The IEEE 7 th Technical Exchange Meeting April 18-19, 2000 Overview Of The Photovoltaic Power System Mohammed A. Al-Jofaish Saudi Aramco/Consulting Services Department
Presentation’s Outline u Photovoltaic (PV) Theory u PV System’s Components u Design Strategy & Considerations u Applications u Advantages & Disadvantages u Summary
Photovoltaic Theory Photovoltaic Theory p-Silicon n-Silicon
PV System’s Components u Solar Array u Storage Batteries u Charge Controller (Regulator) u Inverter (For AC Systems Only)
Photovoltaic System Battery PV Array Charge Controller
PV System’s Components Load Photovoltaic Array Battery Bank Inverter (AC loads) Charge Controller
Design Strategy PV Array: u Type Selection u Sizing u Climate & Geographical Location Considerations
Design Strategy PV Array Types:
Design Strategy PV Array Sizing: u De-rating Factors X Aging 20% X Dirt Accumulation 20% X Future Growth 10% u Recharging Period 4 days u System Voltage u Load Profile
Design Strategy PV Array Climate & Geographical Location: u Solar Insolation (Radiation) u Effective Sun Hours u Array Orientation X Direction (Toward South) X Tilt Angle l Fixed Angle (Latitude + 10 Degrees) l Adjustable (Sun Tracking)
Sun Insolation 5.0 kW/m 2 /day 5.0
Photovoltaic Arrays Field
Design Strategy Storage Battery: u Type Selection u Sizing u Environment Considerations
Design Strategy Storage Battery: Type Selection (cyclic application) u Tubular Plate Lead-Acid u Pocket Plate Nickel-Cadmium
u System Voltage u Load Profile u Backup Time (Autonomy) 7 days u De-rating Factors Lead-Acid Ni-Cad Aging 25% 10% Temp. Compensation19%14% Design10%10% Design Strategy Storage Battery: Sizing
u No Temperature Control Temp. Compensation u Outdoor Battery Enclosure u Shade Requirement Design Strategy Storage Battery: Environment Considerations
Design Strategy Charge Regulator: u Type Selection X Single Stage X Multistage u Sizing (Array Rated Currents) u Temperature Compensation X Lead-Acid-5mV/ o C/cell X Ni-Cad-3mV/ o C/cell u Low Voltage Disconnect X Lead-Acid1.85V/cell X Ni-Cad1.15V/cell
Applications u Cathodic Protection Systems u Telecommunications Systems u SCADA Systems u Offshore Platforms u Highway Lighting u Remote Homes u Irrigation Water Pumping
Advantages u Reliable u No Fuels u Low Maintenance u Long-term Savings u No Pollution u No Noise $ $ $
Disadvantages u High Initial Cost (3-10 times) u Specialized Maintenance X Batteries X Power Conditioning Equipment u Large Space $ $ $ $ $ $
Summary Despite the disadvantages of the photovoltaic power, there are many applications where the PV is the only choice that is economically justifiable.
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