GE 2.x

Zero Power Voltage Regulation Measurement Results

Vincent Schellings

GE Energy

2Vincent Schellings

February, 2006

Introduction

• Voltage Regulation

• Zero Power Voltage Regulation Concept

• Measurement Results

• Conclusions

3Vincent Schellings

February, 2006

Voltage Regulation

To support the network voltage, GE wind turbines supply reactive

power

The GE Wind Farm Management

System controls the wind farm

voltage (or power factor) by

measuring voltage and current at the

substation

The Wind Farm Management System then compares the

actual wind farm output to the

voltage or parameter settings

4Vincent Schellings

February, 2006

Voltage Regulation Example - Colorado Green

Voltage at POI

Wind farm power output

75km

SCR ~3.5

Collector Bus

UtilityTransmissionBus (POI)

Individual WTG

~20 km

20% variability in real power <1% variability in voltage

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February, 2006

Zero Power Voltage Regulation (ZPVR) Concept

Wind turbines generally operate unless:

• Low wind speeds

• High wind speeds, resulting in sudden loss of power

• Abnormal grid conditions

Through appropriate controls in the GE 2.x its converter can deliver reactive power (kVAR) without

wind (kW)

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February, 2006

ZPVR Benefits for the Grid

• Voltage support and regulation continues without active power generation

• Adverse voltage impact due to tripping wind turbines is greatly reduced or eliminated

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February, 2006

ZPVR benefits for the grid

Benefits are greatest in:• Weak grids (e.g. geographically remote systems, end of

long lines)

• Systems with high wind penetration

Alternatives are:• Separate dynamic VAR sources within the farm

• Grid reinforcements

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February, 2006

Measurement results

1. Turbine out of operation

2. Turbine supplies 200 kVAR reactive power and no active power

3. Turbine supplies 1100 kVAR reactive power and no active power

-200

100

400

700

1000

1300

1600

0 19 37 56 75 94 112 131

time (s)

Po

wer

(kW

) / R

eact

ive

po

wer

(kV

AR

)

active power reactive power

2

3

1

5980

6000

6020

6040

6060

6080

6100

6120

0 19 37 56 75 94 112 131

time (s)

volt

age

(V)

2

3

1

1. Mean value of 6025.8 V

2. Mean value of 6033.4 V

3. Mean value of 6083.7 V, an increase in grid voltage of 1%

Grid voltage can be influenced with a non-operating turbine

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February, 2006

Measurement results

-200

100

400

700

1000

1300

501 513 526 538 550 563 575 588 600

time (s)

po

wer

(kW

) /

reac

tive

po

wer

(k

VA

R)

power reactive power

Turbine continues constant supply of reactive power during operation of the turbine

10Vincent Schellings

February, 2006

Conclusions

•Wind turbines can stabilize the grid voltage by supplying and absorbing reactive power

•The GE 2.x wind turbine contains a “Zero Power Voltage Regulation“ feature to provide reactive power without active power generation

•Zero Power Voltage Regulation is benificial for weak grids and systems with high wind penetration

•As a result of Zero Power Voltage Regulation, considerable savings can be achieved on the need for grid reinforcements or VAR sources in the wind farm

Thank youfor yourattention!

GE Energy