voltage stabilization with shunt reactors

Voltage stabilization in transmission grids with fixed and variable shunt reactors

ABB Transformers, Tomas Olsson, Syracuse (NY), 6/4/2013

ABBMonth DD, YYYY | Slide 2

ABB Red Tie event, 6/4/2013.Agenda

Reactive power compensation, Why shunt reactors?

Reliable Design of shunt reactors General design Sound and Vibrations Variable shunt reactor (VSR) Testing

Transmission applications with VSR

References and summary

Reactive power compensation,Why shunt reactors?

ABB Transformers, Tomas Olsson, Syracuse (NY), 6/4/2013


Apparent power consists of active(true) and reactive power components

P = S*cos Q = S*sin

Reactive power compensationDefinitions


Active (True) power

Voltage and current in phase, cos = 1



Reactive power

Voltage and current out of phase 90 deg, cos = 0ind

Inductive circuit, we say that the current lags the voltage.Capacitive circuit, we say that the current leads the voltage.



To run a marathon with your hands in your pockets is very tiresome

The swinging movement of your bodyhas to be compensated with your arms.

This arm movement could be called a reactive power needed to help you move forward and also to keep the body balance

Likewise in an electrical power system the reactive power in balance is the carrier of the true power.If the reactive power is consumed the voltage decreases, its ability to transport the true power decreases.



Reactive power compensationVoltage control

Transmission planning in North AmericaThe ISO/RTO Council (IRC) is comprised of 10 Independent System Operators (ISOs) and Regional Transmission Organizations (RTOs) in North America. These ISOs and RTOs serve two-thirds of electricity consumers in the United States and more than 50 percent of Canada's population


1. Stability on long line transmissions2. Voltage control during light load

conditions

Reactor restores voltage to specified value

Voltage increase fromcapacitive generation

X

X

1

U

XQ

Q

Q

Q

X

Application of shunt reactors


AC power cable is never loaded with its natural load (losses, heating and cooling)

Always more reactive power is produced than what is absorbed

Need for shunt reactors.

Reactive Power Generation in cables


Zc = sqrt( l/c) Surge impedancePSIL = V02 / Zc Natural load at transmission voltage V0At PSILInsulation is uniformly stressed at all points along line

Power factor is unity, cos = 1The natural reactive power is zero


A

B

B

B

A

T

r

a

n

s

f

o

r

m

e

r

s

-

2

1

-

The shunt reactorA voltage

regulating device Electrical power systemTransmission line at no load condition, I2=0

V1 V2

I1 I2

V1 = Vr cosVrAt 200 miles, electrical length at 60 Hz is 23,2 degrees (at 50 Hz is 19,3 degrees)V2 will be 1,088 pu (1,06 pu)

I1 = 0,429 pu !!! Q1 = 0,429 PSILThere is a line charging current in the sending end generators

A

B

B

B

A

T

r

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n

s

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o

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m

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The shunt reactorA voltage

regulating device Electrical power system

V1 V2

I1 I2

Transmission line at no load condition and X chosen so that V2 = V1

At 60 HzMidpoint voltage = V1/cos (/2)= 1,021 puI1= I2= Q1 = Q2 = 0,2055 PSIL

Required rating of shunt reactorAt 500 kV voltage system, ZSIL = 250 ohm

Q2 =

= 205 Mvar (3 phase)


Degree of shunt compensationZc = Zc / sqrt( 1-ksh) ; ksh positive, inductive compensation

Shunt reactors - increase virtual surge impedance Zc- reduce virtual natural load PSIL

100 % inductive shunt compensation, ksh =1- reduces PSILto zero- increases Zcto implies a flat voltage profile at zero load.


P2, Q2

U2U1

(R) + X

Q

At natural loading, SIL; P2 = PSIL ( reactive power balance)

U1 U2

1,0 pu

Application of shunt reactorsVoltage profile

P2, Q2

U2U1

(R) + X

Q

At no or low load (P2), voltage profile, Ferranti effect

U1 U2

1,0 pu


P2, Q2

U2U1

(R) + X

Q

At no or low load (P2), voltage profile with connected SR

U1 U2

1,0 pu


P2, Q2

U2U1

(R) + X

Q

Increased load (P2), voltage profile with connected SR

U1 U2

1,0 pu


P2, Q2

U2U1

(R) + X

Q

Increased load (P2), voltage profile with connected VSR

U1 U2

1,0 pu

Reactor power less than rated power.

