ANALYSIS AND TESTING OF SMALL WIND TURBINES

CONNECTED TO WEAK AND AUTONOMOUS GRIDS

LUIS CANO

LUIS M. ARRIBAS

CIEMAT (Spain)

EWEC 2006, Athens

INDEX

• Background

• SWT connected to the grid:

o State of the art

– SWT

– Inverters - Measurements

o Standards revision

• SWT connected to Autonomous systems.

o DC-coupled

– Case study: CICLOPS system.

o AC-coupled

– Case study: HYBRIX system.

EWEC 2006, Athens

BACKGROUNDS

General view: phase I

100 m Mast

SWT Measuring

EWEC 2006, Athens

BACKGROUNDS

General view: phase II

SWT Measuring

Meteorological

Masts

EWEC 2006, Athens

BACKGROUNDS

CIEMAT’s TEST FACILITY:

• Power Performance Tests. (IEC 61400-12)

• Noise Emission Measurement (IEC 61400-11)

• Safety and Function Tests (IEC WT 01)

• Measurements of grid connected SWT (IEC 61400-21)

• Duration Tests (IEC WT 01)

• Other Test

-Generators performance

-Blade Test

EWEC 2006, Athens

SWT connected to the grids: State of the art

CONNECTION TOPOLOGIES:

1

RECTIFIER CHOPPER INVERTER

2

GRID (Optional)

GRID

EWEC 2006, Athens

SWT connected to the grids: State of the art

Principal SWT connected to grids in Europe (I)

MANUFACTURER COUNTRY SWTRATED

POWER (kW) CONVERTERINVERTER orCONVERTER

WT600 0.6 1 Windy BoyPROVEN UK WT2500 2.5 1 Windy Boy

WT6000 6 1 Windy BoyWT15000 15 1 Windy BoyInclin 250 0.25 1 BORNAYInclin 600 0.6 1 BORNAY

BORNAY Spain Inclin 1500 neo 1.5 1 BORNAYInclin 3000 neo 3 1 BORNAYInclin 6000 neo 6 1 BORNAY

Whisper 100 0.9 1 Windy BoySOUTHWEST USA Whisper 200 1 1 Windy Boy

Whisper 500 3 1 Windy BoyGEV 5/5 o 6/5 5 2 Vergnet

VERGNET France GEV 7/10 10 2 VergnetGEV 10/20 20 2 VergnetGEV 15/60 60 2 Vergnet

ROPATEC Italy WRE.030 2.5 1 Aurora or SMDWRE.060 5 1 Aurora or SMD

WT Scirocco 5 1 MWIEOLTEC France WT Wind Runner 25 1 Ingecon Hybrid

WT Cinook 75 1 Ingecon HybridWINDECO Spain VENTO 5000 5 1 Ingecon Wind

Source: Manufacturer webpages

EWEC 2006, Athens

SWT connected to the grids: State of the artPrincipal SWT connected to grids in Europe (II)

MANUFACTURER COUNTRY SWTRATED

POWER (kW) CONVERTERINVERTER orCONVERTER

SOLENER Spain Velter II 2 1 LenzeVelter XV 15 1 LenzeEspada 0.8 1 Sun ProfiPassaat 1.4 1 Sun Profi

FORTIS The Netherlands Montana 5.8 1 Sun ProfiAlize 10 1 Sun Profi

Boreas 20-30 1 Sun ProfiAVENTA Switzerland AV-7 6.5 1 UnknownAIRCON Germany Aircon 10 9.8 1 Unknown

FUHRLANDER Germany FL 30 30 2 FuhrlanderFL 100 100 2 Fuhrlander

INVENTUS Germany Inventus 6 6 2 InventusWINDTOWER Germany WT 10P 10 1 Unknown

WT 50 50 1 UnknownACSA Spain ACSA-LMW-1003 1 1 Unknown

BERGEY USA BWC Excel-S 10 1 Gridtek 10Butterfly 1K 1.5 1 Unknown

ENERGOTECH Greece Butterfly 3K 3.5 1 UnknownButterfly 6K 7 1 Unknown

EWSI USA EW15 50 2 EWSIAERODYN and SMA Germany Aerosmart 5 5 2 SMA

Source: Manufacturer webpages

EWEC 2006, Athens

SWT connected to the grids: State of the art

Inverters

• 6 THYRISTOR BRIDGE INVERTER

R S T

DC

Output Current in 6 pulse-thyristor inverter

-40.00

-30.00

-20.00

-10.00

0.00

10.00

20.00

30.00

40.00

0 100 200 300 400 500 600 700 800 900 1000

Cu

rren

t (A

)

