Quadrature-booster Report – SDRC 9.8

Flexible Plug and PlayQuadrature-booster Report – SDRC 9.8 By UK Power Networks, Fundamentals Ltd and Wilson Transformer Company

August 2013

Definitions

Boost Increaseflowofactivepowerinacircuit

Buck Reduceflowofactivepowerinacircuit

CombinedHeatandPower(CHP) Co-generationoruseofpowerstation tosimultaneouslygenerateelectricityand

usefulheat

CDM Construction,DesignandManagement–regulationsusedintheconstructionindustry

inUK

DigSILENT ManufacturerofPowerFactory–apowersystemsmodellingtoolusedbyUKPower

Networks

DistributedGeneration(DG) Electricitygenerationconnectedtothedistributionnetwork

EPN EasternPowerNetworksplc,theholderofadistributionlicence

Ellipse The asset catalogue which contains information on all of UK Power Networks’

electricalassets

FPPTrialZone AnareaofUKPowerNetworks’EPNdistributionnetworkthatservesapproximately30km

diameter(700km2)betweenPeterboroughandCambridgeintheEastofEngland,UK

LowCarbonNetworkFund(LCNF) AfundingmechanismintroducedbyOfgemtopromoteresearchanddevelopment

forsmartdistributionnetworks

Ofgem TheOfficeofGasandElectricityMarkets:regulatorfortheelectricityandgasmarkets

inGreatBritain

Onloadtapchanger Aconnectionpointselectionmechanismalongapowertransformerwindingthat

allowsavariablenumberofturnstobeselectedindiscretesteps

Pointofconnection The interface between the UK Power Networks’ equipment (main fuse, energy

meter)andtheconsumer’sequipment(supplypanel)

Term Description

Quadrature-booster Aspecialisedformoftransformerusedtocontroltheflowofrealpoweronathree-

phaseelectricitytransmissionnetwork

RealTimeDigitalSimulator(RTDS) A digital electromagnetic transient power system simulator that operates in real

timetoprovidepowersystemssimulationtechnologyforfast,reliable,accurateand

cost-effectivestudyofpowersystemswithcomplexHighVoltageAlternatingCurrent

(HVAC)andHighVoltageDirectCurrent(HVDC)networks

SCADA SupervisoryControlandDataAcquisition–computercontrolledsystemsthatmonitor

andcontrolelectricitydistributionnetwork

StandardRunningArrangement Thedistributionnetworkconfigurationundernormalnetworkoperatingconditions

Term Description

4 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8

7.2 ColdCommissioning 38

7.3 FinalCommissioning 38

7.4 Demonstrationofimprovedbalancebetweenthe

circuitsallowingincreasedpowerflowof10MW 39

8 Quadrature-booster: Training 45

9 Learning and next steps 47

10 Figure and tables List 49

Contents Definitions 02

1 Executive Summary 05

2 Introduction 07

2.1 FlexiblePlugandPlay 08

2.1.1 FlexiblePlugandPlay:TheTrialZone 08

2.1.2 FlexiblePlugandPlay:TheSolution 08

2.2 Scopeofreport 10

3 Quadrature-booster: Concept 11

3.1 ProjectDrivers 12

3.2 Background 14

3.3 Thenetworkconstraint 16

3.4 Quadrature-boostersolution 19

4 Quadrature-booster: The Journey 22

4.1 RequirementsSpecification 24

5 Quadrature-booster: Implementation –

detailed design 25

5.1 Electricalinstallation 28

5.2 Protectionsystem 29

5.3 Quadrature-boosterdesign 30

5.4 Quadrature-boostercontrolsystem 32

5.4.1 OperatingPrinciple–

Regulationofpowerflow 32

5.4.2 InterfacewithBritishSugar 32

6 Quadrature-booster: Implementation –

Installation 33

7 Quadrature-booster: Testing and commissioning 36

7.1 Pre-installationtesting 37

1Executive Summary


Executive SummaryTheQuadrature-boosterisdesignedtoshiftrealpowerflows

from an overloaded circuit to a circuit that is less loaded

to achieve improved load sharing and increased network

capacity headroom. The Quadrature-booster is equipped

withanautomaticcontrolsystemthatdrivesanon-loadtap

changertocontrolthepowerflowsindiscretesteps.

Based on the available information and references, we

understand that this is the first Quadrature-booster to

bedeployedona33kVdistributionnetwork in theworld.

Consequentlysignificantnewknowledgehasbeengenerated

throughout the entire process from concept development,

modelling,design,installation,commissioningandultimately

tooperationsandmaintenance.

The Quadrature-booster has been a complex and cutting-

edgeinnovationengineeringprojectdeliveredindemanding

timescalesbyhighly-skilledteamsfromthevariousproject

participants (partners, suppliers and UK Power Networks)

workinginclosecollaborationwitheachother.

The Quadrature-booster project was led by UK Power

Networks and delivered in partnership with a team of

projectpartnersandsuppliers.WilsonTransformerCompany

designed,built,installedandcommissionedtheQuadrature-

booster and Fundamentals Ltd its control system. Carillion

UtilityServiceswasresponsiblefordeliveryoftheciviland

electrical works. Alstom Grid supported the development

of the protection scheme while Mott McDonald provided

assurancestudiesonthedesignoftheprotectionscheme.

TheSDRCwasachievedfollowingthesuccessfuldeploymentof

theQuadrature-boosterinJuly2013andtheFPPprojectintendsto

disseminatefurtherinformationontheoperationandperformance

oftheQuadrature-boosteratlaterstagesintheproject.

Flexible Plug and Play (FPP) is a Second Tier Low

Carbon Network Fund (LCNF) project that aims to connect

Distributed Generation (DG) onto constrained parts of

the electricity distribution network without the need for

conventional network reinforcement. To achieve this, a

number of innovative smart devices and applications will

be trialled to manage constraints and maximise network

utilisation. This will enable alternative smart connection

solutions to be trialled in order to facilitate, accelerate

andcostoptimisetheconnectionandoperationofDGina

constraineddistributionnetwork.

Oneof thesmartdevices tobe trialledaspartof theFPP

project is a Quadrature-booster, which has been designed

anddeployedtobalancepowerflowsthroughparallelcircuits

supplyingalargecustomerwhoseabilitytoexportelectricity

iscurrentlyconstrainedasaresultofunbalancedloadsharing

ontwoparallelcircuits.Akeymilestoneofthisprojectwas

toinstallanddeployaQuadrature-boosteranddemonstrate

thatthiscouldbeusedtoincreasetheexportcapacityofthe

site.Itisreportedthatpowergenerationonthissiteachieves

thebestCombinedHeatandPower(CHP)ratingunderthe

governmentCHPenvironmentalqualityassurancescheme,

further increments of generation exports would therefore

contributetolowcarbongeneration.

This report outlines the design, installation, testing and

commissioningofthisinnovativeassettoexplaintheprocess

whichUKPowerNetworksundertook to successfullymeet

theproject SuccessfulDeliveryRewardCriterion (SDRC) for

the Quadrature-booster referenced as 9.8 in the Project

Direction.Inadditiontoitssuccessfulinstallation,thereport

alsodemonstrateshowtheQuadrature-boosterallows10MW

ofincreasedpowerflowbyimprovingthebalancebetween

thecircuits.

2Introduction


Flexible Plug and Play2.1

DG connections total 144MW,with 158MWofDG capacity

currentlyatvariousstagesoftheplanningprocessseeking

to connect as at July 2013. Using conventional connection

approaches, the connection of this anticipated growth in

DGisexpectedtorequiresignificantnetworkreinforcement

to manage network thermal and voltage constraints and

reversepowerflowissues.

For this reason, the area between Peterborough and

CambridgeservesasanidealtrialareafortheFPPprojectto

explorealternativesmartconnectionsolutions.

2.1.2 Flexible Plug and Play: The Solution

TheFPPprojectistriallingsmartconnectionsolutions,inorder

tofacilitate,accelerateandcostoptimisetheconnectionand

operation of DG in a constrained distribution network. The

projectistriallinganalternativetothepassive‘fitandforget’

approachbasedonconventionalnetworkreinforcement–one

thatconsiderstheactivemanagementofnetworkconstraints

andgenerationexport, drivingan innovativeactive ‘fit and

flex’approachthatwillavoidordefernetworkreinforcement.

