A

MAJOR PROJECT REPORT ON

Simulation Model of Grid Connected Rooftop Solar

Power Plant

BECHALOR OF ENGINEERING
In
ELECTRICAL ENGINEERING

By

Prateek Shrivastava (0901EE15079)

Neetesh Sharma (0901EE151069)
Vaibhav Agarwal (0901EE151115)
Himanshu Pandey (0901EE151050)

Under the guidance of

DR. A.K. Wadhwani

Professor

Department of Electrical Engineering

DEPARTMENT OF ELECTRICAL ENGINEERING

MADHAV INSTITUTE OF TECHNOLOGY & SCIENCE,
GWALIOR (M.P.) – 474005
2018-2019

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 Madhav Institute of Technology & Science,
Gwalior (M.P.)
(A Govt. Aided UGC Autonomous & NAAC Accredited Institute,
Affiliated to R.G.P.V, Bhopal)

CANDIDATE’S DECLARATION
We hereby declare that the work presented in this project entitled “Simulation model of
grid connected rooftop solar power plant” which is being submitted in the partial
fulfillment of the requirement for the award of degree of Bachelor of Engineering in
Electrical Engineering is an authentic record of our own work carried out under the
guidance of Dr. Arun Kumar Wadhwani Professor, Electrical Engineering Department.
The matter presented in this project has not been submitted else where by us for the award
of any other degree/diploma.
Student1: Prateek Shrivastava (0901EE15079)
Student2: Neetesh Sharma (0901EE151069)
Student3: Vaibhav Agarwal (0901EE151115)
Student4: Himanshu Pandey (0901EE151050)

Date:30-april-2019
Place: Gwalior

This is to certify that the above statement made by the candidates is correct to the best of
my knowledge and belief.
Guided by

DR. A.K. Wadhwani

Professor

Department of Electrical Engineering

MITS, Gwalior
Approved by Forwarded by

Dr. Laxmi Srivastava Dr. R. K. Pandit

Professor and Head Director MITS, Gwalior
Department of Electrical Engineering
MITS, Gwalior
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 TABLE OF CONTENT
1. Introduction ………………………………………………………………………………………………………………
1.1 What is Solar Energy ………………………………………………………………………………………………
1.2 How Solar Energy is Converted to Electricity …………………………………………………………
1.3 How Solar Panels Work …………………………………………………………………………………………
1.4 Solar radiations ………………………………………………………………………………………………………
1.5 Considerations to Keep in Mind Before Installing Solar Panels ………………………………
1.6 Environmental Impact……………………………………………………………………………………………
1.7 Potential Overview…………………………………………………………………………………………………
2 Literature Review ……………………………………………………………………………………………………….
3.Software Development ……………………………………………………………………………………………….
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
3.10
4. Results & Discussion ……………………………………………………………………………………………….
5. References ……………………………………………………………………………………………………………….

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 CHAPTER 1
INTRODUCTION

1.1 Solar Energy Introduction :

Scientific findings showed that the earth intercepts 173 trillion terawatts of solar power.
That is ten thousand more power than the entire world population utilizes. This shows
that the sun is the most plentiful source of energy on the entire globe and that it can be
used as the most reliant source of energy.

The world’s electrical needs have been fulfilled by fossil fuels like coal, natural gas, and
oil. On the other hand these energy sources have two main negative impacts:

These play a bigger role in acid rain and global warming pollution, which negatively
impacts many plants, animals, and humans in the ecosystem.
Few countries have full access to fossil fuel-based energy resources, which can lead to
global economic and political instability.

Solar energy is the best alternative , which is a renewable resource, meaning it will not
become unavailable. It provides an unlimited, steady supply through time. Solar energy
is also a green source of energy because it does not emit pollutants during the energy
production process and keeps the environment clean.

“Solar energy is produced by the sun in the form of heat and light”. It is the most
renewable and readily available source of energy on planet Earth. The fact that it is
available in plenty and free makes it one of the most important of the non-conventional
sources of energy. Solar energy has been used by human being since ancient times by
using simple magnifying glasses to concentrate the light of the sun into beams so hot they
would cause wood to catch fire and even in solar cookers.

