Magnetic Amplifier

for Power Flow

Control

A Novel Approach with Conventional Components

Marcus Young, P.E. Aleks Dimitrovski, PhD Power & Energy Systems Group Oak Ridge National Laboratory

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Introduction

• Magnetic amplifier-based device for continuous power flow control

• Combination of familiar and proven concepts with new technology

• Power line (controlled circuit) decoupled from the power electronics (control circuit)

Inexpensive enough to allow system-wide deployment and

comprehensive power flow control

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Top 10 R&D 100 Award Winners

Pacific Northwest National Laboratory

National Institute of Standards and Technology

Varian Associates, Inc.

NASA Glenn Research Center

Argonne National Laboratory

Los Alamos National Laboratory

Lawrence Livermore National Laboratory

Oak Ridge National Laboratory

General Electric

87

87

88

98

112

113

119

137

164

166

Sandia National Laboratories

ORNL is a Leader in Transferring

Technology to Industry

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Project Team

ARPA-E • DOE project sponsor

ORNL • Project lead • Overall design • Power electronics • Prototype testing

SPX Transformer Solutions (Waukesha Electric) • Manufacturer • Large-scale testing

University of Tennessee - Knoxville • Power system analysis • Control strategies/schemes

TVA • Host utility

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Natural Power Flow

Uncontrolled power flows can cause problems such as:

• Overloading of lines and transformers

• Reduced security margins

• Power exchange contractual violations

• Increased fault levels beyond rating

230 kV

100 mi

3 X 150 MVA lines supply 250 MVA load

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Current Technologies Provide Only

Limited Power Flow Control Options

• Switching system elements on/off

– Alleviates congestion, but generally puts system in less secure condition

• Regulating transformers

• Switchable shunt/series reactive elements

– Simple, but coarse (step-change)

• Flexible AC Transmission System Devices (FACTS)

– Complicated & expensive (~$100-120 per kVA)

Line Reactors STATCOM

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Power Flow Control Using Magnetic

Amplifier

• Avoids lines being switched on/off due to congestion

• Adjusts power flow over a continuous range by varying the line reactance

• Provides finer granularity in terms of ΔP than switchable reactive elements since reactance can be adjusted continuously

• Target cost: $40 per kVA (ARPA-E objective)

AC power is completely decoupled from power electronics

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Theory of Operation

Ferromagnetic

B-H Curve

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Single-Core Symmetrical Connection

• Three-legged core

• Equal performance in both half-cycles

• Cancellation of the induced voltage in the dc circuit

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Example: Magnetic Amplifier Provides

Variable Reactance

on

Case 1

•Fixed reactance installed to

relieve congestion.

Case 2

•Fixed reactance remains in

circuit, but load distribution has

changed.

•Line 2 is now operating over

capacity.

on

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Example: Cont…

off

Case 3

•Fixed reactance is removed in

response to line 2 operating over

capacity.

•Line 1 is now operating over

capacity.

Case 4

•Variable reactance provides

adjustment needed to relieve line

congestion before and after

change in load distribution

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Prototype Testing at ORNL

Proof of Concept

• Small-scale demonstration

• DC circuit powered by 9-volt battery

480 Vac Prototype

• Built by SPX/Waukesha

• 3-phase, 200 ARMS

• Currently being testing at ORNL Distributed Energy Communications and Controls (DECC) Laboratory

• DC provided by power electronics

Proof of Concept

480 Vac Prototype at ORNL

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DECC Laboratory is interfaced with the

ORNL owned & operated distribution system

DECC Lab

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Results to Date from Testing at ORNL

• Tested at various AC current operating levels

• Reactance of the 480 V prototype was adjusted from 0.03 to 0.18 Ohms

• Negligible Total Harmonic Distortion (THD)

IRMS

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Next Phase: Large-Scale Testing

• 161 kV single-phase (1 unit)

– To be tested at SPX/Waukesha facilities

– Go/No Go decision based on performance

• 161 kV three-phase (2 additional single-phase units)

– To be tested at SPX/Waukesha facilities

• 161 kV Demonstration at TVA

– The original and two additional 161 kV units installed as a bank

– TVA live operation

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Power System Oscillation Damping

• Previous research indicates variable reactance can be used to damp electromechanical oscillations

• FACTS-type devices typically considered for this role

• Investigation currently underway by ORNL to determine how a magnetic amplifier-based power flow controller can be used to mitigate oscillations

Area 2

Area 1

Area 3

Area 6

Area 5

Area 4

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Summary

• Developed and Built Magnetic amplifier-based device for continuous power flow control

• Technology Incorporates a combination of familiar and proven concepts with new power electronics technology

• Power line (high power controlled circuit) decoupled from the power electronics (low power control circuit)

• Testing of a 3-phase/480V prototype is currently underway at ORNL

• Larger device (161 kV) to be tested at SPX/Waukesha

• Utility testing planned at TVA

ORNL’s approach is simple and inexpensive enough for wide-area

deployment for comprehensive AC power flow control and for

oscillatory damping which is being studied.

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Thank You!

For further information, please contact:

Marcus Young

youngmaii@ornl.gov

865-547-8052