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Abstract--The development and testing of an innovative and compact saturating-reactor High Temperature Superconductor Fault Current Limiter (HTS FCL) is described. The development includes an initial dry-type magnetic core design with iron cores partially encircled by an HTS DC coil and a recently completed oil-immersed design with magnetic cores enclosed in a metallic tank placed inside the warm bore of a rectangular HTS DC magnet. The first 15 kV HTS FCL was installed in Southern California Edison’s grid in 2009 and the first transmission-class 138 kV Compact HTS FCL is planned to be in operation in American Electric Power’s grid in 2011.

Index Terms--HTS FCL, Fault Current Limiter, Superconducting Coil, Prospective Fault Current, Limited Fault Current, Distribution Class FCL, Transmission Class FCL, Saturating Reactor, Saturated-Core FCL.

I. INTRODUCTION Since 2006, Zenergy Power, Inc. (ZEN) has been

developing a type of high-temperature superconductor (HTS) fault current limiter (FCL) for electric power grid applications. The HTS FCL employs a magnetically saturating reactor concept which acts as a variable inductor in an electric circuit. The inductance of the HTS FCL changes instantly in real-time in response to the current in the electrical circuit being protected and varies from a low steady-state value of inductance during normal operating conditions to a high value of inductance during a fault condition that is sufficient to limit the fault current to the desired maximum value. HTS fault current limiting concepts have been extensively reported to date [1-5].

II. BACKGROUND Figure 1 is a simplified schematic that shows the basic

arrangement of a single-phase ZEN HTS FCL. Referring to Figure 1, one can see that there are two rectangular iron cores arranged side-by-side. The iron cores are surrounded by a single HTS coil that encircles the adjacent inner limbs of the iron cores in the middle. A small DC power supply energizes the HTS coil with a DC bias current to create a very strong DC magnetic field that magnetically biases and saturates the iron cores. Because the DC bias coil is superconducting, very little energy is used to magnetically saturate the iron cores. Conventional copper AC coils are wound on the outer limbs of the iron cores. The AC coils are connected in series to the electrical circuit that is to be protected. These AC coils are

This work was supported in part by the California Energy Commission and the U.S. Department of Energy. F. Moriconi, F. de la Rosa, A. Singh, B. Chen, M. Levitskaya, and A. Nelson are with Zenergy Power, Inc., South San Francisco, CA, USA.

wound in opposite magnetic “sense,” so that during any particular one-half cycle of the AC line current, the AC amp-turns from one of the coils are additive to the DC magnetic bias field (boost the DC magnetic bias field), while the AC amp-turns from the other coil are opposing the DC magnetic bias field (buck the DC magnetic bias field). Using this arrangement, a single-phase device can be made in which each of the rectangular iron cores acts independently during each positive and negative half-cycle of the AC line current.

Figure 1 – The Basic Saturating Reactor HTS FCL Concept Diagram

Figure 2 shows a typical B-H curve for the material used in the iron cores (typically the iron cores are laminated from M-6 grain-oriented silicon magnetic steel using overlapping mitered-joint construction techniques common in transformers). Under typical operating conditions, when the DC bias current is on and no AC line current is flowing, the iron cores are magnetically saturated and very strongly biased into the upper right-hand quadrant of the B-H curve. When the AC circuit is energized and the AC line current is flowing at normal values, the magnetic operating state of the HTS FCL oscillates over a small range in the extreme upper right-hand quadrant of the B-H curve. The AC magnetic flux from the individual half-phase AC coils alternately “boosts” and “bucks” the DC magnetic bias flux during each positive and negative half-cycle of the AC line current, but the magnetic flux variation and associated losses are very small. Figure 2 also shows a representative normal steady-state magnetic operating point for the HTS FCL. Because the slope of the B-H curve is very flat in this extremely magnetically biased condition and the oscillations are very small, the impedance of the AC coils is a very low value of inductance and approximates that of an air-core reactor with only a few AC turns (the nominal steady-state AC voltage drop of the HTS FCL is typically 1% or less on a per unit basis).

