Comparison of measurement methods for the frequency range of 2 kHz to 150 kHz

The accurate and comparable measurement of voltages and currents in the frequency range of 2 kHz to 150 kHz is a basic requirement for the assessment of emission limits, compatibility levels and immunity limits and therefore important for a consistent standardization framework. Currently a measurement method for frequencies of 2 kHz to 9 kHz exists in the informative annex of IEC 61000-4-7, which could be extended in application to 150 kHz. The committee draft for vote of IEC 61000-4-30 Ed.3 proposes a new method for the frequency range of 9 kHz to 150 kHz, which is different from the aforementioned one. This paper identifies parameters with impact on measurement results and compares both methods based on multiple test signals, which are derived from lab measurements of different equipment and field measurements in low voltage networks. The comparison is carried out regarding the necessity of filters, chosen bandwidth, impact of band boundaries and methods for aggregation in time. The results show that the two measurement methods have individual benefits and drawbacks. Finally, the paper proposes several approaches to combine the advantages of both methods.