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IEC TR 63282
Edition 1.0 2020-11
TECHNICAL
REPORT
colour
inside
LVDC systems – Assessment of standard voltages and power quality
requirements
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IEC TR 63282
Edition 1.0 2020-11
TECHNICAL
REPORT
colour
inside
LVDC systems – Assessment of standard voltages and power quality
requirements
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.020 ISBN 978-2-8322-9078-1
– 2 – IEC TR 63282:2020 © IEC 2020
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 8
4 Structure of LVDC systems . 12
4.1 General . 12
4.2 Architecture . 12
4.3 Operation modes . 13
4.3.1 Passive DC systems . 13
4.3.2 Active DC systems . 13
5 LVDC voltage division. 13
5.1 General . 13
5.2 Voltage bands . 14
5.3 Operation ranges with respect to DC voltage and time . 15
5.4 States . 16
6 Power quality phenomena relevant to LVDC networks . 17
6.1 General . 17
6.2 Relationships between voltage band and power quality in LVDC systems . 17
6.3 Supply voltage deviation . 18
6.4 Ripple and high frequency noise . 19
6.5 Voltage swell . 20
6.6 Voltage dip . 21
6.7 Voltage supply interruption. 22
6.8 Rapid voltage change (RVC) . 22
6.9 Voltage surges . 23
6.10 Voltage unbalance . 24
7 Recommendations . 25
7.1 General . 25
7.2 Recommended voltages . 25
7.3 EMC and compatibility levels . 26
7.4 Power quality recommendations . 28
7.5 Measurement methods . 29
7.5.1 General . 29
7.5.2 DC system RMS value integration time . 29
7.5.3 DC power quality measurement methods . 29
Annex A (informative) PQ waveforms collected from a certain LVDC project . 30
Annex B (informative) Load distance in DC distribution systems . 32
Annex C (informative) Electric power and power quality computation in DC systems . 33
C.1 DC RMS value of voltage or current . 33
C.2 General electric power system: decomposition of a general electric load . 33
C.3 Computation of electric powers and PQ indices. 34
C.4 Representation of electric powers in AC system . 37
C.5 Representation of electric powers in DC system . 37
C.6 Power quality indices in DC system. 38
C.7 Illustration example of deformation power in DC system . 39
C.8 Main conclusions on electric value computation in DC systems . 40
C.9 Need of characteristics of DC voltage . 41
Annex D (informative) District LVDC system demonstration project in Tongli, China . 42
D.1 Project overview . 42
D.2 Voltage level selection principle . 42
D.3 System operation . 43
Annex E (informative) An office building with general building utilities and office work
places . 44
Annex F (informative) An example of configurations for active DC systems . 50
F.1 General . 50
F.2 Structure . 50
F.3 State of grid (SOG) . 50
Annex G (informative) Preferred voltage in different countries . 55
G.1 Preferred voltage in China . 55
G.2 Preferred voltage in the Netherlands . 57
G.3 Preferred voltage in Germany . 58
Annex H (informative) Voltage with respect to earth . 59
Annex I (informative) CIGRE approaches for DC systems . 62
Bibliography . 63
Figure 1 – Unipolar, balanced and bipolar DC systems . 12
Figure 2 – Voltage bands in DC systems . 14
Figure 3 – DC Voltage areas for safe interoperability . 15
Figure 4 – Relationships between voltage band and power quality in LVDC systems . 18
Figure 5 – Voltage swell example. 20
Figure 6 – Voltage dip example . 21
Figure 7 – RVC event: example of a change in average voltage that results in an RVC
event . 23
Figure 8 – Example of voltage surge . 24
Figure 9 – A schematic of a bipolar system (the CIGRE B4 DC test system) . 25
Figure 10 – Relation between disturbance levels (schematic significance only) . 26
Figure 11 – LVAC voltage compatibility and immunity levels . 27
Figure A.1 – Voltage deviation caused by load switching . 30
Figure A.2 – Voltage ripple in steady state . 30
Figure A.3 – Voltage dip caused by the start-up of motor load . 31
Figure C.1 – Equivalent model of a general electric load . 34
Figure C.2 – Representation of electric powers in AC system . 37
Figure C.3 – Representation of electric powers in DC system . 37
Figure C.4 – Ripples . 38
Figure C.5 – DC powers . 40
Figure C.6 – Compatibility level measured in differential mode values . 41
Figure D.1 – Architecture of the district LVDC system in Tongli . 42
Figure E.1 – Office building with general building utilities and office work places . 44
Figure E.2 – Overview of DC-zones for DC system . 46
Figure F.1 – Active DC distribution system . 50
– 4 – IEC TR 63282:2020 © IEC 2020
Figure F.2 – DC distribution system with one load and one source . 52
Figure F.3 – DC distribution system with more than one load and a source and
increasing source power . 53
Figure F.4 – Distribution system with more than one load and a source and DUMP
LOAD active . 53
Figure F.5 – Distribution system with more than one load and source in overloaded
mode . 54
Figure H.1 – DC voltage definitions .
...