When an AC fault occurs, the AC amp-turns generated by the AC coils increase linearly with the fault current, and the range of oscillation of the HTS FCL magnetic operating state

Franco Moriconi, Francisco De La Rosa, Senior Member, IEEE, Amandeep Singh, Member, IEEE, Bill Chen, Marina Levitskaya, Albert Nelson, Member, IEEE

An Innovative Compact Saturable-Core HTS Fault Current Limiter - Development, Testing

and Application to Transmission Class Networks

978-1-4244-8357-0/10/$26.00 ©2010 IEEE

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increases proportionally. Figure 2 also shows a representative magnetic operating point for the HTS FCL during fault conditions in which the magnetic state of the HTS FCL is fluctuating from extreme saturation in the flat, upper right-hand quadrant of the B-H curve down into the steep, nearly vertical portion of the B-H curve and into lower left-hand quadrant of the B-H curve. In this condition the iron cores are alternately magnetically unsaturated by the large excursions in AC magnetic flux, and because the slope of the B-H curve is very steep and the oscillations in the HTS FCL magnetic operating state are very large, the impedance of the AC coils is a large value of inductance and approximates that of an iron core reactor.

Figure 2– Transition of HTS FCL Magnetic Core States During Fault

Conditions

From the simple schematic in Figure 1, it is easy to envision a three-phase HTS FCL using a single HTS DC bias coil. Figure 3 shows an arrangement in which three single-phase devices are arranged radially with their corresponding inner core limbs inside a single cryostat (silver cylinder) containing the HTS DC bias magnet. The copper AC coils (red cylinders) are located on the outer limbs of the iron cores and spaced equidistantly. This arrangement constituted the basic design for the ZEN HTS FCL and was used to construct the first two full-scale test devices.

Figure 3 – A Three-Phase Saturating Reactor HTS FCL with a Single HTS

DC Bias Coil

The essential “technology” of the ZEN HTS FCL is creating an integrated design that optimizes the performance of the iron cores, the DC HTS magnetic coils and the AC copper coils so that over the range of expected AC steady-state line currents the iron cores remain magnetically saturated and the AC line

impedance is low, but over the range of expected potential AC fault currents, the iron cores become partially or completely magnetically unsaturated and the AC line impedance is sufficiently high. Since 2006, ZEN has devoted extensive resources to modeling, simulation, design, manufacture, testing and experimental verification of the predicted performance of the HTS FCL in order to be able to reliably and accurately design a magnetically saturating reactor HTS FCL for a specific AC circuit application. As a result of the extensive modeling, simulation and testing (both full-scale and sub-scale) that has been performed over the last three years, ZEN is confident that its HTS FCL technology has been proven and is ready for commercial deployment.

III. THE FIRST FULL-SCALE ZEN HTS FCL This device was built and tested to verify the basic

operating principles and concepts of the ZEN HTS FCL. It consisted of six rectangular iron cores arranged with a single cryostat in the middle, the six AC coils arranged peripherally around the structure, along with the supporting structure and AC electrical bus-work. This device was nominally rated at 15 kV and 1,250 amperes RMS (root-mean-square), and was designed to limit an AC fault current by about 15%-20%. The HTS FCL was manufactured using conventional dry-type (air-insulated) transformer construction techniques for a 110 kV BIL (basic insulation level) rating. The cryostat was an open-loop system using liquid nitrogen, which was replenished as necessary to compensate for boil-off, and the HTS coil was constructed on a G-10 glass reinforced composite structure using 800 turns of 4-ply BSSCO 1G wire which was supplied by American Superconductor.

The HTS FCL was subjected to full-scale testing first at Pacific Gas and Electric’s High-Voltage Test Facility in San Ramon, California in October 2007 and later at British Columbia Hydro’s Powertech Laboratories in Surrey, British Columbia, Canada in December 2007. The HTS FCL was subjected to a full-range of testing to determine dielectric performance, steady-state AC voltage drop (insertion impedance) under normal operating conditions, and fault limiting performance, as well as to characterize steady-state heat loads on the HTS DC coil and in the cryostat, coupling during steady-state and fault conditions between the AC coils and the DC coil, and the effects of faults on the HTS coil and the DC power supplies.

Figure 4 shows the typical performance of the first HTS FCL during a fault. During testing of the first FCL at Powertech Laboratories, a total of 54 tests were performed, including 12 AC fault tests.

Figure 4 – Typical 16 kA Symmetrical, 37 kA First Peak Fault Test for the

First Full-Scale HTS FCL. Red is Prospective, Black is Limited Fault Current.

