Transcript Template for e7 Presentations

e8 / PPA Solar PV Design Implementation O&M
Marshall Islands March 31-April 11, 2008
1. Solar Photovoltaic Theory
1-3. System configuration
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Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-3.System configuration
• Contents
1-3. System configuration
1-3-1. Cells, Modules and Arrays
1-3-2. Type of system ( Grid interconnection or not )
1-3-3. Power conditioner (Control system)
1-3-4. Batteries
1-3-5. Wiring
1-3-6. Some tips on system design
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e8 / PPA Solar PV Design Implementation O&M
1-3-1. Cells,Modules and Arrays
• Hierarchy of PV
Cell
Volt
Ampere
Watt
Size
0.5V
5-6A
2-3W
about 10cm
5-6A
100-200W about 1m
Module 20-30V
Array
200-300V 50A-200A 10-50kW
about 30m
Array
10 - 50 kW
Module,Panel
100 - 200 W
Cell
2–3W
6x9=54 (cells)
100-300 (modules)
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e8 / PPA Solar PV Design Implementation O&M
1-3-1. Cells,Modules and Arrays
• Module
•Specification
- Configuration
- Inner wiring
- Max Power
- Vopen
- Vpmax
- Ishort
- Ipmax
- Size
- Weight
175W
12x6=72 Cells
All Serial wiring
175 W ( 2.4306w/cell )
44.4V
35.36V ( 0.4911 V/cell)
5.55 A
4.95 A
1574 x 826 x 46 mm
17.0 Kg
Easy estimation
0.4911V x 72cells = 35.36 V
35.36V x 4.95A = 175.03 W
826mm
To obtain high voltage, cells are serially wired
in most of module.
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• Module
Module intersection
Reinforced grass
Rubber packing
46mm
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e8 / PPA Solar PV Design Implementation O&M
1-3-1. Cells,Modules and Arrays
Plastic film
Aluminum
angle
PV cell
( plastic
molded )
826mm
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• Module
Back side view of Module
1574mm
Cable
connector
Cable
Attachment angle
Terminal
box
862mm
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e8 / PPA Solar PV Design Implementation O&M
1-3-1. Cells,Modules and Arrays
Terminal box
Bypass Diode
is inside
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e8 / PPA Solar PV Design Implementation O&M
Marshall Islands March 31-April 11, 2008
1-3-1. Cells,Modules and Arrays
• Module connecting
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e8 / PPA Solar PV Design Implementation O&M
1-3-1. Cells,Modules and Arrays
• Array structure
Side View
•PV modules are mounted on frame that
is tilted the same angle as local latitude.
Local
latitude
•Face should be truly to North or South.
•Frame should be strong enough to
withstand weight of modules and wind
force by storm.
Front View
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• Arrays electrical structure
String
Array
•Serial connected modules form a “String”.
•Parallel connected string form “Array”.
•Each strings are connected with
“Reverse-Current blocking Diode”
+
-
•Parallel connected Array Units form “Arraysystem”
Without Diode
Reverse
current
V= 0.5 x 4 = 2.0 V
Module
V= 0.5 x 2 = 1.0 V
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e8 / PPA Solar PV Design Implementation O&M
1-3-1. Cells,Modules and Arrays
Partially shaded
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Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-3-1. Cells,Modules and Arrays
• How many modules for a string? ( For 30kW system )
Module
Vpmax=35.36V
Power=175W
•Number of serially connecting modules
“m” is determined by Power Controller’s input voltage.
175W
Module
•Typical input voltage of 200V AC power
controller is about 300V (190 – 450V.
See 3-3 ) String voltage should be
adjusted to this.
+
m
•Consider voltage drop caused by
partially shading, PV string’s voltage
should add 10% more.
300 x 1.1 = 330V
• If module voltage is 35.36V,
m = 330 / 35.36 = 9.33 => 9 serial
•Then string voltage is
35.36 x 9 = 318.24V
•String power is
175 x 9 = 1,575W
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• How many strings for an array? ( For 30kW system )
Module
Vpmax=35.36V
Power=175W
•Number of parallel-connecting strings
“n” is determined by total output
power.
175W
Module
•At 9 modules per string, string output
power is
175 x 9 = 1,575 W
+
-
•For a 30kW system
m=9
Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-3-1. Cells,Modules and Arrays
n = 30,000 / 1,575 = 19.05 => 20
(parallel)
•Total system power is
1,575 x 20 = 31.5 kW
n
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• Array layout ( For 30kW system )
Module
Vpmax=35.36V
Power=175W
175W
Module
9 x 20 = 180 modules
175W
+
30kW
system
m=9
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e8 / PPA Solar PV Design Implementation O&M
1-3-1. Cells,Modules and Arrays
1 module
826mm
n=20
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• Array layout ( For 30kW system )
9 x 2 Modules
3.5 m
8m
30 kW system
( 9 x 20 Modules)
25 m
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1-3-1. Cells,Modules and Arrays
With working space, maintenance road
Total area = 15 x kW (m2)
20 m
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1-3-1. Cells,Modules and Arrays
• Array-System
Surge Arrester
10 arrays
+
+
-
+
-
DC Switch
Power
Conditioner
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e8 / PPA Solar PV Design Implementation O&M
1-3-2. Type of system
• Type of system ( Grid interconnection or not )
(a) Off-grid individual power system(Capacity:50W )
PV
•Install a renewable energy system in each
household separately
PV
PV
•This system is applied mainly for a non-electrified
region or a rural area.
