– the Challenge Grid Integration of Wind Powerieee-pels-ies.es/Pels/Pdf/Seminarios/Sevilla/03...

Wind Energy Grid Integration 1

Peter Zacharias, Boris Valov, Kurt Rohrig, Siegfried Heier, Gunter ArnoldUniversität Kassel, Wilhelmshöher Allee 71, D-34109 KASSEL

http://www.evs.e-technik.uni-kassel.deInstitut für Solare Energieversorgungstechnik ISET e. V., Königstor 59, D-34119 KASSEL

http://www.iset.uni-kassel.de

Grid Integration of Wind Power – the Challenge


Content:

• Intro

• Prediction of generated wind power

• E.ON grid code as standard to secure grid stability

• Grid computations before installation

• Integration of off shore wind farms

• Advanced grid control with WEC’s


Intro: Who we are...ISET Institute for Solar Energy Technology• headed by Prof. Schmid, founded in 1988 by

Prof. Kleinkauf• activities in solar, wind, small hydro, sea flow

and bio mass conversion into electricity• power conditioning, grid integration, remote

island grids, grid control, post-graduate studies• >80% funded by projects• 75 employees, annual turn over ~12M€

IEE/EVS Institute for Electrical Power Technology, Electr. Power Supply

• headed by Prof. Zacharias• emphasized on distributed power syst.• power electronics & control, power

conditioning, grid integration, remoteisland grids, grid control

• >50% funded by projejcts• 12 employees


... and where we are:


additional sourceshttp//:europa.eu.intEurObserv‘ER 2004Winpower Monthly2004

Average Wind Speed in Europe

14609

6202

3110

904

912

648

415

399

375

299

258

186

6722

51

28452

5 Ende 2003

m/s

installed Wind Power


Drawn from a proposal of theEuropean Commisionconcerning gridintegration of renewable energysources 10th May 2000

Wind Energy in Europe- Targets of EU Members -

percentage of RE at electricity consumption

generated RE in TWh


Wind Energy Usein Germany 12/2004

installed capacity: 16629MWnumber of WEC: 16543(DEWI Magazin, Febr. 2005 )

Generation:19,1TWh in 200329,9TWh in 2004

...representing~ half of wind energy

production in Europe~ third of wind energy

production world wide

Probably Spain will take over soon


In the past: conventional generationfollows the demand

conv. generation

hours

po

wer

[M

W]

Typical load profile at the E.ON Grid

source: E.ON


now: conventional generation = load – wind power

wind powerconv. power

hours

po

wer

[M

W]


Wind Power is

• depending on meteorological processes,

• can not be pushed (only limited),

• but can be predicted by knowing themeteorological circumstances!

ISET developed software for wind power prediction to plan thepower plant capacities of the utility companies based on meteorological (DWD) and online wind mill data


Online Data Acquisition

Data Basis:

E.ON 39 sites 1337MWVE-T 17 sites 608MWRWE 16 sites 447MWTotal: 72 sites 2392MW


How it works:

1. Deviding regions into 10x10km2

areas for planning and calculation of representativeparameters

2. overall 8585 areas areconsidered monthly

3. For prediction of wind energyproduction the following input of the WEC‘s are used:• number of WEC• rated power of WEC• hub height• profile of territory• type of control of the WEC


Example: 24h Wind Power Forecast for 17th to 24th Februay 2002 for the E.ON Transmission Grid


win

d p

ow

er [

MW

]

time

measurementsforecast

Extended Example of 24h Forecast for Wind Power Delivery to theE.ON Transmission Grid


Deviations by storm caused disconnections of WEC‘s at the 26th

February 2002 with requested Control Power of about 1590MWw

ind

po

wer

[M

W]

time

online24h forecastforecast error


Matching of Power Plant + Wind Energy Generation to Demand:

forecast possible for „smooth“ weather conditions relatively precisely and currently used for power plant capacity planning in Germany

uncertainties at limit exceeding conditions like storms areautomatic switch off

Option 1: Improvement of forecast software

Option 2: Access of utilities to the control of wind farms

Option 2: Long distance energy exchange


Energy Exchange between the 4 major Transmission Grid Areas in Europe

source: E.ON


Energy and Data Exchange for the 4 major Energy Players in Germany

caused by EEG §14 source: RWE


Natural Fluctuations of Wind Power can beForecasted/Calculated

Extreme Situations get not more Stability byWind Integration at the Current Technical Level, but could!