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IV. THE SECOND FULL-SCALE FCL – THE CEC HTS FCL The test results from the first HTS FCL encouraged ZEN to

build a second full-scale HTS FCL with the support of the California Energy Commission (CEC) and the U.S. Department of Energy (DOE). This device, known as the CEC HTS FCL, became the first HTS FCL in commercial service in the United States on March 6, 2009 when it was placed in the Avanti Circuit (otherwise known as the “Circuit of the Future”) in the Southern California Edison (SCE) Company’s Shandin substation in San Bernardino, California. The “Circuit of the Future” is an actual commercial 12.47 kV distribution circuit with real residential, commercial and light-industrial customers that has been established by SCE, CEC and DOE to demonstrate innovative technologies of potential value in the modern electric grid.

Figure 5 is a graphic representation of the CEC HTS FCL. The same central HTS DC magnet and radial AC coil general arrangement was used in the CEC HTS FCL as in the first full-scale HTS FCL. There were major differences, however, between the first HTS FCL and the CEC HTS FCL. Among other things, the CEC HTS FCL employed cast-epoxy AC coils instead of built-up wound copper coils. The CEC HTS FCL also employed a closed-loop cryogenic cooling system that used sub-cooled liquid nitrogen at approximately 68K to increase the IC and the working current of the DC HTS bias magnet coil to increase the available DC amp-turns and the range of DC magnetic bias flux. The cryogenic cooling system employs two Cryomech® AL300-CP970 cryorefrigerators with cold heads located at the top of drip-tubes connected to the liquid nitrogen space of the cryostat. Nitrogen vapor from the liquid nitrogen condenses on the cold-heads, is sub-cooled, and drips back into the liquid nitrogen volume. This recycles the liquid nitrogen and eliminates the need to periodically resupply the CEC HTS FCL with cryogen. The basic design parameters of the CEC HTS FCL are shown in Table 1. Because the Avanti Circuit is a newly constructed distribution circuit with a low duty-cycle and no expected fault issues, the CEC HTS FCL was designed for only modest fault current limiting capabilities and was intended to limit a 23 kA RMS potential steady-state fault current by about 20%. Instead of fault limiting performance, emphasis was placed on accurately modeling and predicting the performance of the HTS FCL and its associated electrical waveforms.

Figure 5 – The CEC HTS FCL Graphic Representation

Table 1 – The CEC FCL Basic Design Parameters

The CEC HTS FCL underwent extensive testing at

Powertech Laboratories in October 2008. In the absence of an industry standard for HTS FCL testing, a comprehensive test plan that incorporated IEEE standards [6-8] for series reactors and transformers was prepared with input from SCE and the National Electric Energy Testing, Research and Applications Center (NEETRAC), a member-financed, non-profit research laboratory of the Georgia Technical University (Georgia Tech) in Atlanta, Georgia. Special emphasis was placed on comparing the performance of the CEC HTS FCL predicted by ZEN’s design protocol with the measured performance of the CEC HTS FCL, including AC steady-state current voltage drop (insertion impedance), steady-state AC current temperature rise, AC fault current limiting, and AC coil and DC HTS electromagnetic coupling. The dielectric performance of the CEC HTS FCL was also tested including BIL, DC withstand voltage, lightning impulse and chopped-wave testing as required by the applicable IEEE standards [6-8]. Dielectric testing was performed before fault testing, and then repeated upon the conclusion of fault testing by SCE at their Westminster, California test facility before installation in the Avanti Circuit.

In all more than 65 separate test events were performed on the CEC HTS FCL, including 32 fault tests. A typical fault test sequence involved the application of full-load steady-state current and voltage (1,250 amperes RMS at 13.1 kV), the application of 30-cycles or more of fault current up to nearly 60 kA first-peak, and returning to the full-load conditions upon clearance of the fault. The CEC HTS FCL performed extremely well and exceeded expectations by withstanding more than an expected lifetime of actual faults during a week of testing. Figure 6 shows a typical insertion impedance test for the CEC HTS FCL. Notice the excellent match between the predicted and the measured voltage drop as a function of AC steady-state current. Figure 7 shows a typical fault sequence test in which the AC fault current is limited by approximately the targeted 20% reduction level. Figure 8 is an endurance test of the CEC HTS FCL in which it was subjected to an 82-cycle fault, and Figure 9 is a double-fault sequence test, which was performed to measure the CEC HTS FCL performance under an automatic re-closer scenario. Figure 10 shows the CEC HTS FCL in the Avanti Circuit at SCE’s Shandin substation, where it remained as of November 2009.

