FACTS Control for Long‐

and Short‐ Term Energy Storage

Mehdi FerdowsiMissouri University of Science and Technology

Funded by the Energy Storage Systems Program of the U.S. Department Of Energy (DOE/ESS) through Sandia National Laboratories (SNL). Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration, under contract DE-AC04-94AL85000.

Issues•

Short‐

and Long‐Term Energy Storage

•

Storage Integration

•

Cyber Security33

vv

Transmission LineGenerationFACTS

Wind Power

Energy Storage

Solar Power

Energy Storage

FACTS Device

Distributed Decisions

Power Electronics

Communications

Sensing and monitoring Inputs

Power Electronics

Power Electronics

Distributed controland fault/attack detection

2

3

Part I

UPQC Integrated with an

EC & DC‐DC Converter

4

Unified Power Quality Controller

•

Provides bi‐directional protection for load  and system

Left‐Shunt (LS) UPQC Right‐Shunt (RS) UPQC 

5

PSCAD Results

Harmonic Load

Source/System

6

Short‐Circuit Fault

7

UPQC + DC‐DC Converter Fed by EC/BESSs

•

EC/BESS can provide better performance in fault ride 

through

•

Increased operating range for better THD reduction

•

Increased operating range for power factor correction

8

Part II

Hybrid Energy Storage

Systems:  BESS + ECs

Hybrid Energy Storage System with Multiple Converters

9

Double‐Input Converters (DIC)•

They integrate different power sources 

while each one is allowed to have a  different power rating

•

Decreased Cost; Increased Reliability

10

Derivation of DICs

Using H‐Bridge Cell

Double‐Input Buck‐Buck

Double‐Input Buckboost‐Buckboost

Double‐Input Buck‐Buckboost

H-BridgeCell 1

H-BridgeCell 2

H-BridgeCell 1

H-BridgeCell 2

H-BridgeCell 1

H-BridgeCell 2

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Double‐Input Buck‐Buck Converter

V2 S7

S6

V1 S3

S2

L

C R

S8

S5

S4

S1

i1

i2

iL

iC iO

Vo

+

_

+ -VL

+

-

+

-

+

-

+

-iS2iS1

iS6iS5

VS1 VS2

VS6VS5

12

Simplified Double‐Input Buck‐Buck Converter

V2

S6

V1

S2

L

C R

S5

S1

i1

i2

iL

iC iO

Vo

+

_

+ -VL

13

Voltage Transfer Ratios

2211 *Vd*VdVO

Buckboost‐Buckboost

Buck‐BuckboostBuck‐Buck

22

21

21

221

1

11*V

TT

dd

d*V

TT

dd

dVO

22

21

2

1 *1

*1

Vd

dV

dd

VO

14

15

Part III

Detecting and Preventing

Interference in Cooperating

Power Electronics 

Distributed Control•

Each power electronics subsystem 

contributes to the overall system operation.

•

Previous work showed the sensitivity of the  system to the controllers

–

Failed or compromised controllers can cause  serious power system failures

•

Cyber and physical interactions cause new  vulnerabilities:

–

Frequency domain interactions

–

Confidentiality interactions  16

FACTS Interaction Laboratory•

FACTS Interaction Laboratory–

Real FACTS Devices and Programmable Load

–

Real‐Time Simulated Large Power System

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D/A Output

A/D Input

FACTS

Controllable Load

Power System Simulation Engine

Information Flow

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Embedded PC

Long TermControlDynamicControl

DSP Board

Power Electronics

UPFC

Long TermControlDynamicControl

Embedded PC

DSP Board

Power Electronics

UPFC

Embedded PC

Long TermControlDynamicControl

DSP Board

Power Electronics

UPFC

Computernetworks

Computernetworks

Local powernetwork

Local Powernetwork

Local Powernetwork

Bulk Power Grid

Low-level security domain Medium-level security domain High-level security domain

UPFC: Unified Power Flow Controller DSP: Digital Signal Processing

Explicit Communication

Implicit Communication

Information Flow Security in CPS

•

The physical nature of a security boundary  tends to expose information outside the 

cyber world.

•

The timing pattern could expose high‐level  system behaviors since time is global and 

can be observed by all the security levels.

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Summary•

UPQC –

Provides a bidirectional ac‐ac interface 

between the bulk power system and distributed  energy resources

•

DIC –

Provides long and short‐term energy  storage capabilities to improve performance in 

both the bulk and distributed systems

•

CPS –

Determines and mitigate vulnerabilities in  power electronic based systems in the bulk 

power grid 

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Special Thanks

•

Imre Gyuk ‐

DOE

•

Stan Atcitty ‐

Sandia National Laboratories

•

John Boyes ‐

Sandia National Laboratories

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