Power Systems Consulting and Software

4 March 2004

BWEA Conference: UK Offshore Wind 2004

Integration of Offshore Wind Farms into the Local Distribution Network

Charles A. Lynchca.lynch@ipsa-power.com

4 March 2004

BWEA Conference: UK Offshore Wind 2004

2 Power Systems Consulting and Software

DTI Project K/EL/0272

• Final Reporthttp://www.dti.gov.uk/energy/renewables/publications/pdfs/kel00272.pdf

4 March 2004

BWEA Conference: UK Offshore Wind 2004

3 Power Systems Consulting and Software

Partners

• IPSA Power Ltd.

• EEPS Group, UMIST

• Innogy/National Wind Power

• Powergen

4 March 2004

BWEA Conference: UK Offshore Wind 2004

4 Power Systems Consulting and Software

Objectives

• Establish viability of 100MW+ of wind generation connected to 132kV

• Establish validity of analysis tools for systems with doubly fed generators

• Compare the behaviour of the different types of wind generator

• Investigate using converter controls to assist is local area voltage control

4 March 2004

BWEA Conference: UK Offshore Wind 2004

5 Power Systems Consulting and Software

Project Phases

• DFIG Model Development• Steady State and Dynamic

• Connections Studies

• Optimal Power Flow Development• DFIG model

• Voltage Control Studies

4 March 2004

BWEA Conference: UK Offshore Wind 2004

6 Power Systems Consulting and Software

Generation Alternatives

• ‘Fixed Speed’ Induction Generator

• Variable Speed Synchronous or Induction Generation via Static Converters

• Doubly Fed Induction Generator (DFIG)

4 March 2004

BWEA Conference: UK Offshore Wind 2004

7 Power Systems Consulting and Software

4 March 2004

BWEA Conference: UK Offshore Wind 2004

8 Power Systems Consulting and Software

Double Fed Induction Generator

• What is a DFIG?• Wound rotor Induction Machine• Variable frequency voltage applied to the rotor

windings

• Why is it needed?• Variable speed, from about 0.7 to 1.3 per unit• Optimise performance over a range of wind

speeds

4 March 2004

BWEA Conference: UK Offshore Wind 2004

9 Power Systems Consulting and Software

Typical configuration of DFIG wind turbine

• As

rvri

sv

si aigi

PowerSystem

Controller

ac / dc dc / ac

C1 C2

av

gg jQP

Crowbarprotection

4 March 2004

BWEA Conference: UK Offshore Wind 2004

10

Power Systems Consulting and Software

Modelling Requirements

• Load Flow Studies• Voltage Stability and Control• Variation of real and reactive power over

operating regimes

• Fault Analysis Studies

• Dynamic Analysis Studies• Transient and Dynamic stability

4 March 2004

BWEA Conference: UK Offshore Wind 2004

11

Power Systems Consulting and Software

Modelling Detail

• Control Modes• Speed Control• plus Power Factor control • Associated AC/DC Converters

• Two Points of Power Injection• May not be explicitly modelled• Rotor reactive power is not provided by the

network

4 March 2004

BWEA Conference: UK Offshore Wind 2004

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Power Systems Consulting and Software

4 March 2004

BWEA Conference: UK Offshore Wind 2004

13

Power Systems Consulting and Software

DFIG Performance Characteristic

4 March 2004

BWEA Conference: UK Offshore Wind 2004

14

Power Systems Consulting and Software

Connection Studies

• Collaborators• Scottish Power, Manweb• United Utilities

4 March 2004

BWEA Conference: UK Offshore Wind 2004

15

Power Systems Consulting and Software

4 March 2004

BWEA Conference: UK Offshore Wind 2004

16

Power Systems Consulting and Software

Variable speed synchronous generation

DEES A1

CC C

DEES A1

SCHP C1SCHP C2SCHP C2

OFSFARM1

HOLY C2

CONQ C4

CONQ C2

CONQ C3

CONQ C1

DEES S1

SHOT C2SHOT C1

HOLY C1

SASA C2SASA C1

COLB C2

SHOT F2SHOT F3

SHOT F1

DEPK C1

HOLY C2

SASA C4

SASA C3

DEES S4

DEPK BN8

SCHP C1 SCHP C2

SCHP G1SCHP G2SCHP G3

OFSFARM1

OFSW12

J2

OFSW33OFSH1

OFSHHOLYWF

DC3 DC4 CON-HO

DC5

DC6

CON-RH

SYN-rh

SYN-HOL

Title: IPSA 132 kV Study 2 Farms Synch. Model IPSA 22DC<0032> 03 Jun 2003 12:13:35

NETWORK DIAGRAM DRAWING AND MODIFYINGType <H> if you need any help

4 March 2004

BWEA Conference: UK Offshore Wind 2004

17

Power Systems Consulting and Software

Steady State Studies

• Fixed Speed Induction Machines• Higher reactive power flows• Increased voltage regulation• Higher make duty fault levels

