Zenergy Power Inc.The superconductor energy technology company

Multi-Objective design optimization of a Superconducting Fault Current Limiter

EnginSoft International Conference 2010

Brescia, IT

22 October 2010

[1]

Franco Moriconi, SVP Engineering

Zenergy Power Inc.

franco.moriconi@zenergypower.com

Overview

• About Zenergy Power

• What is a Superconductive Fault Current Limiter (FCL)

• Design and Product Optimization

• The ModeFrontier Results

• Future Work

• Q&A

[2]

Zenergy Power – Overview

[3]

• Zenergy Power Plc • Admitted to London AIM (ZEN.L) 2006 • Market Cap ~ £90m• Employees 100

• Entities incorporated• Australia 1987 (fault current limiters)• Germany 1999 (MBH, wires, coils, magnets)• USA 2004 (fault current limiters)• UK 2005 (finance, investor relations)

• Intellectual Property – Over 170 patents and applications

Superconductors – The Quantum Leap in Electricity

Superconductors conduct electricity with no resistance – enabling 2 key properties:

- 100% energy efficiency: no electrical losses - 100 times current carrying capability: reduction in material use

‘Superconductivity is the enabling key technology to unlock the future of clean energy -the ‘optical fibres’ of electricity’ Dr. Jens Mueller, CEO.

[4]

Copper Wire

Superconducting Wire

200 A200 A

Zenergy Power’s Products

[5]

Sector Application End Products

Smart Grid Transmission & Distribution Fault Current Limiters

Industrial Machines Energy Efficiency Induction Heater

Renewable Power Power Generation Generators

[6]

Save more than 800 barrels of oil a year with superconducting heating

Industrial Heater – World's 1st Superconductor Energy Product

"This process is a quantumn leap for the metal processing industry – as up to 5% of the electricity of industrialised countries is consumed in conventional induction heaters" Dr. Fritz Brickwedde, General Secretary of the German Enviromental Fund

German Environmental prize 2009

Superconductor Induction Heaters: Commercial advantages

- World’s first industrial-scale commercial superconductor product- High-efficiency superconductor coils: 50% reduced energy consumption- High-power superconductor coils: 25% increased productivity - Superconducting coils: improved heating quality- Used globally by metals producers to heat metal

Comparison: 0.5 MW heating requirement

Copper Induction Heater HTS Induction Heater

Investment €1.2m ≥ €1.4m

Annual electricity savings 0 €50k - €300k

Productivity increase per annum 0 €200k - €2m

Efficiency levels 40% 90%

Management calculation based on performance data provided by customer “Weseralu”

[7]

8

Landmark Installation: Los Angeles, March 2009

115 kV LINE

115/12kVTransformer

BYPASSSWITCH

12 kV AVANTI “Circuit of the Future” - Los Angeles California

First installation in U.S. electricity gridOperated by Southern California EdisonInstalled in Avanti “Circuit of the Future”First Energized on March 9, 2009Supported by DOE and California Energy Commission

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Landmark Installation: Los Angeles, March 2009

FCL

FC

L

one second3.5 KA peak

0.2 KA load

Fault Event – 12 kV Installation in Los Angeles

Operational Experience

11

American Electric Power - AEP Project

Requirements

• 138 kV

• 300 MVA• Fault Current Limitation - 50%

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SATURABLE IRON CORE FCL

Picture-Frame Iron-Cores

AC CoilAC Coil

Boost Buck

Configuration for single phase FCL

Operating Principle

Installation - Los Angeles

Proprietary [13]

14

Inductive Fault Current LimiterThe equivalent FCL inductance is a non-linear function of the instantaneous line current, and it may look like the graph below during a fault:

CLRConstantInductance

-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 dramaticallyduring a fault

Operating Principle

Confidential & Proprietary | 15

23kA FAULT LEVEL

0.5 1 1.5 2 2.5 3 3.5 4-50

-40

-30

-20

-10

0

10

20

30

40

50TEST 77 - DOUBLE FAULT SEQUENCE - 20kA X/R=22, FCL IN

Time [sec]

