Hypothesis

1
Introduction

• Hypothesis
• Topology, technical constrains
• Redundancy, budget constrains
• Grounding
• Reliability
• Conclusion

EF
NI
H
K
E. Heine, H.Z. Peek
2
Hypothesis

• PowerVLVnT structure 10 Antares VLVnT power
  lt 5 Antares 100 kW
• Technology progress
• Structure upgrades
• Demands of other users?
• EnvironmentalDistance shore-facility
  100 kmPower cables combined with
  fibersSingle point failures has to avoid

3
Power transmission
mains
Shore

• Cable behavior for AC, DC
• AC systems
• DC systems
• Redundancy (no single failure points)

100kW
100km
VLVnT
4
Node grid
power
power
Node
12
12
Converter Junction
Converter Junction
Node
Node
Node
Node
Node
5
Node grid II
power
power
Opt. station
Sub node
7
Opt. station
Inst. station
10
Opt. station
Sub node
Node
Sub node
35
4
Converter Junction
Converter Junction
6
Node grid III
power
power

• Both stations can handle full power.
• Installation in phases possible.

• How to combine with redundant optical network.

7
Redundant Power distribution

• Two long distance failures, still 84 in charge.
• Installation in phases possible.
• To combine with optical network

power
power
power
power
6
Node
Node
Node
Node
Converter Junction
Converter Junction
6
6
Node
Node
Node
Node
Node
Node
Node
Node
Node
Node
Node
Node
Node
Node
Node
Node
6
6
6
Converter Junction
Converter Junction
Node
Node
Node
Node
8
Long distance to local power
converter junction
AC / AC system
288
shore power

• 2x144 el.units submarine
• low power conversion

Node
AC / DC system
72

• 2x36 4 el.units submarine
• high power conversion

Node
4
DC / DC system
72
4

• 2x36 4 el.units submarine
• 4 el.units on shore
• high power conversion

4
Node
9
Long distance cable behavior

• Higher voltage lower current less Cu losses
  higher reactive losses
• AC losses (Iload²(kUwCcable)²) Rcu gt DC losses
  (Iload²Rcu)
• AC charging/discharging C, DC stored energy
  ½CV²
• DC conversions more complex then AC conversions
• AC cables have be partitionized to adapt reactive
  compensation sections.

AC cable
AC cable with reactive power compensation
Lcable
Lcable
Lcable
Lcable
Rcu
Rcu
Rcu
Rcu
VLVnT
VLVnT
mains
mains
Lcomp.
Ccable
Ccable
DC cable
Rcu
Rcu
VLVnT
mains
10
Redundant Node grid
DC load sharing between two converter junctions
Rcu
Converter Junction
Converter Junction
Node
Node
Node
Node
AC load sharing between two converter junctions
Converter Junction
Converter Junction
Node
Node
Node
Node
11
Conclusions on topology
DC/DC constant output level cable losses running
costs active components initial costs
AC/AC passive components initial
costs losses fixed ratio by transformers extra DC
conversion subm. running costs extra cabling
AC/DC constant output level initial costs active
components subm. running costs







12
Grounding

• Grounding is essential to relate all potentials
  to the environment.
• Prevent ground currents by use of one ground
  point in a circuit.

AC
AC
DC
DC
DC
DC
DC
5kV
DC
DC
5kV
DC
48V
Node
Node
DC
DC
380V
DC
DC
13
Reliability

• Not something we buy, but something we make!

No Defect
20
Software
9
Induced
12
Parts
22
Wear-Out
9
System
management
4
Design
Manufacturing
9
15
Denson, W., A Tutorial PRISM,RAC, 3Q 1999, pp.
1-2
14
General conclusions

• Technical issues to investigate
• DC for long distance is promising-gt breakeven
  study for costs and redundancy
• node grid gives redundancy
• node grid can be made of components used in
  railway industry
• inter module grid can be made of components used
  in automotive industry
• each board / module makes its own low voltages
• Organization
• power committee recommend
• specify the power budget (low as possible, no
  changes)
• coordination of the grounding system before
  realizing
• watching test reports, redundancy and reliability
• try to involve a technical university for the
  feasibility study
• coordination between power and communication
  infrastructures

15
Industrial references
Expanding by technology progress
Installation costs 9000 - 20000 /MW.km
AC
Break-Even Distance
DC
VLVnT
Lower in time bytechnical evolution
Sally D. Wright, Transmission options for
offshore wind farms in the united states,
University of Massachusetts High Voltage Direct
Current Transmission, Siemens HVDC light,
ABB Gemmell, B e.a. HVDC offers the key to
untapped hydro potential, IEEE Power Engineering
Review, Volume22 Issue 5, May 2002 Page(s)
8-11
16
Cable configuration

• Combined with fibers for communication
• Redundancy

Monopolar
Bipolar normal operation
power
Load
power
Load
power
Bipolar
Bipolar monopolar operation
power
power
Load
Load
power
power
High Voltage Direct Current Transmission, Siemens
17
Power factor corrector
Classic
current
voltage

• Classic
• more harmonic noise
• higher I²R losses
• PFC
• constant power load
• voltage and current in phase

dilivered
power
PFC
voltage
current
I
U
control
C
C
200kHz
delivered power
18
Converter types
buck converter


input circuit
control
switching circuit
200kHz
rectifying circuit
output circuit
-
-
boost converter

• Efficiency up to 90
• Power driven

control
200kHz
-
-
transformer isolated converter


-
control
200kHz
-
19
Local power
start up sequence

• Converters on each board or function
• Control of switch on/off sequences
• Control of VhgtVl (by scotky diodes)
• Control of voltage limits
• 1V8 4, 5V 5, 12V 10
• Power consistence
• PCB-layout (noise)
• efficiency

voltage
time
12V
12V
BS250
2k
efficiency
3V3
37k
3V3out
3V35V
1V8
3V3
1V8out
15k
BS170
4k7
Efficiency ()
C2
1V85V
68k
20k
Delay C1 290nF/ms Rise time C2 41nF/ms
C1
power