Solar energy can be used to convert it into electricity or it can be converted into heat
energy. Solar energy is energy harnessed from the sun. It’s harnessed in 2 main ways:

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1 Through production of electricity

This technique utilizes Solar Photovoltaic (PV) modules or solar cells that convert the
sun’s energy into electricity. Photovoltaic modules produce electricity from the sun rays
through an electronic process that naturally occurs in particular material types known as
semiconductors.
Electrons inside semiconductor materials are excited by solar rays and allowed to travel
via an electrical circuit, sending power to the grid or directly powering electrical devices
or storing power in the batteries . This form of energy can be used to power solar street
lights, calculators or traffic signals. They are useful in remote locations that are not
connected to electricity grid

2 Solar collector devices

A solar thermal collector harnesses heat by absorbing the sun rays. This technique
harnesses the sun’s energy to heat up water (solar hot water panels) for home and personal
use such as water heaters, hot tubs, and swimming pools. The solar power plants utilize
the collectors to produce electricity by heating a liquid to turn a turbine which is
connected to a generator. Simple collectors are normally utilized in commercial and
residential buildings for space heating.

The solar energy converted into electricity can be instantly used to power lights or many
other appliances. It can be stored in batteries for future use or can be given to grid. Solar
cells generate DC type electricity. However, it can be converted into AC using a device
known as an inverter. Solar energy that is converted into heat energy for the purpose of
water heating can be utilized or can be stored as hot water in tanks to use it later. Solar
energy is very useful in the remote locations and villages where connectivity of grid is
not feasible.

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1.2 Conversion of Solar Energy into Electricity :

The first step to convert solar energy to electricity is to install Photovoltaic (PV) cells or
solar cells. Photovoltaic means light and electricity. These cells collect the sun’s energy
and convert it into electricity through an electronic process. These solar cells are made
of semiconductor materials that show photovoltaic effect, meaning when the sun rays
strike the Photovoltaic cell, the photons of light excite the electrons inside the cell and
triggering them to start flowing, ultimately producing electricity.
To buy solar panels there are different options available in the marketplace. Here is an
outline of the main one’s with feasible cost and high efficiencies:

• Polycrystalline – This utilizes Multi crystalline Silicon

• Monocrystalline – this has high efficiency
• Thin Film – Typically bigger in size and a lot more efficient during the day

The disparity between the material used to manufacture monocrystalline and

polycrystalline lies in the constitution of the silicon substrate utilized to manufacture
solar cells and ultimately, solar panels. Accordingly polycrystalline implies numerous
crystals on the other hand monocrystalline implies a single crystal. The larger the crystal
sizes, the more efficient the solar cells, which explains the reason monocrystalline cells
are normally 10 – 15% more efficient than the polycrystalline crystals.

1.3 Working of Solar Panels :

Solar panel works by allowing photons, or particles of light, to knock electrons free from
atoms, generating a flow of electricity. It actually comprise of many smaller units
called photovoltaic cells. The solar panel should be mounted on an open area that is not
obstructed by trees or any installation. A roof is normally the best bet. It’s then wired into
the building through the inverter. The inverter is a device that converts AC (alternating
current) to DC (direct current). So, in this case, the direct current is the energy created by
the solar panels. This solar energy is converted into AC. The reason for converting the
direct current into alternating current is to enable the energy to be used by various home

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appliances and connect it to the grid or form a grid hybrid system to provide energy at
peak times.

1.4 Solar Radiation :

Incoming solar radiation from the sun, is modified as it travels through the
atmosphere and specifically known as air mass AM, average solar radiation
reaching earths surface is 1.5AM. Solar radiation is further modified by physical
features of an area and surface features and is intercepted at the earth's surface as
direct, diffuse, and reflected components. Direct radiation is intercepted on the
earths surface in a direct line from the sun. Diffuse radiation reaching earths surface
is scattered by atmospheric constituents, such as clouds and dust. Reflected
radiation reaching is reflected from surface. The sum of the diffuse, direct and
reflected radiation is called total or global.

1.5 Criterion for to Installation of Solar Panels :

Before taking any step to install solar panel in our home, make sure the solar power befits
us and our home. Then, ensure that sufficient sunlight is available in our locality. The
availability of solar energy varies considerably with how much sun an area receives. It
depends on hourly solar radiation, daily solar radiation and monthly solar radiation data.
If our area does not receive sufficient sunlight, investing in solar panels will not be the
best cause of action.

