investigating the impact of removing the undervoltage protection for wind turbines presented by...

Investigating the Impact of Removing the Investigating the Impact of Removing the Undervoltage Protection for Wind Undervoltage Protection for Wind

TurbinesTurbinesPresented byPresented by

KHALED ALGHADHBANKHALED ALGHADHBAN

Chalmers University of TechnologyChalmers University of Technology

School of Electric Power EngineeringSchool of Electric Power Engineering

GGööteborg, Sweden 2003teborg, Sweden 2003

NORPIE 2004NORPIE 2004

Trondheim, NorwayTrondheim, Norway

OUTLINEOUTLINE

ConclusionConclusion

Case StudiesCase Studies

IntroductionIntroduction

Generator Protection OverviewGenerator Protection Overview

IntroductionIntroductionbackgroundbackground

The standard size has increased from 20 kW to 2 The standard size has increased from 20 kW to 2 MW. MW. The production cost: wind =coal based on The production cost: wind =coal based on condensationcondensation

IntroductionIntroductionbackgroundbackground

1981 1983 1985 1987 1989 1991 1993 1995 1997 19990

0.2

0.4

0.6

0.8

1

1.2

1.4

Dan

ish

KK

/kW

h

Year

IntroductionIntroductionbackgroundbackground

24 GW of wind turbines in Europe make utilities 24 GW of wind turbines in Europe make utilities concerned about voltage dipsconcerned about voltage dips

It is required and essential to disconnect the wind It is required and essential to disconnect the wind turbine for serious grid faultsturbine for serious grid faults

whenever possible, the turbine should stay onlinewhenever possible, the turbine should stay online

IntroductionIntroductionbackgroundbackground

The wind turbine undervoltage setting up to now in The wind turbine undervoltage setting up to now in Sweden is 85% for 0.5 seconds.Sweden is 85% for 0.5 seconds.

ok for few turbines, serious if 100 MW of wind ok for few turbines, serious if 100 MW of wind production is lost, then could lead to voltage collapse.production is lost, then could lead to voltage collapse.

IntroductionIntroductionPurpose of PaperPurpose of Paper

Not tripping for undervoltage does not damage the Not tripping for undervoltage does not damage the wind turbine generator in itself, an idea is to trip only wind turbine generator in itself, an idea is to trip only for overcurrent and overspeed.for overcurrent and overspeed. The purpose of this paper is to study the impact on a The purpose of this paper is to study the impact on a small grid as well as for the wind turbines if the small grid as well as for the wind turbines if the undervoltage protection is removed and the protection undervoltage protection is removed and the protection function is taken over by overspeed and overcurrent function is taken over by overspeed and overcurrent protections.protections.

Generator Protection Overview

Protection FunctionProtection Function Trip Value (setting)Trip Value (setting)

FrequencyFrequency Low= 47.5 HzLow= 47.5 HzHigh= 51 HzHigh= 51 Hz

OvervoltageOvervoltage High1= 110%High1= 110%High2= 125%High2= 125%

OverspeedOverspeed @ 110% of nominal speed@ 110% of nominal speed

UndervoltageUndervoltage Low1= 360 V @ 60 seconds Low1= 360 V @ 60 seconds delaydelayLow2= 337 V @ 0.5 seconds Low2= 337 V @ 0.5 seconds delaydelay

Generator Protection OverviewGenerator Protection Overview Overcurrent (Inverse time)Overcurrent (Inverse time)

Case Studies using SIMPOW®Case Studies using SIMPOW®

First CaseFirst Case: 70% Voltage Dip : 70% Voltage Dip on Utility Bus with 600ms on Utility Bus with 600ms DurationDuration

Second CaseSecond Case: Different : Different Voltage Dips with Different Voltage Dips with Different DurationsDurations

Case StudiesCase StudiesFirst Case (Voltage Dip at Utility bus)First Case (Voltage Dip at Utility bus)

G GG G

UTILITYSWING BUS

B

B

B

B

SMALL TRANSMISSION LINE

30.0 KV

10.8 KV

10.8 KV10.8 KV

B B

0.69 KV 0.69 KV 0.69 KV0.69 KV

TRANBUS

DISBUS

LOAD1LOAD2

G1BUSG2BUSG3BUSG4BUS

Voltage Dip Here

MeasurementsMeasurements

Case StudiesCase StudiesFirst Case (High Wind)First Case (High Wind)

Existing Settings (with undervoltage protection)Existing Settings (with undervoltage protection)

Case StudiesCase StudiesFirst Case (High Wind)First Case (High Wind)

Existing Settings (with undervoltage protection)Existing Settings (with undervoltage protection)

Case StudiesCase StudiesFirst Case (High Wind)First Case (High Wind)

Existing Settings (with undervoltage protection)Existing Settings (with undervoltage protection)

Case StudiesCase StudiesFirst Case (High Wind)First Case (High Wind)

Existing Settings (with undervoltage protection)Existing Settings (with undervoltage protection)

Case StudiesCase StudiesFirst Case (High Wind)First Case (High Wind)

New Settings (Without Undervoltage protection)New Settings (Without Undervoltage protection)

Case StudiesCase StudiesFirst Case (High Wind)First Case (High Wind)

New Settings (Without Undervoltage protection)New Settings (Without Undervoltage protection)

Case StudiesCase StudiesFirst Case (High Wind)First Case (High Wind)

New Settings (Without Undervoltage protection)New Settings (Without Undervoltage protection)

Case StudiesCase StudiesFirst Case (High Wind)First Case (High Wind)

New Settings (Without Undervoltage protection)New Settings (Without Undervoltage protection)

Case StudiesCase StudiesFirst Case (Low Wind)First Case (Low Wind)

