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A. SOLAR PHOTOVOLTAIC
POWER PLANTS
The islands of Lakshadweep receive abundant sunlight throughout the
year except for a couple of days during monsoon that provides an ideal
opportunity for the use of solar power in the islands. In this
scenario, the Electricity Department, nodal agency for the
implementation of NRSE systems in these Islands decided to try
SPV systems for Power Generation. Initially the smallest island Bitra was
surveyed and a 5 kWp SPV Plant was set-up during 1988. Based
on the successful operation,
the same was
augmented
to 25 kWp in 1993, a 10 kWp SPV Power Plant was installed in 1996 at
Bangaram Island and a 50 kWp SPV Power Plant in Kadmat Island during
1998.
These
plants were stand alone SPV Power Plants, i.e. the power from the PV
array was used to charge a battery bank and this power was converted
to AC and used to power the loads at night. Apart from these power
plants, solar PV street lighting systems have also been installed in
the islands and solar lanterns have been distributed to individual
houses. With advances in technology, Grid Interactive SPV Power plants
which can be synchronized with the Diesel Grid on the islands has also
introduced. As a
demonstration project, with the financial assistance of Ministry of
Non-Conventional Energy Sources, a 100 kWp Grid Interactive Solar Power Plant was
installed at Kiltan island in the year 2000. Subsequently MNES sanctioned another 100 kWp
Grid Interactive SPV
Power Plant for Minicoy island which was also commissioned in the year 2000.
The successful operation of these SPV grid
interactive plants emboldened the Department to embark on a major
programme of providing electricity through Solar Power Plants to the
various islands. Surveys were conducted in all the
islands and proposal was submitted to MNES . During March 2001, the
Ministry sanctioned an ambitious project of 700 kWp of SPV Power Plants.
This project envisages installation of 7 Nos. of 100 kWp SPV Power
Plants in seven islands. The brief system description is given below:
100 kWp SPV grid
interactive Solar Photovoltaic Power Plant
The 100 kWp SPV grid interactive Power Plant
consists of a PV array generating electricity and supplying
loads through Power Conditioning Units (PCUs) and a Data
Acquisition system provides system information.
The 100 kWp PV array consists 1440 nos. of 70 Wp PV modules
mounted on 72 structures. The PV modules are mounted facing
north – south and tilted at an angle equal to the latitude of
the site.
The DC power generated by the SPV array is fed to two nos. of
Power Conditioning Units (PCU) each rated for 50 KVA. Here the DC
power generated by the SPV array is inverted to synchronized 3 –
phase AC power and fed to the grid through AC Distribution Board
containing isolator, meters etc. The PCUs employ digital Phase
Lock Loop (PLL) technique for synchronization and PWM technique
for inversion.IGBT devices are used for this
purpose so that switching
losses are minimal and hence higher conversion is achieved. The
Maximum Power Point Tracking (MPPT) control provided enables the
PV modules/ array to operate at the maximum power point to obtain
optimum output from the array. The efficiency of the inverter is
above 90% between half to full load and the harmonic distortion is
less than 3%. The inverter uses auto – synchronizer so that
changeover from grid to PV or vice-versa is bumpless i.e. has no
effect on the load.
Grid synchronization from the solar PV modules is achieved by
continuously monitoring the grid voltage and frequency and
comparing with the standard 3 – phase waveform generated in the
micro-controller. Islanding problem is overcome by sensing the
grid current in the feedback loop which shuts off pulses to IGBT
devices, thus isolating the inverter from the grid. The inverter
output frequency is locked too the grid frequency between 47 –
51Hz. The Data Acquisition System (DAS) collects the data at
programmable interval of the minute minimum upto 24 hours. The DAS
has following features.
Integrated logging system with extensive metering of supply
resources.