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Figure 6 – Measured versus Predicted Voltage Drop (Insertion Impedance)

Figure 7 – Design Performance Verification Test for the CEC FCL

Figure 8 – 82-Cycle Endurance Fault Test of the CEC FCL

Figure 9 – A Double-Fault Sequence Simulating Re-Closer Operation on the

CEC FCL

Figure 10 – The CEC FCL Installed at the SCE Shandin Substation in San

Bernardino, California

V. THE INNOVATIVE COMPACT HTS FCL In the course of building and testing the CEC HTS FCL,

ZEN conceived a new concept for saturating reactor HTS FLC design that had the potential to considerably reduce the size and weight of the device, while allowing the dielectric rating of the HTS FCL to be increased to transmission voltages of 100 kV and higher. This concept became known as the “Compact HTS FCL,” and in order to test the concept and evaluate alternative methods for implementing it, ZEN, with financial support from the U.S. Dept. of Energy, built and tested four full-scale prototypes using different internal designs.

All of the Compact HTS FCL prototypes were built using standard “oil-filled” liquid dielectric transformer construction techniques. This allowed the minimum required dielectric offset distances within the HTS FCL to be minimized, greatly reducing the HTS FCL prototypes’ size and weight for equivalent performance. Table 2 shows a comparison between a “dry-type” HTS FCL using the original radial AC coil design and an “oil-filled” Compact HTS FCL of equivalent designed performance. Both of the HTS FCLs are 26 kV, 2 kA steady-state current devices designed to limit a prospective 30 kA symmetrical fault with a 1.6 asymmetry factor by 50%. The Compact HTS FCL requires only 28.4% of the volume and has only 26.6% of the iron core mass of the original design. Another important design innovation was the use of “dry-type” cryogenics to conductively cool the HTS coil without the use of liquid cryogens. This allowed the operating temperature of the HTS coils to be reduced below the freezing temperature of liquid nitrogen, enabling further increases in the IC and working current of the 1G HTS wire used in the DC bias magnet system and correspondingly higher DC amp-turns to magnetically saturate the iron cores. The use of conduction cooling also removes potential utility concerns about having large volumes of liquid cryogens in confined spaces and potential pressure vessel over-pressurization, rupture and venting concerns.

Parameter Old Design New Design Iron Core Weight

(lbs) 252K 67K

Cost of Iron @ $3/lb

$ 756K $ 201K

FCL Size (core iron + AC coils

19' x 19' 10' x 7'

Table 2 – Comparison of Radial AC Coil (Old Design) and Compact (New Design) HTS FCLs

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Table 3 shows all four of the Compact HTS FCL prototypes that were built and tested. These prototypes had the same nominal 15 kV design voltage and 110 BIL rating, but differed in their steady-state AC current ratings and targeted AC steady-state current insertion impedance and AC fault current limiting performance. The designed AC steady-state current levels ranged from 1,250 amperes RMS to 2,500 amperes RMS, and the targeted AC fault current reduction levels ranged from about 30% up to more than 50% of a 25 kA RMS potential steady-state fault current with an asymmetry factor yielding a first-peak fault current approaching 50 kA.

The Compact HTS FCL prototypes underwent full-power load and fault testing at Powertech Laboratories in July 2009 using essentially the same comprehensive test plan that was employed for the CEC HTS FCL. In all 118 separate tests were performed on the four Compact HTS FCL prototypes, including 55 calibration tests, 12 load current only tests, and 51 fault tests. In many cases, the measured performance exceeded expectations, and the test program completely validated both the performance potential of the Compact HTS FCL design and the efficacy of ZEN’s design protocol. Figure 11 shows an illustration of one of the compact HTS FCL prototypes.

Figure 12 shows the results of a typical AC load current voltage drop or insertion impedance test which displays good agreement between the predicted and the measured performance. Figure 13 shows a fault current test in which the Compact HTS FCL prototype reduced a prospective 25 kA RMS fault current with a 1.6 asymmetry factor by about 46%.