Existing Settings (with Undervoltage Protection)Existing Settings (with Undervoltage Protection)

Case StudiesCase StudiesFirst Case (Low Wind)First Case (Low Wind)

Existing Settings (with Undervoltage Protection)Existing Settings (with Undervoltage Protection)

Case StudiesCase StudiesFirst Case (Low Wind)First Case (Low Wind)

Existing Settings (with Undervoltage Protection)Existing Settings (with Undervoltage Protection)

Case StudiesCase StudiesFirst Case (Low Wind)First Case (Low Wind)

Existing Settings (with Undervoltage Protection)Existing Settings (with Undervoltage Protection)

Case StudiesCase StudiesFirst Case (Low Wind)First Case (Low Wind)

New Settings (without Undervoltage Protection)New Settings (without Undervoltage Protection)

Case StudiesCase StudiesFirst Case (Low Wind)First Case (Low Wind)

New Settings (without Undervoltage Protection)New Settings (without Undervoltage Protection)

Case StudiesCase StudiesFirst Case (Low Wind)First Case (Low Wind)

New Settings (without Undervoltage Protection)New Settings (without Undervoltage Protection)

Case StudiesCase StudiesFirst Case (Low Wind)First Case (Low Wind)

New Settings (without Undervoltage Protection)New Settings (without Undervoltage Protection)

Case StudiesCase StudiesSecond CaseSecond Case

Different Voltage Dips with Different Voltage Dips with Different Durations Different Durations

High Wind SpeedHigh Wind SpeedLow Wind SpeedLow Wind Speed

Case StudiesCase StudiesSecond Case (High Wind)Second Case (High Wind)

0.10.1 0.20.2 0.30.3 0.40.4 0.50.5 0.60.6 0.70.7 0.80.8 0.850.85

600ms600msTRIPPTRIPP YY YY YY YY NN NN NN NN NN

Peak QPeak Q w=1.05w=1.05 2.432.43 2.132.13 1.701.70 1.271.27 1.071.07

800ms800msTRIPPTRIPP YY YY YY YY YY NN NN NN NN

Peak QPeak Q W=1.06W=1.06 2.272.27 1.791.79 1.311.31 1.091.09

1000ms1000msTRIPPTRIPP YY YY YY YY YY NN NN NN NN

Peak QPeak Q W=1.13W=1.13 2.352.35 1.841.84 1.311.31 1.091.09

1500ms1500msTRIPPTRIPP YY YY YY YY YY YY NN NN NN

Peak QPeak Q W=1.08W=1.08 1.891.89 1.311.31 1.081.08

Case StudiesCase StudiesSecond Case (High Wind)Second Case (High Wind)

Case StudiesCase StudiesSecond Case (Low Wind)Second Case (Low Wind)

0.10.1 0.20.2 0.30.3 0.40.4 0.50.5 0.60.6 0.70.7 0.80.8 0.850.85

600ms600ms

TRIPPTRIPP NN NN NN NN NN NN NN NN NN

Peak QPeak Q 2.662.66 2.492.49 2.292.29 2.092.09 1.881.88 1.621.62 1.311.31 0.990.99 0.820.82

Max PMax P 0.620.62 0.570.57 0.560.56 0.540.54 0.530.53 0.450.45 0.290.29 0.270.27 0.250.25

800ms800ms

TRIPPTRIPP NN NN NN NN NN NN NN NN NN

Peak QPeak Q 2.682.68 2.532.53 2.322.32 2.122.12 1.891.89 1.621.62 1.331.33 1.001.00 0.820.82

Max PMax P 0.620.62 0.620.62 0.490.49 0.530.53 0.560.56 0.390.39 0.360.36 0.280.28 0.220.22

1000ms1000ms

TRIPPTRIPP NN NN NN NN NN NN NN NN NN

Peak QPeak Q 2.682.68 2.542.54 2.332.33 2.132.13 1.891.89 1.621.62 1.331.33 0.990.99 0.820.82

Max PMax P 0.690.69 0.730.73 0.580.58 0.620.62 0.540.54 0.430.43 0.330.33 0.280.28 0.240.24

1500ms1500ms

TRIPPTRIPP NN NN NN NN NN NN NN NN NN

Peak QPeak Q 2.692.69 2.542.54 2.372.37 2.122.12 1.891.89 1.621.62 1.321.32 1.001.00 0.820.82

Max PMax P 0.820.82 0.660.66 0.750.75 0.550.55 0.520.52 0.430.43 0.320.32 0.280.28 0.230.23

ConclusionConclusion Tripping for undervoltage for a wind turbine can be safely Tripping for undervoltage for a wind turbine can be safely

avoided and thus unnecessary loss of wind power production avoided and thus unnecessary loss of wind power production can be avoided.can be avoided.

Overcurrent and overspeed protection can take over the Overcurrent and overspeed protection can take over the undervoltage function.undervoltage function.

At low wind speeds hardly any dips caused the turbine to At low wind speeds hardly any dips caused the turbine to trip if the undervoltage protection was removed. For high trip if the undervoltage protection was removed. For high wind speeds, the overcurrent protection tripped the turbine wind speeds, the overcurrent protection tripped the turbine for dips lower than 40-60% depending on the dip magnitude. for dips lower than 40-60% depending on the dip magnitude. Using a 10% overspeed limit, generally made the overcurrent Using a 10% overspeed limit, generally made the overcurrent to trip before the overspeed.to trip before the overspeed.

QUESTIONSQUESTIONS

Presented byPresented byKHALED ALGHADHBANKHALED ALGHADHBAN

Investigating the Impact of Removing the Investigating the Impact of Removing the Undervoltage Protection for Wind Undervoltage Protection for Wind

TurbinesTurbines