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33kV Superconducting Fault Current Limiter Dr. Chris Goodhand Northern Powergrid Adrian Wilson Applied Superconductor 1 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 Issues Type 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 7 System Readiness Issues Design and planning • Detailed design complete • Nomenclature agreed • Site Responsibility Schedule updated • Substation Control System • Protection scheme agreed L23 S18 S10 S14 L13 Brinsworth (B371) H23 H13 SGT2 SGT1 1R7 1T2 R2 2K0 SFCL 2K3 1R3 33kV (T365) 33kV (T364) 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 9 Applied Superconductor Ltd. Founded 2004 in Blyth, North East England to commercialise Fault Current Limiters October 2009 First unit to be installed in UK Summer 2012 Three units now installed July 2012 Purchase parts of Zenergy Power Applied Superconductor Globally Applied Superconductor Ltd Blyth Applied Superconductor Inc San Francisco Applied Superconductor Pty Woolongong Fault Current Limiters Inductive Limiters – Principles of Operation (HTS Magnets) 12 Fault Current Limiters Inductive Limiters – Principles of Operation (HTS Magnets) 13 Fault Current Limiters Inductive Limiters – Principles of Operation The equivalent FCL inductance is a non-linear function of the instantaneous line current FCL Inductance I_Limited is small at load current X Coordinate FCL Inductance Increases dramatically during a fault Y Coordinate L_cus Equivalent Inductance 0.0060 +y 0.0050 CLR Constant Inductance 0.0040 0.0030 0.0020 0.0010 0.0000 -x -0.0010 -15.0 +x -y -10.0 -5.0 0.0 5.0 Instantaneous AC Current [kA] 10.0 15.0 Fault Current Limiters Inductive Limiters – Comparison to Reactors 50 % Reactor VOLTAGE DROP FCL 6.2% 2% 1.8% 0.5% 0.42 kA 100 MVA 1.3 kA 320 MVA Current/Power 10 kA 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 VOLTS ACROSS CURRENT VOLTS OUT VOLTS IN Performance Under Fault – 11kV 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