1. The training mainly concern with the development of skilled manpower in the
area of Renewable Energy by having six months training on System Designing,
Sizing, Installation, Commissioning, and Maintenance of Solar Photo-voltaic
Systems at Central Electronics Limited, Delhi. Here I imparted extensive
theoretical/ practical knowledge about all the ingredients of a PV system i. e.
Solar Cells, Solar Modules, Charge Controller, Inverter, PCU (Power Control
Unit), Batteries and Cables etc.
The solar cells are the basic building block of the solar module. The process of
solar cell manufacturing is very simple first clean the silicon wafers by chemical
process using de-ionized water to remove impurities then preferential chemical
etching to make tiny pyramids (to increase the surface area) to absorb more
sunlight. Then we do the phosphorus doping to make the P-N Junction using
screen printing process. After that the plasma etching technique is there to
remove the N-material from the edges of the wafer. Then we do the anti-
reflection coating (ARC) of silicon di-oxide and then the front screen printing is
there for the collection of generated charge carriers. Then Ag-Al printing on back
side to make bus bar and aluminium printing on back side and hence the Solar
Cell is ready and now it will send for testing. There are different types of solar
cells available in the market like mono crystalline, multi crystalline and thin film
are differentiate according to the technique used for wafer manufacturing.
The operation of solar is same as the operation of the P-N junction. As because
there are three steps to produce the electricity from the sunlight. First is the
generation of charge carriers that is done by photons when photons emitted on
the surface of semiconductor. Then there is need to separate that charge carries
to produce the electricity so that is done by the p-n junction. And then there is
need of collection of charge carriers hence done by bus bars. The equivalent
circuit of solar cell consists of a source and a series resistance which is very few
ohms and a parallel resistance which is very high and a diode in parallel of the
source and a load.

2. The module manufacturing can be done by automatic module line
manufacturing or by manual. The basic raw materials required for module
manufacturing are:
 Solar Cell
 EVA (ethyl vinyl acetate) sheet
 Toughened glass
 Al Channel
 Copper strip/Band
 Tedlar sheet/ Back sheet
 Terminal box/junction box with or without lead attachment
The process of manufacturing modules is start with making the string of solar
cells then the toughened glass is cleaned and the EVA sheet is placed on the
glass and then the solar cells string is placed on the EVA sheet and then again
one EVA sheet is placed and then the tedlar sheet is placed on it. Then it will
send to a laminator and kept for 20-23 minutes. There are 5 modules can be
placed in the laminator for lamination. But also depend on the size of laminator
and modules. Then the laminated module will be cleaned and then the framing
and junction box is attached. And at the end it will tested at STC (Standard Test
Conditions). Before lamination the RFID tag should be placed inside the module.
Earlier it war place outside but from 1st
April 2013 it is mandatorily place inside
the module. During the training got the basic knowledge of 40MW automatic
Module manufacturing line. Before the manufacturing process the EVA gel
contain is to be tested, the tedlar sheet test also done and the toughened glass
strength test is done by placing an iron boll in the middle of the glass from 1
meter.
The parameters of solar cell and module. The parameters are Voc (Open Circuit
Voltage), Isc (Short Circuit Current), Im (Current at max. power), Vm (Voltage at
max. power), Fill Factor, Efficiency, Pm (Maximum Power). The efficiency and
the fill factor are most essential parameter to determine whether the cell or
module is better or not.
The Current Voltage (I-V) characteristics and Power Voltage (P-V) characteristics
of Module are essential to calculate the parameters of the module like Isc, Voc,

3. Pm, Im, Vm etc. The PV module is a constant current type device. As shown on
a typical PV Module voltage vs. current curve, current remains relatively
constant over a wide range of voltage.
There are different types of PV modules available in the market ranging from
1WP to 350WP. The module specification at NOCT (Normal Operating Cell
Temperature) and STC (Slandered Test Condition) to describe the module,
contain the information about the type of module like SPR E20, Pm, Voc, Isc, Im,
Vm, Module dimensions, Cell size, No. of cells, weight, efficiency and type of
cells used. The parameters differ from manufacturer to manufacturer.
The practical on PV modules and its various configuration like series and parallel,
I-V curve have been studied. The effect of shading and use of Bypass diode is
realized. The bypass diode is connected in the junction box of the module and it
is connected in the reverse biased as that of solar cell so that when the cells are
under shadow it will just bypasses the cells and hence no hotspot or heat there
so the module will be safe. Another types of diode is there that is blocking diode
that is used to connect for the protection of modules at the night time.
The batteries are most essential part of the solar system. The construction,
working, and testing of batteries is done practically and the effect of series and
parallel connection of batteries. First before connection the battery gravity is to
be checked. The specific gravity (Hydrometer) of battery should be 1225 and the
rating is C10. The capacity of batteries is given in Ah (Ampere hour). For testing
e.g. if it is 75Ah battery the rating is C10 then discharge the battery with the
current 7.5A till 10 hours. If the voltage will less than 1.85 V (per cell) then the
capacity is not what specified and if it is then the capacity what specified. The
battery sizing from home lighting system to solar power plant. Testing of LMLA
& VRLA batteries as per the MNRE guidelines.
Charge controller is a devices used to protect the battery from deep discharging
and over charging. The charge controller are differentiate according to the
current and voltage ration. The concept of connecting the charge controller is
BPL that is first connect the Battery to the charge controller and the Solar Panel
and at last the load. The charge controller used are simple or MPPT (Maximum
Power Point Tracking) type according to the requirement they are used. In the

