statcom - adm eng

Partner company name

ADF Conference 2016

Jonas Persson

Comsys AB

September 16th 2016

STATCOM

Wednesday, September 21,

2016Comsys ADF Power Tuning 1


Powerisn’t perfect



• STATCOM

• Introduction to STATCOM

• Hybrid STATCOM concept

• How-to-guide

• Selected References

STATCOM, System IntegrationAgenda




STATCOM Introduction



• Static synchronous compensator

• VSC based (Voltage Source Converter)

• Traditionally, reactive power only (all quadrants)

• If connected to energy supply, can generate active power

• Faster, more complex than SVC(Static VAR Compensator)


STATCOM Applications



• Dynamic Reactive power usable for:

• Compensating cable capacitance

• Stabilize voltage

• DVR applications

• Flicker reduction

• Other grid applications


STATCOM: VSC



• Converter part (green)

• Identical to what is being used in 2-level active filters and drive inverters (if using IGBT)

• Maximum IGBT blocking voltage typically 6500V

• IGCT is also an option

• Blocking voltage presents majorchallenge!

• Line filter (red)

• Image shows L-filter; in ADF always LC or LCL

• Scales perfectly with current and voltage


STATCOM: VSC:: High voltage



• Voltage limits of converter

• With 2-level, maximum native line voltage <3kV

• Multi-level converter increases this to approx. 6.6 kV

• How to increase voltage tolerance?

1. Series connection(shown)

2. Transformer





1. Series connection

• Series connection requires exact

concurrent ignition of IGBT

(depending on equivalent

inductance in connecting cable)

or single IGBT will take all the

voltage IGBT failure!

2. Transformer

• This is a “simple” solution but

may degrade efficiency; adding

transformer losses to converter

losses. Or?





1. Series connection

• Series connection requires exact

concurrent ignition of IGBT

(depending on equivalent

inductance in connecting cable)

or single IGBT will take all the

voltage IGBT failure!

• Medium voltage series

connected IGBT: prohibitive

complexity!

Image courtesy of ABB. Used without permission





2. Transformer

• Transformer is in itself an inductive component

• By custom-making the transformer, the secondary inductance can be utilized as part of line filter!

• ADF units are then equipped with custom LC line filter

• This is what we did on the first ADF P700

TRAFO1

PPC1-1MCC1 PPC1-2 PPC1-3 PPC1-4

YNyn 0

22.5kV/690V

2000kVA

8%

Dry

Y Y

PPC2-4 MCC2PPC2-3 PPC2-2 PPC2-1WCSC

YNyn 0

22.5kV/690V

2000kVA

8%

Dry

Y Y


STATCOM: LV STATCOM concept



• Modular, 2x2 MVA solution

• 690V low voltage switchgear internally – easier to service

• 22 kV main connection

MCC1 PCC1-1 PCC1-2 PCC1-3 PCC1-4 WCSC PCC2-4 PCC2-3 PCC2-2 PCC2-1 MCC2

PP1

PP2

PP3

PP4

PP5

PP1

PP2

PP3

PP4

PP5

PP1

PP2

PP3

PP4

PP5

PP1

PP2

PP3

PP4

PP5

3 2

PP1

PP2

PP3

PP4

PP5

PP1

PP2

PP3

PP4

PP5

PP1

PP2

PP3

PP4

PP5

PP1

PP2

PP3

PP4

PP5

2 3

5 5

See

PP-M3

See MCC-

M2, M3, M4

5 5 5 5 5 5 5 5 5 5 5 5 5 5

See WCSC-

M4, M5

See MCC-M6

See MCC-M1

See MCC-M1

T

A

See

TA-M4

T

A

T

A

T

A

T

A

T

A

T

A

T

A

X10 X10 X10 X10 X10 X10 X10 X10 X10 X20 X10X10 X20

X30X30

See

PP-M1,M2

See

MCC-M1

See

WCSC-M1

X20

M4 M5


STATCOM: LV STATCOM concept (2)



• We have supplied LV/HV hybrid

STATCOM up to 130 kV so far

• Scales well to at least 10 MVAr

(depending on voltage/project)

• For very high ratings, LV/HV

hybrid solution becomes

impractical


STATCOM: How-to-guide



• Basic idea: stack enough P300 units and connect to large enough transformer!

• Size according to needed MVAr

• For flicker projects, rule-of-thumb is to size so that ADF reactive power exceeds load

• In most cases, custom Transformer/LC-filters are not needed

• Might be considered in some cases

• Special care must be taken with transformer, cooling and CT


STATCOM: How-to-guide: components



• Building blocks:

• Regular ADF P300 units, or

• System integration components (PPM300, SCC2, etc; more on this later)

• Up to 6 modules per computer

• Up to 0.167 MVAr per module (690V Liquid cooled)

• In multi-master, max 15 units;

• 15 computer x 6 modules = 15 MVAr!

• Multi-master not necessary in all cases

• Only difference between separate components and complete products is packaging.


STATCOM: How-to-guide: transformer



• Typically, Yyn or similar “straight” transformer must be used

• Cannot be used with non-symmetrical loads

• Unbalanced loads will overload such transformer

• For DPF and flicker projects, impedance is selected to give a reasonable short-circuit power

• For Harmonics projects, transformer must be custom-ordered – spectrum to be supplied to transformer mfgr


STATCOM: How-to-guide: switchgear



• If using P300 units, dedicated switchgear may not be necessary

• If using gG (or similar fuses), ADF fuses protect connecting cable as well

• Again, short-circuit current must be taken into account

• For example, 4MVA @ uk=6% may give up to 100 kA

• In this case it may be better to divide into two separate transformers

• Take care to follow local regulation!


STATCOM: How-to-guide: CT



• Normally use Open Loop configuration

• STATCOM projects typically pin-point load and/or facility

• All of Comsys STATCOMs have open-loop configuration!

• CTs might need to be custom ordered

• CTs placed on medium voltage do not always have 5A secondary

• In some cases, LEM current transducers must be used to maintain measurement precision


STATCOM: How-to-guide: cooling



• Majority of Comsys STATCOM installations are liquid cooled

• For liquid cooling, system integration concept is presently only option

• P300W will re-appear

• Main difference is power density and overload-ability in flicker applications


STATCOM: (selected) Reference list



Site Year Application Size Voltage

Höganäs 2007 EAF/Flicker 2x2 MVAr +

42 MVAr (THY)

22 kV

Dantysk 2015 Offshore wind farm (DPF) 4x1.5 MVAr 33 kV

Kville 2012 Wind farm/STATCOM (DPF) 2.5 MVAR 130 kV

Lingbo 2012 Wind farm/STATCOM (Flicker) 1 MVAr 33 kV

WDI 2012 Welding/Flicker 2.5 MVAr 20 kV

Sandvik 2010 EAF/Flicker 4 MVAr 10 kV

Global

Casting

2015 Casting/STATCOM (DPF) 4 MVAr 10 kV




ADF – the shapeof power to come

Thank you for your time!




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