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33kV Superconducting

Fault Current Limiter

Dr. Chris GoodhandNorthern Powergrid

Adrian WilsonApplied Superconductor

The Project• Deployment of a 33kV superconducting fault

current limiter (SFCL)

• Builds on a previous project funded through IFI• Some results from this later• Device based on a relatively new class of materials• Collaboration between three DNOs• Device developer - Applied Superconductor Ltd, an SME

• Relatively large and long term project

Project Motivation• The short and medium term future includes an

increase in the connection of low carbon technologies to our networks

• This will include increased distributed generation connection at 33kV

• This can already be seen as an approaching trend – Wind, anaerobic digestion, biomass

• There are barriers to this connection.

Project Motivation• Increased fault level burden associated with these

connections

• Networks are run close to capacity, much switchgear and protection is close to maximum fault level budget

• Additional prospective fault level contribution from distributed generation limits our ability to connect

• Additional investment is therefore required to facilitate – relatively slow and expensive process

Potential Solution• Fault current limiting devices

• Superconducting Fault Current Limiters (SFCL)

• Advantages• Large fault current clamping

• Disadvantages• New devices, lots of potential but little track record• Systems readiness issues

The Project• Install and operate a 33kV Superconducting Fault

Current Limiter• Deliver some key learning outcomes:

• Where can these be applied?• How can they be operated?• How can they be integrated into our current systems?• What technical advantage do they confer?• Can we make a business case for their use?• Can we make a carbon case for their use?• What else can we discover through experiential learning

with these devices?

System Readiness IssuesType Testing Specification

• Non-standard network component – • Significant input from transformer and switchgear experts

at National Grid to identify which parts of their standards apply to the Fault Current Limiter

• List of standards/tests for Type Testing now agreed• Long process to get all technical stakeholders on board

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System Readiness Issues Design and planning

• Detailed design complete

• Nomenclature agreed

• Site Responsibility Schedule updated

• Substation Control System

• Protection scheme agreed

SGT2 SGT1

S10 S14S18 L13L23

2K32K0R2

SFCL

H23 H13

33kV(T365)

33kV(T364)

Brinsworth(B371)

1T2

1R7

1R3

Other Systems Readiness Issues• Currently a health and safety problem, unrelated to

the project, prevents access to the identified site• Project too advanced to move to alternative location• Eight month delay to installation and commissioning

• Supply Chain Problem• Key supplier and intellectual property owner in

administration• ASL acquired IP and identified alternative component

source• Not critical path

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Founded 2004 in Blyth, North East England to commercialise Fault Current Limiters

October 2009First unit to be installed in UK

Summer 2012Three units now installed

July 2012Purchase parts of Zenergy Power

Applied Superconductor Ltd.

Applied Superconductor GloballyApplied Superconductor LtdBlyth

Applied Superconductor PtyWoolongong

Applied Superconductor IncSan Francisco

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Fault Current Limiters Inductive Limiters – Principles of Operation (HTS Magnets)

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Fault Current Limiters Inductive Limiters – Principles of Operation (HTS Magnets)

The equivalent FCL inductance is a non-linear function of the instantaneous line current

CLRConstant

Inductance

-15.0 -10.0 -5.0 0.0 5.0 10.0 15.0 -0.0010

0.0000

0.0010

0.0020

0.0030

0.0040

0.0050

0.0060 +y

-y

-x +x

X Coordinate Y Coordinate

I_Limited L_cusEquivalent Inductance

Instantaneous AC Current [kA]

FCL Inductanceis small at load current

FCL InductanceIncreases dramatically

during a fault

Fault Current Limiters Inductive Limiters – Principles of Operation

100 MVA0.42 kA

320 MVA1.3 kA

2%

6.2%

10 kA

50 %

0.5%

1.8%

Current/Power

VOLTAGEDROP

Reactor

FCL

Fault Current Limiters Inductive Limiters – Comparison to Reactors

Scunthorpe, Station Rd. – 11kV Installation

5 Lorry loads

Precision lifts

Clean Room Activities

Performance Under Fault – 11kV

• There was a three phase fault cable on a circuit out of Station Road, Scunthorpe on 7th August 2012. The SFCL had 3.3kA flowing through it on all 3 phases for 0.6s

• Device worked as expected under fault condition• LV power lost, DC power maintained by batteries• All systems recovered following the fault

clearance

Performance Under Fault – 11kVVO

LTS

INVO

LTS

OU

TCU

RREN

TVO

LTS

ACRO

SS

Key Learning – Dealing With The Unexpected• Un-expected site access issue, despite attempted

mitigation, has resulted in project delay.

• Loss of key supplier and core intellectual property• Difficult to foresee

• Exogenous Risks! • Need a plan for when the unforeseen occurs.

Key Learning – Still Much To Learn• Installation at Scunthorpe complex and resource

consuming• 33kV project will address this learning

• Fault performance on 11kV device has been good• System behaved as expected – good clamping• Boosts confidence for the 33kV installaion

• 11kV Ancillary and support systems were impacted by fault• GPRS monitoring and warnings never received• 33kV systems needs to be “hardened” against such

problems

Project Outlook• Initial analyses and system design are complete.• Systems readiness issues overcome (?)• SFCL build in progress• Device installation and commissioning due

summer 2013 after access issues resolved in Spring 2013

• Dissemination of learning expected, late 2012-2013