After examining that our area receives adequate sunlight, make sure installation space is
available. We’ve learned that solar panels are typically set on roofs of buildings. While
this is desirable, it’s not the only option. If you have an open space in your backyard, it
would be an ideal place for ground mounts. The backyard option is ideal for those whose
roofs are heavy shaded or not structurally essential for solar panels. It is compulsory to
know the local laws regarding solar panel installation to avoid getting into trouble with
the local authorities. We can get these information from our local solar energy consultant.

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1.6 Environmental Impact :

Solar energy is considered as one of the cleanest renewable sources of energy among
the available sources, however it has some environmental impacts. The manufacturing
of the photovoltaic cells requires silicon and produce some waste products to produce
that energy. Inappropriate handling of these materials may lead to hazardous exposure
to the environment and humans. Installing solar power plants may require large piece of
land that impacts existing ecosystems and environment. Solar energy does not pollute
the air and the atmosphere. It is found in infinite quantity and does not cause global
warming

1.7 Potential Overview :

The geographical location of Gwalior is given. With the solar tilt angle and solar monthly
radiation striking the city.

Madhya Pradesh

The Government of Madhya Pradesh(GoMP) has taken record of the impact for the
growing of climate changes at the local, national and global levels and taking steps to
lead to this, the GoMP has decided to use its vast potential for Solar energy. The state of
Madhya Pradesh has a high potential of Solar radiation with around 300 days of clear
sun and offers good sites with potential of more than 5.5 kWh/ sq.m./day for installation
of Solar based projects.
The state of Madhya Pradesh has started a pioneer movement towards adoption and
promotion of renewable sources of energy as a potential solution to the alarming energy
crisis and take charge by promotion of Solar projects in the state.

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Table 1.1 potential overview of Gwalior.

Tabel 1.2 Data from ISRO of Gwalior city.

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 CHAPTER 2
LITERATURE REVIEW

2.1 Introduction :
Solar energy from the Sun gives life to all living organism on planet Earth and human
beings. The existence of an atmosphere with greenhouse gases (GHG) between the Sun
and the Earth is responsible for the survival of human beings in the terrestrial region. The
Sun is the major renewable energy sources on Earth, which meet the needs of human
being. Solar radiation is treated as an electromagnetic wave with wavelength between
0.30 and 3 µm as well as photons in a visible wave length. These solar radiation are
trapped by the solar cells and converts it into electrical energy, which is fed to grid.The
following figure shows the block diagram of solar PV array connected to grid, using
converters and inverters.

Fig 2.1 Block diagram of Solar PV module connected to grid

2.2 Overview

In the building of integrated photovoltaic system’s various algorithms are carried out.
It’s performance reveal that an average losses of about 20%-25% in electricity
production. These losses are caused mainly due to partial shadows, mismatching losses
and variation in current-voltage (I-V) characteristics, difference in inclination of solar
surfaces, and temperature effects. These losses can be minimized by means of suitable
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electronics devices, a low cost high efficiency dc-dc boost converter and dc-ac converter
with net metering functions. Analysis on simulation of grid connected PV system were
proposed.

PV inverter, which plays a very important role in the operation of the PV system, is used
to convert dc power obtained from the PV array into ac power which would be fed into
the grid. The output of the PWM inverter can be improved by reducing its respective
harmonic content, and hence the size of the filter used and the interference due to the
switching action of the inverter. In recent times, multilevel inverters have become more
attractive due to their advantages over conventional PWM inverters.

In this system we have not used battery to reduce the cost of the system.

2.2 Net-Metering
In this system, we have a single new bi-directional meter. When we consume electricity
from the grid, the meter readings will move forward (positive); but, when we produce
electricity and send it to the grid, the meter readings shall move backward (negative).
Suppose we consume 10 units per day and produce 8 units, our meter will show a reading
of 2 units. And if we use 10 units of electricity and produce 12 units, then our meter will
show -2 units. Our bill at the end of month will be based on net units consumed/produced.
If we generate extra electricity in any month, the surplus is carried over to the next month
and netted. At the end of a year, if our total production is more than, that what we
consumed, then we will get paid for the next surplus electricity produced at the cost
decided by our state’s electricity regulatory commission

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 CHAPTER 3
SOFTWARE DEVLOPMENT

3.1 Indroduction :
This model proposes a method of modelling/simulation of rooftop grid connected solar
Photovoltaic (PV) arrays. The main objective here is to achieve a circuit based simulation
model of a solar Photovoltaic (PV) power plant in order to estimate the electrical power
output of the practical rooftop solar power plant with respect to change in environmental
parameters like irradiation and temperature. The proposed method is implemented in
MATLAB/Simulink environment and the results reveal the array output power, the
power has maximum pick with respect to the voltage for particular environmental
condition. The following model is implemented using simulation/Matlab.