The FPP solution will demonstrate this active ‘fit and flex’

approach through the integration of smart devices, smart

applicationsandsmartcommercialarrangements:

Smart Devices:Thesolutionwilldeploysmartdevicesfrom

variousvendorstoaddressandmanagespecificexistingor

anticipatednetwork constraintsandoperational limitations

of the network that either restrict DG connections or are

introduced by the connection of DG. The range of smart

devices include: dynamic line ratings; active voltage

management;aQuadrature-boosterandassociatedcontrol

system;andgenerationcontrollers.

Smart Applications:Asmartapplicationwillbeinstalledat

UKPowerNetworks’controlcentreatForeHamlet,Ipswich,

providinganActiveNetworkManagement (ANM) solution

The FPP project, funded under Ofgem’s LCNF Second Tier

scheme,aimstofacilitatethefasterandcheaperconnection

ofDGonto thedistributionelectricitynetworkwithout the

need for conventional network reinforcement. Rather, the

FPPmethodsachieve this objectivebymanagingnetwork

constraints and maximising network utilisation. The FPP

projectwilldothisthroughtheintegrationofsmartdevices,

smartapplicationsandsmartcommercialarrangements.

One of the smart devices deployed by the project is the

Quadrature-booster. The Quadrature-booster is a power

systemsdevicethatcanbeusedtoimprovebalancethepower

flowsacrosstwoparallellinesinthedistributionnetworkand

releaseheadroomintheexistingassets.Thisadditionalcapacity

canbeusedbyeithergenerationordemandcustomers for

theirconnectiononthedistributionnetwork.

The FPP project, led by UK Power Networks, addresses

this requirement in partnership with 10 project partners1:

Vodafone(formallyCable&WirelessWorldwide),SilverSpring

Networks, Alstom Grid, Smarter Grid Solutions, GL Garrad

Hassan, University of Cambridge, Imperial College London,

the InstituteofEngineeringandTechnology,Fundamentals

andGEPowerConversion.

2.1.1 Flexible Plug and Play: The Trial Zone

The location chosen for the FPP project is an area of UK

Power Networks’ EPN distribution network that serves

approximately 30km diameter (700km²) between

PeterboroughandCambridge(theFPPTrialZone)intheEast

ofEngland,UK. Thisarea is favourable toDGdevelopers –

windandsolarfarmsinparticular–duetogeographyand

favourableweatherconditions.

Over recent years UK Power Networks has experienced

increased activity in DG development in this area, and a

rapid rise in connection applications; existing renewable

1 The project has also a number of project suppliers: Wilson Transformer Company, Mott McDonald, PA Consulting, Baringa Partners and DNV Kema.

Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 9

to monitor real time network parameters by the smart

devices.TheANMwillalsomanagethegenerators’output

using the generation controllers, which will allow the DG

exporttotrackthereal-timeexportcapacityavailablewithin

the real-time constraints on the distribution network. The

ANMwill perform these functionswhileensuring that the

distribution network maintains its reliability and performs

withinoperationallimits.

Smart Commercial Arrangements: As generators’ export

willbeactivelymanaged(i.e.theiroutputwillberegulated

tomeetdistributionnetworkconstraints),newcommercial

andconnectionarrangementswillbeestablishedthatdefine

accesstothedistributionnetworkcapacityavailableinreal

time.Thiswillbeintheformofan‘interruptible’connection

agreement;thefirstofwhichhavebeenpresentedaspart

of the connection offers to eligible generation developers

withintheFPPtrialarea.


Scope of report2.2This report looks to provide evidence to demonstrate the

successfulcompletionoftheprojectSDRCfortheQuadrature-

booster workstream. This SDRC is evidenced by the

commissioningofthedeviceandthisreport.

Thereportisstructuredasfollows:

Section 3 Outlines the Quadrature-booster concept as

adoptedbyUKPowerNetworks

Section 4 Provides an overview of the Quadrature-

boosterspecificationanddesign.Inthissection

technical requirements and specifications on

theQuadrature-booster,theQuadrature-booster

control system, and the Quadrature-booster

protectionsystemarediscussed.

Section 5 Describes the Quadrature-booster architecture,

electrical installation, protection system and the

Quadrature-booster control system operating

principletocontrolandregulateactivepowerflow.

Section 6 Outlines the installation activities associated

withtheQuadrature-boosterandthesupporting

infrastructure.

Section 7 Provides a summary of the testing and

commissioningactivitiesandoutcomes.

Section 8 Dealswiththetrainingforkeystaffinreadiness

fortheQuadrature-boosterdeploymentonthe

distributionnetwork.

Section 9 Concludesthereport.

3Quadrature-booster: Concept


Project Drivers3.1

During peak export, the thermal capacity of one of the

paralleled circuits is exceeded before that of the two

othercircuitsbecausetheloadsareunbalancedacrossthe

paralleled circuits. This constraint restricts the seasonal

export limit to approximately 54MW which is 23%

below the installed generator turbine capacity (70MW).

It is reported that Wissington British Sugar generation

achieves the best CHP rating under the government CHP

qualityassurancescheme2.Assuch,furtherincrementsof

generationexportscanprovidevaluablecontributiontothe

electricitygenerationfleet.

The Wissington British Sugar factory runs the CHP at full

exportduringthesugarbeetcampaignmonthsfromOctober

toMarch.Thisiswhentheconstraintconditionsusuallyoccur.

The Quadrature-booster trial is primarily driven by a

generation export constraint on a CHP generation plant

that is locatedatWissingtonBritishSugarFactory,Norfolk.

WissingtonBritishSugar isa sugarbeetprocessing factory

whichalso runsaCHPelectricitygenerationplantwithan

installedturbinecapacityof70MW.

This network constraint is due to the thermal capacity of

oneof the threeoutgoingelectrical circuits, twoofwhich

areconnectedinparallel.Generationexportissharedacross

the three circuits according to their electrical impedance

which, amongst other factors, is related to their relative

lengths.Largedistributedgeneratorscanhighlightcapacity

sharingissuesonournetworkwhichhadnotpreviouslybeen

consideredasaconstraintondemandcustomers.

Figure 1: Aerial photograph of Wissington site CHP point of connection

2 http://www.britishsugar.co.uk/Files/FactoryPDFs/About-Wissington-Factory-pdf.aspx - accessed 25 July 2013, 1100hours

CHPPlant

Existing33kVsubstation

30MVAQuadratureBooster


The concept to deploy a Quadrature-booster at British

Sugar’s site at Wissington was investigated as part of the

developmentoftheoverallFPPprojectbidsubmission.This

included the high level design of the system, which was

developedtoenablebudgetcostingforthisdevice.

Thekeyactivitiesundertakenduringthishigh leveldesign

phaseoftheprojectincluded:

• Verificationofthenetworkconstraint

• Budgetcostingfortheproject

• Identificationoftheexpectedbenefitsoftheproject

Thekeyoutputofthisphasewasaformaltechnicaldesignreview

byUKPowerNetworks.Thefollowingsub-sectionsprovidean

overview of this high level design, along with the rationale

associatedwiththerealisationoftheseexpectedbenefits.


Background3.2

Arrangement(SRA)3,showninFigure2,thesiteconnectionis

providedviathree33kVcircuitsrunninginterconnectedwithfour

132/33kVsites–MarchGrid,SwaffhamGrid,KingsLynnSouth

GridandWalsokenGrid(notshowninFigure2).

