dtu dong ivan arana overvoltage protection

Industrial PhD project, Dic 2008 to Nov 2011

Iván Arana

Switching overvoltages in offshore wind power grids. Measurements,

modelling and validation in time and frequency domain.

PhD Thesis, 2012

Overvoltages and protection in offshore wind

power grids

Contents

General overview of the Industrial PhD

project

Framework

PhD cooperation in DONG Energy

Offshore wind farm general overview

Switching transient source

Measurements and simulations

Avedøre

Radial disconnection

Wide band transformer model

Voltage ratio

Recommended SFRA

L/R variation

Value creation

Conclusions

06-12-2011

Electrical oscillations between wind energy installations, their

components and the power grid, Stockholm. 2

06-12-2011



General overview of the Industrial PhD project

1. Measurements

2. Data analysis

3. Model creation

4. Model application

5. Validation

06-12-2011



Framework

Harmonics in offshore wind farms

Transients in offshore

wind farms

Compatibility of electrical

main components

in wind turbines

06-12-2011



PhD cooperation in DONG Energy

• Universities

• Research centres

• Companies

06-12-2011



Type D

WTT_22CB_LV22 CB_MV22

CB_HV

Converter Reactor

Filter

TR1CB_MV1CB_MV

CB_MV2

CB_MV3

CB_MV4

CB_MV5

Aux

Load Compensation

Offshore wind farm substation

MV

Type C


Generator

Converter

Type A

WTT_A09CB_LVA09 SD_MVA09

Generator

Capacitor

ReactorPCC

Submarine cable

Shore line Filter BRK_f

BRK_r

Onshore wind farm substation

Land cable

BRK_c

BRK

Offshore wind farm voltage overview

06-12-2011



Offshore wind farm frequency domain measurements overview

Type D


CB_HV

Converter Reactor

Filter

TR1CB_MV1CB_MV

CB_MV2

CB_MV3

CB_MV4

CB_MV5

Aux

Load Compensation


MV

Type C


Generator

Converter

Type A

WTT_A09CB_LVA09 SD_MVA09

Generator

Capacitor

ReactorPCC

Submarine cable

Shore line Filter BRK_f

BRK_r

Onshore wind farm substation

Land cable

BRK_c

BRK

Wind turbine

TransformerCB_LV CB_MV CB_PCC

PCC

Land cable

MMVMLVMLVcon

Converter Reactor

Filter

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Source of transient in wind turbine

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Source of transient in collection grid

Wind turbine BB22


CB_PCC

PCC

Submarine cable

MV_22LV_22

Converter Reactor

Filter

TR1CB_MV1CB_MV

CB_MV2

CB_MV3

CB_MV4

CB_MV5

Wind turbine BB38


MV_38LV_38

Converter Reactor

Filter

Aux

Load

Land cable

Capacitor bank

MV_Radial

Onshore substation

Shore line

MV

06-12-2011



Source of transients in export grid


MV1

MV2

TR1

TR2

CB1_MV CB1_HV

CB2_MV CB2_HV

CB0_HV CB_HV

PCC

Submarine cable

Land cable

Shore line

MMV1

MMV2

MHV

06-12-2011



Source of transients in external grid


MV1

MV2

TR1

TR2

CB1_MV CB1_HV

CB2_MV CB2_HV

CB0_HV CB_HV

PCC

Submarine cable

Land cable

Shore line

MMV1

MMV2

MHV

Measurements and simulations

Measurements

wind turbine switch in

switch out radial feeder

NHP/BB/HR1/GFS

Other work not shown here

switch out AVV

switch in radial feeder in NHP

switch in wind turbine transformer in BB

switch in wind turbine transformers during

emergency situation MW

export grid validation GFS

external grid disturbance validation GFS

point-on-wave application at WOW2

transient recovery voltage at WOW2

external grid disturbance prediction

WOW1

->high frequency phenomena that

standard models can not reproduce

->detail and std models are sufficient for

some switching operations

->additional work is needed

->operational guidelines can be created

based on simulations

06-12-2011



All the models and methods

developed have been done for

operational or under development

offshore wind farms!

06-12-2011



Avedøre

06-12-2011



Switch in AVV measurements

Wind turbine

TransformerCB_LV CB_MV CB_PCC

PCC

Land cable

MMVMLVMLVcon

Converter Reactor

Filter

06-12-2011



Switch in AVV measurements (1)

06-12-2011




06-12-2011



Switch in AVV measurement analysis(1)

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Switch in AVV measurement analysis(2)

All frequencies are

excited

06-12-2011



Radial disconnection under production

Switch out radial feeder NHP/BB/HR1/GFS measurements

06-12-2011



Wind turbine BB22


CB_PCC

PCC

Submarine cable

MV_22LV_22

Converter Reactor

Filter

TR1CB_MV1CB_MV

CB_MV2

CB_MV3

CB_MV4

CB_MV5

Wind turbine BB38


MV_38LV_38

Converter Reactor

Filter

Aux

Load

Land cable

Capacitor bank

MV_Radial

Onshore substation

Shore line

MV

Switch out radial feeder NHP/BB/HR1/GFS measurements Temporary overvoltages

06-12-2011



20MW


High frequency models

Simplified transformer model with

equivalent capacitances in terminals

Gray box model

Black box model

FRA on transformers for off-line

monitoring

06-12-2011




06-12-2011



Transformers

Wind turbine

300kVA@SINTEF/NTNU

100kVA@DTU

100kVA@BB

150kVA@BB

2.6MVA@STV(Middelgrund)

2.6MVA@STV(Nysted)

4MVA@BB(....)

2.5MVA@SWP(HR2)

4MVA@SWP(AVV)-lost

Wind park

90MVA@BB

2x120MVA@ABB(WOW2)

2x120MVA@Bladt(WOW2)

R&D

Transformer

FRA measurements

Y(f)

Y(f) correction

Vector fitting

FDTF in PSCAD

Compare PSCAD results with measurements

Maintenance

Spare

Supplier

Maintenance

Supplier

Construction


06-12-2011



1W

1V

1U

2W

2V

2U

2N

0.1MVA

10.5/0.69kV

FRAX

I1

U

Ch0

Ch1

Positive sequence voltage ratios (10.4/0.69[15; 0.06])

06-12-2011



180kHz 27kHz

06-12-2011



Measured admittance from recommended SFRA test on the 100kVA transformer at DTU

06-12-2011



Measured wind farm transformers positive sequence voltage ratio

Standard model or method

Developed model or method

Guidelines

Increase reliability

Reduce costs

06-12-2011



Value creation

Cooperation

Detail models provided by manufacturers

Some switching operations can be replicated with standard component models,

but not all

Additional work is needed to develop models

Operational guidelines can be created based on simulations

Wide band transformer model can be created with a commercial SFRA

equipment

Some recommended SFRA measurement resonances match the positive

sequence voltage ratio resonant frequencies

Different transformer types, present different L/R ratio

06-12-2011



Conclusions

Thanks for your time

Iván Arana

M.Sc.E.E., PhD-student

Renewables Grid Analysis

DONG Energy

Nesa Allé 1

DK-2820 Gentofte

Mobile: +45 99 55 63 55

Email: [email protected]

mailto:[email protected]

dtu dong ivan arana overvoltage protection

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