(b) Micro grid power system
(Capacity:10 to 50kW )
•Install a renewable energy system in a small
DG
community by combining with diesel generators
•It aims to save diesel fuel consumption and to
enhance power supply.
(c) Small grid power system
DG
DG
(Capacity:50 to 500 kW )
•Same as (b), but the system capacity is bigger.
(d) Normal grid power system
(Capacity: > 500kW )
Main Grid
• Install a renewable energy system to the main
( > 500kW )
grid.
G
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1-3-1. Cells,Modules and Arrays
• System Structure
50 – 70 W
Solar Home System(SHS)
Module
DC 12V
Battery Controller
(DC)
DC 12V
e8 / PPA Solar PV Design Implementation O&M
For every household
Battery
1 to 50 kW
Stationary PV system
Array
For Community
DC 300V
Power Conditioner
(DC -> AC)
AC 200V
Battery
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• Diagram of power conditioner
Seek Max
Power of PV
DC190
to
450V
DC-DC
Converter
(Voltage
Regulator)
DC300V
DC-AC
Inverter
(PWM)
AC200V
Voltage is
example one
To Seek Pmax point.
Input voltage is
automatically
(A
controlled
)
Battery
For PMW, input
voltage should be
maintained
282.2V(300V)
200 2  282.8(V )
Voltage
Convert
DC to AC
Power Conditioner
Current(I)
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e8 / PPA Solar PV Design Implementation O&M
1-3-3. Power conditioner
PWM (Pulse Wise
Modulation)
Chop by
thirstier
Smoothing
AC200V
(V
)
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• Basic voltage control rules
Power Conditioner
DC190
to
450V
Seeking
Pmax point.
(A
)
DC-DC
Converter
(Voltage
Regulator)
DC300V
DC-AC
Inverter
(PWM)
AC200V
Width control
Seeking ideal
charge voltage
PWM (Pulse Wise
Modulation)
Chop by
thirstier
Battery
Current(I)
Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-3-3. Power conditioner
Smoothing
AC200V
Voltage
(V
)
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• Voltage allowance of DC-DC Converter
• Due to the converter loss, DC-DC
converter’s voltage allowance is narrow.
(A)
DC190
to
450V
Narrow for voltage
DC-DC
Converter
(Voltage
Regulator)
DC300V
Wide for current
High intensity insolation
Current(I)
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e8 / PPA Solar PV Design Implementation O&M
1-3-3. Power conditioner
Acceptable input zone
of DC-DC Conv.
(Typical example)
Low intensity insolation
190V
300V
450V
(V)
See 3-5
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e8 / PPA Solar PV Design Implementation O&M
1-3-3. Power conditioner
• “Unit style” power conditioner
• PV system is built based on unit capacities such as
10 kW, 30 kW, 50 kW, and 100 kW units.
• If you need a 80 kW system, you can parallel 30 and 50 kW units.
10 kW
10 kW
10 kW
Panel
Panel
Panel
DC
80 kW
AC Output
Data Link
for
Parallel Operation
10 kW x 3 = 30 kW
10 kW
10 kW
10
kW
Panel
10 kW Panel
10 kW
Panel
Panel
Panel
30 kW
Conv.
DC
50 kW
Conv.
10 kW x 5 = 50 kW
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• “Unit style” power conditioner
30kW power
conditioner
•Typical “Unit style” power conditioner.
•Each unit is 10kW.
•Left side photo is 30kW system.
PV
array
10kW
Display
unit
I/O Unit
1950 mm
Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-3-3. Power conditioner
10kW
10kW
I/O unit
10kW Unit power
conditioners
Display
unit
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e8 / PPA Solar PV Design Implementation O&M
1-3-3. Power conditioner
• Small power conditioner for SHS
• Load of SHS is DC, power conditioner is not include inverter.
• Main function of power conditioner is “battery charge controller” to
avoid over charging or over discharging.
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Marshall Islands March 31-April 11, 2008
1-3-3. Power conditioner
• Small power conditioner for SHS
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e8 / PPA Solar PV Design Implementation O&M
1-3-3. Power conditioner
• Small power conditioner for SHS
DC type fluorescent lamp
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1-3-4. Batteries
• why battery is necessary?
• In an SHS or Independent small grid system, PV’s output power
does not meet with demand.
• PV’s can generate in daytime only. But demand, such as lighting
television, is almost nighttime load.
• In main grid interconnected system, other diesel generator
compensate this unbalance. So battery is not necessary.
e8 / PPA Solar PV Design Implementation O&M
• Most systems of this type require “power shifting” by battery.
• But batteries are expensive and their lifetime is not enough for PV’s.
