Overview Renewable Energy Systems 402 .pdf - Curtin University

Curtin University of Technology
Division of Engineering, Science and Computing
Department of Electrical Engineering
Renewable Energy Systems 402/604
Semester 2, 2007
Lecture 1
Professor Chem Nayar
Office: 204:205
Telephone: 9266 7934
Email: c.v.nayar@curtin.edu.au
Unit website:
www.ece.curtin.edu.au/~pe301

Renewable Energy Systems
402/604
Tuition Pattern:
5 Hours:
Lecture 2.00 hours, 1.00 weekly
Tutorial 1.00 hour, 1.00 weekly
Laboratory 2.00 hours fortnightly
Assessment Details:
Assignments : 4 0%
Assignment – 1 (20%)
Assignment - 2 (20%)
Final Examination (2hours) : 60%
Closed book , restricted exam.
( Students can bring a single page of A4 size notes handwritten or typed on
both sides and calculators)

Recommended Texts and Principal References
1. H. L. Willis and W.G. Scott, “Distributed Power Generation, Marcel
Dekker Inc., 2000
1. G. Boyle, “Renewable Energy, power for sustainable future”, Oxford,
2004.
2. J.F. Manwell, et al, “Wind Energy Explained”, John Wiley and Sons,
2002.
3. S. Wenham, M. Green and M. Watt, “Applied Photovoltaics, UNSW,
ISBN 0 86758 909 4.
2.S. AustraliaTM, "AS 4777.3: Grid connections of energy systems via
inverters Part 3: Grid protection requirements," in Standards AustraliaTM,
2002.
3.S. AustraliaTM, "AS 4777.1: Grid connections of energy systems via
inverters Part 1: Installation requirements," in Standards AustraliaTM, 2002.
4.S. AustraliaTM, "AS 4777.2: Grid connections of energy systems via
inverters Part 2: Inverter requirements," in Standards AustraliaTM, 2002.

Renewable Energy Systems 402 Semester 2, 2007
Week Day Topics Lecturer Duration Pre-readings Tutorial Assignment Due
1 31-Jul Introduction Prof. Nayar 4-6pm Lecture Notes
2 7-Aug PV Systems 1 M. Dymond 4-6pm Lecture Notes Tutorial No.1
3 14-Aug PV Systems 2 M. Dymond 4-6pm Lecture Notes Tutorial No.2
4 21-Aug Wind Energy Systems 1 Prof Nayar 4-6pm Lecture Notes Tutorial No.3
5 4-Sep Wind Energy Systems 2 Prof. Nayar 4-6pm Lecture Notes Tutorial No.4
6 11-Sep Wind Energy Systems 3 Prof. Nayar 4-6pm Lecture Notes Tutorial No.5
7 18-Sep Energy Economics Prof. Nayar 4-6pm Lecture Notes Tutorial No.6
8 2-Oct Small Hydro Systems Dr. Sumedha 4-6pm Lecture Notes Tutorial No.7 Assignment No.1
9 9-Oct Fuell Cells 1 Dr. Sumedha 4-6pm Lecture Notes Tutorial No.8
10 16-Oct Fuell Cells 2 Dr. Sumedha 4-6pm Lecture Notes Tutorial No.9
11 23-Oct Distributed Generation 1 Dr. Sumedha 4-6pm Lecture Notes Tutorial No.10
12 30-Oct Distributed Generation 2 Dr. Sumedha 4-6pm Lecture Notes
13 6-Nov Study week Assignment No.2

Renewable Energy Systems 402/604 Lab

Overview of Renewable
Energy Systems, Distributed
Generation

What Are Distributed Generators?
• Distributed generation (DG) systems are small
modular electric power generation units
(

DG – A Future Mode of Generation
• Central generation stations vs DG systems (now)
• Super computers vs Personal Computers (25 years ago)

Tremendous DG Market Potential
• Global electricity consumption:40% of total global energy consumption
• Present global DG capacity:30 GW installed capacity
• DG growth rate:currently 8-9GW/year or 3% of newly installed
generation capacity; will be 6% of newly installed capacity by 2020
Global new-capacity Global new DG capacity