EWEC 2006, Athens

SWT connected to the grids: State of the art

Inverters

• 6 IGBT PWM INVERTER

R

DC

S T

Output current in 6 IGBT PWM Inverter

-400

-300

-200

-100

0

100

200

300

400

1

12

23

34

45

56

67

78

89

10

0

11

1

12

2

13

3

14

4

15

5

16

6

17

7

18

8

19

9

21

0

22

1

23

2

24

3

25

4

26

5

27

6

28

7

29

8

30

9

32

0

33

1

34

2

35

3

36

4

Vo

lta

ge

(V

)

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

Cu

rre

nt

(A)

Voltage (V) Current (A)

EWEC 2006, Athens

SWT connected to the grids: State of the artInverters. Case: 6 IGBT PWM INVERTER

Uthd, Ithd and Pthd in a 6 GBT PWM inverter

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

0

50

0

10

00

15

00

20

00

25

00

30

00

35

00

40

00

45

00

50

00

Power (W)

Ith

d,

Uth

d a

nd

Pth

d (

%)

Inverter Current and Voltage Waves

-400

-300

-200

-100

0

100

200

300

400

1 11 21 31 41 51 61 71 81 91 101

111

121

131

141

151

161

171

181

191

201

211

221

231

241

Vo

ltag

e (V

)

-8

-6

-4

-2

0

2

4

6

8

Cu

rren

t (A

)

Voltage (V) Current (A)

EWEC 2006, Athens

•Measurements of grid connected SWT

Data of SWT measured. Case of a 5kW 6 IGBT PWM inverter Current Harmonics in a Sudden Connection

0.0

0.2

0.4

0.6

0.8

1.0

1.21 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Harmonic

Cu

rren

t H

arm

on

ics

(%)

Connection current (A) 0.4 kW Connection current (A) 3kW

EWEC 2006, Athens

•Standards revision. IEC 61000 standards on EMC:

3-2: 2001. “Limits for harmonic current emissions (equipment input current up to and including 16 A per phase).”

3-3: 1997. “Limitation of voltage fluctuation and flicker in low-voltage supply systems for equipment with rated current of 16 A.”

4-7: 2004. “Harmonics and Interharmonics Measurements and Instrumentation for Power Supply Systems”

4-11: 2004. “Voltage Dips, Short Interruptions, and Voltage Variations Immunity Test”4-15: 2004. “Flickermeter”

6-3 Ed 2 (RDIS): 2004. “Generic standards -Emission standard for residential commercial and light industrial environments”

6-4: 2002. “Generic standards -Emission standard for industrial environments”

EWEC 2006, Athens

•Standards revision. Other local Standards.American Standards:UL 1741 Static Inverters and Charge ControllersIEEE 519 Harmonic Control in Electric Power SystemsIEEE 929 Utility interface of PhotovoltaicANSI C62.41, C1, C2 Surge Voltages in Low-Voltage AC Power Circuits

British Connection StandardsGE 59, 83 Embedded Generating Plants, Small-scale generators (up to 16A)

GE 77 Single-phase photovoltaic generators up to 5kVA

German Standards VDE 0126 Automatic Disconnection Facility for PV Installations

OthersKEMA K150 Small Grid-connected Photovoltaic SystemsJIS C 8962 Power Conditioners for Small PV Power Generating Systems ÖNORM/ÖVE 2750 Austrian Guideline - PV Power Generation SystemsNEN1010 Grid-connected PV SystemsAS3000, AS4777 Australian - Connection of Energy SystemsCSA F381 Canadian - Power Conditioning Systems

EWEC 2006, Athens

•SWT connected to Autonomous systems.

Connection Topologies (I): DC-Coupled

Energy Use Energy UseEnergy UseEnergy Use

+-

Rectifier+

Regulator

WindTurbine

BatteryStorage

Back-upGenset

~Stand-alone Inverter

DC Side

AC Side

EWEC 2006, Athens

•SWT connected to Autonomous systems.

