Measurement of voltage and current harmonics for frequencies up to 9 kHz according to IEC61000-4-7

Abstract

The number of distributed energy sources (DER), the huge increase of loads with switching supplies and the massive use of compact saving lamps brings the need to measure and evaluate voltage and current up to 9 kHz. Annex B of the latest update of the IEC 61000-4-7:2002/A1:2008 unifies the length of the basic time window for the evaluation of signal components up to 2 kHz and for the evaluation of signal components in the range of 2 kHz-9 kHz. This fact, together with latest measurement technologies, allows the simultaneous evaluation of signal components in the entire range of 50 Hz-9 kHz, even for very small amplitudes of frequency components. This paper analyzes and describes the technical problems to be solved in order to meet the requirements of IEC 61000-4-7:2002/A1:2008. The paper presents the results of measurements performed on different loads with expected significant signal components in the frequency range of 2 kHz-9 kHz, such as PC power supply. Compatible levels for frequency components in the range of 2-9 kHz are discussed.