• DFIG• Lower increase in make duty fault levels

• Variable Speed Synchronous Machines• Least impact

4 March 2004

BWEA Conference: UK Offshore Wind 2004

18

Power Systems Consulting and Software

Dynamic Analysis

• All three generation types modelled

• Fault clearance studies for faults at the wind farm and on the 132kV network

• Further development of controller modelling by User Defined Modelling

• DTI Project: K/EL/0321• Facilitating the modelling of embedded

generation

4 March 2004

BWEA Conference: UK Offshore Wind 2004

19

Power Systems Consulting and Software

Fault at 132kV, example 1

IPSA 22.0b

Graph 1: BUSBAR VOLTAGE - PU

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0

OFSW11 OFSW12 OFSW13 OFSH1 OFSH2

Graph 2: IM POWER (S) - MVA

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.0

OFSW11 OFSW12 OFSW13 OFSH1 OFSH2

Graph 3: IM MOTOR TORQ. - MJ

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

-50.0

-40.0

-30.0

-20.0

-10.0

10.0

20.0

30.0

40.0

50.0

0.0

OFSW11 OFSW12 OFSW13 OFSH1 OFSH2

Graph 4: BUSBAR ANGLE - degrees

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

-180

-135

-90

-45

45

90

135

180

0.0

OFSW11 OFSW12 OFSW13 OFSH1 OFSH2

Title: 132 DFIG network for TS-1 DC<0032> 16 Sep 2003 15:24:55

132 DFIG network for TS-1

4 March 2004

BWEA Conference: UK Offshore Wind 2004

20

Power Systems Consulting and Software

Fault at 132kV, example 2

IPSA 22.0b

Graph 1: BUSBAR VOLTAGE - PU

0.5 1.0

0.5

1.0

0.0

OFSW11 OFSW12 OFSW12 OFSH1 OFSH2

Graph 2: IM POWER (Q) - MVAR

0.5 1.0

-100

-50

50

100

0.0

OFSW11 OFSW12 OFSW13 OFSH1 OFSH2

Graph 3: IM MOTOR TORQ. - MJ

0.5 1.0

-100

-50

50

100

0.0

OFSW11 OFSW12 OFSW13 OFSH1 OFSH2

Graph 4: BUSBAR ANGLE - degrees

0.5 1.0

-180

-135

-90

-45

45

90

135

180

0.0

OFSW11 OFSW12 OFSW13 OFSH1 OFSH2

Title: 132 DFIG network for TS-1 DC<0032> 06 Oct 2003 16:49:12

132 DFIG network for TS-1

4 March 2004

BWEA Conference: UK Offshore Wind 2004

21

Power Systems Consulting and Software

User Defined Modelling

In(1)

In(2)

A

B

In(6)

In(3)

In(4)

A

B

F(12)

F(15)In(5) F(17)F(18)

A

B

Ka+Tas

Kb+Tbs

Ka+Tas

Kb+Tbs

Ka+Tas

Kb+Tbs

Ka+Tas

Kb+Tbs

Ka+Tas

Kb+Tbs

Ka+Tas

Kb+Tbs

Ka+Tas

Kb+Tbs

In(7)

Ka+Tas

Kb+Tbs

A

B

B

A x

xA

xB xy

y

OU(1)

IPSA 22DC<0032> 01 Ju l 2003 16 :19 :07

B L O C K D IAG R AM D R AW IN G U T IL IT Y - H F O R H E L P

WIND INC IDENT M O DELLING

G O VERNO R AND TURBINE

FREQ UENC YREF

4 March 2004

BWEA Conference: UK Offshore Wind 2004

22

Power Systems Consulting and Software

Voltage Control Studies

• Load Flow and Optimal Power Flow (OPF) studies

• Compare fixed speed and variable speed machines

• Determine optimal control strategy over a range of network conditions

• Coordinated area based voltage control

• Maximise generation penetration

4 March 2004

BWEA Conference: UK Offshore Wind 2004

23

Power Systems Consulting and Software

Voltage Control Results

• Significant improvement operating wind farm under voltage control compared with constant power factor control (DFIG)

• Increased generation penetration possible

• Fixed speed machine power factor correction is an additional constraint

• OPF very helpful in addressing a wide range of issues

4 March 2004

BWEA Conference: UK Offshore Wind 2004

24

Power Systems Consulting and Software

Conclusions

• Alternative generation types successfully modelled in system wide studies

• Connection of 100+ MW of offshore generation is possible at 132kV

• More generation can be connected if it participates in voltage control

• Full report:http://www.dti.gov.uk

/energy/renewables/publications/pdfs/kel00272.pdf