TheWissingtonBritishSugarsubstationisaUKPowerNetworks’

33kVsubstationlocatedwithintheBritishSugarsiteandprovides

thepointofconnectionforBritishSugartoimportandexporttoUK

PowerNetworksdistributionnetwork.UnderStandardRunning

Figure 2: The general Wissington 33kV Network Interconnection under Standar Running Arrangement

KingsLynnGridTeeWaltington

OutwellMoors

Littleport

DownhamMarket

Northwold

Swaffham

Watton

1

12

1

2

3

123

WissingtonBSC33kV

WissingtonCHP

Southery

8.275km 8.154km

5.36

km

11.07km

(IDP5432)

6.31km

Key

Existing33kV

Future33kV

Existing11kV

CircuitBreakerClosed

CircuitBreakerOpen

DisconnectorClosed

DisconnectorOpen

Generation

CombinedHeatandPower

InfrastructureDevelopmentPlan

3 The distribution network configuration under normal network operating conditions - all three outgoing 33kV circuits are connected and on load

CHP

IDP


ThisnetworksupportsBritishSugar’sexistingCHPinstallation,

which has an overall generator capacity of 95.2MVA, and

comprisesa58.8MVAgasturbinegeneratoranda36.4MVA

steam turbine generator. The installed turbine capacity is

82.4MVA (or 70MW at 0.85 power factor) and is reported

by Wissington British Sugar to be limited by the available

exportcapacityonthedistributionlines.Theoutputofthese

generatorsis,therefore,managedbyanexistingautomatic

generatorturndownschemewhichmonitorstheloadingson

theoutgoing33kV circuits, alongwith the statusof circuit

breakers. In the event of a circuit loss, or the combined

power flows exceeding the seasonal limits, an automatic

generator turndown is activated to reduce generation to

withinsetlimits.

In thepast,UKPowerNetworkshas consideredenquiries for

increasing theexport limits,but the local33kVoverhead line

wasidentifiedasthemainrestrictiontoprovideacostefficient

solution.TheprevioussolutionidentifiedwastoconnectBritish

SugardirectlytothemainconnectionpointatSwaffhamGrid,

whichcouldbeachievedviatwooptionsbelow:

1.Anewoverhead33kVlinefromWissingtontoSwaffhamat

acostofcirca£3.0millionandliabletoaSection37planning

consent,withanexpectedthreeyearpublicenquiry.

2.A new fully underground 33kV cable between Wissington

andSwaffhamatacostofcirca£6.0million,whichwouldnot

requireSection37planningconsent.

Neither of the above options were considered a viable cost

effectivebusinesssolutiontoBritishSugarandsotheCHPplant

continuedtooperatewithinthepresentexportconstraints.

The Quadrature-booster project spend is forecasted to be

approximately £1.6 million including all costs for project

management,civilworks,thenewelectricalinstallation,the

device,controlandprotectionsystems.Themethodcostsfor

futurereplicationofthedeviceareexpectedtobelowerbut,

evenatthecostoftheprojecttrial,theQuadrature-booster

is a more cost effective solution for releasing additional

networkcapacity.


The network constraint3.3Duringnormalnetworkoperatingconditions(nocircuitoutages)

thelimitatwhichtheoutputofthegeneratorsisconstrainedisset

bytheseasonalratingsofthe33kVcircuits,whicharedescribed

withinTable1.Thethreecircuitshavethesameconductorsize

(200SCA)andthereforehavethesameseasonalthermalrating

valuesasshowninTable1.

Inthecurrentnetworkconfiguration,thenetworkisconstrained

asaresultofthedifferencesinimpedancebetweenthethree

lines,whichresultsinanimbalanceinthepowerflowsthrough

these circuits. The present high loading of the Downham

Marketlinemeansthatseasonalexportlimitsareincludedin

theexisting“Connection&UseofSystemAgreement”between

BritishSugarandUKPowerNetworksasshowntheTable2.

Combinedwiththeseoverallnetworklimits,thereisalsolocalline

currentlimitsonthethreeoutgoing33kVcircuitstoNorthwold,

SoutheryandDownhamMarketwithacomplexcontrolsystem

tomakesurethelinewiththehighestelectricalloadflowisnot

overloaded(alwaystheDownhamMarketline).TheDownham

Marketline(totheTeepoint)isconnectedelectricallyinparallel

to theNorthwold line,but it isalmosthalf the lengthof the

Northwoldline.Duetothisdifferenceinlength,theDownham

Marketlinehaslowercircuitimpedance,whichresultsinalmost

twicetheamountpowerflowthroughtheDownhamMarket

linecomparedtotheNorthwoldline.TheCHPoutputisreduced

inordertopreventtheDownhamMarketlinebeingoverloaded.

Thenetworkconstraintwasillustratedthroughmodellingofthe

network, which was undertaken in PowerFactory modelling

software(fromDigSILENT)basedonthefollowingassumptions:

• Thenetworkisoperatinginitsnormalconfiguration

• WissingtonCHPgenerationdispatchis54.58MVA

Table 1: Seasonal ratings for circuits within the Wissington 33kV Network interconnection

Table 2: Maximum seasonal export limits for the British Sugar, Wissington generation

Northwold 443 25.3 512 29.3 553 31.6

DownhamMarket– 443 25.3 512 29.3 553 31.6NorthwoldTeedsection

Southery 443 25.3 512 29.3 553 31.6

UseofSystemAgreement(2007)

Circuit Summer Spring/Autumn Winter Amp MVA Amp MVA Amp MVA

Summer 46 May,June,July,August

Spring/Autumn 49.5 March,April,September,October,November

Winter 54 December,January,February

Season Maximumseasonal Months exportlimits(MVA)


• Thereisanadditional17.5MVAofwindturbinegeneration

connectedtothenetworkat11kV

• The minimum load condition, which occurred on 21

June2011at1421hours.Thisinformationissuppliedby

NationalGridandreferstoatimewhenthenational(UK

wide)minimumdemandwasrecordedinthesummerof

2011,justbeforetheinitialmodelingoftheQuadrature-

boosterwascompleted

• There was a discrepancy between the Wissington CHP

modeldispatch(54.58MVA)andtheactualwinterexport

limit,with theUKPowerNetworksPowerFactorymodel

beingupdatedtoreflectthecorrectinformation

The system has been modeled under minimum load and

maximum generation conditions which correspond to the

worst case scenario for the distribution network. This is

consistentapproachusedinplanningdistributionnetworks,

itisanapproachthatwillyieldconservativeresults.

Inaddition,thecycleofoperationoftheBritishSugarfactory

dictatesthehighestexportduringwintermonthsandassuch

themaximumgenerationexportandwinterlineratingsare

theconditionwheretheconstraintmightariseandformthe

basisofthenetworkanalysis.

The indicative resultsof thepowerflowstudy inFigure3

show that circuit 2 (DownhamMarket circuit) approaches

the 31.6MVA capacity limit (winter seasonal constraint)

whilecircuits1(Northwoldcircuit)and3(Southerycircuit)

arebelowtheirrespectivecapacities.

Figure 3: PowerFactory Load Flows

Wissington BSC Generator

Wissington BSC

123

P=10.39MVVQ=1.74MvarS=10.54MVA




P=

0.00

...Q

=0

.00.

..S

=0.

00...


WinterExportLimit

ThermalCapacityLimitreached

P=46...Q=8.8...S=47.1...

P=25...Q=6.0...S=26.1...



Key

Northwold

DownhamTeed

Southery

Generation

Circuitbreakerclosed

Disconnectorclosed

Transformer

1

2

3

UI=33.89kVu=1.03p.u.phiu=46.9...


Followingfurtherinvestigationofthehistoricalloadprofiles

forthesethreecircuits,asshowninFigure4,itcanbeseen

that circuit 2 (Downham Market circuit shown in red) is

generally loaded approximately twice as much as circuits

1(Northwoldcircuitshowninteal)and3(Southerycircuit

showninpurple).

Figure 4: Historical circuit loadings

KeyNorthwold

DownhamMarket

Southery

Summer

Spring/Autumn

Winter

MVA

01.01

.2011

0

5

10

15

20

25

30

Date

35

15.01

.2011

29.01

.2011

12.02

.2011

26.02

.2011

12.03

.2011

26.03

.2011

09.04

.2011

23.04

.2011

07.05

.2011

21.05

.2011

04.06

.2011

18.06

.2011

02.07

.2011

16.07

.2011

30.07

.2011

13.08

.2011

27.08

.2011

10.09

.2011

24.09

.2011

08.10

.2011

22.10

.2011

05.11

.2011

19.11

.2011

03.12

.2011

17.12

.2011


Quadrature-booster solution3.4Basedon this initialnetworkassessment itwas clear that

there is value in trialling a solution that would enable

improved load sharing on the Downham Market and

Northwold 33kV circuits. The proposed solution was to

investigate the installation of a new Quadrature-booster

completewithanonloadtapchanger.