This is the reason to implement the E.ON GridCode into WEC performance


Situation for the E.ON Transmission Grid

50 % of wind power in Germany

Concentration of wind power,

But low demand

Balance zone

36 000 km Length of lines

11 300 kmTransmission grid

Substations

HVDC links

In planning

380 kV -Line 220 kV- Line

Source: E.ON 2002


⇒ Outage of the wholewind power

New solutions arerequired!

low loadWEC model: el. converter3 phase short circuit at Dollem

near Hamburg

source: E.ON 2002


1. At the old Grid Code all suppliers would beswitched off at Ugrid<70%

2. For the concerned area a disappearing of max. 2,7GW installed wind power can exceed theavailable grid control power instability of thegrid

In opposite to thermal power plant turbines+generatorsWEC have small real‚ spinning reserves‘, but...

...there are many options for injection of reactivecurrent to support the current grid stage


Wind farms shall be able to be operated withina given voltage and frequency bandwidth

V, %

f, Hz47,5 49 50,25 51,5

87,5

110

115

Continuousoperation

< 30 minutes

Frequency < 47,5 Hz or > 51,5 Hz: undelayed trip

P>90% P P=P P=P * (1- -------------)act act act 1,25 Hz

f – 50,25 Hz


0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1,0

0,5 1,0 1,5 2,0 2,5 3,0

U[pu]

0,7

0,15

0,45

t [sec]

Requirementsto conventionalpower plants

WEC-SAFEWEC-SAFE

WEC-DISTURBEDWEC-DISTURBED

• Procedure in the event of a disturbance in the grid Automatic disconnection of the generating unit from the grid must not occur above the sketched curve progression of the line-to-line voltage.

• Active power must return directly after fault clearing with 20 % of the nominal active power of the WEC’s

• Within the hatched area an active power return with 5% of the nominal active power of the WEC’s per second is allowed. As an alternative, WEC’scan be disconnected in this area for a very short time (re-synchronization 2s after fault clearing, full active power return after 10s is required)

Requirements at Grid Voltage Dip: E.ON Grid Code

automatic disconnection only allowed below the scetched curve


During fault clearing WEC‘s have to support the grid by injection of reactivecurrent!

Every generator concept acts different at the considered grid fault:


0 .0 0 0 .2 5 0 .5 0 0 .7 5 1 .0 0t [s e c ]

-1

0

1

- 1 0

0

1 0

-1 0

1 0

0

P [ p .u . ]P [ p .u . ]Q [ p .u . ]Q [p .u . ]

U ( L 1 _ E , L 2 _ E , L 3 _ E ) [ p .u . ]U ( L 1 _ E , L 2 _ E , L 3 _ E ) [p .u . ]

I ( L 1 _ E , L 2 _ E , L 3 _ E ) [ p .u . ]I ( L 1 _ E , L 2 _ E , L 3 _ E ) [p .u . ]

ASG3

grid

Simple Induction Generator w/o Converter in Case of Fault:• due to the generator principle low support of the grid with reactive or active power• performance can be enhanced by using a back to back converter for grid coupling

induction generator in it‘ssimplest configuration: squirrel cage inductiongenerator

simulations: Siemens PTD, 2002


0 1 2 5 2 5 0 3 7 5 5 0 0t [ m s e c ]

1

- 2

0

2

- 1

0

- 5

0

5

P [ p . u . ]P [ p . u . ]Q [ p . u . ]Q [ p . u . ]

U ( L 1 _ E , L 2 _ E , L 3 _ E ) [ p . u . ]U ( L 1 _ E , L 2 _ E , L 3 _ E ) [ p . u . ]

I ( L 1 _ E , L 2 _ E , L 3 _ E ) [ p . u . ]I ( L 1 _ E , L 2 _ E , L 3 _ E ) [ p . u . ]

