Magnetic field distribution around power transmission line viewed from actual line current condition

For the precise measurement of the magnetic field around a power transmission line, it is important to consider many conditions affecting the magnetic field: conductor sag; three-phase current; and various conditions of line current, such as unbalanced current, superimposed harmonics, etc. In this paper, the authors measured the current flowing in a power transmission line and its magnetic field distribution simultaneously. In addition, they measured the conductor position (sag) and the current in an overhead ground wire. As a result, the magnetic field distribution under the current condition of about 2-3% unbalance rate largely changed from that under balanced current conditions.