Connection Topologies (I): DC-Coupled

•Power electronics • Rectifier (for the SWT)

• DC/DC converter (optional)

• Stand-alone Inverter

• self-commutated

• voltage controlled

• Stabilizing Unit• long-term storage (battery)

• “One-way” converter (inverter)

• Traditional and common way of connection

• Well known (stand-alone systems)

• High quality, relative low price

•PQ dependant on:

• the inverter

• the load

• not on the SWT

Energy Use Energy UseEnergy UseEnergy Use

+-

Rectifier+

Regulator

WindTurbine

BatteryStorage

Back-upGenset

~Stand-alone Inverter

DC Side

AC Side

EWEC 2006, Athens

•DC-Coupled SWT connected to Autonomous systems. Case Study: CICLOPS Project Description

7.5 kW SWT 5 kWp PV array20 kVA Genset595 C10 Battery Storage

EWEC 2006, Athens

•DC-Coupled SWT connected to Autonomous systems. Case Study: CICLOPS Project – Data Logging Description

IFVNREG

VFVNREG

VBAT

IFVREG

ICarga(DC) PCarga(DC)

FREC.AERG.

IBAT

IAS(DC)

IA(AC) VA(AC) TBAT

GP

VV

EWEC 2006, Athens

•DC-Coupled SWT connected to Autonomous systems. Case Study: CICLOPS Project – WT Power Curve

EWEC 2006, Athens

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

%

UhdfIhdfPhdf

•DC-Coupled SWT connected to Autonomous systems. Case Study: CICLOPS Project – Inverter characterization

Harmonic Distortion for orders from 2 to 50 (3400 W resistive load)

-400

-300

-200

-100

0

100

200

300

400

0 2 4 6 8 10 12 14 16 18 20

Time (miliseconds)

Vo

ltag

e (v

olt

s)

-25

-20

-15

-10

-5

0

5

10

15

20

25

Cu

rren

t (A

mp

eres

)

UI

Wave form (3400 W

resistive load)

EWEC 2006, Athens

•DC-Coupled SWT connected to Autonomous systems. Case Study: CICLOPS Project – Inverter characterization

0.0

0.5

1.0

1.5

2.0

2.5

0 500 1000 1500 2000 2500 3000 3500 4000

AC power (W)

% U

thd

an

d I

thd

)

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

% (

Pth

d)Uthd

Ithd

Pthd

Harmonic Distortion for 1 phase (U, I, P) for different resistive loads (cos Φ = 1).

EWEC 2006, Athens

•SWT connected to Autonomous systems.

Connection Topologies (II): AC-Coupled

Energy Use Energy UseEnergy UseEnergy Use

+-

~ Bi-directional

Converter Grid-connected

Inverter

WindTurbine

BatteryStorage

Back-upGenset

AC Side

~

EWEC 2006, Athens

•SWT connected to Autonomous systems.

Connection Topologies (II): AC-Coupled•Power electronics

• Rectifier

• DC/DC converter (optional)

• Inverter (optional)

• Bi-directional converter

• Stabilizing Unit• long-term storage (battery)

• Bi-directional converter

• Recently developed

• AREP Project

• SMA concept technology

•PQ dependant on: • AC coupled devices (including the SWT)

• the inverter

• the load

Energy Use Energy UseEnergy UseEnergy Use

+-

~ ~ Bi-directional

Converter Grid-connected

Inverter

WindTurbine

BatteryStorage

Back-upGenset

AC Side

~

EWEC 2006, Athens

•SWT connected to Autonomous systems.

10 kW Vergnet SWT; 30.8 kW PV array and 20 kVA diesel genset. 3 lead acid batteries (2x2200 Ah, 1x800 Ah, 60 volts)

Case Study: HYBRIX Project Description

Sunny Island Inverters

From “Iberinco desarrolla el sistema híbrido de generación eléctrica aislado Hybrix ”. Infoenergía.com

EWEC 2006, Athens

•SWT connected to Autonomous systems.

Case Study: HYBRIX Project PQ issues - Sunny Island characteristics

Harmonic Distortion

EMC interference

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CONCLUSIONS

• Each country has its own Grid-connection standards

• Lack of optimal coupling between the converter and the turbine. (Most of manufacturers buy the inverter and don´t adapted it)

• Except few ones, it´s not easy to know if the inverters fulfilled the standards

• Inverters are carried out for PV market

• Technology is not mature

• Certification in each country is very costly

EWEC 2006, Athens

THANK YOU FOR YOUR ATTENTION!