Parameter Units FCL # 1

FCL # 2

FCL # 3

FCL # 4

Line-to-Line Voltage kV 12.47 12.47 12.47 13.8 Number of Phases # 3 3 1 1 Line Frequency Hz 60 60 60 60 Prospective Fault Current

kA 35 46 80 25

Limited Peak Fault kA 27 30 40 18 Prospective Fault Current RMS Symmetrical

kA 20 20 40 11

Limited Symmetric Fault Current

kA 15 11.5 18 6.5

Load Current Steady-State RMS

kA 1.25 1.25 1.25 2.5 – 4.0

Voltage Drop Steady-State Maximum

% 1 1 1 2

Line-to-Ground Voltage

kV 6.9 6.9 6.9 8.0

Asymmetry Factor # 1.2 1.6 1.4 1.6 Source Fault Impedance

Ohms 0.346 0.346 0.173 0.724

Fault Reduction % 25 43 55 41 Table 3 – The Four Full-Scale Compact HTS FCL Devices Tested at

Powertech Laboratories July 2009

Figure 11 – Compact ZEN 12 kV HTS FCL undergoing testing at Powertech

High Power Laboratory

Figure 12 – Typical AC Steady-State Load Current Voltage Drop (Insertion

Impedance) Measurements

Figure 13 – Compact FCL Fault Test at Powertech Laboratories July 2009. The black curve is the prospective fault current, the red curve is the limited fault current, and the blue curve is the voltage measured at the FCL terminals

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Figures 14-16 portray a comparison between calculated and measured fault current waveforms for one of the compact prototypes under a 15kA symmetric fault to ground condition.

Figure 14 - Measured vs. Calculated 15kA Prospective and Limited Fault

Current

Figure 15 - Measured vs. Calculated Back EMF for 15kA Fault Level

Figure 16 - Measured vs. Calculated Voltage Drop for 1.1kA Load Current

A particularly important result from the Compact HTS FCL testing program was the fact that the AC coils and the DC HTS Coil exhibited very little electromagnetic coupling. Figure 17 shows that the DC current in the HTS bias coil varied only about 5% as the Compact HTS FCL was subjected to up to a 30 kA peak fault current. These results were very typical for all of the Compact HTS FCL devices during fault current testing. The steady-state voltage drop (insertion impedance) of the Compact HTS FCL typically remained low with increasing AC currents and also exhibited very “clean” AC power characteristics with Total Harmonic Distortion levels well within the requirements of IEEE 519-1992 [9].

Figure 17 – AC Coil and DC HTS Coil Electromagnetic Coupling during AC

Fault Current Testing

VI. A COMPACT HTS FCL DESIGN FOR TRANSMISSION CLASS APPLICATIONS

As a result of the successful testing of the Compact HTS FCL prototype, ZEN has initiated the commercial sale of the Compact HTS FCL for medium-voltage applications. Also, ZEN has entered into an agreement with American Electric Power (AEP), Columbus, Ohio, to partner for the demonstration of a 138 kV three-phase Compact HTS FCL as a part of ZEN’s ongoing DOE-sponsored HTS FCL development program. A single-phase 138 kV Compact HTS FCL prototype will be built and tested in 2010, and a three-phase Compact HTS FCL demonstration unit will be built, tested and installed in AEP’s Tidd substation located near Steubenville, Ohio in 2011.

ZEN has considered a potential application for a “typical” 154 kV transmission application in an Asian electric power grid. The design approach taken was for a device with a relatively modest level of fault current reduction and a low value of steady-state voltage drop (insertion impedance). Figure 18 shows the simplified transmission line one-line diagram PSCAD model that ZEN created to represent a “typical” 154 kV transmission line. The voltage source parameters with the corresponding line impedances are shown on the left-hand side of the diagram, and a single lumped load is shown on the right-hand side of the diagram along with the “Timed Fault Logic.” The FCL is located in the middle of the diagram, and the graphical representation of the HTS FCL model that is inserted into the circuit is shown in Figure 19. Figure 20 shows the prospective fault current with the FCL bypassed and a 2,000 amp load current bypassing the FCL. In this scenario, the prospective first peak asymmetric fault current is 103 kA and the prospective symmetrical fault current is 40 kA. Figure 21 shows the resulting limited fault current under the same scenario as Figure 18, but with the HTS FCL in the circuit instead of being bypassed. In this scenario, the limited first peak of the fault current is 75 kA (a 28% reduction) and the limited symmetrical fault current is 24.8 kA (a 38% reduction), and the normal steady-state voltage drop (insertion impedance) with a 2,000 amp load current through the HTS FCL is 1.0% or about 890 volts (this voltage drop is proportional to the load current and is less under lighter loads).