VSR = Variable Shunt Reactor

Application of shunt reactorsFine tuning of the voltage with a variable shunt reactor

ABB Reactors (oil immersed), Types and usage

Shunt reactorsVoltage control

Reliable Design of shunt reactorsABB Transformers, Tomas Olsson, Syracuse (NY), 6/4/2013

Rigid gapped core limb for low sound level1. Non-flexible grain oriented steel core sheet 2. Bounded with well proven stiff steatite spacers3. Spacers are machined to exactly the same heightPrecision crafted process ensures: Small axial movements Low vibrations & sound

DesignLow sound

Earthed shieldno stress concentrationtowards core or winding

Winding centre entry and ground potential towards yokes reduces overall size and losses

Neutral

HV line terminal

DesignWinding arrangement

It should withstand the loadof 40 cars, applied 120 times per second for 30 years continuous without rattling and high noise

DesignWhy to be careful when buying a reactor?

Options for sound reduction Typical sound levels

Internal noise control only:Sound power level 80 95 dB(A)Sound pressure level 65 75

dB(A)

With sound panels:Sound power level 70 85 dB(A)Sound pressure level 55 65

dB(A)

With sound enclosure:Sound power level 65 80 dB(A)Sound pressure level 50 60

dB(A)

OvervoltageOperating voltagesVoltage

Current

Application of shunt reactorsLinearity

Variable Shunt Reactor (VSR)ABB Transformers, Tomas Olsson, Syracuse (NY), 6/4/2013

ABB Group June 10, 2013 | Slide 39

Variable shunt reactor applicationsTo foresee the future?

We cannot today foresee the grid conditions of the future

Generation and load patterns Interconnections Regulations Need for reactive power compensation

Trend towards controllability, flexibility and intelligence of the networks

The expected life time of a reactor is 30-40 years

This talks to the favor of variable shunt reactors

Neutral

Phase terminal

Neutral

Phase terminal

OLTC An unconventional Reactor built on conventional technology

Design solutions taken from our way of building Shunt Reactors and Power Transformers

VSR winding concept

Normal shunt reactor Regulated shunt reactor

VSR design concept

Feasible regulation ratio, R, versus operation voltage

VSR feasible Mvar output ranges

On-load tap changer ABB

Three-phase neutral point tap changer of the diverter switch type

With conventional or vacuum current interrupters

VSR

Control of LTC of a VSR

Manual / Remote control

Automatic relay controlControl parameters, voltage and Mvar


TestingABB Transformers, Tomas Olsson, Syracuse (NY), 6/4/2013

Winding resistance Applied voltage test Inductance and loss measurement Zero-sequence impedance Accessories and small wiring Switching impulse test Lightning impulse test PD-measurement Audible noise test and vibrations Test of temperature rise Measurement of harmonics Inductance curve measurement Insulation resistance measurement Capacitance and power factor in insulation

DesignFull scale test

GC C

T1 T2

R

DesignFull scale test

Transmission applications with VSRABB Transformers, Tomas Olsson, Syracuse (NY), 6/4/2013

Variable Shunt Reactors (VSR) benefits

Statnett Norway

Reduced voltage jump at switching on operation.Coarse tuning of SVC equipment for best dynamical operation.Reduction of number of breakers. No parallell fixed reactors.Adjusting of seasonal related loads.Adjusting of daily dependable loads.Flexible spare unit possibility.Flexibility for new load conditions in the network. At revisions for example.Flexibility to move reactor to other locations.

Variable Shunt Reactors (VSR)

420 kV120-200 Mvar

ABB GroupJune 10, 2013 | Slide 51

High voltage level situation in the state, especially in the north.

Surplus of reactive power . Therefore big need for inductive power compensation. VSR solution gives flexible voltage control.

Dominion (VA)Variable shunt reactor applications


Dominion (VA)

A, Substation Carson.B, Substation Garrysonville.C, Substation Yadkin.D, Substation Hamilton.E, Substation Jefferson street.F, Substation Idylwood.

Voltage stabilisation, Virginia state.

VSR 50-100 Mvar, 242 kV, 7 units.

