Measurement of phase
angles of voltage and
current harmonics
Dr. Michael Schwenke, EM DG PRO D PA
© Siemens AG 2016
siemens.com
Measurement of phase angles of voltage and current harmonics
1. Harmonics: cause – impact – measurement - countermeasures
2. Related standards/measurement methods
1. IEC 61000-4-7: General guide on harmonics and interharmonics measurements and
instrumentation
2. IEC 61000-4-30: only PQ measurement methods for harmonic/interharmonic magnitudes are
defined
Harmonic subgroup and
Interharmonic centered subgroup acc.
IEC 61000-4-7/IEC 61000-4-30
3. Goal of measurement and applications
1. Prevailing phase angle, variation factor and prevailing ratio PR
2. Sign of harmonic active power
3. Improved power measurement
4. Implementation in SICAM Q100
5. Example
© Siemens AG 2016
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Dr. Schwenke / EM DG PRO D PA
Power Quality
What to Do? - The ABC Approach
• Ensure that the obtained energy is according to a defined quality.
• Ensure that negative influences to the connected power supply network are within a certain limit.
A
Measure
• Continuous measurement of relevant
parameters at important points in the
power supply network:
• Point of coupling: In-feed from the utility
• Transformer feeders
• Point of coupling of specific production units/lines
B
Evaluate
• Concentrate, analyze and evaluate
recorded parameters:
• Assigning data to the point where they are
measured
• Evaluate data according to necessary limits and
criteria (e.g. EN 50160)
• Big loads causing disturbances
• Identification of trends, deviations and limit value
violations together with the duration and value
• Use of standardized measurement methods
(Class A, Class S)
• Assigning evaluation results to the related points
C
Optimize
• Definition of proper mitigation measures:
• Dedicated energy supply contract with a defined
level of Power Quality
• Filters, redundancies etc.
• Process optimization
• Use of less sensitive devices and equipment
• Identification of possible originator of the
disturbance
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Dr. Schwenke / EM DG PRO D PA
Harmonics
What to Do?
• Caused by: power electronic devices, UPS, converter drives, rectifier, fluorescent lamps, power supply for IT equipment,
PV and wind power inverters
• Impact: heating of motors, cables, transformers; malfunction of breakers, relays, PLC communication, resonances
A
Measure
B
Evaluate
C
Optimize
• (Active) harmonic filter
àreduce impact on neighborhood
equipment
• power factor correction
à Improve energy efficiency
U = 230 V
I = 160 mA
Total Harmonic Distortion
THD U: 2 %
THD I: 190 %
© Siemens AG 2016
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Applications of phase angle information
Goal
Analysis of harmonic power flow
Analysis of prevailing phase angles
Measurement
“relative” phase angle:
· measurement of phase angles
between harmonic voltages and
currents (same order number)
· Evaluation of harmonic flows
throughout the system
· Assignment of responsibilities in
the system through the
identification of harmonic sources
and harmonic sinks
· Calculation of active, reactive and
apparent powers
“absolute” phase angle
· phase angle in relation to the voltage
fundamental
Applications
·
·
·
·
Assessment of harmonic current
measurements in different points in the
system
Assessment of summation factors of
harmonic currents from different
disturbing loads when they are
connected to the same node
Modeling of disturbing loads and
evaluation of their disturbing effect
Design of countermeasures for disturbing
loads
© Siemens AG 2016
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Prevailing phase angle, variation factor and prevailing ratio
Prevailing phase angle: aggregation of phase angles over time (e.g. 10 min)
Variation factor VF
Prevailing ratio: PR = 1 - VF
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Philips ML 100: High-pressure mercury tube in series with a tungsten filament
Voltage/current of 100 pcs.
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Example
voltage/current characteristics and harmonics
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Harmonic measurement:
Magnitude, phase angle, Prevailing phase angle, Prevailing angle ratio
Voltage phase A
Current phase A
© Siemens AG 2016
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Dr. Schwenke / EM DG PRO D PA
Example
voltage/current charcteristics
Harmonic direction detection: sign of harmonic active power
© Siemens AG 2016
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Dr. Schwenke / EM DG PRO D PA
Improved power calculation
Reactive power for
phase p, quadrature
phase shift formula
Reactive power for
phase p, Budeanu’s
harmonic definition
Qp = Qpquad
1 M -1
=
× å (vpk - N / 4 ´ ipk )
M k=0
Qp = Qpharm =
hmax
åI
i=1
i, p
× Vi, p × sin(j i, p )
© Siemens AG 2016
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Contact page
Dr. Michael Schwenke
Senior Key Expert Power Quality
EM DG PRO D PA
Wernerwerkdamm 5
13629 Berlin
Phone: +49 30 38620136
Mobile: +49 162 1325063
E-mail:
michael.schwenke@siemens.com
siemens.com
© Siemens AG 2016
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