Development and Verification of Control and Protection Strategies in Hybrid AC/DC Power

311 Pages·2016·11.45 MB·English

Florida International University
FIU Digital Commons
FIU Electronic Theses and Dissertations University Graduate School
11-2-2012
Development and Verification of Control and
Protection Strategies in Hybrid AC/DC Power
Systems for Smart Grid Applications
Vahid Salehi Pour Mehr
Florida International University, [email protected]
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Salehi Pour Mehr, Vahid, "Development and Verification of Control and Protection Strategies in Hybrid AC/DC Power Systems for
Smart Grid Applications" (2012).FIU Electronic Theses and Dissertations.Paper 804.
http://digitalcommons.fiu.edu/etd/804
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FLORIDA INTERNATIONAL UNIVERSITY
Miami, Florida

DEVELOPMENT AND VERIFICATION OF CONTROL AND
PROTECTION STRATEGIES IN HYBRID AC/DC POWER
SYSTEMS FOR SMART GRID APPLICATIONS

A dissertation submitted in partial fulfillment of
the requirements for the degree of
DOCTOR OF PHILOSOPHY
in
ELECTRICAL ENGINEERING
by
Vahid Salehi Pour Mehr

2012
To: Dean Amir Mirmiran
College of Engineering and Computing

This dissertation, written by Vahid Salehi Pour Mehr, and entitled Development and
Verification of Control and Protection Strategies in Hybrid AC/DC Power Systems
for Smart Grid Applications, having been approved in respect to style and intellectual
content, is referred to you for judgment.

We have read this dissertation and recommend that it be approved.

_______________________________________
Nezih Pala

_______________________________________
Jean Andrian

_______________________________________
BerrinTansel

_______________________________________
Stavros Georgakopoulos

_______________________________________
Mark Roberts

_______________________________________
Osama Mohammed, Major Professor

Date of Defense: November 2, 2012

The dissertation of Vahid Salehi Pour Mehr.

_______________________________________
Dean Amir Mirmiran
College of Engineering and Computing

_______________________________________
Dean Lakshmi N. Reddi
University Graduate School

Florida International University, 2012

ii
© Copyright 2012 by Vahid Salehi Pour Mehr
All rights reserved.

iii
DEDICATION
I would like to dedicate this dissertation to my wife, Maryam, who brought love into my
life and my parents who always encourage and support me in all of my educational life.

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ACKNOWLEDGMENTS
I would like to express my gratitude to my advisor, Professor Osama Mohammed,
whose expertise, understanding, and patience, added considerably to my graduate
experience. I appreciate his vast knowledge, significant contribution and technical skills
in many electrical engineering areas (e.g., power systems, electric machinery, magnetics,
power electronics and signal processing). I also appreciate his excellent ability and
assistance in writing reports (including journal and conference papers, proposals,
scholarship applications and this dissertation). These have made my work more
technically and highly prestigious. He provided support at all levels of research including
technical guidance and discussions, laboratory facilities and financial support for
developing the smart grid test-bed at Florida International University.
I would like to thank the members of my committee, Dr. Jean Andrian, Dr. Nezih
Pala, Dr. Berrin Tansil and Dr Stavros Georgakopoulos for the assistance they provided.
Also, I would like to thank the external dissertation committee member, Dr. Mark
Roberts from Naval Surface Warfare Center for the many technical discussions and for
his practical insights.
I’d like to acknowledge the university graduate school for awarding the Doctoral
Evidence Acquisition Fellowship (DEA) to me in 2012. It significantly enhanced my
ability to collect the evidence needed for my doctoral research.
Finally, I’d like to acknowledge my doctoral student colleague, Ahmed Mohamed
for his significant contribution and cooperation in my research and other doctoral
students who put efforts in implementing and testing required equipment used for my
dissertation. Also, I’m grateful for the help of undergraduate student interns who are
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involved in developing smart grid test-bed at Energy System Research Laboratory of
FIU.
In addition, I recognize that this research would not have been possible without
the partial financial support from the Office of Naval Research (ONR), and the US
Department of Energy (DOE) as well as other sources brought to the ECE Department
through my major research advisor.