Variable shunt reactor applications

B

DF

C

E


Q Q

EHVEHV

X X

Reactor placed on the high-voltage side

Reactor power compensation from generators not longer reliable

Minimize number of breaker operations

Extended use of cables put higher demand on reactive power compensation

Eliminating air core reactors on transformer tertiary

Air core reactors take place and are spreading magnetic field

Tap changer used to keep voltage at constant value

Variable Shunt Reactor to Dominion, Virginia USA.

NEW OLD


Variable Shunt Reactor50-100 Mvar, 242 kV


Variable Shunt Reactor

Equipped with sound housing for sound level environmental impact.

50-100 Mvar, 242 kV.

Case, Wind Power generation in Texas

Sharyland Utilities part of CREZ

Wind energy transmission to consumer centres in eastern TX

ABB Inc. June 10, 2013 | Slide 57

Wind Power Generation in TexasSharyland Utilities part of CREZ

Wind Power generation in TexasFinal stage

Flexibility use for transmission line expansion and voltage stability

Variable shunt reactor applicationsSharyland Utilities

ABB in tank tap changer VUCG for variable Mvar output.

Variable shunt reactor applicationsSharyland Utilities

Reactive power compensation flexibility for better voltage control. More cost effective customer solution to two or more reactors with fixed ratings.Smaller footprint.Less number of breakers and breaker maintenance.Customer chooses ABB VSR for the reliability.

50-100 Mvar/345 kV

Zero Miss Phenomena (and other VSR application)

Siphon transmissionline, 400 kV

Cable transmissionline from wind mill park, 235 kV

1. Askaer S/S, 50-110 Mvar, 2 units to avoid zero miss phenomena. TC in min Mvar position when cable is energized.

2. Tjele S/S, 70-140 Mvar, to minimise voltage jump min Mvar position when switched in.

3. Revsing S/S,70-140 Mvar, to minimise voltage jump min Mvar position when switched in.

4. Grenaa S/S, 120 Mvar, compensation of sea cable from wind mill park.

5. Trige S/S, 60 -120 Mvar, 2 units to compensate for variable wind power generation and loss optimisation.

1

2

3

45

ABB VSR World wide referencesCustomer Nominalvoltage

(kV)Ratingrange,3phase(Mvar)

Type Yearofdelivery

Ghana,Africa 161 918 OLTC 4units19891unit2001

GEWCologne,Germany

110 1030 DETC 1unit1996

ChannelIslands,UK 132 716 OLTC 2unit1999

Sonabel,BurkinaFaso,Africa

225 1330 OLTC 1unit2004

Statnett,Norway 420 120200 OLTC 1unit2008Statnett,Norway 420 120200 OLTC 2units2010Statnett,Norway 300 80150 OLTC 2units2010ECoVannkraft,Norway

420 120200 OLTC 1unit2010

DominionVirginia,USA

242 50100 OLTC 3units20094units20101unit 2014

SvenskaKraftnt,Sweden

400 110180 OLTC 1unit2010

Energinet dk,Denmark

235 60120 OLTC 2units2011

Statnett,Norway 420 90200 OLTC 8units 2012/20131unit 2014

Sharyland Utilities TX,USA

345 50100 OLTC 1unit 2013

Energinet dk,Denmark

400 5011070140

OLTC 3units 2013/20142units 2013/2014

CenterPointEnergyTX,USA

143 2550 OLTC 1unit 2014

ReferencesABB Transformers, Tomas Olsson, Syracuse (NY), 6/4/2013

ABB Shunt reactorsReferences

170 Mvar, 525 kVto APS, Arizona

150 Mvar, 345 kVto New York Power AuthorityEquipped with a sound enclosure for very low sound emission ~ 55 dB



80 Mvar, 230 kVto PEPCOequipped with sound panels

Summary

AC apparent power (MVA) has two components, Active power (MW) and

Reactive power (Mvar).

Voltage is influenced by the level of Reactive power (AC system).

The Shunt Reactor is a regulating device to limit the voltage.

High manufacturing accuracy is requested to make reliable shunt reactors.

The Variable Shunt Reactor (VSR) principle is to regulate number of

electrical turns by a tap changer.

VSR is used by customers to satisfy the demand for improved flexibility

(economy driven) in the grid.

voltage stabilization with shunt reactors

Documents

natural reactive power

yyyy slide

reactive power generation

reactive power componentsp

apparent power

cables abbmonth dd

reactive powervoltage

true power decreases