Impact of Third Harmonic Currents on Magnetic Field Measurements from Distribution Lines

Experimental work was done to validate computed results of magnetic fields from distribution lines with current harmonic distortion. Measurement results agree well with simulation. Results show that the magnetic field could be as much as 35 times greater (total-harmonic distortion (THD) = 20%) if the harmonic distortion is overlooked. We show that a discrepancy occurs between the maximum and resultant definitions of the magnetic field value when the harmonic currents are considered. Furthermore, the paper shows that the variation in phase displacement of the 3rd harmonic current may increase the field at one side while decreasing it on the other side. This, in fact, may help avoid the critical side where field exposure hazards are more likely.