Solar PV System
Indian Market for Solar Power
The Jawaharlal Nehru National Solar Mission is a major initiative of the Government of India with active participation from States to promote ecologically sustainable growth while addressing India’s energy security challenge. It will also constitute a major contribution by India to the global effort to meet the challenges of climate change. The objective of the Mission is to establish India as a global leader in solar energy, by creating the policy conditions for its large-scale diffusion across the country as quickly as possible.
The Mission has set a target, amongst others, for deployment of grid connected solar power capacity of 100 GW by 2022 and is planned to be implemented in three phases with phase-1 by 2013, phase-2 by 2017 and phase 3 by 2022.
The plan of action to achieve the target of 100 GW by 2022 is under preparation which broadly consists of 40 GW Grid Connected Rooftop Projects and 60 GW Large and Medium Size Land based Solar Power Projects. No direct financial assistance is provided by the government for setting up solar power projects connected to the grid.
MNRE has established the Solar Energy Corporation of India (SECI) for handling the power procurement from the second batch of the JNNSM. SECI (MNRE)’s role would be limited to providing a subsidy known as Viability Gap Funding (VGF), which is basically a part payment, made by SECI to the project developer in order to make the project viable.
Solar Photovoltaic Systems
The word Photovoltaic can be broken down into two parts; photo and voltaic which means light and voltage respectively. Photovoltaic signifies electric voltage caused by sunlight. The photovoltaic system is the conversion of solar energy into electrical energy by using semiconductor cells. Crystalline silicon (SC) is used to manufacture photovoltaic cells from semiconductor materials.
PV power plants use solar photovoltaic modules to produce electric power. PV power plants also called solar parks are made up of thousands of PV modules, used to develop photovoltaic systems to produce large scale power either for grid integration or islanded mode. PV power plants produce electricity by converting solar energy directly into electricity via solar cells. The nameplate capacity of photovoltaic power plants differs from countries to countries. These variations are MWp (megawatt-peak) which refers the DC power produced at the array, MWAC is the ac power produced at inverter output and finally MVA known as mega volts-amperes.
The generation of Solar plant depends on many factors such as:
- Location
- Solar irradiation
- Climatic Conditions
Cables :
The size of the cables between array interconnections, array to junction boxes, junction boxes to PCU
etc shall be so selected to keep the voltage drop and losses to the minimum. The bright annealed 99.97% pure bare copper conductors that offer low conductor resistance, they result in lower heating thereby increase in life and savings in power consumption.
Components of the Solar Photovoltaic System
Solar Modules :
Solar module is the heart of a photovoltaic system. Many solar cells are wired together to form a solar module. They are composed of silicon having different structures based on which the solar modules can be of three types, namely monocrystalline, poly crystalline and thin film. Mono-crystalline solar cells are made of silicon ingots which are cylindrical in shape. They have highest efficiency but are the most expensive of all. Poly-crystalline cells are made of square shaped ingots and consist of small crystals. They are less expensive with a bit lower efficiency than the monocrystalline cells. Thin film cells are constructed by wedging several layers of photovoltaic material of minimum thickness onto a substrate such as glass or metal. They are least expensive but have lowest efficiency as compared to others. Poly-crystalline silicon solar modules will be used here owing to their lesser cost and good efficiency. The efficiency of the solar module will be approximately 16%.
- Easily Available to Any Module Manufacturer/ Supplier.
- Lead delivery time is much less compared to other Watt peak modules
- Price per Watt peak is the lowest compared to the other Watt Peak modules
Solar Inverters :
Inverters are used to convert dc power generated by solar panels into required ac power. The inverter must be large enough to handle the total amount of Watts you will be using at one time. For grid tie systems or grid connected systems, the input rating of the inverter should be same as PV array rating to allow for safe and efficient operation. Multiple MPPT inverters are used to get maximum power output from the inverters.
Module Mounting Structure :
The module mounting structure is designed for holding suitable number of modules in series. The frames and leg assemble of the array structures is made of MS hot dip galvanized of suitable sections of Angle, Channel, Tubes or any other sections conforming to IS:2062 for steel structure to meet the design criteria. All nuts and bolts considered for fastening modules with this structure are of very good quality of Stainless Steel. The array structure is designed in such a way that it will occupy minimum space without sacrificing the output from SPV panels at the same time it will withstand severe wind speed up to maximum 100 kmph.
Protection System :
a)Earthing
The array structure of the PV yard will be grounded properly using adequate number of earthing kits. All metal casing / shielding of the plant shall be thoroughly grounded to ensure safety of the power plant.
b) Lightning Protection
The SPV Power Plant shall be provided with lightning & over voltage protection. The main aim in this protection shall be to reduce the over voltage to a tolerable value before it reaches the PV or other sub system components. The source of over voltage can be lightning, atmosphere disturbances etc. Metal oxide variastors shall be provided inside the Array Junction Boxes. In addition suitable SPDs also shall be provided in the Inverter to protect the inverter from over voltage.
- Solar Thermal System
- Solar Pump System