Electric Power Generation, Transmission, and Distribution

If the system is a 12 V DC system, a set of deep discharge batteries will need to have a capacity of 185 Ah
for each day of battery back-up (day of autonomy). For 3 d of autonomy, a total of 555 Ah of storage
will be needed, which equates to eight batteries rated at 70 Ah each.

3.2.2.4 Hybrid PV-Powered Single Family Dwelling

In areas where winter sunlight is significantly less than summer sunlight, and=or where winter electrical
loads are higher than summer electrical loads, if sufficient PV is deployed to meet winter needs, then the
system produces excess power for many months of the year. If this power is not used, then the additional
capacity of the system is wasted. Thus, for such cases, it often makes sense to size the PV system to

MPT 3/4 HP

AAAA

J

AAA

F F F F F

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a. Simple PV-powered fan. b. Water pump with maximum power tracking.

55 W

modules

50 A

+ 1500 W

48vdc-

120vac

− Inverter

To main panel

neutral bus

GFI circuit

10 A

30 A

d. A hybrid residential installation.

8 A

A =

Start

100 A

φ 2

φ 1

2500 W

Gen

4 kW, 120/240 V

Controller/

Inverter

100 A

120/240 V

1 φ

3W

Main

Panel

# 8

# 10

# 4

c. A 1.5 kW residential rooftop utility interactive system connected on customer side of revenue meter.

To load side of 1P 20A

circuit breaker in main

a-c distribution panel

Fan

N

FIGURE 3.1 Examples of PV systems.