4. practical the low, high cut off the battery and load cut off, idle current, efficiency
has been verified. The internal circuit diagram of the charge controller and its
switching for low and high cut off. Sizing of inverter according to the system
voltage and current.
The inverter is used to convert the D. C. electricity generated from PV modules
to A. C. Electricity to run the households. The inverter is to be chosen according
to its KVA rating. The inverter sizing includes the input voltage of the inverter,
output voltage of the inverter the KVA rating of the inverter etc. and the
specification includes some more parameters like sine wave or square wave,
Output phase, frequency, efficiency, THD, operating voltage range etc. There are
different types of inverters like grid tied inverter, inverter for stand-alone
system, inverter for hybrid systems. Testing of inverter as per the MNRE
guidelines. A DC to DC converter is used to convert the level of DC voltage to run
the different load.
The wire sizing is the most essential part for the system sizing. And before the
sizing we should know about wires. For large and long distance transmission of
power the aluminium wires are used. But the losses in this types are more so for
small distance the copper wires are used. The ampacity and voltage drop are
two main concern in sizing of the wires. The proper wire type and insulation is
to be selected for the system. In connection the colour sizing is also plays an
important role.
The structure design for the plant like 50x50x5 or 45x45x5 (L section other are
also available e.g. C, I section) and significance of various parameters in
designing.
Sizing, from a small home lighting system to solar power plant. That includes the
sizing of solar panels, structure designing, wire sizing, circuit breakers, fuse
rating, blocking diodes rating, battery sizing if it is stand-alone, inverter sizing,
charge controller sizing, transformer if it is a large power application i.e. grid
tied, Low tension panel, high tension panel, bus bar, ACDB, DCDB sizing. And this
sizing is done by considering the meteorological data after doing the site survey.
There are three types of plant there: stand-alone, grid tied with battery or
without battery, or hybrid system.

5. The solar street light system installation practice (9 W/ 11W) as per the MNRE
guidelines and the home light systems according to the MNRE guidelines.
The solar water pumping system designing as per the water requirement and
the total head. The pump (centrifugal or positive displacement) is to be selected
according to the head and according to the water requirement. Advantages of
the centrifugal and positive displacement pumps. Calculation of total dynamic
head for elbow and check valve. Calculation of solar modules and charge
controller according to the motor wattage and nominal voltage requirement.
The selection of the motor depends on the efficiency of the motor which is to
be calculated by total head, water requirement, wattage applied and a constant.
MNRE guidelines for Solar Water Pumping are most essential.
Apart from these we have learnt about the grounding in the power plant. There
are two types of grounding in the power plant. One is structure grounding and
another is the circuit grounding. There is a lighting arrester which is placed on
the top of the building which attract the lighting occurs form natural purpose.
This is very essential for the safety of the plant. We also tested the grounding of
the distribution line at CEL.
While installing the system we have to consider other several aspects. It is
important to select wires, connectors, over current protection devices such as
switch and fuses. But there are other aspects like to install these carefully for
reliable operation. And site selection, foundation structure for array, array
assembly, wiring procedure, battery assembly protection methods, grounding
procedures and control centre wiring.
The different stages of planning in the process of installation are transportation
plan, human needs plan, selection of tools, general considerations, site location
for arrays, foundation plan, array mounting, array assembly, pre-assembly/
wiring, field wiring, battery installation, wiring of control centre/ equipment,
commissioning and testing of the system, documentation preparation.
The 1MWP project at Kasna, Greater Noida is developed by CEL. This is a grid tied
power plant located in the area of 3.5 acres. This project is divided into two
unites. The total modules of 327WP are 3068. There are two inverter of 500KVA
each and input voltage rating is 450V to 1000V. SCADA Monitoring is there in

6. this plant. The transformer is used with LT side voltage is 270V and HT side
voltage is 11000 V which is send to the 11KV grid. The plant generates 5,000
units a day.
The 50KWP grid tied power plant at HHEC, Noida Sector 15 is installed by CEL.
This is a roof top project and divided into three units 10KWP, 20 KWP, 20 KWP.
There are two inverter of rating 20KVA and 30KVA the output from inverter
230V is connected to the LT panel of the building’s supply. The total modules for
this plant is 180 of 300WP the system voltage is 650 V and the system current is
40 A. there is no SCADA Monitoring units. There 18 modules are connected in
series that generates 650V. Hence the 10 strings are there.
The 100KWP stand-alone power plant is located at CEL and was installed by CEL.
There are a total of 620 modules of 165 WP. The plant is divided into two units
each of 50KWP. The system voltage is 340V the single units has a total of 310
modules and in this 10 modules are connected in series. Hence there are 31
strings are connected in parallel. The PCU of rating is 50KVA (2 PCU’s one for
each unit) and the input voltage range is 250VDC to 450VDC and the output
voltage is 230VAC. The total batteries cells are 240 (2 V and 1000Ah) for single
unit 120 batteries are there and all are connected in series so the total voltage
is 240 VDC. The circuit breaker is connected in each size of the PCU call DCDB is
DC circuit Breaker and ACDC the AC circuit breaker. The Microwave building load
is connected to this plant.
Other industrial visits are 10KWP at Jantar Mantar, Delhi which is a stand-alone
system and Sabderjan tomb, Delhi which is also 10KWP.
Other than these, can prepare DPR (Detailed Project Report), Proposal, the
layout of the plant, total design of the plant including from site survey.