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ABSTRACT OF THE DISSERTATION
DEVELOPMENT AND VERIFICATION OF CONTROL AND
PROTECTION STRATEGIES IN HYBRID AC/DC POWER
SYSTEMS FOR SMART GRID APPLICATIONS
by
Vahid Salehi Pour Mehr
Florida International University, 2012
Miami, Florida
Professor Osama Mohammed, Major Professors
Modern power networks incorporate communications and information technology
infrastructure into the electrical power system to create a smart grid in terms of control
and operation. The smart grid enables real-time communication and control between
consumers and utility companies allowing suppliers to optimize energy usage based on
price preference and system technical issues. The smart grid design aims to provide
overall power system monitoring, create protection and control strategies to maintain
system performance, stability and security.
This dissertation contributed to the development of a unique and novel smart grid
test-bed laboratory with integrated monitoring, protection and control systems. This test-
bed was used as a platform to test the smart grid operational ideas developed here. The
implementation of this system in the real-time software creates an environment for
studying, implementing and verifying novel control and protection schemes developed in
this dissertation. Phasor measurement techniques were developed using the available
Data Acquisition (DAQ) devices in order to monitor all points in the power system in real
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time. This provides a practical view of system parameter changes, system abnormal
conditions and its stability and security information system. These developments provide
valuable measurements for technical power system operators in the energy control
centers. Phasor Measurement technology is an excellent solution for improving system
planning, operation and energy trading in addition to enabling advanced applications in
Wide Area Monitoring, Protection and Control (WAMPAC).
Moreover, a virtual protection system was developed and implemented in the
smart grid laboratory with integrated functionality for wide area applications.
Experiments and procedures were developed in the system in order to detect the system
abnormal conditions and apply proper remedies to heal the system.
A design for DC microgrid was developed to integrate it to the AC system with
appropriate control capability. This system represents realistic hybrid AC/DC microgrids
connectivity to the AC side to study the use of such architecture in system operation to
help remedy system abnormal conditions.
In addition, this dissertation explored the challenges and feasibility of the
implementation of real-time system analysis features in order to monitor the system
security and stability measures. These indices are measured experimentally during the
operation of the developed hybrid AC/DC microgrids. Furthermore, a real-time optimal
power flow system was implemented to optimally manage the power sharing between AC
generators and DC side resources.
A study relating to real-time energy management algorithm in hybrid microgrids
was performed to evaluate the effects of using energy storage resources and their use in
mitigating heavy load impacts on system stability and operational security.
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TABLE OF CONTENTS
CHAPTER PAGE
1 INTRODUCTION ........................................................................................................... 1
1.1 Introduction ............................................................................................................. 1
1.2 Literature Review.................................................................................................... 5
1.3 Motivation and Objective ..................................................................................... 11
1.4 Problem Statement ................................................................................................ 13
1.5 Original Contributions of the Dissertation ............................................................ 17
1.6 Organization of Dissertation ................................................................................. 21

2 REVIEW OF POWER SYSTEM OPERATION AND CONTROL ............................. 25
2.1 Modern Hybrid AC/DC Power System ................................................................ 25
2.2 Power System Operation Limits ........................................................................... 30
2.3 Cascading Events and System Blackout ............................................................... 33
2.4 Power System Monitoring with SCADA .............................................................. 37
2.5 Wide Area Monitoring, Control and Protection ................................................... 39
2.6 Phasor Measurements Units .................................................................................. 42
2.7 Applications of PMUs in Power System .............................................................. 47

3 DEVELOPMENT OF SMART POWER SYSTEM TEST-BED ................................. 53
3.1 Hardware Employed on the Test Bed ................................................................... 56
3.1.1 Generation Station Model ............................................................................ 56
3.1.2 Transmission Line Model ............................................................................ 59
3.1.3 Bus Model .................................................................................................... 60
3.1.4 Load Model .................................................................................................. 62
3.1.5 Synchronizer Model ..................................................................................... 64
3.2 Real-Time System Monitoring and Control Platform .......................................... 65
3.2.1 Data Acquisition Devices ............................................................................ 65
3.2.2 Real Time LabVIEW Software .................................................................... 66
3.3 Test and Verification of Developed Techniques .................................................. 67

4 PHASOR MEASUREMENT UNITS AND THEIR APPLICATIONS IN SMART
GRID LABORATORY .................................................................................................... 74
4.1 Introduction ........................................................................................................... 74
4.2 Measuring Synchronous Phasors .......................................................................... 76
4.2.1 Phasor Representation of Sinusoids ............................................................. 76
4.2.2 Techniques for Signal Analysis ................................................................... 77
4.2.3 Phasor of Nominal Frequency Signals ......................................................... 78
4.2.4 Nonrecursive Updates of Phasors ................................................................ 79
4.2.5 Recursive Updates of Phasors ...................................................................... 81
4.2.6 Effect of Noise Signal on Phasor ................................................................. 83
4.2.7 DC Offset in Input Signal ............................................................................ 86
4.2.8 Input Signal at Off-Nominal Frequency ...................................................... 86
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