Capacity (GW)
Rapid DG Growth – Wind Capacity
80
70
60
50
40
30
20
10
0
Cumulative Capacity
Installed Capacity
90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06
Year

Rapid DG Growth – PV Capacity

Driving Forces for Rapid DG Growth
Deregulation and
Economics:
Trade
Investment
Environmental
Concerns:
GHG reduction
Energy efficiency
Electricity
Sector
Technological
Innovation
Demands:
Increasing demand
Supply quality
Supply security

Electricity and GHG Emissions
Coa l 34. 1%
Courtesy of Hydro Quebec
Nuc l ear 17. 0%
Nat ual Gas 18 . 8%
Oi l 9. 9%
Ren ewabl es 20 . 2%
Electricity: 0.51kg/kWh, or 20% of global GHG

Increasing Electricity Demand
Annual World Electricity Consumption Will Increase at 2.3%
(Developing Countries at 3.5%)
Electricity Consumption (TWh)
25000
20000
15000
10000
5000
0
EE/FSU
Developing
Industrialized
North America
2001 2010 2015 2020 2025
Year

Energy Security: Oil and Gas Will
Deplete, Sooner or Later

A Direct Drive Wind Turbine

A Wind Turbine System –
Kinetic ⇒Mechanical ⇒Electric Energy
• Turbine input power
Pwind =
1 1
mu = ρ Au
2 2
2 3
• Turbine output power
Pmech =
1
2
3
Au Cp ρ
• Turbine performance factor Cp. Theoretical
maximum Cp: Cpmax=16/27=0.593,
practical maximum Cp=0.4 - 0.5

Photovoltaic Cells
• Solar cell operation is based on the ability of
semiconductors to convert sunlight directly into
electricity. In the conversion process the incident energy
of light creates mobile charged particles in the
semiconductor, which are then separated by the device
structure and produce electrical current.

Characteristics of PV Cells
6
5
4
3
2
1
0
1000W/m 2
800W/m 2
600W/m 2
0 5 10 15 20 25

6
5
4.6
Current (A)
4
3
2
1
0
VI Characteristic Curve
Nominal 12V array
0 5 10 15 20 25
Voltage (V)
17.4
120
100
80
60
40
20
0
79
Power(W)

Effect of Solar Radiation Level
6
5
4
3
2
1
0
1000W/m 2
800W/m 2
600W/m 2
0 5 10 15 20 25

6
5
4
3
2
1
0
Effect of Temperature
75C
50C
25C
0 5 10 15 20 25
This characteristic is important in determining the dc voltage window
of grid connected inverters
0C

Photovoltaic Power Systems
(a)
DC Input
Power
Electronics
Interface
(b)
Utility

Wind Electric Systems
Generator
and
Power Electronics
Utility

Power Electronic Converters:
Enabling Technology for DG Systems
Converters in components, functions and systems of distributed generators

Functions of Power Electronic
Converters for DG Systems
• Power Conversion
– ac-dc, dc-ac, ac-ac, dc-dc; voltage and
frequency control
• Interconnection with Grid & System Protection
– meeting requirements of interconnection standards
• Resource Control (optimize sources and loads)
– maximum power point tracking
• Power System Support
– power and reactive power control, dispatch etc.

Bidirectional Switching Power Pole
Ref: Mohan

Low Frequency PWM Generation
Ref: Mohan
V
d a =
V
aN
d

Single-Phase Inverter
Ref: Mohan
v =
Vˆ
o sin
w
o 1
t

Single Phase Grid Connected Inverter

Three-Phase Inverter-Sine PWM
3
( Vl ) V
l max =
d ~ 0.
867V
2
d

Three-Phase Inverter- Sine PWM

Current Source/Voltage Inverter
• A current source inverter (CSI)
has an inductor in series with
the DC input
• A voltage source inverter (VSI)
has a capacitor across the DC
input
– Voltage controlled VSI (VCVSI)
– Current controlled VSI (CCVSI)
Idc
Vdc
L
Q1
Q2
Q1
C
Q2
Io
Io
Load
Load
Q4
Q3
Q4
Q3

