Is CISPR quasi-peak an appropriate metric for evaluating power line communications?

Power line communication (PLC) technologies are gaining relevance transmitting the electricity telemetry information measured by smart meters. Conducted disturbances generated by rectifier- and inverter-based devices are unintentionally injected in the low-voltage (LV) grid in the 2-150 kHz range, where PLC data are also transmitted. To avoid the impact of conducted emissions on equipment and PLC transmissions, the IEC 61000-2-2 standard defines the compatibility levels, described in terms of quasi-peak (QP) values, applying the CISPR 16-1-1 method. This contribution analyzes the adequacy of the QP detector, as defined in CISPR 16-1-1, to analyze this scenario: firstly, to evaluate the performance of the QP detector for PLC transmission bursts and, secondly, to assess impulsive emissions that may degrade PLC transmissions. For that purpose, this work examines the specifications of the CISPR 16-1-1 method against the power spectral density specifications of the most used open PLC technologies (PRIME and G3-PLC). In addition, this analysis is applied to recordings measured in the LV grid containing PLC frames and impulsive disturbances. The results reveal that the QP detector is blind to fast amplitude fluctuations, impeding a proper measurement of PLC frames. Consequently, an advanced metric is required to assess PLC transmissions and impulsive disturbances effectively.