Presentatie Event “Power Quality | Changing landscape”

1. Power Quality Measurements
in Low-Voltage DC Grids
Helko van den Brom
VSL B.V.
Dutch Power & Cigre C4
Power Quality – Changing Landscape
23 November 2023, TenneT, Arnhem

2. 2

3. 3
AC or DC?

4. 4
From AC to DC

5. 5

6. 6

7. 20NRM03 DC grids – consortium
7

8. 20NRM03 DC grids project
8
AIM: traceable measurement and characterizationof PQ parameters to support
standardization in further development and deployment of DC grids.
• New on-site
instrumentation for
DC distortions
• Onsite measurement
campaigns in LVDC
grids
• New definitions of
DCPQ phenomena
• New analysis
algorithms to
categorize DCPQ
• Traceability for DC
power and DCPQ
parameters
• New reference
systems for DC PQ
and DC metering
• New PQ severity
indices for DC grids
• New methodologies
for PQ level surveys
in DC grids

9. ▪ Designed for on-site measurements
at metered supply points
▪ DC waveform recorder:
− Adapted 3-phase V & I recorder for 50 Hz
− Minicomputer with dedicated software
− 8-channel, 12-bit, 1 MSa/s digitizer (Picoscope 4824)
− 2000 V, 1:1000, 1.0 %, 10 MHz voltage probe (Hioki 9322), with additional 2-stage, 500 kHz RC-filter
− Openable 200 A, 10 mV/A, 0.3 %, 500 kHz current probe (Hioki CT6843-05)
− Pass-through 50 A, 40 mV/A, 0.03 %, 1 MHz current probe (Hioki CT6862-05)
VSL waveform recorder
𝑈𝐷𝐶 =
1
𝑛
෍
𝑖=0
𝑛−1
𝑢𝑖 𝑈𝑟𝑚𝑠 =
1
𝑛
෍
𝑖=0
𝑛−1
𝑢𝑖
2
𝑈𝑟𝑝𝑙 = 𝑈𝑟𝑚𝑠
2 − 𝑈𝐷𝐶
2

10. Measurements LVDC grid Lelystad Airport
▪ Operated by Alliander & Dynniq
▪ Lelystad airport business park
▪ 750 V unipolar voltage
▪ Non-configurable grid
▪ Only streetlights

11. Measurements LVDC grid Green Village Delft
V
MPPT
AC/DC
I3
I1
I2
Street-
lights
DCO
LED
▪ Operated by DC opportunities
▪ Configurable grid in urban environment
▪ 350 V bipolar voltage
▪ Grid-connected (bidirectional) or islanding mode

12. Measurements LVDC grid Green Village: voltage
-50
0
50
100
150
200
250
300
350
400
0 600 1200 1800 2400 3000 3600
Voltage
(V)
Time (s)
DC voltage
RMS voltage
Ripple voltage

13. Measurements LVDC grid Green Village: current
-0,20
0,00
0,20
0,40
0,60
0,80
1,00
1,20
1,40
1,60
0 600 1200 1800 2400 3000 3600
Current
(A)
Time (s)
DC current
RMS current
Ripple current

14. LVDC grid Green Village: spectrum
▪ Single frequency component of 82 kHz with a
resolution of 200 Hz
▪ Recalculation using a resolution of 5 Hz

15. LVDC grid ASR in Utrecht
AC-DC
converter
EVCS 1 EVCS 2 EVCS 3
2 x 14 PV
panels +
MPPT
2 x 14 PV
panels +
MPPT
2 x 14 PV
panels +
MPPT
LED
V
I1 I2
I3
▪ Operated by HvA & Kropman
▪ Open parking garage
▪ 700 V unipolar voltage
▪ Grid-connected (bidirectional) or islanding mode

16. LVDC grid ASR in Utrecht: voltage and current
0
100
200
300
400
500
600
700
800
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
0 1000 2000 3000 4000 5000 6000 7000 8000 9000
DC
voltage
(V)
Ripple
voltage
(V)
Time (s)
Ripple
DC value -5
0
5
10
15
20
25
30
35
40
0.0
0.4
0.8
1.2
1.6
2.0
2.4
2.8
3.2
3.6
0 1000 2000 3000 4000 5000 6000 7000 8000 9000
DC
current
I
1
(A)
Ripple
current
I
1
(A)
Time (s)
Ripple
DC value

17. ▪ LV DC grids as local extensions of the AC grid
▪ How to measure PQ in DC grids?
− Initial DC PQ definitions and considerations
− Onsite measurement equipment
− Onsite PQ measurement results
− Reference systems for DC electricity
metering
▪ Future:
− Improved standardization of DC PQ
− Utilities: DC PQ planning levels
− Surveillance authorities: DC PQ compatibility
PQ Measurements in LV DC Grids

18. ▪ Helko van den Brom, hvdbrom@vsl.nl
▪ VSL B.V., Thijsseweg 11, 2629 JA Delft, www.vsl.nl
▪ 20NRM03 DC grids project, www.dc-grids.nl
Contact details
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