Therefore, batteries need replacing.
Power Shifting
Excess
Power
Demand Demand
PV Power
＋
－
Battery
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e8 / PPA Solar PV Design Implementation O&M
1-3-4. Batteries
• Technical requirements for battery
To allow optimal use of battery storage in a PV system, the
following requirements should be met:
• High efficiency (ratio between supply energy and storage
energy);
• Long lifecycle in frequent charge/discharge regimes;
• High resistance at high temperature environments;
( 0 to 50deg.C);
• Low self-discharge;
• High ratio capacity/volume;
• Low cost;
• Rare maintenance processes.
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1-3-4. Batteries
• Various type of battery
•The below rechargeable batteries are available, but lead -acid batteries are
used most often for power-shifting with solar cells because of their price and
reliability.
•Lead-Acid battery
•NiCd battery ( Nickel Cadmium)
Rechargeable battery
•NiMH battery ( Nickel metal hydrant )
•Li battery
( Lithium )
•Outlook of Lead-Acid batteries
Shielded style
Clad style
Automotive
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• DOD (Depth Of Discharge)
50
%
DOD
100%
Full
Charged
100%
DOD
50%
75%
DOD
• Lifetime shortens if the battery is completely discharged, therefore
discharging is limited in use.
• The ratio of discharge level to the battery’s full capacity is called as
DOB (%).
• If DOD is kept shallow, the amount of chargeable energy will be low,
even with the same kind of battery. However, lifetime will be longer.
Remaining power in battery
Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-3-4. Batteries
DOD
(Depth of discharge)
Empty
Discharge/Charge sequence
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e8 / PPA Solar PV Design Implementation O&M
1-3-4. Batteries
• Comparison of battery type
type
Capacity
range
(Ah)
Expected
lifetime
Expected life
cycle
Shield Shielded
lead-acid
ed
style
50 – 3000
7 - 9 years
150 - 3000
12 - 15 years
(long life type)
Miniature
shielded
lead-acid
0.7 – 144
3 - 5 years
- - 500
DOD 50%
50 - 130
5 - 6 years
(long life type)
DOD 50% - 700
Clad
style
Clad
lead-acid
for PV
system
50 - 3000
Other
Automoti
ve leadacid
21 - 160 Ah
(5 hr rate)
-
DOD 50% - 1000
DOD 75% - 1800
12 - 15 years
4 - 5 years
Water
Refilling
DOD 50% 300
No
(Maintenance
free)
Necessary
Necessary
DOD : Depth of discharge
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Marshall Islands March 31-April 11, 2008
1-3-4. Batteries
• Battery installation housing
• Actual battery size is big and weight is very heavy.
• Floor and lower part of wall should be covered with acid-resistant
paint.
• Ventilate air continuously to avoid hydrogen explosion.
200kWh System ( MSE500x2P )
e8 / PPA Solar PV Design Implementation O&M
13 tones
900mm
Acid-resistant
floor
1200mm
1400mm
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Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-3-4. Batteries
• Automotive battery ( Conventional battery )
• For conventional SHS system,
automotive battery is widely
applied.
• Mainly for DC-Load. (no Inverter)
• Cheap but cycle life time is short
(about 2 to 3 years)
• Capacity of one module is
12V x 100Ah
about $90
12V x 100A x 0.75 = 900 Wh
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e8 / PPA Solar PV Design Implementation O&M
1-3-5. Wiring
• Module wiring in arrays
•There are may kind of wiring rules. Witch is better?
( 8 Serial 4 Parallel )
Row-wise serial
Column-wise Serial
Array
Building
In the mid day, some
part of array is
shaded by Building !
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Marshall Islands March 31-April 11, 2008
1-3-5. Wiring
• Module wiring in arrays
• About characteristic of power conditioner, voltage allowance
is narrow.
• If array voltage goes down under 190V, power conditioner
cannot maintain operation. (in this case)
(A)
Acceptable input zone
of Power conditioner
(Typical example)
Narrow for voltage
Wide for current
Max Power
Current(I)
e8 / PPA Solar PV Design Implementation O&M
High intensity insolation
Low intensity insolation
190V
300V
450V
(V)
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• Module wiring in arrays
(A)
Column-wise serial
- Voltage will be half.
- Out of operational region.
“Lost-Voltage” causes shutdown
Without shadow, both wiring
are same as Max-power point
Half voltage
Current(I)
Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-3-5. Wiring
Half current
Row-wise serial
- Current will be half.
- Operation continue.
190V
300V
450V
(V)
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Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-3-6. Some tips for system design
• Surrounding environment and anticipated damage
Falling leaf
Falling nuts
Stone throwing
Sand breeze
•Sand scratch
(like frosted grass)
Sea breeze
•Contamination
•Electrically grounding
Animal bait
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Marshall Islands March 31-April 11, 2008
e8 / PPA Solar PV Design Implementation O&M
1-3-6. Some tips for system design
• Surrounding environment and anticipated damage
Rain
Lightning
Lightning rod
Strong enough
for stormy wind
Heat up
Enough ventilation
for cooling
Trench for heavy rein
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