Methodology and Power Spectral Density Limits Proposal for Non Intentional Emissions in frequencies below 150 kHz

IEC 61000-2-2 has been evolving to establish compatibility levels for low frequency conducted disturbances and signaling in public low voltage (LV) power supply systems in the frequency range 2 kHz to 150 kHz. One of the objectives of these compatibility levels is to guarantee coexistence of NB-PLC (Narrowband Powerline Communications) technologies, a widely extended solution among utilities for several LV applications such as smart metering, with the presence of Non-Intentional Emissions (NIE) injected in the distribution grid by electrical and electronic devices. However, as it has been demonstrated in several researches, the aforementioned compatibility levels are not sufficient to guarantee a good performance, and new generation NB-PLC technologies (as any other telecommunication technology or system) are impaired when such levels are encountered in the grid. The main reason is that the limits set in Electromagnetic Compatibility (EMC) standards are based on quasi-peak values measured over 200 Hz bands and not on total power injected over the operating frequency range, which actually is the parameter impacting NB-PLC technologies performance. This paper presents the results of a group of tests that demonstrate this limitation, and proposes a complementary limit in terms of unintentional total power injected (Power Spectral Density or PSD) to complement the existing limit definition. The spectral power density of NIE should be limited in EMC standards to ensure a correct coexistence of NIE sources and NB-PLC technologies.