Detection of High Frequency Conducted Emission using Radiated Fields

The increasing popularity of inverter based Distributed Energy Resources (DERs) and single-phase power electronics based consumer load in North America, has resulted in an increase in emission in the frequency range 2 to 150 kHz, also known as `supraharmonics'. Despite increased awareness, measurement of such emission is beyond the capability of existing Power Quality (PQ) monitoring infrastructure for most American utilities. Further, upgrading existing PQ measurement infrastructure to extend its capabilities is a costly and time intensive endeavor. This paper proposes to overcome this problem by detecting the magnetic field radiated by sources of supraharmonics using cheap `off the shelf' sensors, rather than the conducted emission. It was found that by sensing magnetic fields, the spectrum of supraharmonic emission can be easily determined, while determining the magnitude of the emission using this method may require careful calibration. This paper describes the theory behind this method, the details of its implementation and measurement results from low power rooftop solar inverters. The paper also shows the use of this method to characterize the radiated emission from solar PV plants, by mounting electromagnetic sensors on a mobile robotic platform. Finally, the paper closes with a discussion of the conclusions and the expected future work in this field.