Fig 3.1 Simulation Model

3.2 Description :

The above figure shows the simulation model of grid connected roof top solar PV module
with the concept of net metering .i.e. we calculate the net energy which the system pay
to the grid or get from the grid.

Following are the components of the model.

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3.2.1 PV array :

The basic element of a PV System is the photovoltaic (PV) cell, also called a Solar Cell. It
convert solar energy into DC electricity through photovoltaic effect.
To increase their utility, a number of individual PV cells are interconnected together in a
sealed, weatherproof package called a Panel (Module).
To achieve the desired voltage and current, Modules are wired in series and parallel into
what is called a PV Array. The flexibility of the modular PV system allows designers to
create solar power systems that can meet a wide variety of electrical needs. no matter
how large or small.
Table 3.1 of solar PV array.

Parallel strings Series strings Maximum power

66 5 318.354 x 71= 22578 W

3.2.2 Solar irradiation :

Solar irradiance (SI) is the power per unit area received from the Sun in the form
of electromagnetic radiation in the wavelength range of the measuring The solar
irradiance integrated over time is called solar irradiation, insolation, or solar exposure.
Irradiance may be measured in space or at the Earths surface after atmospheric
absorption and scattering.

Fig 3.2 of Irradiance and temperature.

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3.2.3 DC Chopper :

A chopper is a device that converts fixed DC input to a variable DC output voltage

directly. Essentially, a chopper is an electronic switch that is used to interrupt one signal
under the control of another.

Fig 3.3 of Dc Chopper

Pulse width modulation

The output dc voltage can be varied by the following methods. Pulse width modulation
control or constant frequency operation.

In pulse width modulation the pulse width (tON ) of the output waveform is varied
keeping chopping frequency ‘f’ and hence chopping period ‘T’ constant. Therefore
output voltage is varied by varying the ON time, tON . Figure shows the output voltage
waveforms for different ON times. Íß

Fig 3.4 Graph of Pulse Width Modulation

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3.2.4 Three phase voltage source inverter :

When a DC source (voltage or current) is available an inverter can be used to convert the
energy to an AC source, To invert the direct current voltage to alternating current voltage
the opposite process of the rectifying process should be done. There are several methods
to steer the inverter bridge but here the description is narrowed to the 180°-inverter
principle.
The circuit configuration of a three-phase inverter as shown in Figure consists of three
poles. Each pole is switched independently of each other, and the two switches in each
pole are alternately switched. However, to achieve three-phase voltages, each pole
voltage should be displaced from each other by 120 electrical degrees. In such switching,
three of six switches are always turned on, and their switching sequence goes on in the
order of switch numbers shown in Fig. such as …123, 234, 345, 456, 561, 612 and back
to 123.

Fig 3.5 Circuit Diagram of three phase voltage source inverter.

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 (a)

(b)

Fig 3.6 (a)Graph of Three Phase Inverter,

(b) Figure of three phase inverter.

3.2.5 Triggering circuit of inverter (VSC) :

The DC bus voltage is regulated by three level Voltage Source Convertor (VSC) and it
also keeps power factor at unity .it uses the control system which further consist of two
control loop. one is external control loop and another is internal control loop . The DC
link voltage is regulated by external control loop whereas the active and reactive current
components are regulated by an internal control loop. To control the current of inverter
of each phase we use PI compensator .here we use three level VSC to reduce harmonic
content in output voltage instead of two level VSC.

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 Fig 3.7 VSC main controller.

Id current reference is the output of external control loop and Iq current is set to zero
in order to maintain power factor at unity.
Vd and Vq voltage are outputs of current loop, which are converted to three modulating
signals .these modulating signals are used by three –level PWM pulse generator.
The synchronization control over the grid voltages is achieved by the three –phase locked
loop(PLL).

Fig 3.8 VSC.

3.2.6 Three phase transformer (100KVA,260V / 25KV) :

The three phase setup transformer is used to raise the voltage level from 260 Volt to
25KV in order to maintain voltage matching with grid system .the input of three phase
transformer is connected from inverter system’s output .

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 Fig 3.9 Transformer.

