Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 By UK Power Networks, Fundamentals Ltd and Wilson Transformer Company August 2013
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
6 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
8 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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.
10 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
12 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 13
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.
14 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 15
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.
16 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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)
Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 17
• 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=29.03MVVQ=1.23MvarS=29.06MVA
P=15.13MVVQ=0.58MvarS=15.14MVA
P=54.56MVVQ=1.09MvarS=54.57MVA
P=
0.00
...Q
=0
.00.
..S
=0.
00...
P=54.56MVVQ=1.09MvarS=54.57MVA
WinterExportLimit
ThermalCapacityLimitreached
P=46...Q=8.8...S=47.1...
P=25...Q=6.0...S=26.1...
P=46.40MVVQ=13.32MvarS=48.28MVA
P=25.47MVVQ=7.86MvarS=26.66MVA
Key
Northwold
DownhamTeed
Southery
Generation
Circuitbreakerclosed
Disconnectorclosed
Transformer
1
2
3
UI=33.89kVu=1.03p.u.phiu=46.9...
18 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 19
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
20 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 21
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
Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 23
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
24 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
26 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 27
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.
28 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 29
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
30 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
32 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
34 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 35
Theinstallationphaseoftheprojectwassuccessfullycompleted,
andFigure14toFigure16showstheinstalledequipment.
Figure 14: Installed Quadrature-booster
Figure 15: Installed 33kV Switchboard Figure 16: Installed Quadrature-booster control system
7Quadrature-booster: Testing and commissioning
Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 37
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.
38 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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.
Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 39
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
Wissington Generator Export (MW)
24 40 54 64
35
40 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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).
Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 41
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
Wissington Generator Export (MW)
24 40 54 64
35
-5
42 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
WinterLineThermalRating
Linear(Actual-NorthwoldwithQuadrature-booster)
Circ
uit L
oadi
ng (
MW
)
100
5
10
15
20
25
30
Wissington Generator Export (MW)
24 40 54 64
35
Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 43
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
WinterLineThermalRating
Linear(Actual-SoutherywithQuadrature-booster)
Circ
uit L
oadi
ng (
MW
)
100
5
10
15
20
25
30
Wissington Generator Export (MW)
24 40 54 64
35
44 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
WinterLineThermalRating
Linear(Actual-DownhamcircuitwithQuadrature-booster)
Linear(Actual-NorthwoldwithQuadrature-booster)
Circ
uit L
oadi
ng (
MW
)
10
0
5
10
15
20
25
30
Wissington Generator Export (MW)
24 40 54 64
35
-5
8Quadrature-booster: Training
46 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 47
9Learning and next steps
48 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
50 | Flexible Plug and Play Quadrature-booster Report – SDRC 9.8
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
Figure 20: Quadrature-boosterCapacityHeadroom
(Northwold)attap11 42
Figure 21: Quadrature-boosterCapacityHeadroom
(Southery)attap11 43
Figure 22: Quadrature-boosterCapacityHeadroom 44
Figure 23: EngineeringStandardsandManuals 46
Flexible Plug and Play Quadrature-booster Report – SDRC 9.8 | 51
TablesTable 1: Seasonalratingsforcircuitswithinthe
Wissington33kVNetworkinterconnection 16
Table 2: Maximumseasonalexportlimitsfor
theBritishSugar,Wissingtongeneration 16
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