation of power lines magnetic field

This paper presents a systematic semiheuristic method to locate the most effective passive shield with the aim of mitigating the magnetic field generated from overhead power lines, at both sides from the line. As an example, the method is applied to two different phase arrangements used frequently in EHV: flat and double-circuit vertical, with shields of a single loop (two conductors), two loops with a common conductor (three conductors), or two separate loops (four conductors). Numerical results of mitigation, obtained with different solutions and further discussion, are also provided.