1. Emission by modern energy-efficient equipment and possible impact on communication

2. Content: Distortion at electronic loads
Measuring technology from 2 to 150 kHz
Analyzing techniques
Measurements of light equipment
Trends of harmonics and power consumption at LAN-parties

3. Remains from switching
Scheme of SMPS for power conditioning

4. Diversity of current drawn by electronic loads
Examples of small electronic devices containing power electronics (plus an incandescent lamp).

5. Fig. 2.3 Harmonic spectrum of the current waveforms shown in Fig. 2.2.

6. Diversity of current drawn by similar electronic loads
Current drawn by 6 different ballast powering 2x49 W tubes

7. Measuring technology 2 to 150 kHz

8. Standards covering different frequency range
Harmonic range (up to 2 kHz) is covered by IEC , IEC , IEC
2 to 9 kHz is covered by IEC , Annex B
9 kHz and up is covered by CISPR 16

9. Some features of IEC 6100-4-7 Annex B (2 to 9 kHz)
Prescribes time domain based measurements
A band-pass filter is prescribed between 2 to 9 kHz. The attenuation below 2 kHz is used to damp the fundamental > 560 times (55 dB). The attenuation above 9 kHz is used to avoid anti-aliasing. This can be skipped if the dynamic range of the instrument is large enough
The sampling frequency should be chosen in accordance with the established rules of signal analysis
A 200 ms rectangular window of the signal should be taken, not necessary synchronized with the fundamental

10. Some features of IEC 6100-4-7 Annex B (2 to 9 kHz)
A DFT should be used resulting in 5 Hz frequency separation. These frequency components, Yc,f, should be grouped into 200 Hz band according to:
This to comply with CISPR band A between 9 and 150 kHz.

11. Some features of CISPR 16 (9 to 150 kHz A-band)
Prescribes measurements of the frequency domain using measuring receivers
The resolution bandwidth should be 200 Hz
Different types of detectors is prescribed QP, RMS, Peak, Average

12. Different types of instrument to use for this frequency range

13. Measurement at lower frequencies
PQ instruments

14. Measurements at higher frequencies
Measuring receivers

15. Oscilloscopes

16. Memory recorders

17. Analyzing technology

18. Ex. signal

20. Resulting DFT

21. Short Time Fourier Transform (STFT)

22. Short Time Fourier Transform (STFT)

24. Time-frequency separation

25. Ex. Measurement on fluorescent lamp

29. 0 to 48 lamps project

30. Measurement setup Individual lamp current is also measured
Itot and U is measured

32. Resulting voltage spectrums
51 kHz
28 kHz

33. Resulting total current spectrums

34. Resulting lamp current spectrums

35. Circuit theory model of the remnants of the lamps

38. ,
IL1 and IL2 in phase
IL1 and IL2 in opposite phase
Iem
Vem

40. ,
IL>2 in phase and opposite phase to IL1
All IL in phase
Iem
Vem

41. Measured result from the “0 to 48 lamp project”

42. Trends of harmonics and power consumption at LAN-parties 2002-2009

43. Mean power per computer in Watt

45. Relative neutral current magnitude

46. 3rd, 5th and 7th harmonics over the years

47. Conclusion
Different types of electronic loads shows diverse frequency spectrums, both in harmonic range and in the higher frequency range. Also same type of equipment shows differences
Measurements using time-domain sampling instrument is useful. It is more flexible to use and provides the opportunity to use different types of analyzing methods
In the frequency range above 2 kHz the STFT has been shown as a useful analyzing tool to achieve information about signals
Cont->

48. Distortion generated at HF-ballast equipped with active PFC can be categorized into, narrow- and broadband- distortion. Also these ballast creates recurrent oscillations close to the zero-crossing
The distortion from switching seems to stay within the groups of lamps instead of traveling towards the transformer
Conclusion of measurement on LAN-parties Between 2002 and 2009 is:
no change in current amplitude
no change in power consumption
large reduction in harmonic distortion