3.4.1 What is a Quadrature-booster?

Quadrature-boostersarephaseshiftingtransformersusedto

control the flow of active power in electricity transmission

networks. They consist of two transformer units; a shunt

transformerandaseries transformeras illustrated inFigure

5.Theshunttransformerisfittedwithtapchangertoextract

acomponentofthesystemvoltage,typicallyintherangeof

±20%ofthenominalsystemvoltage(33kV,132kVor400kV).

Theseries transformer isconnected inserieswith themain

transmissioncircuitandshouldhaveratingsequivalenttothe

circuitrating.Thevoltagecomponentfromshunttransformer

is inducedinquadraturei.e.90degreestothesystembase

voltageintheseriestransformertoaffectthevoltageangle.

TheoveralloutputvoltageoftheQuadrature-boosteristherefore

thevector sumof thesupplyvoltageand the90°quadrature

component. Theoutput voltage is approximatelyequal to the

inputvoltagebutwitha(variably)shiftedphaseangle.Thisshiftin

phaseangleenablesthecontrolofpowerflowacrosstwoparallel

lines,withthecircuitcontainingtheQuadrature-boostersaidtobe

“Boosting”powerflowwherethepowerflowthroughthecircuit

isincreased(boosttapping),or“Bucking”powerflow,wherethe

powerflowthroughthecircuitisreduced(bucktapping).

TheQuadrature-boosterisamaturetechnologyandhasbeen

usedbytransmissioncompanieslikeNationalGridandacross

continental Europe since the 1970s, and pictures of typical

unitsareshowninFigure6.Oneofthemajordifferenceswith

theunitdesignedforthedistributionnetworkisitssize.

Figure 5: General symbol representation of a Quadrature-booster

Figure 6: General views of typical Quadrature-boosters used on transmission networks

SeriesUnit Output

MainUnit(Shunt/Exciting)

Input

OLTC

Key

OnLoadTapChanger

OLTC


Basedonavailableinformation,theFPPQuadrature-boosteris

thefirsttobedesignedspecificallyforadistributionnetwork,

andthegeneraloverviewofthisunitisshowninFigure7.

3.4.2 How was it be deployed?

The Quadrature-booster is series-connected in circuit 2, as

shown in Figure8, to “buck” real powerflow to achievea

closelybalancedloadsharingbetweencircuit1and2.

3.4.3 Expected benefits

The results obtained from the modelling are such that

balancing the load through lines 1 and 2 would increase

availableexportcapacityheadroomby10MW.Inadditionto

this, thedeliveryof theQuadrature-booster isexpected to

achievethefollowingbenefits:

• Improvingutilisationofexistingassets

• Smarternetworkwithimprovedcontrollability

• Deployment of the first Quadrature-booster on the 33kV

distribution network

Figure 7: General view of the Wissington Quadrature-booster: 3D design, and during construction


Figure 8: Schematic illustration of existing distribution network around the Wissington British Sugar substation

KingsLynnGridTeeWaltington

OutwellMoors

Littleport

DownhamMarket

Northwold

Swaffham

Watton

1

12

1

2

3

123

WissingtonBSC33kV

WissingtonCHP

Southery

PositionofQuadrature-booster

8.275km 8.154km

5.36

km

11.07km

(IDP5432)

Key

Existing33kV

Future33kV

Existing11kV

Generation

Circuitbreakerclosed

Disconnectorclosed

Transformer

InfrastructureDevelopmentPlan

IDP

4Quadrature-booster:TheJourney


Followingthecompletionofthedesignreview,theproject

movedintothedefinitionstage,inwhichUKPowerNetworks

developed specifications describing the performance

requirements for the Quadrature-booster, along with the

associatedcontrolandprotectionsystems,necessaryforthe

successfuldeploymenton to thedistributionnetwork. This

enabledprojectpartners,WilsonTransformerCompanyand

Fundamentals, along with UK Power Networks contractor,

CarillionUtilityServices,toagreeonscopeanddeliverables

fortheproject.

Thekeyactivitiesundertakenduringthisphaseincluded:

• Productionofspecificationsforthesystems

• Agreementofprojectcostsandcontractualarrangements

• Developmentofaprojectimplementationplan

Thekeyoutputsofthisphasewere:

• EngineeringDesignStandardfortheQuadrature-booster

• Protection and Control design brief for the Quadrature-

boosterinstallation

• Fixedpricedquotationforthedesign,delivery,installation

and commissioning of the Quadrature-booster and the

associatedcontrolsystem

• Target price for overall electrical design, civilworks and

electricalinfrastructureworks

• ProjectagreementwithWilsonTransformerCompany

• ProjectagreementwithFundamentalsLimited

• WorkpackageorderforCarillionUtilityServices

• ProjectImplementationPlan


Requirements Specification4.1The requirements specifications describe the performance

requirementsforQuadrature-boostersandtheassociatedcontrol

andprotectionsystemsnecessaryforthesuccessfuldeployment

onthenetwork.SpecificationswereproducedfortheQuadrature-

booster,controlsystemandtheprotectionsystem.

Quadrature-booster requirements

The Quadrature-booster was designed as a dual core unit

consistingof interconnectedseriesandshunttransformers.

Itsnominalratingis30MVAandhasamaximumimpedance

of2.3ohm(6.34%on30MVAbase),soastoensurethatthe

existingprotectionschemecanremainfunctional.Toachieve

thenecessarycontrolof thepowerflowbetweenthe two

lines,theQuadrature-boosterhasbeendesignedtoprovidea

phaseshiftinthevoltagebetweentherangesof±12°.

Quadrature-booster control system requirements

The Quadrature-booster control system is designed for

automatic control of the On Load Tap Changer (OLTC) to

optimise the load sharing between the Northwold and

theDownhamMarketTeedNorthwoldcircuits.Thiswillbe

achieved by monitoring active power flow down each of

thelinesandissuingcontrolstotheQuadrature-booster,to

tapupor down, and control thephase shift,whichaffect

thepowerflow.Thesystemalsocontainsappropriateauto-

switching and interlocking so as to prevent mal-operation

duringplannedand/orunplannednetworkreconfiguration.

Protection system requirements

The protection of the Quadrature-booster consists of fast

acting main protection, Inverse Definitive Minimum Time

(IDMT) backup protection and mechanical protection

devices. The protection system is also designed to be

immunetoinrushcurrentsandissuitablefortherangeof

tappositionsusedintheschemetointerfacewithexisting

protectionschemes.

5Quadrature-booster:Implementation–detaileddesign


The detailed design for the Quadrature-booster system

was completed in accordance with the aforementioned

performancerequirementsidentifiedbyUKPowerNetworks

andwassubjecttoareviewbyindividualsfromUKPower

Networks,FundamentalsandWilsonTransformerCompany.

The final design is such that the deployment of the

Quadrature-boosterhasnotadverselyaffectedtheoperation

ofthenetwork,andthatsafetyofpersonnelandplantthat

maybeaffectedbyitsoperationhasbeenassured.

Thekeyactivitiesundertakenduringthisphaseoftheproject

included:

• Completionofthedetaileddesign

Thekeyoutputsofthisphaseoftheprojectincluded:

• Installation, Operating and Maintenance manual for the

Quadrature-booster

• Installation, Operating and Maintenance manual for the

ControlSystem

• Constructionissuedrawings

AsummaryoftheQuadrature-boosterarchitectureisshown

inFigure9below.

