# On high-frequency distortion in low-voltage power systems

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```					     Assessment of emission and signal
propagation in electrical power systems in the
2 - 150 kilohertz range
MO-AM3-2

Anders Larsson, Luleå University of Technology, Sweden
Outline of the presentation
• Signal emitting equipment
• Measurement equipment
• Long term measurement
• High frequency components
• Summary
Some signal emitting equipment in the frequency
range from 2 to 150 kHz
SMPS

EMC filter    Rectifier   Smoothing    Active PFC   Chopper   Transformer   Rectifier
capacitor

Power line communication

Concentrator

Power
Meter
Diversity of current drawn by equipment
Resulting harmonic spectra
Resulting spectra 2 to 150 kHz                                           IEC 61000-4-7
b100 Hz
Gb      C
f b95 Hz
f
2

-3         Adjustable speed drive                                        -3           CFL 11 W
x 10                                                                     x 10
5                                                                         5

0                                                                         0
20   40       60      80    100    120   140                             20   40    60      80    100    120   140
-3                  Laptop                                                                LCD-TV
x 10
2                                                                      0.01

1                                                                     0.005
Current (RMS)

0                                                                         0
20   40       60     80     100    120   140                             20   40    60      80    100    120   140
-4                  VCR                                                  -3               CRT-TV
x 10                                                                     x 10
5
2
1
0                                                                         0
20   40      60     80    100      120   140                             20   40    60     80    100   120     140
-3            Mobile charger                                             -3     Incandescent lamp 100 W
x 10                                                                     x 10
1.5                                                                        2
1
1
0.5
0                                                                         0
20   40       60      80    100    120   140                             20   40    60      80    100    120   140

Frequency (kHz)
Measurement at a house containing both electronic
equipment together with PLC

1.6

1.4                                   Induction cooker

1.2

PLC
1
Voltage

0.8

0.6

0.4

0.2

0
20        40        60            80       100     120   140
Frequency (kHz)
Measuring and analyzing
technology, 2 to 150 kHz
Instrumentation

Current and voltage
PQ instruments                             Memory recorders
probes

Short Time Fourier Transform (STFT)
f1 t   100 cos(2 200t )
50 cos(2 400t ) if 0  t  100 ms
f 2 t   
0                   otherwise
f 3 t   25 cos(2 500t  40 sin(2 10t ))

Time-domain
200

150

100

50
Magnitude

0

-50

-100

-150

-200
0   20   40     60        80       100    120   140   160   180   200
Time (ms)
Resulting spectra

80

70

60

50

40

30

20

10

0
0   200   400        600         800   1000   1200
Frequency (Hz)
Short Time Fourier Transform (STFT)
Spectrogram

1200

1000

800
Frequency (Hz)

600

400

200

0
0   0.02   0.04   0.06   0.08     0.1    0.12   0.14   0.16   0.18   0.2
Time (s)
Measurement on fluorescent lamps
Long-term measurements where carried out in different locations:
Fluorescent lamp
1

0.5
Current (A)

0

-0.5

-1
0   20       40   60        80     100       120    140   160    180   200

1

0.5
Current (A)

0

-0.5

-1
0        5             10           15             20       25         30
Time (ms)
Fluorescent lamp
0.3

Current (A)       0.2
0.1
0
-0.1
-0.2

0               5    10   15      20       25     30         35         40
Time (ms)
-3
x 10
6
Current (RMS)

4

2

0
20   40    60       80      100        120        140
Frequency (kHz)
STFT
200                                     200

180                                     180

160                                     160

140                                     140
Frequency (kHz)

120                                     120

100                                     100

80                                          80

60                                          60

40                                          40

20                                          20

0                                          0
0    10   20      30       40   50   60    0      5
-3
1                                               x 10

0
-1
0   10   20      30       40   50   60
Time (ms)
1                           2
1                           1

0                           0

-1                          -1
0   20       40   60        0   20       40   60
3                           4
1                           1

0                           0
Current (A)

-1                          -1
0   20       40   60        0   20       40   60
5                           6
1                           1

0                           0

-1                          -1
0   20       40   60        0   20       40   60
7                           8
1                           1