=≈

=≈

ASGL3

Q

3grid

~1/3 P

Double Fed Induction Generator in Case of Fault:• control unit off• rotor short circuited by thyristor crow bar• restoration of grid activities after relaxation of currents• controlled injection of limited reactive power from back to back converter possible


generatorconcept in regularoperation

~2/3 P


t/s1 ,9 2 ,0 2 ,1 2 ,2 2 ,3 2 ,4 2 ,5 2 ,6 2 ,7

- 1 ,0

- 0 ,5

0 ,0

0 ,5

t /s1 ,9 2 ,0 2 ,1 2 ,2 2 ,3 2 ,4 2 ,5 2 ,6 2 ,7- 2

0

t /s1 ,9 2 ,0 2 ,1 2 ,2 2 ,3 2 ,4 2 ,5 2 ,6 2 ,7

P [M W ]

2 ,0

1 ,0

Q [M v a r ]

U L 1 U L 2 U L 3 [p .u . ]

I L 1 I L 2 I L 3 [M V A ]

0 ,0

+ 2

1 ,0


=

≈=

≈

SG3

Q grid

P

Synchronous Generator with Converter in Case of Fault:• reactive currents can be controlled injected limited only by cooling• active power is of course limited by the wind speed

generatorconcept in regularoperation


Use of Generators in Wind Energy Converters

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%19

88

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

Year

SG

ASGL

ASG

(new installations)

source: WMEP report 2004


Who talks about problems must not neglect theopportunities of wind energy integration:

• virtual expanding spinning reserve possible for someseconds

• according to the maximum current capabiltiy reactivepower compensation is possible with WEC as add on.

• grid control is possible by control of the injectedreactive power

• active filtering is possibe the same way.


Quelle: (www.emd.dk)

Grid Integration first Step: Choice of the site


Criteria:

•voltage rise

•rise of short circuit power

•voltage change caused byswitching events

•flickers

•harmonics

Grid Integration 2nd Step: check of grid performance

example: island grid Sifnos/Greece

voltage rise at grid nodes

number of grid node

max. allowed due toEN50160

max. allowed due toVDEW standard

conn. grid node


...now available as software modul „eGRID“

for

„WindPro2 - Software forWind Energy Planning and Project Desingn“

Quelle: Erneuerbare Energie, Heft 1, Jg. 2005

INTEGRID – gridcomputation tool of theUniversity of Kassel


Max Load

"Les Saintes" network

TR WTG5

2

TR WTG4

2

TR WTG3

2

TR WTG2

2

TR WTG1

2

TR WTG8

2

TR WTG6

2

TR WTG7

2

TR

311 9

TR

312 9

Zozio Load

Los Santo..

Marigot Load

Anse Mir ..

Anse du B..

Mairie Load

Ans

e R

odr.

.

Fond de c..Fernand LoadChameau L..Sarkis LoadDuplessis..

Felicite Load

Crawen Load

Pentite a..Labas Load

Subsea ca..

Sub

sea

ca..

Z-Mairie-..

Ans

e R

odr.

.

Fond de c..Fernand-F..T-Fernand..

T-F

elic

it..

Centrale-..

Vie

ux-F

or..

Z-Mairie-..

Z-B

ourg

-A..

Z-M

ir-A

ns..

Marigot-L..

Ext Grid

Mor

el-Z

ozio

Mrig

ot-M

orel

Z-M

ir-M

arig

ot

Z-Bourg-Z-Mir

PCC-WTG S..

T-F

elic

e-P

CC

T-R

odrig

u..

Chameneu-..Sarkis-Ch..Duplessis..Cra

wen

-Du.

.

Z-L

abas

-L..

WT

G S

tati.

.Z

-Lab

as-L

..Z

-Lab

as-L

..W

TG

5-W

TG

6..

Z-L

abas

-L..

Z-L

abas

-L..

WT

G5-

WT

G6

WT

G S

tati.

.

Z-L

abas

-P..

PC

C-Z

-Lab

as

0 Ohm(1)

0 Ohm(2)

0 Ohm(3)

0 Ohm(4)

0 Ohm(5)

0 Ohm(6)

0 Ohm(7)

0 Ohm(8)

WTG 1

G~

WTG 2

G~

WTG 3

G~

WTG 4

G~

WTG 5

G~

WTG 6

G~

WTG 7

G~

WTG 8

G~

Load Vieu..

