microgrid solar,A microgrid is a local electrical grid with defined electrical boundaries, acting as a single and controllable entity. It is able to operate in grid-connected and in island mode. A 'Stand-alone microgrid' or 'isolated microgrid' only operates off-the-grid and cannot be connected to a wider electric power system

1. 1
Session :Design of
Solar Panel Energy
System
Punjab Energy Development Agency, PEDA
Solar Passive Complex-Sector 33-D,Chandigarh

2. 2
Content
1. How a PV cell works
2. PV Cell Electrical Characteristics
3. PV Modules
4. Quantifying PV Module Performance
5. Types of PV Modules technology
6. PV Module Protection
7. Module Reliability
8. PV Module specifications

3. 3
How a PV Cell Works
• Solar photovoltaic (PV) cells convert sunlight into electricity.
• Photovoltaic (PV) cells generate electricity by absorbing sunlight and using that light energy to create an electrical current.
• Most photovoltaic (PV) panels are made from crystalline silicon-type solar cells. These cells are composed of layers of silicon,
phosphorous, and boron.

4. • The I–V curve of a solar cell is found by setting up the solar
cell in series with a variable resistor.As the resistance
changes, the current and voltage are measured and plotted to
form an I-V curve, this known as the load line method.
Circuit used to determine the I–V
curve of a solar cell using the load
line method.
PV Cell Electrical Characteristics
2. The I–V Curve
• The I–V curve of a solar cell shows the relationship between
the current and voltage of the electricity generated by the
cell. Each point along the curve represents a possible
operating point of the solar cell. The I–V relationship is
dependent on the internal resistance of the solar cell and is
affected by the levels of solar radiation being received and
the temperature of the cell.

5. PV Cell Electrical Characteristics
• The Solar Cell I-V Characteristic Curves shows the current
and voltage (I-V) characteristics of a particular PV cell,
module or array.
• It gives a detailed description of its solar energy conversion
ability and efficiency.
• The current-voltage (I-V) characteristic is the basic descriptor
of photovoltaic device performance. This is plotted on a graph
with voltage (the independent variable) on the x axis and
current (the dependent variable) on the y axis, while keeping
irradiance and temperature levels constant.
I-V characteristics curve of a PV module

6. PV Cell Electrical Characteristics
The power produced by a solar cell is found by
multiplying the current and voltage.
𝑃 = 𝐼×𝑉
This power output is known as I-V curve. There is
a point on the I-V curve that shows the maximum
amount of power this is known as the maximum
power point (MPPT). This point is at the ‘knee’ of
the I-V curve , and occur when the load resistance
is equal to the internal cell resistance.
Power output plotted for each point on the I-V curve

7. • a)The I–V characteristics of a single cell; b) the I–V characteristics of three of those cells connected in series.
• If dissimilar solar cells are wired together in series, the voltage output will be equal to the combined voltage
outputs of those cells, but the current output will be equal to the lowest individual cell current output.
PV Modules
1. Creating a PV Module
• PV modules are units of series interconnected PV cells that have been encapsulated to protect the cells and their
interconnecting wires from external damage. Connecting identical solar cells in series results in the same current output as
a single cell but having a combined voltage output.

8. 1. Creating a PV Module
• Since the PV module will then have electrical characteristics that are
defined by the cells, the I-V characteristics are the following:
• Maximum power point (MPP): the point on the I-V curve at which the PV
module will produce the most power
• Maximum power (PMP): the maximum power output of the PV module
• Voltage at PMP (VMP): the PV module voltage at the MPP of the I-V curve
• Current at PMP (IMP): the PV module current at the MPP of the I-V curve
• Open circuit voltage (VOC): the maximum voltage of the PV module when
there is no load connected to it and hence no current output
• Short circuit current (ISC): the maximum current available from the PV
module when the terminals of the module are connected together with no
resistance (short circuited) and hence with no voltage differential across the
cell
PV Modules
(a) The I–V characteristics of two
dissimilar cells
(b) The resulting I–V characteristic two
dissimilar cells connected in series

9. PV Modules
2. Combining PV Modules
• Solar modules are connected in series to form a PV string, and PV strings are connected in parallel to
form a PV array.
• The electrical specifications of the required array will determine the number of modules in each
string and how many strings there will be in total.
• As with solar cells, connecting solar modules
in series results in a voltage output
that is equal to the combined voltage
outputs but a current output that is
equal to the lowest individual module
output.
• Connecting strings in parallel results in
a voltage output that is equal to the
lowest output of the individual strings
and a current output that is equal to the
combined current outputs of the strings.

10. Standards and certification of PV Modules
Standards:
• IEC61215: Crystalline Silicon Terrestrial Photovoltaic (PV) modules - Design QualificationAnd TypeApproval
• IEC 61730 (Part 1): Photovoltaic (PV) Module Safety Qualification Part 1 Requirements for Construction
• IEC 61730 (Part 2): Photovoltaic (PV) Module Safety Qualification Part 2 Requirements for Testing
• IEC 61701:2020: Salt mist corrosion testing of photovoltaic (PV) modules
• IEC 60068-2-68:1994: Environmental testing - Part 2-68: Tests - Test L: Dust and sand
• IEC 62716:2013: Ammonia (NH3) Corrosion Testing
• IEC 62804-1:2015: Photovoltaic (PV) modules - Test methods for the detection of Potential-Induced Degradation.