0                           0

-1                          -1
0   20       40   60        0   20       40   60
Time (ms)
1                           2
150                        150
100                        100
50                          50

0   10       20   30       0    10       20   30
3                           4
150                        150
100                        100
Frequency (kHz)

50                          50

0   10       20   30       0    10       20   30
5                           6
150                        150
100                        100
50                          50

0   10       20   30       0    10       20   30
7                           8
150                        150
100                        100
50                          50

0   10       20   30        0   10       20   30
Time (ms)
0 to 48 lamps project
Spreading of components in the range
of 2 to 150 kHz
Measurement setup

Individual lamp
Itot and U is           current is also
measured                measured

1

Feeding      2
cable
3

….12
Resulting voltage spectrums
Voltage spectrum (n)

45

40

35

30
n (lamps)

Primary
25
emission
20
Secondary
15                        emission

10

5

0
20      40   60       80            100   120   140
Frequency (kHz)
Resulting total current spectrums
Total current spectrum (n)

45

40

35

30
n (lamps)

25

20

15

10

5

20    40     60       80           100   120   140
Frequency (kHz)
Resulting lamp current spectrums
Current spectrum for one lamp (n)

45

40

35

30
n (lamps)

25

20

15

10

5

0
20   40         60       80          100      120   140
Frequency (kHz)

Peak 2 kHz from 9.5 to Itot
Max value of current above amplitude of 11 ms into the window

0.6

0.5

0.4
Current (A)

0.3

0.2

0.1

0
0   5      10      15      20        25     30    35      40        45
n (lamps)
Frequency according to ESPRIT
3.5

3
Frequency (kHz)

2.5

2

1.5

1
5   10   15     20        25     30       35   40   45
n (lamps)
Summary
• Most of the distortion in this frequency range can be
classified into:
• Narrowband components
• Recurrent oscillations
• Our experience is that PLC generates the highest levels of
emission in this frequency range in the LV power systems
• The emission from different ballast varies
Cont->
• When this equipment is installed in large numbers the
components aggregate in different ways. This impacts how
emission standards should be carried out
• The use of time-domain sampling instruments should be
used even for the frequency range 9 – 150 kHz
• Different analyzing tools are needed to detect and quantify
different components. It is shown that not only one
analyzing tool should be used to disclose and describe
different components in the measured signal
• Work is needed to close the gap in emission, compatibility
and immunity standards

• Larsson, A & Bollen, M 2009, 'Emission and immunity of equipment in the frequency range 2 to
150 kHz', i L Toma & B Otomega (red), 2009 IEEE Bucharest PowerTech Proceedings, IEEE,
Piscataway, N.J., s. 2325-2329.

• Rönnberg, S, Wahlberg, M, Bollen, M, Larsson, A & Lundmark, M 2009, 'Measurement of
interaction between equipment in the frequency range 9 to 95 kHz', CIRED 20th International
Conference on Electricity Distribution, I E T Conference Publication Series, The Institution of
Engineering and Technology, s. 231-234.

• Bollen, M, Ribeiro, P, Larsson, A & Lundmark, M 2008, 'Limits for voltage distortion in the
frequency range 2 to 9 kHz', I E E E Transactions on Power Delivery, vol 23, nr 3, s. 1481-1487.

• Larsson, A, Bollen, M, Wahlberg, M, Lundmark, M & Rönnberg, S 2010, 'Measurements of
high-frequency (2-150 kHz) distortion in low-voltage networks', I E E E Transactions on Power
Delivery, vol 25, nr 3, s. 1749 - 1757.

• Larsson, A & Bollen, M 2010, 'Measurement result from 1 to 48 fluorescent lamps in the
frequency range 2 to 150 kHz', 14th International Conference on Harmonics and Quality of
Power (ICHQP), IEEE, Piscataway, NJ .

• Larsson, A 2011, On high-frequency distortion in low-voltage power systems, Doctoral thesis /
Luleå University of Technology, Luleå tekniska universitet, Luleå.
• 2011 – Lecture, Luleå University of Technology
• 2011 – Ph.D, Luleå University of Technology
• 2007 – Licentiate degree, Luleå University of
Technology

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