Power Transmission and DistributionMedium voltage

Optimized Energy Exchangein Primary Distribution Networkswith DC-Links

Uwe Krebs, Product Manager SIPLINK

Joint Chapter Meetings of the IEEE IAS PELS IES PES, May 12th-14th 2004, Berlin, Germany2s

Definition of „Optimized Energy Exchange“

Optimized Energy Exchange = controlled load flow

Joint Chapter Meetings of the IEEE IAS PELS IES PES, May 12th-14th 2004, Berlin, Germany3s

System design

Optimized Energy Exchange = controlled load flow

Network 1 Network 2

IGBT-Converterspulse frequency 3kHz

Q1 Q2

P

Network 1 Network 2SIPLINK

Joint Chapter Meetings of the IEEE IAS PELS IES PES, May 12th-14th 2004, Berlin, Germany4s

Working principle

vCvcp

XC i

∆v

∆v

vC vcp

vC

i

vC vcpvcp ∆v vcp∆v

vC

iBi iiW

without load capacitive load inductive load inductive load +active power flow

Joint Chapter Meetings of the IEEE IAS PELS IES PES, May 12th-14th 2004, Berlin, Germany5s

SIPLINK Control

P

UDC

I1

Closed loop control

Converter 2

Closed loop control

Converter 1

U1, I1 U2, I2

UDC / Q1

UDC / U1or

P / Q2

P / U2or

Open loop control

U2

with power generation

without power generation(isolated network)

Network 2:

Q1 Q2

Network 1 Network 2I2

U1 U2

Joint Chapter Meetings of the IEEE IAS PELS IES PES, May 12th-14th 2004, Berlin, Germany6s

Network Application

Extended inductively earthed systems Extended inductively earthed systems exceeding the permissible capacitive exceeding the permissible capacitive earth fault currentearth fault current

Different starpoint treatments in Different starpoint treatments in distribution systemsdistribution systems

Limited short circuit capabilityLimited short circuit capability

Different frequencies of networksDifferent frequencies of networks(60, 50, 16 2/3 Hz)(60, 50, 16 2/3 Hz)

Separation of networks with disturbed Separation of networks with disturbed power supply from other distribution power supply from other distribution systems

Netw. II

Netw. I

≈

=

=

≈

systems

Joint Chapter Meetings of the IEEE IAS PELS IES PES, May 12th-14th 2004, Berlin, Germany7s

Benefits

DC-Link

Controlled power transfer / exchange Controlled power transfer / exchange between different distribution networksbetween different distribution networks

Cost savings by “Load Optimization”Cost savings by “Load Optimization”

Improvement of power quality: Improvement of power quality: -- More reliable power supplyMore reliable power supply-- Stabilization of voltage by generationStabilization of voltage by generation

reactive powerreactive power

Investment cost cutting by alternative Investment cost cutting by alternative solutions in network extensions specifically solutions in network extensions specifically in high loaded areas in high loaded areas

Joint Chapter Meetings of the IEEE IAS PELS IES PES, May 12th-14th 2004, Berlin, Germany8s

SIPLINK Basic Designs

Network 1U1, f1

≈=

Q1≈=

Q2

P

≈=

≈=

Mas

ter ≈

=

≈=

Mas

ter

Sla

veS

lave

Sla

veS

lave

...

...

≈=

Q21

P2

≈=

≈=

≈=

Q22M

aste

r ≈=

≈=

Mas

ter

Sla

veS

lave

Sla

veS

lave

≈=

Qn1

Pn

≈=

≈=

≈=

Qn2

Mas

ter ≈

=

≈=

Mas

ter

Sla

veS

lave

Sla

veS

lave

...

...

...

...

...

...

Q11

Q12

P1

Network 2U1, f1

1,2 MVA2 .. 5 MVA up to 30 MVA

Joint Chapter Meetings of the IEEE IAS PELS IES PES, May 12th-14th 2004, Berlin, Germany9s

Load flow control betweenon-board network and shipyard network

sSIPLINKAdvanced Power F low Control

Network 1U1, f1

≈=

Q1

P

≈=

Q2

Network 2U1, f1

Joint Chapter Meetings of the IEEE IAS PELS IES PES, May 12th-14th 2004, Berlin, Germany10s

Load flow control betweenon-board network and shipyard network

• Power supply from the 400V, 50Hz shipyard-networkinto the 440V, 50/60Hz on board-network

• Reverse power supply from the 440V, 50/60Hz on board networkinto the 400V, 50Hz shipyard-network (Generator test)

Optional in operation with:

rot. converter / shipyard-network

Active Power

Distribution network

on board-network

LSIP INK

Active Power

ReactivePower

Distribution network

on board-network

G

3/50Hz, 450V

3/60Hz, 450V

Shipyard-network3/50Hz, 400V

SIPLINK

3/50Hz, 440V

3/60Hz, 440V

MSIPLINK G

3/60Hz, 440V

Active Power

ReactivePower

Shipyard-network3/50Hz, 400V

Shipyard-network3/50Hz, 400V

ReactivePower

3/50Hz, 440V

Isolated network

on board-network

Joint Chapter Meetings of the IEEE IAS PELS IES PES, May 12th-14th 2004, Berlin, Germany11s

Load interchange in distribution networks

Network 1U1, f1

≈=

≈=

≈=

≈=

Mas

ter ≈

=

≈=

Mas

ter

Sla

veS

lave

Sla

veS

lave

...

...

Q1

P

Q2

Network 2U1, f1

Joint Chapter Meetings of the IEEE IAS PELS IES PES, May 12th-14th 2004, Berlin, Germany12s

Load interchange in distribution networks

110

115

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125

130

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Time

Net

wor

k lo

ad [M

W]

0

10

20

SIPL

INK

load

[MW

]

LimitLoad with SIPLINKLoad without SIPLINKSIPLINK load

„We were in a position to invest in new technology despite the tough Economic climate. The Siemens system allows us to utilize existing energy and capacity reserves at times of peak demand without having to buy in costly regulating energy“

Jürgen Schäffner, Chief technical officer of SWU Energie GmbH