Figure 9: Quadrature-booster architecture

Key

Power

Measure

Monitor

Control

Indication

CurrentTransformer

Northwold

DownhamTeed

Southery

VoltageTransformer

OnLoadTapChanger

QuadBooster

DR-

C50

Calis

to9

QB

Prot

ectio

n

OLT

C

Control

SCADA

Monitoringviawebaccess

WissingtonCHP

123

QBCSTapCON260

VT

VT

1

2

3VT

OLTC


TheQuadrature-boostercontrolsystemcontrolstheMWflows

inordertoachieveimprovedpowerflowsharingbetween

line1andline2(seefigure9),bycomparingthepowerflow

ofline1andline2andtappingupordowntominimisethe

powerdifferencebetweenthecircuits.Thecurrentreference

willbeprovidedbyloopingintotheinstrumentationsingle

phasecurrent transformer(CT)circuitoneachof the lines.

Thevoltagereferenceisprovidedbytappingintothenon-

protectionpartofthevoltagetransformer(VT)circuitoneach

ofthelines–installedontheloadsideoftheQuadrature-

booster.Ifthecurrentorvoltagevalueismissingfromany

one of the controlled circuits 1 and/or 2, theQuadrature-

boostercontrolsystemisprogrammedtoreverttofailsafe

modebyreturningtheOLTCtonominaltapwhereithasno

effectonpowerflowsonthecircuits.

TheQuadrature-booster control systemcanbeoperated in

either auto mode or manual model, although the system

is designed to ensure single mode operation, and can

be selected locally and remotely. In manual mode it can

be operated locally via the front panel, or remotely via

hard wired inputs and IEC 61850 based communications

network.InautomodetheQuadrature-boosteriscontrolled

automatically by the TAPCON 260 (Quadrature-booster

controlsystem)relay.

The Quadrature-booster control system settings can be

accessed and modified via a dial in user interface to the

TAPCON260 relay by remote access for configuration. This

accesscanbepasswordprotected.TheQuadrature-booster

controlsystemschemeiscapableofbeingdisabledwhilethe

Quadrature-boosterisinbypassmode.

The Quadrature-booster is equipped with enhanced

monitoring functions through the Calisto 9 and DR-C50

systems.TheCalisto9monitorsdissolvedgases inside the

Quadrature-booster tank,andtheDR-C50providedynamic

ratingmanagementoftheOLTCandtheQuadrature-booster

unit.Themonitoringactivitiesof theCalisto9are fed into

theDR-C50,andbothareaccessiblefromremoteviaaweb

interfacefordownloadandfurtheranalyses.

Anumberofcommands,indicationsandalarmsareprovided

toUKPowerNetworks’controlroomviaSCADA.


Electrical installation5.1TheQuadrature-booster is connectedviaanewfivepanel

switchboard located in a newbrick switchhouse adjacent

to an enclosure that contains the Quadrature-booster.

The alterations to the existing network, necessary to

accommodatetheQuadrature-booster,areillustratedinthe

singlelinediagramshowninFigure10.

The new 33kV switchgear for the Quadrature-booster,

including the aforementioned five-panel switchboard, is

equippedwithabussectioncircuitbreakerwhichisusedasa

by-passovertheQuadrature-booster.Theby-passisnormally

OPENduringnormaloperatingconditions. It canbeclosed

underplannedoremergencyconditions,keepingthecircuit

connectedtothenetwork.

Varioussafetyinterlockingschemesandrestrictionsapplyto

reducerisktoplantandoperator.Theby-passcircuitbreaker

and the two Quadrature-booster related circuit breakers

operate in an OPEN before CLOSE logic. Network Control

EngineersareresponsibleforoperationsoftheQuadrature-

boosteranditsassociatedequipment.

Figure 10: Single Line Diagram showing 33kV Network re-configurations

CHP

123

E

A B D

C

Dow

nham

Mar

ket

Tee

Nor

thw

old

NorthwoldSouthery

WissingtonBritishSugar33kVSwitchingStation

NC

QB5-panelSwitchboard(QBSwitchingStation)

Key

CircuitBreakerClosed

CircuitBreakerOpen

Downham/NorthwoldCircuitBreaker

Quadrature-boosterDownham/NorthwoldSideCircuitBreaker

Quadrature-boosterBy-passCircuitBreaker(normallyopen)

Quadrature-boosterWissingtonBritishSugardSideCircuitBreaker

Quadrature-boosterCircuitBreakeratWissingtonBritishSugarSwitchingStation

Disconnector(normallyclosed)

Quadrature-booster

OnLoadTapChanger

Generator

Quadrature-boosterrelatednetworkre-configuration

A

B

C

Circuit Breaker reference:

D

E

NC


Protection system5.2TheprotectionoftheQuadrature-boosteranditsconnection

canissplitintothefollowingschemes:

• Quadrature-boosterprimarywindingsunitprotection

• Quadrature-boostersecondarywindingsunitprotection

• Overfluxingprotection

• Gasandoiloperatedprotection

• Quadrature-boosterearthfaultbackupprotection

• Busbarunitprotection

• OverallQuadrature-boosterandbusbarbackupprotection

These schemes overlap with each other and with the

existing line and switchgear protection schemes to create

thenecessarycrossoveraswellasdiscriminationrequired

for33kVprotectionsschemes.

The Quadrature-booster primary and secondary windings

unitprotectionschemesandtheearthfaultbackupscheme

are based on recommendations within the IEEE Standard

C57.135-20014.

Over fluxing protection was applied to reduce the risk of

damagecausedbycorefluxgoingoutoflimitundercertain

runningcondition.Thisisanissuethatislikelytobepresentif

operatingontheextremitiesofthetappingrangeandunder

loadimbalanceoropencircuitfaultsonthe33kVnetwork.

Thegasandoiloperatedprotectionschemesapplied,such

as Buchholz and Pressure Relief Device, are in line with

standard practice for primary and grid transformers. An

additional schemewasalso introduced to carryoutonline

conditionmonitoring through thebespokeDynamicRating

Managementfortransformers(DR-C50)andonlinedissolved

gasanalysesbyMorganSchafferCalisto9device.Thiswill

help in assessing the suitability of the Quadrature-booster

designinthistrialproject.

Thebusbarunitprotectionschemecomprisesoftwozones

ofcirculatingcurrentprotectiontodetectanddiscriminatefor

faultinthe33kVswitchgear.

TheoverallQuadrature-boosterandbusbarbackupprotection

isadifferentialschemeusingIDMTprotection.Thisprovidesa

specificzonebackupschemeforbothwhentheQuadrature-

boosterisinserviceorbeingbypassed.

4 IEEE Standard C57.135-2002™.Guide for the Application, Specification and Testing of Phase-shifting Transformers, Cl 4.2, page 4


Quadrature-booster design5.3The final design for the Quadrature-booster satisfies

UKPowerNetworks’performancerequirementsandcanbe

illustratedbythetransformernameplate,acopyofwhichis

showninFigure11.

AspertheschematicinFigure11,circuit2(lowimpedance

circuit) draws increasing active power (MW) when the

Quadrature-boosterisoperatedfromtap10totap1which

isassociatedwithadvancephaseangle,anddecreasingMW

fromtap10totap19forretardphaseanglechange.Circuit1

(highimpedancecircuit)behavesinanoppositemanner.This

is in linewithQuadrature-booster theory5 that“advanced”

phase angle results in active power “boost” and “retard”

phaseangleresultsinactivepower“buck”inatransmission

line.Whenpowerflowsbetweentwoparallelsystemswith

different impedances, a Quadrature-booster placed in the

branchwithlowerimpedanceneedstooperatein“retard”

phaseanglemodetobuckthepowerinthatbranch.

With theQuadrature-booster installed in circuit 2 (with its

lowerlineimpedancecomparedtoCircuit1),theQuadrature-

boosterneeds tobeoperatedbetween taps10 –19, that

is,inretardmode.However,thehighertaps18and19are

likelytocauseariskofover-fluxingtheQuadrature-booster.

Toavoidover-fluxing(duetoloadphaseangleaddingtothe

noloadphaseshift),itmustbeoperatedbetweentaps10–

17.Taps18and19areelectricallyblocked.Taps9–1arealso

blockedasshowninFigure11.

5 IEEE Standard C57.135-2002™.Guide for the Application, Specification and Testing of Phase-shifting Transformers, Cl 4.2, page 4

Figure 11: Quadrature-booster nameplate


Quadrature-booster control system5.4The Quadrature-booster control system uses a TAPCON260

relay.ApictureoftypicalTAPCON260relayisshowninFigure

12,andismanufacturedbyMRinGermany.