Line

Cur

rent

[kA

]

Phase A

Phase BPhase C

0.5 1 1.5 2-50

-40

-30

-20

-10

0

10

20

30

40

50TEST 77 - 1.25s - 80 cycles FAULT - 20kA X/R=22, FCL IN

Time [sec]

Lin

e C

urr

en

t [kA

]

Phase A

Phase BPhase C

-40000

-30000

-20000

-10000

0

10000

20000

30000

40000

50000

60000

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Time [s]

Cu

rren

t [A

]

FEA - Iac No FCL

FEA - Iac With FCL

Prospective fault current = 19.2 kArmsLimited fault current = 10.26 kA (46.6% reduction)

Single phase AEP 2x1 D-core with 21mm thick tank. If' = 19.2kA. Sing;le Phase Fault Current results.

VS = 138kV l-l Rs =34.79mΩ Xs = 4.1495Ω RLOAD = 79.5Ω X/R = 119

ACORE = 0.20m2 NAC =122 NIDC =730kAT HAC = 3.5m HCORE = 4.0m HDC = 400mm

Fault Current Waveforms

Confidential & Proprietary | 16

Trade-off Considerations to Meet Requirements

typermeabili relative

length coil

section cross coil

turns AC n

Inductance

AC

r

rAC

l

A

ol

AnL

;2

changedensity Flux

B An dt V

t

BAnemf

t

Φemf

coreAC

coreAC

B

Low InsertionImpedance:nac, A, permeabilitylength

High Fault CurrentReduction:nac, Acore, DB

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FCL Design

Confidential and Proprietary Information

MAGNET OPTIMIZATION

HTS COIL OD 1700 mm

• Electromagnetic force in a magnet is AMPS x TURNS• Cost of magnet is driven by Amp-turns needed and amount of cooling• Price of conductor can be several hundreds $$ / kA-m

we need high current density to reduce cost• For fixed current density we want to reduce conductor length (volume)• Current Density is inversely proportional to working temperature

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multi-objective optimization

Weighted Function approach: transform the given multi-objective problem into an equivalent single-objective problem. The solution depends on the values of the weights αi .

Multi-objective optimization problem:

i=1,…, n objectives

Sx

xg

xf

j

jk

ji

0)(

)(max

Sx

xg

xfxh

j

jk

ji

n

iij

0)(

)()(max1

True Multi-objective approach: An alternative to combining metrics in a predetermined way, approach design as the solutions defined within the n-dimensional space of the design objectives and variables.

19

Pareto Frontier: definition

With conflicting objectives, the aim is to find good compromises rather than a unique solution. So, this approach results in a set of solutions, called the “Pareto Frontier”. In any solution contained in the Pareto Frontier, none of the objectives can be improved without

deterioration of at least one other objective. Hence these solutions are known as “non-dominated” solutions.

Performance

Cost

Maximum Performance Solution(1)

Minimum Cost Solution (2)

Compromise Solution (3)

Non-Optimal Solution (0)

Pareto Frontier

Image courtesy of EnginSoft

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Problem Formulation: x, the variables

D_H

TS

H_c

ore

H_a

c

Gap_tank

Gap_tank

HTS_OD/2

h_HTS

Tank_th

Tank_OD

Independent

1: Cryo_Gap

2: Cu_r1

3: Cu_r2

4: Cu_rad

5: D_HTS

6: Gamma1

7: Gamma2

8: H_core

9: NDC_h

10: NDC_v

11: h_ac

12: nac_h

13: r11

14: r12

15: r13

Dependent

1: HTS_th

2: H_ac

3:NDC

4: h_HTS

5: nac

6: v_ac

Constants

1: h_dc

2: v_dc

3: nac_v

4: Thick_Tank

5: Gap_Air

Design Parameters 26+ Variables: 21

Independent: 15 Dependent: 6+

Constants: 5+

nac= nac_h* nac_v

nac_h

nac_v

21

Solution

• Used modeFRONTIER®, a multi-objective optimization software

• It wraps around ANSYS, performing optimization by• modifying the values assigned to the input variables, and • analyzing the corresponding outputs calculated by ANSYS, using genetic algorithms.