3.2.7 Interconnected Grid System( 25KV,2500MVA) :

The connection of several generating stations in parallel is known as interconnected grid

system .
Grid interconnection of photovoltaic power generation system has the advantage of more
effective utilization of generated power. However, the technical requirements from the
utility power system grid side and PV system side need to be satisfied,to ensure the safety
of PV installer and the reliability of utility grid .
Conditions for grid interfacing or synchronizing the SPV system with a grid are ,
1. Phase sequence matching-Phase sequence of SPV system with conventional grid
should be meshed.
2. Frequency matching –Frequency of the SPV system should be same as grid
.Generally grid is of 50 Hz frequency
3. Voltage matching -voltage level of both systems should be same.

Fig 3.10 Interconnected Grid.

Conclusion :
The proposed simulation model of rooftop solar PV module gives maximum power
output under specific environmental condition. Here we do the detailed study of each
component of model.

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 CHAPTER 4
RSEULTS & DISCUSSIONS
4.1 RESULTS :
There are two meters connected in our simulation model one is called import
meter another is export meter. Now from these we can conclude that the reading
of net meter are ,
Export meter reading – Import meter reading =power fed to the grid from solar PV
module.
So now we can determine what amount of energy is fed to the grid from solar power.
That much of tariff will differ from conventional power tariff.

Table 4.1 Net Power

s.no Time Temperature Irradiance Power Power Power
(sec) c generated by grid consumed
by solar by load
module
1 0.5 38 1000 85.45 -14.60 100.06
kw kw kw
2 1 38 2000-1000 118.01 11.92 100
kw kw kw

Table 4.2 Net Energy

s.no Time Temperature Irradiance Energy Energy Energy
(sec) c generated by grid consumed
by solar by load
module
1 0.5 38 1000 43.32 -6.68 50
kwh kwh kwh
2 1 38 2000-1000 111.92 11.92 100
kwh kwh kwh

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The following graph is for power with Grid ,Solar PV and Load respectively. This shows
that load consumes 100KW power which is full filled by 85.45 KW from solar musule
and 14.55 from the grid.

Time(sec)
Graph 4.1 Power for 0.5 sec.

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The following graph is for Energy with Grid ,Solar PV and Load respectively. This shows
that load consumes 50 kwh Energy which is full filled by 43.32kwh from solar module
and 6.68 from the grid.

Graph 4.2 Energy for 0.5 sec.

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The following graph is for power with Grid ,Solar PV and Load respectively. This shows
that load consumes 100KW power which is full filled by 118.01 KW from solar module
and 11.92 KW is fed into the grid.

.
Graph 4.3 Power for 1 sec.

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The following graph is for Energy with Grid ,Solar PV and Load respectively. This shows
that load consumes 100 kwh Energy which is full filled by 111.92 kwh from solar module
and 11.92 is fed to the grid.

Graph 4.4 Energy for 1 sec.

4.2 DISCUSSIONS :
Here net power and energy are calculated with the help of net metering , we have a load
of 100kw. Which is connected between solar module output and grid of 25kv 2500Mva.
We get result as above .when power generated by PV module is more than the power
consumed by load then excess power goes to grid, On the other hand if the power
generated by PV module is less than the power consumed by the load the the load
consumes remaining power from the grid .

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 CHAPTER 5
CONCLUSION & FUTURE SCOPE

5.1 CONCLUSIONS :

In this paper, the installation of solar panels on roof tops is being proposed to reduce the
energy consumption from the non renewable sources. Solar power has the flexibility that
it can be used anywhere and everywhere. The work is to be carried out in a college
building with an aim to cater to the electricity demand through the solar power. It was
concluded that the initial set up of solar power generation is costly but it is a viable
solution for sustainable operation of the building.
It can be a great method to not only reduces electricity bills, but also the generated power
can be routed to places which have a shortage of electricity.

5.2 FUTURE SCOPE :

Generation of solar energy has vast scope in India. The geographical location of the
country has its large benefits for generating solar energy. Solar Energy generation that
contribute largely in Green Energy Production to help to reduce the Climatic Changes in
the country and full fill the deficit demand of power generation.
Improvement to this project can be made by reducing the harmonics generated during
synchronization with the grid.

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 REFERENCES

1. https://ieeexplore.ieee.org/Xplore/home.jsp
2. https://www.wikipedia.org
3. https://www.mathworks.com
4.

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