WTG 7/0.4(1)

WTG8/0.4(1)

WTG1/0.4

WTG 2/0.4

WTG 3/0.4

WTG4/0.4

WTG 5/0.4

WTG 6/0.4

WTG1/0.4(1)

WTG 2/0.4(1)

WTG 3/0.4(1)

WTG4/0.4(1)

WTG 5/0.4(1)

WTG 6/0.4(1)

WTG 7/0.4

WTG8/0.4

Z-Labas

T-Felicite

Felicite

Anse Mir

Las Santos

Zozio

Morel

Marigot

Z-Mir

Z-Bourg

WTG 4/20

WTG 3/20

WTG2/20

WTG1/20

Z-Mairie

WTG 8/20

WTG 7/20

WTG6/20

WTG 5/20

WTG Station

PCC

Mairie

Anse du Bour..

T-Rodrigue

Centrale

Crawen

Les Saintes

Vieux-Fort

Grid 63 kV

Sar

kis

Cha

mea

u

T-F

erna

nd

Fer

nand

Fo

nd

de

cu

re

Anse

Rod

rigu.

.

Dup

less

is

LabasPetite anse

DIg

SIL

EN

T

...for Grid Analysis


Example for 4 scenarios:

being analyzed here:

1. Change of magnitude and direction for active and reactive power

2. Power and voltage losses3. Reactive power compensation needs4. Thermal and other physical overload margin

...for Power Flow Analysis (with and w/o wind farms) for varying load conditions


´´

maxmax 1.1

k

WTni

S

Pku

⋅⋅

⋅=∆λ

...for changes due to switching events


...for calculation of yield, noise, revenue etc. togetherwith the EMD program system

Energi- og Miljødata


Additionally to software tools IEE/EVS and ISET implemented medium voltage grid hardware simulatorfor physical evaluation of solutions


Simulator for medium voltage grid hardware to validatetheoretical approaches for integration of WEC‘s


Off-shore Wind Farms Being Discussed and Planned

When these projectsbecome reality, verybig installations haveto be connected to the high voltage gridon shore!

The question is:What are the impacts?


20.000-25.000 MW2011 – 20304. further extensions

2.000-3.000 MW2007 – 20103. 1st extension

min. 500 MW2004 – 20062. start up

0 MW2001 – 20031. preparing phase

poss. capacitydurationPhase

How Will these Power Flows Interact with the On-Shore Grid?


Windgeschwindigkeit

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7 8 9 10

t

W(m

/sec

)

W(m/sec)

Deutsches

Verbundnetz

station 1

station N

Windpark 1

seacables

Wirkleistung

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7 8 9 10

t

W(m

/se

c)

Windgeschwindigkeit

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7 8 9 10

t

W(m

/sec

)

W(m/sec)

Wind byDWD

Wirkleistung

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7 8 9 10

t

W(m

/se

c)

±QEin(t)

Wind byDWD

wind farm N

U21(t) U22(t)

±QAus(t)

∆P(t), ± ∆Q(t), ∆U(t)

PEin(t)

PAus(t) ±QAus(t)

PnEin(t)

results forPCC:PAus(t)

Wirkleistung

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7 8 9 10

t

P(t)

Wirkleistung

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7 8 9 10

t

P(t

)

Wirkleistung

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7 8 9 10

t

P(t

)

PEin(t)

needs?

dispatcherNo control of WEC‘s and wind farms

direction of computations UPCC(t)

...uncontrolled coupling of off shore wind farms


Windgeschwindigkeit

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7 8 9 10

t

W(m

/sec

)

W(m/sec)

Deutsches

Verbundnetz

station 1

station N

wind farm 1

sea cables

Wirkleistung

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7 8 9 10

t

W(m

/se

c)

Windgeschwindigkeit

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7 8 9 10

t

W(m

/sec

)

W(m/sec)

Wind byDWD

Wirkleistung

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7 8 9 10

t

W(m

/se

c)

±QEin(t)

Wind byDWD

wind farm N

±QAus(t) – max. allow. value

∆P(t), ± ∆Q(t), ∆U(t)

PEin(t)

PAus(t) ±QAus(t)

PnEin(t) Wirkleistung

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7 8 9 10

t

P(t)

Wirkleistung

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7 8 9 10

t

P(t

)

Wirkleistung

0

2

4

6

8

10

12

14

16

18

1 2 3 4 5 6 7 8 9 10

t

P(t

)

PEin(t)

needs?

