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Evaluation of Flicker Severity in Standards and Calibration Laboratory (SCL)

Evaluation of Flicker Severity in Standards and Calibration Laboratory (SCL). Speaker: Chung Yin, Poon Standards and Calibration Laboratory (SCL) The Government of the Hong Kong Special Administrative Region. Learning Objectives. To introduce the meaning of flickers in power line

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Evaluation of Flicker Severity in Standards and Calibration Laboratory (SCL)

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  1. Evaluation of Flicker Severity in Standards and Calibration Laboratory (SCL) Speaker: Chung Yin, Poon Standards and Calibration Laboratory (SCL) The Government of the Hong Kong Special Administrative Region

  2. Learning Objectives • To introduce the meaning of flickers in power line • To describe a method for calibrating flicker source and flickermeter

  3. Introduction • Flicker is the change in brightness of a lamp due to rapid fluctuations in the voltage of the power supply • Cause disturbance to human visual perception system • Voltage change characteristic at the terminals of the equipment under test, such as microwave ovens, washing machines • All types of voltage fluctuations may be assessed by direct measurement using a flickermeter

  4. Introduction Source: Figure B.1, IEC 61000-4-15-2010 Flickermeter - Functional and design specifications

  5. Evaluation of flicker parameters • Flickermeter (Functional and design specification in IEC 61000-4-15) • Flicker source (Limits of voltage changes produced by an equipment in IEC 61000-3-3) • SCL developed a system to evaluate the accuracy of flicker source and flicker measurement functions of flickermeter

  6. Operating Principle • Flicker waveform is modeled as an amplitude modulated (AM) signal in power line (120 V / 230 V)

  7. Operating Principle • Relative voltage change / Voltage fluctuation • Vupper: Amplitudes of upper sideband • Vlower: Amplitude of lower sideband • Vcarrier: Amplitude of the carrier

  8. Calibration of flicker source - Setup

  9. Resistive voltage divider

  10. Calibration of flicker source - Setup

  11. Calibration of flicker source • Voltages of lower sideband (Vlower), carrier (Vcarrier) and upper sideband (Vupper) in dBare measured by signal analyzer • Accuracy of the voltage fluctuation of standard flicker source can be determined

  12. Calibration of flickermeter • Flickermeters under test are calibrated by direct comparison with the standard flicker source • Calibration in terms of voltage fluctuation and modulating frequency • Instantaneous flicker sensation (Pinst) will be compared against the theoretical values as illustrated in IEC 61000-4-15

  13. Calibration of flickermeter - Setup

  14. What to be measured?

  15. Measurement uncertainties • Depends on • Amplitude accuracy of signal analyzer • Performance of standard flicker source • Calibration setup

  16. Maximum uncertainty of voltage fluctuation measurement

  17. Measurement uncertainties • Flicker source: Measurement uncertainty < 0.03% at 95% confidence level • Flickermeter: Measurement uncertainty < 0.3% for determination of flicker severities at 95% confidence level • Type testing of Class F1 flickermeters according to IEC 61000-4-15 • Tolerance of 8% in Pinst for sinusoidal voltage changes

  18. Ratio between the specifications of standard flicker source and maximum measurement uncertainty (TUR)

  19. Thank you

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