Experimental study of the relationship between maximum common mode current and maximum magnetic field strength using a simple power distribution line model

Abstract

The relation between maximum common mode current and maximum radiated magnetic field strength was experimentally studied using a simple power distribution line model. The common mode current was measured along the cable and the radiated magnetic field strength was measured around the model. They were evaluated using the S 21 parameter. The frequency characteristic of both the maximum current and the maximum strength showed a closely similar pattern. Our evaluation of their correlation indicated that the relation between the maximum common mode current and the maximum radiated magnetic field strength could be represented by a straight line, and that 80% of the measured data was contained within 2 dB of the regression line.

Evaluation of influence to electromagnetic environment on outside of building by PLC system using three‐wire three‐phase power line

“…The source of radiated emission is common‐mode current, 8 and electromagnetic field generated by power lines inside a building propagate outside through the walls. Thus, we used relationship between maximum common‐mode current flowing in power lines and maximum equivalent electric field strength at a distance of 10 m 13 and shielding effect of building outer walls for estimation. This section compares the assumed results with electromagnetic environment at 240 points at PLC turned OFF to discuss why no difference in electromagnetic environment was observed between PLC OFF and PLC ON.…”

“…The wave source of equivalent leakage electric field is common‐mode current 8 ; thus relationship between common‐mode current and equivalent leakage electric field in three‐wire power lines was explored to show that the ratio between normalized maximum output |S 21,C | of current probe and normalized maximum output |S 21,M | of loop antenna placed at 10 m apart from power line is proportional to frequency 13 . However, characteristics of current probe and loop antenna are not taken into account in this report, and ratio between maximum common‐mode current I c ,max and maximum equivalent electric field strength E max at 10 m was found using Equation .…”

“…PLC modems used in this measurement were products by Toho Technology Corp. rated at 200 V and type‐designated in accordance with Japan's PLC technical standards 9,15 . Emissions radiated from power lines equipped with PLC are known to be produced by common‐mode current flowing in the power lines 13 . Thus, according to the technical standards, 9,15 T‐ISN (model: T‐ISN (PLC) by Kyoritsu Technology Corp.)) was used to determine magnitude of common‐mode current underlying the radiated emission; PLC common‐mode current measured by average‐detector is shown in Figure 2.…”

“…However, in case of three‐wire three‐phase distribution systems, ground wire is not necessarily connected to the same distribution board as the other two wires, and may be attached in mid‐course; that is, power line connections are different in three‐wire single‐phase systems and three‐wire three‐phase systems. Thus, a number of studies were done on leakage characteristics of PLC signals in three‐wire three‐phase distribution systems; these studies dealt with evaluation of impedance characteristics of distribution lines as seen from distribution board, 12 exploration of relationship between common‐mode current and electromagnetic radiated emission in three‐wire power line model, 13 and electromagnetic environment measurement outside factory buildings in case of PLC using three‐wire three‐phase distribution system 14 . However, as regards electromagnetic environment measurement outside of factory buildings, measurement positions were limited, while there were no details provided about measurement methods and examples.…”