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Historic data logging including summation
and Historic event logging. |
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Recording periodically grid and inverter
parameters viz: AC voltage, Power, Power Factor, frequency
etc. |
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Recording DC link parameters such as link
voltage and current |
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Access to the integrated "SCADA"
components via a computer enabling event logging of all
system status changes and system faults as they occur. |
SPV Power Plants in Lakshadweep
|
Sno |
Island |
Date of Commissioning
|
Installed Capacity kWp |
|
1 |
Kiltan |
02/03/2000 |
100 |
|
2 |
Minicoy |
27/11/2000 |
100 |
|
3 |
Agatti |
02/02/2002 |
100 |
|
4 |
Kadmat |
08/03/2002 |
150 |
|
5 |
Andrott |
31/03/2002 |
100 |
|
6 |
Kavaratti |
26/04/2002 |
100 |
|
7 |
Bitra |
20/01/2004 |
50 |
|
8 |
Kalpeni |
02/05/2004 |
100 |
|
9 |
Suheli |
02/05/2005 |
15 |
|
10 |
Bangaram |
09/06/2005 |
50 |
|
11 |
Chetlat |
02/03/2009 |
100 |
|
12 |
Amini |
09/05/2009 |
100 |
|
(Figures
are as on
01/09/2009)
Total |
1065 |
The 25 kWp stand alone system working at Bitra since 1988 is augmented
to 50 kWp in the year 2004. Since then entire load demand during day
time of the island is met from the plant. 10 kWp stand alone SPV power
plant at Bangaram is also augmented to 50 kWp Solar – Diesel (120 kW)
hybrid plant, perhaps it may be first of its kind in India.
CONCLUSION
The islands present a different set of logistical problems where power
generation is concerned due to their distance from the mainland. In this
scenario, the extensive of solar power has provided a solution by which
decentralized power can be generated near the users. This clean eco
friendly power provides an ideal fit for the power needs as well as
environmental considerations for these idyllic islands. The Lakshadweep
Administration has now decided to extend the use of renewables in the
islands, so that at least 20% of the total power demand is met by these
alternate energy sources initially and then progress to 100%
electrification through renewable energy.
B. OTHER ACHIEVEMENTS
4 units of 50 kg Fish Drier is installed at Caning Factory, Minicoy island.
50 Nos of Solar Photo Voltaic Street Lights purchased during 2008-09 is
installed at Kalpeni, Cheriyam, Kavaratti & Bangaram islands. 1500 Nos of
Solar Lanterns procured and distributed to the public as per MNRE scheme for
the year.
FUTURE PLANS
I. Solar Power Plant:-
100 kWp grid interactive SPV power plants at Kavaratti, Andrott & Minicoy
and 150 kWp SPV power plant at Kadmat will be augmented to such capacity, so
that these plants will be able to replace one of the Diesel Generating Sets
from operation during day time. 15 kWp stand alone SPV power plant at Suheli
will also be augmented to 50 kWp capacity. Another 50 kWp Stand alone SPV
power plant is in pipe line for Cheriyam island. Possibilities of stand
alone SPV power plants for largest single consumers is also being explored.
M/s Bharat Heavy Electrical Limited, Electronics Division, Bangalore is
entrusted with the preparation of Detailed Project Report for these plants.
II.
Wind Electric Generators:-
3 Nos of 250/220 kW Wind Electric Generators are proposed to be installed at
Kavaratti island. During windy monsoon season these WEG in operation will
replace one of the 400 kW DG set from operation, thereby reducing the
consumption of the Diesel for generation of electricity. Centre for Wind
Energy Technology (C-WET) Chennai is entrusted with the preparation of the
Bid Documents for the projects. The projects will be installed on turn key
basis with the operation & maintenance entrusted to the supplier for
five/ten years.
Wind monitoring stations of 50 M mast height are being installed at 6
islands to study the wind parameters to explore the viability of installing
WEGs at other islands.
III.
Biomass Gasifier Plant:
The existing 250 kW Biomass Gasifier plant at Kavaratti is being refurbished
with the assistance of MNRE & IISc. Dual fuel engine will be replaced with a
120 kWp Producer Gas Engine making the plant free from the use of Diesel for
power generation.
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