Power point presentation on SOLAR POWER BASED UPS

SOLAR--BASED SOLAR  -BASED UNINTERRUPTED POWER SUPPLY (UPS)

By C. Krishna Sunder (07841A0222) I. Sir Sirees eesha ha (07 (07841 841A02 A0218 18)

ABSTRACT y

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Photovoltaic (PV) solar cells are semiconductor devices that convert sunlight into direct d irect current (DC) electricity. electricity. Groups of PV cells are electrically configured into modules and arrays. With the appropriate power conversion equipment, PV systems can   produce alternating current (AC) compatible with any conventional appliances, and operate in parallel with and interconnected to the utility grid.

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PV ARRAY + BALANCE OF SYSTEM COMPONENTS = PV SYSTEM

BLOCK DIAGRAM OF SOLAR BASED UPS

PV

ARRAYS

CHARGE CONTROLLER

BATTERY

DC LOAD

INVERTER

AC LOAD

PV TECHNOLOGY y

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 Photovoltaic (PV) solar cells as they are often referred to, are semiconductor devices that convert sunlight into direct current (DC) electricity. A  MODULE  is the basic building block of photovoltaic systems. Groups of modules can be interconnected in series and/or parallel to form an  ARRAY .

Working of PV cell

TYPES OF PV CELLS y

There are four types of PV cells x

Multicrystalline silicon

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Monocrystalline silicon

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Ribbon silicon

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Thin-film

PHOTOVOLTAIC MODULE PERFORMANCE y

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Electrical characteristics of photovoltaic modules determine the compatibility with loads. I-V (current-voltage) curve gives the electrical characteristics. The current-voltage (I-V) curve is based on the module being under  standard conditions of sunlight and module temperature. It assumes there is no shading on the module.

A TYPICAL CURRENT VOLTAGE CURVE

FACTORS EFFECTING OUTPUT OF MODULES

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Tilt

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Shadowing

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Temperature of the module

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Orientation

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Sunlight conditions

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Less than one sun will reduce the current output of the module by a  proportional amount.

I-V Curve for an Unshaded Module and for a Module with One Shaded Cell.

I-V Curve for a Module at 250C (770F) and 850C (1850F)

PHOTOVOLTAIC ARRAYS AND MOUNTING

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Modules can be connected in series, parallel, or both to increase either  output voltage or current to form Arrays.

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Combinations of series and parallel connections are also used in arrays.

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Different types of arrays are developed with different features.

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Various ways in which a PV array can be mounted on a building. 

Bracket mounting

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Pole mounting

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Structure mounting

SOLAR CHARGE CONTROLLER  y

The primary function of a charge controller in a stand-alone PV system is to maintain the battery at highest possible state of charge while protecting it from overcharge by the array and from over discharge by the loads.

The important functions of solar charge controller are: 1.

Prevent Battery Overcharge

2.

Prevent Battery Over discharge

3.

Provide Load Control Functions

MAXIMUM POWER POINT TRACKING(MPPT)

THERE ARE THREE TYPES OF CHARGING PROCESSES

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Bulk charge

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Absorption charge

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Float charge

UN--INTERRUPTIBLE POWER SUPPLY UN

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Rectifier & battery charger 

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Battery

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Inverter 

BATTERIES

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 primary functions of a storage battery in a PV system are to: - Energy Storage Capacity and Autonomy. - Voltage and Current Stabilization. - Supply Surge Currents.

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Two types of storage batteries: Primary and Secondary.

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There is no ³perfect battery´ suitable for PV systems in general.

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Typical batteries used in stand-alone PV systems can deliver up to several thousand amps under short-circuit conditions, requiring special precautions.

BATTERY SELECTION CRITERIA y

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Selection of battery depends upon very many factors and will be influenced  by system management and climatic conditions. Special requirements made of the battery in operation can be broadly classified according to : 1. The operating time per year. 2. The type of loads (high or low power drain). 3. The number of cycles per week.

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In general, transparent housings should be preferred.

FACTORS EFFECTING BATTERY PERFORMANCE

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Corrosion

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Battery Gassing

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Sulfation

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Stratification

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Temperature

WORKING OF SOLAR BASED UPS SYSTEM

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Two types of PV systems

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GRID CONNECTED PV SYSTEMS

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STAND ALONE PV SYSTEMS

GRID CONNECTED PV SYSTEMS y

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Operate in parallel with and interconnected with the electric utility grid. Back-feeds the grid when the PV system output is greater than the on-site load demand.

GRID-INTERTIED SOLAR  GRIDSOLAR--ELECTRIC SYSTEMS WITH BATTERY BACKUP

STAND ALONE PV SYSTEMS

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Operate independent of the electric utility grid.

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The load only operates during sunlight hours.

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For maximizing the power transfer from the array to the load, impedance matching is to be optimized. Optimum matching for resistive loads can be as high as 94.34% at 25 C. Optimum matching factor for electrolytic loads is 99.83% at 25C.

ECONOMY OF SOLAR BASED UPS y

Based on two factors - Energy payback time - Energy returned on energy invested (EROEI)

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Another factor ± Grid parity

COST COMPARISON OF SAPV PANELS VERSUS THERMAL

S.NO

Functions

SAPV ( Euro million)

1

Installation cost 17 104.35

Thermal ( Euro million) 12 274.44

of Power Plants

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Transmission

 Nil

5521.45

Nil

5809.37

and distribution

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Production cost

ADVANTAGES y

Saves your money

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Environmentally friendly

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Independent/ semi-independent

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Low Maintenance

APPLICATIONS y

Remote weather monitoring system.

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Remote communication system.

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Satellite communication.

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Solar power based transport system.

CONCLUSION

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High

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The excess generated power can be pumped in to the grid.

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life of the equipment.

Per unit cost is much less when compared with the power supply companies. Power can be supplied to both DC and AC loads.