6/10/2003 – e.heine VLVnT facility-power 1EFNI HK

IntroductionIntroduction

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

EFNI HKE. Heine, H.Z. Peek

6/10/2003 – e.heine VLVnT facility-power 2EFNI HK

HypothesisHypothesis

• PowerVLVnT structure = 10 * Antares VLVnT power < 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

6/10/2003 – e.heine VLVnT facility-power 3EFNI HK

Power transmissionPower transmission

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

Shore

VLVnT

100km

mains

100kW

6/10/2003 – e.heine VLVnT facility-power 4EFNI HK

Node gridNode grid

Node Node Node Node Node

Node

12ConverterJunction

ConverterJunction

powerpower

12

6/10/2003 – e.heine VLVnT facility-power 5EFNI HK

Node grid IINode grid II

Node

435

Node Node Node Node

ConverterJunction

ConverterJunction

powerpower

Subnode

Subnode

7

Opt.station

Opt.station

Opt.station

10

Subnode

Inst.station

6/10/2003 – e.heine VLVnT facility-power 6EFNI HK

Node grid IIINode grid III

power power

Node

ConverterJunction

Node

Node

Node

Node

Node

Node

Node

Node Node

NodeNodeNode

ConverterJunction

Node

Node

Node

Node

Node

Node

Node

NodeNode

Node Node

• Both stations can handle full power.

• Installation in phases possible.

• How to combine with redundant optical network.

6/10/2003 – e.heine VLVnT facility-power 7EFNI HK

Redundant Power distributionRedundant Power distribution

Node

Node

Node

Node

NodeNodeNodeNode

NodeNodeNodeNode

Node

Node

Node

NodeNodeNode

NodeNode

NodeNode

NodeNode

66

6

6

6

6

power

ConverterJunction

ConverterJunction

power power power

ConverterJunction

ConverterJunction

• Two long distance failures, still 84% in charge.

• Installation in phases possible.• To combine with optical network

6/10/2003 – e.heine VLVnT facility-power 8EFNI HK

Long distance to local powerLong distance to local power

AC / DC system

Node

DC / DC system

Node

AC / AC system converterjunction

shore power

Node

•2x144 el.units submarine•low power conversion

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

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

288

72

4

724

4

6/10/2003 – e.heine VLVnT facility-power 9EFNI HK

Long distance cable behaviorLong distance cable behavior

• Higher voltage = lower current = less Cu losses = higher reactive losses• AC losses (Iload²+(kUCcable)²) Rcu > 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

DC cable

AC cable with reactive power compensation

VLVnT VLVnT

VLVnT

mai

ns

Rcu Rcu Rcu Rcu

Rcu Rcu

Ccable

Lcable

Lcomp. Ccable

Lcable Lcable Lcable

mai

ns

mai

ns

6/10/2003 – e.heine VLVnT facility-power 10EFNI HK

Redundant Node gridRedundant Node grid

DC load sharing between two converter junctions

Rcu

AC load sharing between two converter junctions

ConverterJunction

ConverterJunction

Node Node Node Node

Node Node Node Node

ConverterJunction

ConverterJunction

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Conclusions on topologyConclusions on topology

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

DC/DC

constant output level

cable losses

running costs

active components

initial costs

++

+++

+

+

6/10/2003 – e.heine VLVnT facility-power 12EFNI HK

Node

GroundingGrounding

Node

AC

DC

DC

DC

DC

DC

DC

DC

AC

DC

DC

DC

DC

DC

48V=

380V=

5kV= 5kV=

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

6/10/2003 – e.heine VLVnT facility-power 13EFNI HK

ReliabilityReliabilityNot something we buy, but something we make!

Denson, W., “A Tutorial: PRISM”,RAC, 3Q 1999, pp. 1-2

Parts22%

Manufacturing 15%

Design9%

Induced12%

No Defect20%

System management

4%

Wear-Out9%

Software9%

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General conclusionsGeneral conclusions

• Technical issues to investigate– DC for long distance is promising-> 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

6/10/2003 – e.heine VLVnT facility-power 15EFNI HK

Industrial referencesIndustrial references

0

100

200

300

400

500

600

0 50 100 150 200 250 300

submarine distance (km)

po

wer

(M

W) HVDC, conventional

HVDC, VSC-based

HVAC

MVAC VLVnT

Sally D. Wright, Transmission options for offshore wind farms in the united states, University of MassachusettsHigh Voltage Direct Current Transmission, SiemensHVDC light, ABBGemmell, B; e.a. “HVDC offers the key to untapped hydro potential”, IEEE Power Engineering Review, Volume:22 Issue: 5, May 2002 Page(s): 8-11

0

2 0

4 0

6 0

8 0

10 0

0 50 100 150 200 250 300

CO

ST

S

VLVnT

Break-Even

Distance DC

AC

Installation costs;

9000 - 20000€/MW.km

Lower in time bytechnical evolution

Expanding by technology progress

6/10/2003 – e.heine VLVnT facility-power 16EFNI HK

Monopolar

Cable configurationCable configuration• Combined with fibers for communication

• Redundancy

power Load

Bipolar

power

power

Load

Bipolar normal operation

power

power

Load

Bipolar monopolar operation

power

power

Load

High Voltage Direct Current Transmission, Siemens

6/10/2003 – e.heine VLVnT facility-power 17EFNI HK

Power factor correctorPower factor corrector

Classic

PFC

dilivered power

current

voltage

delivered power

current

voltage

C Ccontrol

I U

~200kHz

Classic: • more harmonic noise• higher I²R losses

PFC• constant power load• voltage and current in phase

6/10/2003 – e.heine VLVnT facility-power 18EFNI HK

Converter typesConverter types

buck converter

boost converter

transformer isolated converter

control

~200kHz

input circuitswitching circuitrectifying circuitoutput circuit

control~200kHz

control~200kHz

+

-

+

-

+

-

+

-

+

-

+

-

• Efficiency up to 90%• Power driven

6/10/2003 – e.heine VLVnT facility-power 19EFNI HK

start up sequence

Local powerLocal power

Converters on each board or function • Control of switch on/off sequences• Control of Vh>Vl (by scotky diodes)• Control of voltage limits;

1V8 ± 4%, 5V ± 5%, 12V ± 10%

Power consistence• PCB-layout (noise)• efficiency

0

2

4

6

8

10

12

14

0 2 4 6 8 10

12V3V33V3out

12V12V

3V3

3V33V3out

1V8out1V8

3V3+5V

1V8+5V

C1

C2

Delay C1; 290nF/msRise time C2; 41nF/ms

68k

15k

37k

BS

250

BS

170

20k

4k7

2k

efficiency

20

40

60

80

100

0 20 40 60 80 100

input voltage

temperature

output power

time

power

Eff

icie

ncy

(%

)

volt

age