dispatcher

direction for computation

control possible: targetdata for WEC‘s and wind farms aregenerated

Input for calculation set forPCC:PAus(t) – max. allow value

...and controlled coupling of off shore wind farms


0.0 5.0 10.0 15.0 20.0

-100 mHz

-400 mHz

-200 mHz

-300 mHz

100 mHz

0 mHzE.ON E.ON gridgrid codecode implementedimplemented sincesince 01.08.200301.08.2003

old old standardsstandards usedused

t [sec]

Simulation of grid frequency after a 3-phase fault in the 380kV grid with implemented E.ON Grid code and without (assumption 2005)

source: E.ON Netz GmbH


visit us at http://www.DISPOWER.org

Wind Energy Grid Integration 46Quelle: (www.emd.dk)

Advanced Grid Control for Distributed Generation Integration into the Grid using the Converters itself

• Implementation of new communication devices and protocols

• Improvement of the decentralised measurement data acquisition

and control hardware (modular PLC devices)

• Programming of improved GCU software with advanced grid control

algorithms

• Tests and demonstration of the improved GCU system at the site

Friedland-Deiderode

One of the German test sites:


measurmentprocessing unit

MV gridi. e. 20kV, 50Hz, 3~

u, itransducer

measurement dataP, Q, U, etc.

U I

Control andof the wind energy

converter

WECcontrol

Field Control Level

Control and parameter settings

dispatcher

data acquisition & messagesGrid Control Level

data transmission &configuration

Grid Control Unit (GCU)CPU

Site Control Level

grid status

The Idea: Using Inverter Power Capacity to Control the Grid Voltage, the Principle:


Example of Data Acquisition for the GCU-Systems at Deiderode

-20..+20mA

-20..+20mA -20..+20mA -20..+20mA-20..+20mA-20..+20mA

3~ 3~ 3~

WTG Enercon E30(200 kW)

WTG AN Bonus 44-3(600 kW)

WTG AN Bonus 44-3(600 kW)

WTG Enercon E40(500 kW)

CHP “Mülldeponie”(2*440 kW)

P, Q, UL1-L2 P, Q, UL1-L2 P, Q, UL1-L2P, Q, UL1-L2

PLC

#3

P, Q, UL1-L2

PLC

#2

PLC

#4

PLC

#5

PLC

#6

PLC

#1

U ,

U ,

U

L1-L2

L2-L3

L3-L1

Ethernet

e.g. Ethernet

Substation (SST) Friedland

3~ /20kV /50 Hz

Trafo Substation “UW Grone”

Data transmission via radio connection (e.g. W-LAN)

Ethernet Ethernet Ethernet Ethernet

ModemRS 232

Remote control by Power Dispatch Centre

Distance: 1200 m Distance: 230 m Distance: 210 m Distance: 180 m

Dis

tan

ce:

3700

m

Advanced

Grid-Control-Unit

Main Controller

PC

3~3~

HV-Systeme.g. 110kV, 50Hz, 3~

U I

-20..+20mA P,Q,UL1-L2

P

t

P

t

P

t

P

t

P

t


Remote Data Acquisition for the GCU-Systems at Deiderode


BHKW "Mülldeponie" - Generator 1; 5.10.2000

-50

0

50

100

150

200

250

300

350

14:11:00 14:12:00 14:13:00 14:14:00 14:15:00 14:16:00 14:17:00 14:18:00 14:19:00 14:20:00

Uhrzeit

Wir

klei

stu

ng

[kW

]; B

lin

dle

istu

ng

[kV

Ar]

395

396

397

398

399

400

401

402

403

Net

zsp

ann

un

g [

Vo

lt]

P - Gen.1

Q - Gen.1

U12

... and it works really surprisingly good: grid voltage followsthe injected reactive power

similar installations together with I.T.E.R. can be found at Teneriffe and La Palma


This way the statement is:

• Ongoing integration of wind power will change the gridsituation,...

• but wind energy converters with power electronicinverters itself can potentially act to

increase short circuit power

control grid voltage level

compensate reactive power of loads

compensate harmonics

The crucial point is: To exploit this potential!

– the Challenge Grid Integration of Wind Powerieee-pels-ies.es/Pels/Pdf/Seminarios/Sevilla/03...

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Transcript of – the Challenge Grid Integration of Wind Powerieee-pels-ies.es/Pels/Pdf/Seminarios/Sevilla/03...