Voltage Controlled VSI
P
g
VgVc
VgVc
V
= sin δ;
Qg
= cosδ
−
X
X X
L
L
2
g
L

Current Controlled VSI
ϕ
Real power and Reactive power can
be controlled by regulating the magnitude,
and the angle φ
φ
P g = Vg
I g cosφ; Qg
= Vg
I g sinϕ
I =
Pg= VIg cosφ Qg= VIg sinφ
L
I
g

Current Controlled VSI
• Fast current response
• Inherent current protection
• Appropriate for gridconnected
inverters such
as for PV/Wind generators
– Hysteresis current
controller
– Ramp controller
– Predictive controller
– Current-based space vector
controller

Hysteresis Current Controller

Active and Reactive Power Control

PV/Grid Energy System Configurations
• Large Single Inverter Type (Central
Inverter)
• Multiple Small Inverter Type (String
Inverter)
• DC Bus (Multi-string Inverter)
• “AC” Module

Large Single Inverter Type
• Series and Parallel
connection on DC
side
• All PV panels
connected to single
DC bus
• Single Central
Inverter
• Affected by partial
shading of panels
• Only one protection
system required

Multiple Small Inverter Type
• One inverter per
string
• Panels grouped into
smaller inverter –
rated power of
Inverter ( 0.7-5kW)
• Not so badly
affected by shading
• Not badly affected
by inverter failure

Grid-Connected PV Inverter (String Type)
@ 3.3kW

Grid-Connected with Energy Back up System
AC Line
DC from PV
160 to 240 V
AC Grid Line
DC 48 V
Controller Back up Line
AC Line
DC 48 V

Grid-Connected PV System
with Back up Inverter
Kang Som-Mao, Ratchaburi
75 Wp x 42 modules
PV
CONTROLLER -
BATTERY batteries for S-218C
INVERTER APOLLO G –304 And S-218C

• Each panel or
group have a DC-
DC step up
converter
• High voltage DC
link feeds
transformer-less
converter
DC Linked

• One Inverter per
panel
• High volume/
low cost?
• Plug-and-play?
AC Modules

Wind
Wind Energy Conversion System
Mechanical Power Electrical Power
Wind Turbine
Rotor
Gearbox/
Transmission
Generator
Power
Converter
Power
Transformer
Electric Grid

Permanent Magnet PM Generator
GB
L DC
C DC
V DC
L AC

Applications of Single-Phase
Inverters for Small Wind Turbines
Wind turbine system

AC/DC/AC Full Power Converter
for Three-Phase Grids (PWM Rectifier)

Micro Hydro

Fuel Cells
• Fundamentals
and
background
• Energy
Conversion
Principle

Microgrid
• A MicroGrid power system
– Is a local scale power system using distributed resources scaled to
the local system demand.
– Is designed to transfer seamlessly between connection with the
local utility and isolated operation.
• Benefits
– Improved power reliability and power quality
– Potential economic benefits: CHP, higher efficiency, diversified fuel
supplies
– Possible ancillary services for power system operators
– Transmission and distribution support in constrained areas.
– Potential for reduced emissions compared to centralized utility.
– Ability to allow high penetration of renewable generation.

Case study : The Republic of Maldives
1,192 islands
with a land area of
about 300 km2,
formed on a chain
of 26 coral reef
atolls in the Indian
Ocean
80 percent of
the total landmass
of the Maldives is
less than 1 meter
above sea level

Kondey
Maldives Remote Islands
Uligam
Raimandhoo

Advantages of the Renewable Energy
Micro-Grid System
+ + +
POWER
ELECTRONICS
• Can Provide 24 hours of Electricity
• Diesel Generator operating hours will be reduced which leads
to save in fuel plus O&M cost
• Reduced Cost of Electricity
• Fast pay back period [2-3 Years]
• Reduced noise and air pollution
• Reduced Greenhouse Gas Emission
+

Micro Grid for Uligam lsland

Micro Wind Farm