Testing Harmonics and Flicker

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TestingHarmonics and Flicker
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Harmonics Flicker

• Two different test standards
• EN61000-3-2 EN61000-3-3
• EN 61000-3-2 controls the level of distortion of
  the current drawn by all equipment rated up to 16
  amps.
  
• EN61000-3-3 controls the level of voltages
  changes that equipment rated up to 16 amps will
  impose on the ac supply.
  
• Both standards have evolved over time
• Harmonic standard. originally called IEC 555 Part
  2 1987
  
• Flicker standard. originally called IEC 555 Part
  3 1987
  
• Now referred to as EN61000-3-2 EN61000-3-3
  Standards
  
• EN is short for Euro Norm the version
  enforceable in law in European countries. The EN
  is usually identical to the IEC version.

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Current Harmonic Distortion
Most modern power supplies draw current that is
non-sinusoidal.
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Current Harmonic Distortion

• The distorted current causes problems for
  electricity suppliers, consumers and product
  manufacturers.

• The extra distorted current drawn does no useful
  work. The power factor is WThis
  means more electricity must be generated,
  distributed and paid for than is consumed as
  useful energy.
• The current distortion leads to to the phenomenon
  of triplen harmonic currents flowing in the
  neutral of three-phase systems a fire risk in
  large office installations.
• and to voltage distortion that can cause
  overheating in motors.

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Current Harmonic Distortion
Fourier analysis is used to describe any
repetitive waveform in terms of sine-waves that
are at multiples of the fundamental frequency.
EN61000-3-2 controls current distortion by setti
ng limits for the amplitude of the 1st 40 current
harmonics.
50HZ
100HZ
150HZ
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Requirements of EN61000-4-7

• How to measure to the harmonics is defined by
  EN61000-4-7
  
• It is a not a simple requirement. The following
  measurements must be made
  
• Power, Power Factor , Voltage Harmonics,
  Fundamental Current, POHC (Partial Odd Harmonic
  Current) as well as Current Harmonics.
  
• And in a very specific way NEW REQUIREMENTS
• Measurements are made every 200mS, continuously
  without gaps.(10 cycles _at_ 50Hz, 12 cycles _at_
  60Hz).
  
• Inter-harmonics must also be measured for current
  harmonics

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Requirements of EN61000-4-7

• Harmonic measurements every 200mS - 400
  measurements!
  
• Continuous no-gap analysis
• All measurements filtered by 1.5s time-constant
  filter

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Inter-harmonic groups
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Example Inter-harmonic group

• 6th harmonic (300Hz _at_ 50Hz)

1/2
1/2
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Applying Limits to Harmonics - EN61000-3-2

• The limits for pass and fail are set by product
  groups called Classes
  
• The limits are different for each harmonic and
  each of the 4 classes, A, B, C D
  
• Class Determination is -
• If device power is 75-600W and a PC , Monitor or
  TV then Class D
  
• If handheld portable tool, then Class B
• If Luminaries then Class C
• If not Class B ,C, or D, or 3 phase then class A.

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Applying Limits to Harmonics - EN61000-3-2

• Example Class C limits - calculated from AH01
  and PF
  
• Information from the PC Software Help system

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Applying Limits to Harmonics - EN61000-3-2
Limit 2
Limit 1
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Applying Limits to Harmonics - EN61000-3-2
Maximum reading Vs Limit 2 Average reading Vs
Limit 1

• Limits are set for the average of each harmonic
  during the test (L1) AND the maximum of each
  harmonic (L2).

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Flicker - Causes
The AC supply cabling to a building will have a
source impedance Any variation of loads will caus
e a voltage change at the distribution point
This fluctuation of voltage will then make the
lamps Flicker
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Flicker The Pst 1 Curve

• The Human tolerance to light flicker is mapped on
  the Pst 1curve.
  
• Any point on the curve has the same perceived
  level of annoyance
  
• Pst Perceptibility short term

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EN61000-4-15 The Flickermeter

• For real-life random voltage changes, a
  flickermeter is used is used to duplicate the
  human perception of flicker.
  
• A flickermeter measures rms voltage changes every
  half-cycle (10ms) and filters the measurements
  just like the lamp-eye-brain chain.
  
• The filtered changes are classified to generate a
  table of the probability that a class of
  voltage change will occur.
  

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Flicker Pst test results from Voltech software
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Measurement Equipment

• The Harmonics and Flicker standards require fast
  and accurate analysis of electrical power
  quantities
  
• Continuous harmonics
• 400 measurements every 200ms.
• Discrete Fourier Transform for a reference
  instrument.
  
• Continuous voltage changes
• every 10ms (1/2 cycle_at_50 Hz),
• real-time flickermeter processing.
• Limit checking and reports
• Calculation of harmonic limits from averaged and
  maximum readings
  
• Comparison to different class limits
• Recording and presentation of results

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The PM6000

• Up to 6 wattmeter channels
• Accuracy 0.02 of reading, 0.05 of range
• Bandwidth 10MHz
• Sampling rate 40 MSPS
• Display Bright color VGA
• Connectivity RS232, IEEE488, Printer, Ethernet
• Connectivity (Future Release) PCMCIA for analog
  I/O including torque and speed, USB

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PM6000 Measurement Channel

• Built on 15 years of Voltech analog know-how
• Unrivalled accuracy and bandwidth combination
• Layout and timing minimise phase delay for best
  Watts accuracy
  

• PCI Bus
• Continuous 5 MSPS data from every channel.
• No analysis gaps, no missing data

• A- D Convertor
• 14-bit
• 40MSPS Max
• 5MSPS Min

5V
i
DSP 200MHz
v

• Isolation
• 4kVpk
• CMRR
• 140dB _at_ 60Hz
• 95dB _at_ 1MHz

• Pulse Transformers
• Data and control.
• Provide superior CMRR than opto-isolators

12V
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Why the Voltech PM6000?
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References
Harmonic Limits IEC 61000-3-2 -Consol.Ed.2.1 (200
1) All electrical and electronic equipment up to
16A. 220 to 240V 50 or 60Hz. IEC 61000-3-12. All
electrical and electronic equipment rated 16A to
75A. 230/400V 50 or 60Hz. Harmonic Measuring Equi
pment IEC 61000-4-7 (2002)- 200ms window and Int
erharmonics requirement mandatory end 2007
Flicker Limits IEC 61000-3-3 -Consol.Ed.1.1 (2001
) All electrical and electronic equipment up to 1
6A. 220 to 250V line to neutral at 50Hz.
IEC 61000-3-11 Ed.1 (2000) All electrical and ele
ctronic equipment 16A to 75A. 220 to 250V 50Hz.
Flickermeters IEC 61000-4-15 Ed.1.1.(2003) Hel
p information Voltech IEC61000 software for the P
M6000. Standards from www.iec.ch Software f
rom www.voltech.com (free download).
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End of Presentation

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