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Figure 18 – The Simplified 154 KV Transmission Line PSCAD Model

A summary of a possible design of the modeled HTS FCL is presented in Table 4. Each phase of the three-phase HTS FCL would be about 1.5 meters in diameter and about 7 meters long. Using a horizontal orientation, it would fit in a footprint about 5 m x 7 m x 4 m.

Figure 19– The 154 kV HTS FCL Model for PSCAD Analysis

Figure 20 – The Prospective Fault Current in the 154 kV Circuit without the

HTS FCL

Figure 21– The Fault Currents in the 154 kV Circuit with the HTS FCL

Again, it is important to understand that while this is an HTS FCL design that could be manufactured today and which ZEN is confident would work as modeled, it is not the only possible design and other potential HTS FCL devices of different sizes, orientations and performance can also be designed and manufactured. For example, an HTS FCL with a lower steady-state voltage drop could be built, if a longer device were acceptable. If desired, the fault limiting performance of the HTS FCL could also be increased by increasing the diameter and length of the device.

154 kV Single-Phase FCL Parameters Units Value Line-to Line Voltage kV 154 Line Frequency Hz 60 Rated Current Amperes 2,000 Asymmetry Factor # 2 Base Power MVA 100 Maximum Allowable Voltage Drop Percent of Line Voltage

% 2

Line-to-Ground Voltage kV 89 FCL Fault Impedance Ohms 2 Steady-State FCL Allowable Inductance µH 1,698 Maximum Induced EMF for Desired Fault Current Limiting

kV 44

Maximum De-Saturation Flux Change Tesla 4 Steady-State FCL Maximum Allowable Impedance Ohms 1 Coil Height Meters 5 Core Height Meters 7 Core Weight Kg 48,912 HTS Wire Length Meters 37,762 NI HTS Coil Amp-

Turns 730,000

Overall FCL Width Oriented Horizontally (three, single-phases in array)

Meters 5

Overall FCL Length Oriented Horizontally (three, single-phases in array)

Meters 7

Overall FCL Height Oriented Horizontally (three, single-phases in array)

Meters 4

Table 4 – The 154 kV HTS FCL Basic Design Parameters

R=0

Line LoadFCL0.12485 [ohm]

5.8868e-3 [H]

BRK1

293.6 [MVAR]485.4 [MW]

154 kV ACSource

453 [MW] 281 [MVAR]

Ea

ABC->G

TimedFaultLogic

8

VII. CONCLUSIONS Design, testing and application issues of a saturable core

HTS Fault Current Limiter are described. The first in its class 15 kV FCL prototype sponsored by the California Energy Commission and the US Department of Energy has already been put in operation at Southern California Edison. Four 15 kV compact design prototypes have been successfully tested. Based on this, design and testing of commercial HTS FCL devices has been initiated, including a single phase 138 kV compact design prototype and a compact three-phase demonstration unit will be installed in an American Electric Power substation in Ohio in 2011.

VIII. REFERENCES [1] Schmitt, H., Amon, J. Braun,D., Damstra, G., Hartung, K-H, Jager, J.,

Kida, J, Kunde, K., Le, Q., Martini, L., Steurer, M., Umbricht, Ch, Waymel, X, and Neumann, C., “Fault Current Limiters – Applications, Principles and Experience”, CIGRE WG A3.16, CIGRE SC A3&B3 Joint Colloquium in Tokyo, 2005

[2] CIGRE Working Group, “Guideline of the impacts of Fault Current Limiting Devices on Protection Systems”. CIGRE publishing, Vol A3.16, February 2008. Standard FCL and Cigre

[3] CIGRE Working Group, “Fault Current Limiters in Electrical medium and high voltage systems”. GIGRE publishing, Vol A3.10, December 2003.

[4] Noe. M, Eckroad. S, Adapa. R, “Progress on the R&D of Fault Current Limiters for Utility Applications,” in Conf. Rec. 2008 IEEE Int. Conf Power and Energy Society General Meeting pp.1-2.