Thiscontrolsystem:

• providesalocaldisplayofallpertinentQuadrature-booster

operationalinformation

• provides facility to manually tap the Quadrature-booster

locallyonsite,orintheeventofSCADAfailure

• ensuresthattheQuadrature-boosteron-loadtapchangeris

onlyusedwhenitissafetodoso

• inhibitsoperationbelowtap10topreventtheQuadrature-

boosterboostingthepowerandoverloading line. inhibits

operation above tap 17 to avoid over-fluxing of the

Quadrature-booster

• provides appropriate alarms and indications to UK

Power Networks via SCADA to the distribution network

managementsystem

5.4.1 Operating Principle – Regulation of power flow

The TAPCON260 relay regulates the active power of the

Quadrature-booster through an on load tap changer. This

is achieved by monitoring the single phase analogue

measurementsofthevoltageandcurrentontheDownham

Market teedcircuit (LINE2)and theNorthwoldcircuit (LINE

1). Using these analogue measurements, the TAPCON260

calculatesthetotalactivepowerflowinLINE1(P1)andLINE2

(P2)andadjuststhetappositiontoachieveimprovedpower

sharingbetweentheNorthwold(LINE1)andDownhamteed

(LINE2) circuits towithinapproximately5%ofeachLine1

andLine2,unlesssystemoperatingconstraintsdecreesmaller

variations.ThiscomparisonincludesasetMWbandwidthto

ensurestablealterationstothetapposition.Ifthemeasured

activepowershareisoutsidethisbandwidth,theTAPCON260

emitsaswitchingpulseafteradefineddelaytimeafterwhich

the switching pulse triggers an on-load tap-changer tap

changewhichcorrectstheQuadrature-booster’sactivepower.

StandardoperationmodefortheQuadrature-boosterTAPCON

260 relay is Auto/Remote mode. In this mode the relay

controlstheQuadrature-booster,andSCADAcontrolisenabled.

IftheQuadrature-boosterisrequiredtooperatemanuallyfrom

thecontrolpaneltherelayneedstobeswitchedoutofRemote

mode(switchedto“Local”mode).Whenmanualoperationis

completedtherelaymustbeswitchedbacktoRemote.

5.4.2 Interface with British Sugar

As previously mentioned, British Sugar currently operate

automaticturndownschemeontheirgenerationwhichtakes

intoaccounttheWissingtonBritishSugarsubstationoutgoing

33kV feeder circuit breakers status as well as analogue

measurementsonfromthefeeders.Inorderforthisscheme

to incorporate the Quadrature-booster operations it was

necessarytoprovide‘Tappinginprogress’statusinformation

for the Quadrature-booster, to trigger the masking of the

generation turndown scheme and ensure the generator

ignores any changes on line currents for which it would

normallyinitiateareductioningenerationoutput.

Figure 12: TAPCON 260 relay (Source: TAPCON260 Operating Manual)

6Quadrature-booster:Implementation–Installation


Theoverviewofhighlightsof theprogramme is shown in

Figure13.

Constructionworks, includingthepreparationactivities, took

approximately eight months. The key activities undertaken

during this phase of the project included: Production and

maintenanceofhealthandsafetydocumentationProcurement

of all materials and equipment Installation, testing and

commissioningofthesystem

Thekeyoutputsofthisphaseoftheprojectincluded:

• ConstructionPhaseHealthandSafetyPlan

• ProtectionProgrammableSchemeLogic(PSL)andsettings

files

• Commissioningplan

Theconstructionactivitiesassociatedwiththeinstallationofa

Quadrature-boosterareverysimilartothatforatransformerof

asimilarsizeandincluded:

• Theerectionofanewswitchhouseandtransformerbund

• ManufactureandinstallationoftheQuadrature-booster

• Manufacture and Installation of the Quadrature-booster

controlsystempanel&scheme

• Manufacture and Installation of the Quadrature-booster

protectionpanel&schemeInstallationofPanelBoardwith

voltagetransformer

• ManufactureandinstallationofanewRemoteTerminalUnit

atWissington

• ModificationoftheexistingcircuitprotectionTelemetryto

UKPowerNetworksSCADA

• TelemetrytoBritishSugar

Figure 13: Overview of programme highlights

Jul2013

Jun2013

May2013

Apr2013

Jan2013

Dec2012

Sep2012

Jun2012

Mar2012

Quadrature-boosterSpecifications

SupplyContracttoWilsonTransformerCompany

Quadrature-boostermanufactured

Onsitecivilworkscommence

Quadrature-boosterdeliverytosite

Coldcommissioning

Energisation

FactoryDesignReview

FactoryAcceptanceTest

Quadrature-boosteronsitecommissioning

Quadrature-boosteronsitesimulationtests


Theinstallationphaseoftheprojectwassuccessfullycompleted,

andFigure14toFigure16showstheinstalledequipment.

Figure 14: Installed Quadrature-booster

Figure 15: Installed 33kV Switchboard Figure 16: Installed Quadrature-booster control system

7Quadrature-booster: Testing and commissioning


Whilst undertaking during the implementation phase of

theproject, thetestingandcommissioningelementsof the

projectwerekey to thedemonstrationof theSDRCand,as

such,havebeenrecordedasaseparatesectionofthisreport.

The section documents key commissioning activities which

werecompletedandprovidesevidencethattheQuadrature-

boosteroperates inaccordancewith itsdesignandreleases

theappropriatelevelsofheadroomatmaximumgeneration

exportconditions,expectedtobeapproximately10MW.

Pre-installation testing7.1ThefactoryacceptancetestingfortheQuadrature-boosterwas

undertakeninMelbourne,Australiaduringthesecondweekof

January2013,withsnaggingrectifiedintimeforitsdispatch

on21January2013.

Before commencing the tests, a test programme was

prepared and discussed between UK Power Networks and

WilsonTransformerCompanyprior to confirm the suitability

ofthetests.AllcomponentsfortheQuadrature-boosterwere

installedforthetypetestingatthefactorytoensurethatthey

couldbefittedandareofthecorrecttypefortheprojectto

ensure a satisfactory onsite installation. The DR-C50 was

initiallybench testedat theDR laboratoryandwasbrought

totheQuadrature-boosterandconnectionsmadetothetap

changer,gasmonitorandtemperaturesensor.

The electrical type and routine tests were satisfactory and

allwithinthetoleranceofthespecification.TheQuadrature-

boosterwasprepared fordespatchand shippedon time in

accordancewiththeprogrammeofworks.

The factory acceptance testing for the Quadrature-booster

ControlsystemTAPCON260relaywassuccessfullycompleted

inMay2013,atFundamentals’factoryinSwindon.


Cold Commissioning7.2Coldcommissioning,whichconsistsofanumberofoff-load

testsdesignedtoconfirmcorrectinstallationandconfiguration

of the system prior to the final connection, commenced in

earlyJune2013andweresuccessfullycompletedinJuly2013.

Thetestsincluded,amongothers,thefollowingkeyactivities:

• Drawing checks –allwiring in theprotectionpanelsand

circuitbreakers,Quadrature-boosteretcwerecheckedwith

referencetorelevantwiringdrawings,andallterminations

checkedtoensurethattheywerecorrectlyterminated.The

drawings were also checked against the relay standard

drawings to ensure that standard schemes were correct

to the manufacturer’s standard schemes. All wiring was

subjectedtoInsulationtestswithaMeggertypeInstrument

withnolessthan500Volts.

• CT Checks–allcurrenttransformers(CT)oncircuitbreakers

weretestedwithanOmicronCTanalysertestset.TheCT

analyser measures the CT secondary resistance, ratio,

polarity and magnetising curve. The CT circuits for the

Quadrature-boosterandswitchgearhavebeentestedwith

theCTanalyserandalsoprimaryinjectedtoprovestability

andoperationforinZoneandoutofZonefaults.