• For this particular problem:• evaluated 960 Designs• In each evaluation:

• idc kept constant at 130A• iac 25 values : 1.25k:500:13.25kArms• 24000 inductance calculations• @1inductance calculation/min: 400+ hrs: 16+ days

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Results

TBbuck 5.3

HL statesteady 100_

■Pareto Frontier: Feasible Solutions Unfeasible Solutions

faultL

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Results

24

Results

25

Results

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Results: max performance

27

Results: min cost

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Results: compromise

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Design Solution D_HTS HTS_th H_ac NDC h_HTS nac v__acStarting Design 1.35 0.01376 2.1014 2000 0.2425 38 0.0254

Best Performance 1.38666 0.00999 1.872 1591 0.1849 36 0.0236Least Expensive Solution 1.13114 0.00999 1.944 1517 0.1763 36 0.0278

Best Compromise 1.08794 0.00999 1.872 1517 0.1763 36 0.0278

Design Solution BB_buck_Eff_Point Lbuck_Mean_Maximize Lbuck_Min Volume_HTSMax Performance 36.6% 33.3% 27.5% -58.8%

Min Cost 41.4% -12.1% 17.7% -60.7%Compromise 45.9% -6.3% 16.2% -60.7%

Design Solution CRYO_GAP Cu_r1 Cu_r2 Cu_rad D_HTS_Normalized Gamma1 Gamma2 H_core NDC__h NDC__v h__ac nac__h r11 r12 r13Starting Design 0.1 0.05 0.05 0.0254 0.75 0.0254 0.0254 2.6 50 40 0.0553 38 0.01 0.02 0.02

Best Performance 0.0725 0.025 0.04 0.0236 0.8 0.02 0.035 2.665 43 37 0.052 36 0.044 0.027 0.009Least Expensive

Solution 0.0725 0.045 0.015 0.0278 0.6 0.04 0.04 2.385 41 37 0.054 36 0.044 0.027 0.011Best Compromise 0.07 0.045 0.03 0.0278 0.6 0.04 0.04 2.425 41 37 0.052 36 0.044 0.027 0.014

3 alternative designs provided, each improving the initial design under all 4 objectives:

Comparison of Output Variables

Comparison of Dependent Input Variables

Results: summary

Summary

)min(

)min(

)max(

)max(

_

_

coildc

statesteady

fault

buck

vol

L

L

B

30

Thermal Optimization of HTS Coil

Initial Design Model

Copper Mass 348.5

HTC Max Temp 34.58

HTC Min Temp 31.15

HTC Avg Temp 33.19

31

Thermal Optimization - Workflow

Input geometric variables of the parametric model

Output Variables

Objectives & Constraint

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Thermal Optimization – Sensitivity Analysis

Ranking- The correlation index

Line Correlation+1=Direct Effect-1=Inverse Effect

33

Thermal Optimization

Avg Temp

CopperMass

All Designs

34

Thermal Optimization of HTS Coil

Avg Temp

CopperMass Design

1105

Design2130

InitialDesign

Design1906

Design1070

35

Thermal Optimization – Summary of Results

Description DesignNumber

% Copper Mass Difference

% Max HTC Difference

Initial Design 2178 0.0% 0.0%

Minimum HTC Temp 1105 -247.78% 29.15%Compromise Design 1 2130 2.67% 18.48%Compromise Design 2 1070 42.70% 4.34%Minimum Copper Mass 1906 44.51% -12.32%

Designs Comparison with Initial Design Configuration

+ % refers to reduction

-% refers to increase

36

FUTURE WORK

Combine Geometry- Cooling and Magnetic Field Effects

DecreasingTemperature

simply better

[37]

Franco Moriconi

SVP Engineering

Zenergy Power Inc.

franco.moriconi@zenergypower.com