11. Types of PV Modules Technology
Commercially available technology:
Solar Cell Technology
Silicon Crystalline cells
Monocrystalline
Polycrystalline
Thin-film cells
Amorphous Silicon(a-Si)
Cadmium Telluride(CdTe)
Copper-Indium gallium
di-selenide(CIGS)

12. Types of PV Modules Technology (There are three types of PV cell technologies dominating)
Lab efficiency: 26%
Field efficiencies of 18 – 22.5%
Maximum capacity 710 Wp
Lab efficiency: 22%
Field efficiencies of 15 – 19%
Maximum capacity 500 Wp
Lab efficiency: 22.1%
Field efficiencies of 6 – 18%
Maximum capacity 450 Wp

13. • If a cell is damaged or shaded, the current from the whole
module is reduced. This reduces the current of the whole
string.
• If a cell is damaged, the whole array can force current
through this failure point, producing a significant
temperature rise in the cell, which then leads to further
damage of that cell. This phenomenon is called ‘hot-spot’
formation and results in reduced array output. In the
extreme case of an open circuit cell, the array output will
be zero.
• The effect of the above situation can be minimised by
the use of bypass diodes and/or blocking diodes.
PV Module Protection

14. PV Module Protection
2. Blocking Diodes
• Blocking diodes (or series or isolation diodes) can prevent current from flowing backwards through the
modules at night and to prevent current flowing into a faulty parallel string.
• Blocking diodes are used in systems that contain an external power source, such as a battery, which can
possibly cause reverse power flow at night.
• They are less commonly used in system today as many charge controllers now also have inbuilt functions
preventing reverse current.
Blocking diode in series with a PV module.

15. Module Reliability
• Modules generally last for around 25 years. However, throughout this time they will be exposed to numerous
internal and external factors that affect this value: weather exposure, yellowing, micro fractures, hot spots and
potential induced degradation.
1. Weather Exposure
• Solar PV systems should be installed in locations that receive suitable solar
radiation. These locations will also experience other weather conditions that
modules must be resistant to, including:
□ Rain and Humidity
□ Hail
□ Thermal Cycling
□ Wind and Snow

16. Module Reliability
Yellowing:
• Module manufacturing involves solar cells being laminated to glass using encapsulant
of EV
Awhich may discolour over time known as yellowing
• It is likely to affect all of the module in a batch
• It do not effect the module performance but due to discolouring of EV
Alayer become
opaque and prevent light from hitting the cells
Microfractures:
• Microfractures are discrete cracks occurring in the cells used in a PV Module
• These cracks can be caused by localized pressure and can occur during module
manufacturing or during installation
• It can effect the performance of the module.

17. Generation Loss:
1. Operating Temperature
2. Dirt or Soiling
3. Tilt angle and orientation
4. Shading
Losses in PV System
Losses in
PV system
17

18. Losses in PV System
Loss due to temperature of the PV module:
• As cell temperature increases, the short circuit current marginally
increases
• As cell temperature increases, the open-circuit voltage decreases
• As cell temperature increases, the maximum power decreases
• These temperature coefficients can be used to determine the
change in voltage, current and maximum power when the cell
temperature is above or below STC temperature.
Module Type Typical Power temperature coefficient
Mono-crystalline - 0.38% to - 0.40%/oC
Poly-crystalline - 0.45% to - 0.50%/oC
Thin film - 0.2% to – 0.3%/oC
18

19. Losses in PV System
Loss due to Dirt (Soilage)
• Are the modules installed at an angle of elevation so that
rain will wash any dirt or debris away?
• Is there pollution that will form a film on the glass?
• Is the site dusty?
• How often does it rain?
• Is water used for cleaning the module is hard?
Example of soiling along the bottom edge of a PV module
19

20. Loss due to shading
1. If enough of the array is shaded,
then, MPPT voltage may drop
outside the inverter voltage window
2. If a string inverter is used and there
are multiple solar module strings, the
shading on one string may affect the
output of the other strings
Losses in PV System
20

21. Orientation and tilt angle for solar modules
Loss due to orientation & module tilt angle
• The amount of irradiation available to the PV array
will be affected by their tilt angle and orientation.
Solar data for the specific site may be available at a
range of orientation and tilt angles, or tables with
radiation ‘efficiency’ factors relative to irradiance on
the horizontal plane or optimal tilt for the latitude can
be used to determine the actual incident irradiation.
• For Off-Grid PV systems, the tilt angle is decided
based on a comparison of the available irradiation
and the load demand of a site for each month.
Losses in PV System
21

22. Types of Inverter
DC to AC Conversion: Inverters
Solar Inverter
Off-grid Inverter
Grid connected
Inverter
Hybrid Inverter
22

23. 9
Image Credit: Arin Energy
Off-Grid PV system
Types of Solar Inverter
23

24. 10
Image Credit: Arin Energy
On-Grid PV system
Types of Solar Inverter
24

25. 11
Image Credit: Arin Energy
Hybrid PV system
Types of Solar Inverter
25

26. Following parameters are considered while estimating load
requirement
• Type of load (AC or DC)
• Number of Loads
• Power rating of each load
• Hours of operation
• Energy requirement per day(wh/day)
Load estimation

27. Load estimation
Households
Load
Wattage Hr/day Number Wh
LED 4 5 2 40
FAN 40 8 1 320
TV 150 5 1 750
Total energy required per day
1,110
wh/day
SME loads Wattage Hr/day
Number of
business
Wh
Milling and
pressing
1100 3 1 3,300
Welding
workshop
2500 6 1 15,000
Total energy required per day
18,300
wh/day

28. LOVEROOP SINGH,
Project Manager, PEDA
Ex. Scientific officer, MoE(erstwhile MHRD)
#9878837500
(loveroop.singh91@punjab.gov.in)
THANK YOU