• Functional testsofthe33kVvacuumcircuitbreakerswere

undertaken, including open/close inhibits, in the correct

operational sequence. The Quadrature-booster protection

wasprovedtoensurecorrectalarmsandtrips,intertripping

and all the electrical interlocking operations. Correct

operationofthetapchangerandcontrolcircuitswasalso

proventoconfirmcorrectoperation.

Theaboveshowsomeofthekeytestsonly.Manyotherrelevant

testsnotdiscussedherewerecarriedoutinaccordancewith

thetestplan.

Final Commissioning7.3Thefinalcommissioningfortheprojectwasundertakenand

theQuadrature-boosterwasenergisedinJuly2013.Adynamic

typecommissioningplanincludedthreestages:

• Soak stage–theQuadrature-boosterwasenergisedandleft

runningwithoutloadforaperiodof24hours.

• Load stage – the Quadrature-booster was put on load

carrying current as part of the live network, with the

Wissingtongeneratoroffline.

• Generation stage – the Wissington generator was then

switchedonwiththeQuadrature-boosterincircuit.

Duringthesestageschecksweremadeonthefunctionand

responseofQuadrature-boostertothenetworkandtheBritish

Sugargeneration.


Demonstration of improved balance between the circuits allowing increased power flow of 10MW

7.4Figure17presentsthemodelledloadingofthethreecircuits

under different generation export scenarios. The modelling

methodologyandassumptionsaredetailedinsection3.3.

All lines have a winter thermal rating of 31.6MVA and the

graph below illustrates the sub-optimal distribution of the

export across the three lines. As discussed in section 3.3,

themaximumexportfortheBritishSugargenerationsiteis

limitedto54.58MVAasanyadditionalgenerationwillresult

totheDownhamMarketlinebreachingitswintermaximum

thermal ratingwhile theNorthwold line is loadedat about

50%ofitsrating.

Figure 18 shows themodelled loadingof the three circuits

under different generation export scenarios with the

Quadrature-booster in-service in theDownhamMarket line.

Forconsistency,thegraphdatapresentedinallgraphsinthis

sectionarebasedontheQuadrature-boostersetattap11.

Figure 17: Circuit Loadings – Modelled without the Quadrature-booster

Figure 18: Circuit Loadings – Modelled with the Quadrature-booster (at tap 11)

KeyModel-DownhamcircuitwithoutQuadrature-booster

Model-NorthwoldcircuitwithoutQuadrature-booster

Model-SoutherycircuitwithoutQuadrature-booster

WinterLineThermalRatingCirc

uit L

oadi

ng (

MW

)

100

5

10

15

20

25

30

Wissington Generator Export (MW)

24 40 54 64

35

KeyModel-DownhamcircuitwithQuadrature-booster

Model-NorthwoldcircuitwithQuadrature-booster

Model-SoutherycircuitwithQuadrature-booster

WinterLineThermalRatingCirc

uit L

oadi

ng (

MW

)

100

5

10

15

20

25

30


24 40 54 64

35


Inordertoprovethecapacityheadroomcreatedonthe33kV

circuits, current measurements (amps) on the three circuits

wererecordedfromtheprotectionrelaysonthelocalcontrol

panel.Thesewerethencomparedwiththemodelleddata.

Measurementsofthepowerflowsacrossthethreeincoming

feeders were taken at different generation export levels

(10MW,24MW,40MW)withtheQuadrature-boosterinservice

atnominaltap10andalsoattaps11and12.

Due to generator maintenance currently being underway at

theWissingtonsite,themaximumavailableexportgeneration

duringthetestswasapproximately40MWandhencesomeof

theresultshadtobeextrapolatedinordertoachievelike-for-

likecomparisonwiththemodelledcircuit loadingsat54MW.

Theactualobservationofthesystemunder54MWofexportwill

bepossiblefromSeptemberonwardswhenthefullgeneration

capacitywillbeoperational.

The following graphs compare the modelled data with the

actualmeasuredonsiteforeachofthelinesanddiscussthe

operationoftheQuadrature-booster.

Downham Market Tee Northwold line

Figure 19 presents the modelled and actual values for the

loading of the Downham Market Tee Northwold line. The

DownhamMarket is the linewhere theQuadrature-booster

hasbeeninstalled.Byoperatingit,itisexpectedthatitwill

move power flow from the Downham Market line to the

othertwolines.ThiseffectisdemonstratedinFigure19bythe

actualmeasuredvaluesofthepowerflowacrosstheline.It

isobservedthatbyintroducingtheQuadrature-boosteratTap

11,powershiftsawayfromtheDownhamMarket line.The

measureddatademonstrate thesametrendand trackvery

closelytothemodelledones.

This behaviour demonstrates that the Quadrature-booster

operatesasdesignedandhasthedesiredeffectontheline.

The measurements and overall system analysis have also

confirmedthelinearnatureoftherelationshipbetweenthe

Wissington generator export and the circuit loadings. This

providestheabilitytoextrapolatetheactualmeasurements

curve and demonstrate the loading of the line for higher

exportlevels(54MWand64MW).


Figure19showsthatwiththeQuadrature-boosterinservice

the line will stay within limits (loaded at approximately

27MVA)whenthegenerationexportisincreasedat64MW.

It can be seen in Figure 19 that an error between the

modelleddata for the circuit loadingswith theQuadrature-

booster inserviceandtheactualdatahasbeen introduced.

This is expected as the software model has been set up

usingaspecificsetofassumptionswhilethemeasureddata

represent a snapshot of the network which corresponds to

differentnetworkconditions.Furtherworkwillbeundertaken

tocalibratethemodelagainsttheactualdataandgaininsights

inthedataandthesystempowerflows.

It isworthnoting thatbothmodelledandactualdatahave

assumed low demand (summer) conditions. It is therefore

expected thatduringwinter conditionsand in thepresence

ofhigherdemand in thenetwork, the lineswillbeable to

accommodate even higher amounts of generation before

reachingtheirlimits.

Figure 19: Quadrature-booster Capacity Headroom (Downham Market) at tap 11

KeyModel-DownhamcircuitwithQuadrature-booster

Model-DownhamcircuitwithoutQuadrature-booster

Actual-DownhamcircuitwithQuadrature-booster

WinterLineThermalRating

Linear(Actual-DownhamcircuitwithQuadrature-booster)

Circ

uit L

oadi

ng (

MW

)

10

0

5

10

15

20

25

30


24 40 54 64

35

-5


Northwold line

The results for the Northwold line are shown in Figure 20.

TheactualmeasureddatawiththeQuadrature-boostertrack

verycloselythemodelleddataanddemonstratedthedesired

behaviour.Inthisinstance,theloadingofthelineisincreasing

byusingtheQuadrature-boosterastheloadisshiftedaway

fromparallelline(DownhamMarket).

Figure 20: Quadrature-booster Capacity Headroom (Northwold) at tap 11

By extrapolating linearly the actual values from the 40MW

leveltothe64MWlevel,weareabletodemonstratethatfor

a 64MW generation export the Northwold line will remain

withinitsseasonallimits.

KeyModel-NorthwoldcircuitwithQuadrature-booster

Model-NorthwoldcircuitwithoutQuadrature-booster

Actual-NorthwoldcircuitwithQuadrature-booster


Linear(Actual-NorthwoldwithQuadrature-booster)

Circ

uit L

oadi

ng (

MW

)

100

5

10

15

20

25

30


24 40 54 64

35


Southery line

TheSoutherylinereceivesthelowerpercentageoftheload

that is being shifted away from the Downham Market by

theuseof theQuadrature-booster. Themodelledbehaviour

ofthecircuitandtheactualsitemeasurementsdemonstrate

consistentbehaviour.

Figure 21: Quadrature-booster Capacity Headroom (Southery) at tap 11

The actual measurements presented in Figure 21 show a

higher than forecasted power transfer to Southery and this

willbesubjecttofurtheranalysis.However,theactualresults

confirmtheexpectedoutputsandthevalidityofthemodel.