[5] Orpe, S. and Nirmal-Kummar, C.Nair, “State of Art of Fault Current Limiters and their Impact on Overcurrent Protection”, EEA Apex Northern Summit 08, November 2008, Power Systems Research Group, The University of Auckland

[6] IEEE Std C57.16-1996; IEEE Standard Requirements, Terminology, and Test Code for Dry-Type Air-core Series-Connected Reactors.

[7] IEEE Std C57-12.01-2005: IEEE Standard General Requirements for Dry-Type Distribution and Power Transformers, Including Those with Solid-Cast and/or Resin Encapsulated Windings

[8] IEEE Standard Test Code for Liquid-Immersed Distribution, Power and Regulating Transformers”, IIEEE Std. C57.12.90-1999.

[9] ANSI/IEEE 519-1992, “Recommended Practices and Requirements for Harmonic Control In Electric Power Systems”, ANSI/IEEE Standards

IX. BIOGRAPHIES

Franco Moriconi leads Zenergy Power’s Engineering effort in the development of a commercial Superconducting Fault Current Limiter. Under his technical leadership Zenergy Power installed and energized a first-ever HTS FCL in the US electric grid. In 1992, he joined ABB Corporate Research to lead R&D work in the areas of numerical and Finite Elements methods, short-circuit strength and noise reduction of power transformers, Gas Insulated Switchgear technology, and high-speed

electrical motors and generators. He also participated in two IEC working groups, and was the Convener of the IEC Scientific Committee 17C on seismic qualification of GIS. Currently, he is an active member of the IEEE Task Force on FCL Testing. Franco Moriconi earned a Bachelor of Science degree and a Master of Science degree in Mechanical Engineering from UC Berkeley. He is the co-author of six patents in the field of HV and MV electrical machines.

Amandeep Singh has led the in-depth understanding of FCL action in Zenergy Power since joining in January 2008 and has been instrumental in the modeling of the first-ever HTS FCL installed in US grid. He holds a Bachelor of Electronics & Telecommunications degree from GNDEC, Ludhiana (Punjab). He has worked as Senior Executive Engineer for ten years in utility generation (plant control systems), transmission (sub-station O&M) and distribution (planning, augmentation,

metering and revenue) sectors. He has an EIT in the State of California and is pursuing a professional engineer’s registration. He is a member of IEEE.

Francisco De La Rosa joined Zenergy Power Inc. in April 2008 as Director of Electrical Engineering. Before joining Zenergy Power, Inc., Francisco had held various positions in R&D, consultancy and training in the electric power industry for around 30 years. Francisco holds a PhD degree in Electrical Engineering from Uppsala University, Sweden. He is a Collective Member of CIGRE and a Senior Member of IEEE PES where he contributes in several WG’s including the TF on FCL Testing. . .His main

interests include the assessment and integration of new technologies in the electric power system.

Bill Chen joined Zenergy Power Inc. in August of 2009, but has worked as a consultant since February of 2007. While still adapting to the power industry, Bill has been involved in the development and automation of HTS FCL prototype along with the automation of the data acquisition equipment. He has enjoyed using his skill set across multiple applications, from data acquisition, PAC\PLC programming, data storage and trending, user interface development, and project management. Bill holds a bachelors degree in computer science

from the University of Texas, along with certifications in various programming languages.

Marina Levitskaya joined Zenergy Power, Inc. in September 2008 and has been instrumental in the mechanical design of the first HTS FCL unit that was successfully tested and installed in US grid. She earned a Bachelor of Civil Engineering degree from VSUACE, Volgograd, Russia. Her working experience combines six years of the successful HVAC design for commercial projects in Russia and four years of various mechanical designs in the US.

Albert Nelson has been COO of Zenergy Power, Inc. since its founding in 2006. Prior to joining Zenergy Power, Inc., he was a cofounder of Direct Drive Systems, Inc., a manufacturer of high-speed motors and generators, and Cheng Power Systems, Inc., a developer of technologies and systems to improve the efficiency, increase the power output and reduce the emissions of combustion turbines. From 1991 to 1999, he was Director of Project Finance for Raytheon Engineers and Constructors,

Inc. and Manager of Special Projects and Technology Development for Raytheon Systems Nevada, Inc. at the U.S. Department of Energy Nevada Test Site. Mr. Nelson retired from the U.S. Navy Submarine Service as a Commander