25-08-2017, 09:32 PM
1460657341-SOLARPROJECTFINAL.docx (Size: 5 MB / Downloads: 7)
Abstract:This project deals with the designing of a PV system for a home considering different types of loads and the procedure to be followed keeping in mind different factors to be considered. PV systems can also include battery backup or uninterruptible power supply (UPS) capability to operate selected circuits in the residence for hours or days during a utility outage.
. FACTORS TO BE CONSIDERED:
• RELIABILITY
• COST
• PERFORMACE
There is a trade-off between these parameters. If the system is made complex,it becomes.Costly. But when the cost is kept under control, the designer must not sacrifice reliability. So an optimum balance of these three factors is to be achieved.
II. PROCEDURE:
• FLOOR PLAN
• LOAD DETERMINATON
• BATTERY SELECTION
• DETERMINING PV ARRAY SIZE
• SELECTON OF CHARGE CONTROLLER
• SELECTION OF INVERTER
• BALANCE OF SYTEM COMPONENTS
CHARGE CONTROLLER:
• More than 96% efficiency at full load in 12V and 24V systems
• Supports Wide Input Voltage Range: 15VDC - 44VDC
• Flexible design supports both 12V or 24V solar panels
• Output Current: 20A max
• Small Board Form Factor: 130 mm x 84 mm x 22 mm
The charge controller used is PMP 7605
SELECTION OF INVERTER:
The inverter selected has an efficiency of 95%.
The inverter ac voltage is 120V and dc voltage is 48V.
X. BALANCE OF SYSTEM COMPONENTS:
A germanium or schottky blocking diode are preferred over silicon diodes
WIRE SIZES:
#8 USE-2 insulated copper wire is used to keep the voltage drop below 2%. # 10 can be used but the VD is around 2.4%. (All according to the NEC).
De-rating factor must also be considered (Must be higher than 156% of Isc).
For combiner boxes and inverter to utility #6 wire is used taking ampacity levels into account
#10 is used for all other grounding equipment’s.
FUSES, CIRCUIT BREAKERS,SURGE SUPRESSION:
Fuses are sized at 15A.
Surge suppression devices are normally inputs to the charge controller.
Battery disconnect is connected to the inverter input terminals along with charge controller outputs. The inverter ac input is given to inverter bypass witch that is connected to the emergency distribution panel.
A 60A circuit breaker is back fed from inverter ac output as overcurrent protection.
A 60A circuit breaker back fed at main distribution panel serves as point of utility.
The two circuit breakers can be on/off at a time but not simultaneous. For this 1-pole and 2-pole circuit breakers are ganged together.
Inverter ac output delivers power only to loads, but the inverter ac input can accommodate bilateral power flow.
CONCLUSION:
Hence by determining the appropriate load and following the procedure of selecting the appropriate components we can design a standalone PV system as shown above. However there are many factors to be considered while designing a PV system.