KeyModel-SoutherycircuitwithQuadrature-booster

Model-SoutherycircuitwithoutQuadrature-booster

Actual-SoutherycircuitwithQuadrature-booster


Linear(Actual-SoutherywithQuadrature-booster)

Circ

uit L

oadi

ng (

MW

)

100

5

10

15

20

25

30


24 40 54 64

35


Conclusions

The actual measurements and their comparison with the

modelled and forecasted effect of the Quadrature-booster

haveconfirmedthat:

• theQuadrature-boosterhasthedesiredeffectonthe line

thathasbeeninstalledin,bybuckingpowerawayfromit

the lines will be able to accommodate additional 10MW

ofgenerationexport(total64MW)whentheQuadrature-

boosterisincircuitandsetattap11(illustratedinFigure22)

• there is an improved balancing of the lines can be

demonstrated. As shown in Figure 22, the Quadrature-

booster balances significantly the lines at 64MW of

generationexportinordertobeabletoaccommodatethe

additional10MW.

• thereisapotentialformorethan10MWofheadroomrelease.

The projected figures for loading of the lines at 64MW of

generation export are 27MW and 29MW respectively for

DownhamMarketTeeNorthwoldandNorthwoldrespectively.

Given that the winter limit for the lines is 31.6MVA and

thatthesevalueshavebeencalculatedunderlowsummer

demandconditions,thereispotentialforadditionalgeneration

exporttobeaccommodatedbythelines.

Figure 22: Quadrature-booster Capacity Headroom

KeyActual-DownhamcircuitwithQuadrature-booster

Model-DownhamcircuitwithoutQuadrature-booster

Actual-NorthwoldwithQuadrature-booster

ModelNorthwoldcircuitwithoutQuadrature-booster


Linear(Actual-DownhamcircuitwithQuadrature-booster)

Linear(Actual-NorthwoldwithQuadrature-booster)

Circ

uit L

oadi

ng (

MW

)

10

0

5

10

15

20

25

30


24 40 54 64

35

-5

8Quadrature-booster: Training


AspartofintroducingtheQuadrature-boosteranditscontrol

systemto theoperationalnetworkstaff,onedayclassroom

sessionswerearrangedforselectedUKPowerNetworkskey

technical staffexpected toworkon theQuadrature-booster,

andcontrolengineersandmanagersfromthecontrolcentre.

These training sessions included presentations by Wilson

TransformerCompanyandFundamentalswith theobjective

ofprovidingsufficientinformationtopreparekeystaffbefore

thearrivalof theQuadrature-boosterand its control system

forinstallation.Threepresenters,onefacilitatorandatotalof

twenty threeparticipants receivedtrainingandweredrawn

from UK Power Networks’ Capital Programme, Network

Operations,Health&Safety,andCarillionUtilityServices.

Thetrainingpresentationscovered:

• WhatisaQuadrature-booster/Quadrature-booster

controlsystem

• HowdoesaQuadrature-booster/Quadrature-booster

controlsystemwork

• Whatitcanandcannotdo

• Installation/commissioning/operations/control/

maintenancebrief

• Casestudiesorapplicationselsewhere

• Traininghandoutstoparticipants

• Questionandanswersession

On-siteinductionsatWissingtonBritishSugarsubstationwere

subsequentlyundertakentoprovidealivedemonstrationof

howtheQuadrature-boosterworks;alongwiththecontrols,

operationsandmaintenanceregimes.Goingthroughdetails

ofmeasured,alarmsandindications–whattheymeanand

actionstobetakeninanemergencyetc.

Finally,EngineeringOperatingStandards(EOS)wereproduced

for both the Quadrature-booster and the associated control

systemtoprovideasinglepointofreferenceforoperational

andcontrolstaffresponsibleforcarryingoutsafeoperations

andmaintenanceoftheQuadrature-booster.Thesedocuments

supplement the user manuals for the equipment and will

bemadeavailable tootherDNOs for theirownuse. Figure

23 shows the set of documents available for reference.

Figure 23: Engineering Standards and Manuals

EDS 04-8002Quad-boosters

EOS 04-0042WissingtonQuad-booster33kV

EOS 04-8003Quad-boosterControl System33kV

6330-1238U10Quad-boosterInstallation Operating & Maintenance Manual

3334188/00ENActive Power RegulatorTAPCON260Operating Instructions


9Learning and next steps


AspartoftheFPPproject,thefirstQuadrature-boosterinthe

worldfora33kVdistributionnetworkapplicationwasdesigned

and installed. The Quadrature-booster was successfully

commissionedonthedistributionnetworkinJuly2013.

Thiswasapproximatelyamonth laterthan initiallyplanned

duetotechnicalchallengesfacedincoldcommissioningand

duringthedesignandcommissioningofitsprotectionscheme.

ThesechallengesaredescribedintheFPPprojectsix-monthly

report(June2013).

Significantknowledgewasgeneratedaspartof thedesign,

construction and testing process. Key learning has been

producedacrossallstagesofthelifecycleoftheprojectwith

particularfocusintheareasofmodellingandspecificationfor

Quadrature-boostertransformersfordistributionnetworksand

protectionschemedesignandimplementation.

Thelearninggeneratedwillsupportandimproveanyfurther

implementations of a Quadrature-booster by UK Power

NetworksandanyotherDistributionNetworkOperators.

The operation of the Quadrature-booster and its ability to

control thepowerflow,balance the linesandcreate10MW

headroomwithinthenetworkhasbeendemonstrated.

Atrialplaniscurrentlybeingdevelopedinordertotestthe

Quadrature-booster under various operational scenarios and

conditions.Thesetrialswilltakeplaceduring2014.

Thelearningwillbedisseminatedthroughalearningreport,

alearningevent,academicpapersandbilateralengagement

with DNOs and interested parties. In addition, UK Power

Networks is working on a guidance note for modelling of

Quadrature-boosters in PowerFactory software with the

softwareproviders.

TheQuadrature-boosterimplementationhasbeenacomplex

and challenging engineering feature that has developed

knowledge, skills and a new solution for maximising the

utilisationofdistributionnetworks.

10Figures and tables list


FiguresFigure 1: AerialphotographofWissington

siteCHPpointofconnection 12

Figure 2: ThegeneralWissington33kV

NetworkInterconnectionunder

StandarRunningArrangement 14

Figure 3: PowerFactoryLoadFlows 17

Figure 4: Historicalcircuitloadings 18

Figure 5: Generalsymbolrepresentation

ofaQuadrature-booster 19

Figure 6: GeneralviewsoftypicalQuadrature-boosters

usedontransmissionnetworks 19

Figure 7: GeneralviewoftheWissingtonQuadrature-

booster:3Ddesign,andduringconstruction 20

Figure 8: Schematicillustrationofexisting

distributionnetworkaroundthe

WissingtonBritishSugarsubstation 21

Figure 9: Quadrature-boosterarchitecture 26

Figure 10: SingleLineDiagramshowing33kV

Networkre-configurations 28

Figure 11: Quadrature-boosternameplate 31

Figure 12: TAPCON260relay(Source:

TAPCON260OperatingManual) 32

Figure 13: Overviewofprogrammehighlights 34

Figure 14: InstalledQuadrature-booster 35

Figure 15: Installed33kVSwitchboard 35

Figure 16: InstalledQuadrature-booster

controlsystem 35

Figure 17: CircuitLoadings–Modelledwithout

theQuadrature-booster 39

Figure 18: CircuitLoadings–Modelledwith

theQuadrature-booster(attap11) 39

Figure 19: Quadrature-boosterCapacityHeadroom

(DownhamMarket)attap11 41


(Northwold)attap11 42


(Southery)attap11 43

Figure 22: Quadrature-boosterCapacityHeadroom 44

Figure 23: EngineeringStandardsandManuals 46


TablesTable 1: Seasonalratingsforcircuitswithinthe

Wissington33kVNetworkinterconnection 16

Table 2: Maximumseasonalexportlimitsfor

theBritishSugar,Wissingtongeneration 16

UK Power Networks Holdings LimitedRegisteredoffice:NewingtonHouse237SouthwarkBridgeRoadLondonSE16NPRegisteredinEnglandandWalesRegisterednumber:7290590

[email protected]

Quadrature-booster Report – SDRC 9.8

Documents

Transcript of Quadrature-booster Report – SDRC 9.8