On the suitability of the CISPR 16 method for measuring conducted emissions in the 2–150kHz range in low voltage grids

The IEC 61000–2–2 standard defines the compatibility levels to evaluate the conducted disturbances in the low voltage grid for the 2-150 kHz range. For frequencies 9–150 kHz, they are defined in terms of quasi peak values measured according to CISPR 16–1–1 standard, but no clear guidance is given on how to apply this standard to grid measurements. The definition of the method in CISPR 16–1–1 accepts a wide range of different implementations, all of them fulfilling the compliance requirements. The reasons are that the standard does not propose a fixed implementation but a ‘black-box’ approach, and some of the proposed configuration values are non-normative and/or wide tolerances are allowed. In this context, some parameters have a pivotal role in the results provided by the method. The impact of variation of these parameters on the measurement results is addressed in this work. In particular, the accuracy requirements and the reproducibility issues of the standard are studied. For that purpose, a high number of different compliant implementations have been developed and the influence of different features of the CISPR 16–1–1 method on the results of these implementations is identified and analyzed. The results show that the wide tolerances allowed by the CISPR 16 specification impede the comparison of results provided by measuring receivers based on different implementations of the standard. Results of the study also show that reproducibility issues for the same input signal may be relevant and generate inconsistences. Moreover, a fixed specific configuration does not ensure that uncertainty issues are solved, as the technical approach used in the implementation of the damped meter has a strong influence on the outputs. An unambiguous guidance of digital implementation of the standard could fix these issues.