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Flashcards in PV System Sizing Principles Deck (27):
1

A crystalline silicon PV array that has bipolar outputs of +252V and -252V with a common grounded conductor under STC is selected for a large single-family residence. For this system, if the maximum system voltage is close to 605V, what is the lowest expected temperature at the installation site?

-25 degrees Fahrenheit

2

Subpart E of OSHA PART 1926 describes regulations regarding...

OSHA Rules for personal protection and life-saving equipment

3

What should be connected on the side of a battery between two batteries? 

The charge controller battery temperature sensor

4

What does a transformer do?

Transforms radio waveforms in frequency applications; transforms amperage; transforms voltage, and/or transforms current

5

System availability is the percentage of what?

Average time percentage per year a stand-alone PV system meets its load requirements

6

Are 110 volts, 120 volts, and 240 volts, two phase?

No

7

True or False: Ohm's law states that an increase in current is inversely proportional to an increase in voltage.

False

8

Ampacity is determined by what?

Wire width

9

What are the only inverters that have low harmonic distortion?

Sine waves inverters, since they are required for connection to utility lines

10

What electrical property increases on a hot day?

Voltage drop

11

If a cold front moves in, what will increase?

The voltage of a PV system

12

Where are the OSHA Rules for personal protection and life-saving equipment found in OSHA PART 1926?

Subpart E 

13

If the output of the inverter is connected to the optional standby system panel through a 30 A circuit breaker, what is the appropriate size of the equipment grounding conductor between the inverter and the emergency panel?

10 AWG copper

14

What starts at the load size and ends at the array?

System sizing

15

According to the NEC, if flooded lead-acid batteries are selected for energy storage for a PV system, the battery enclosure must have what?

Provisions for sufficient diffusion and ventilation of the gases from the battery to prevent the accumulation of an explosive mixture, and if a tray is used it shall be resistant to deteriorating action by the electrolyte.

16

Where should the charge controller battery temperature sensor be connected?

The sides between two batteries

17

PV module and determining the array configuration based on the current and voltage parameters is selected when?

During the final step of the sizing process

18

What is the term for the percentage of time that a stand-alone PV system meets its load requirements in an average year?

System Availability

19

The inverter should not supply power to the terminals connected to utility point-of-connection in the event of what?

In the event that the utility voltage is lost in a utility-interactive system that has battery backup and an optional standby system AC distribution panel, and if the inverter is programmed in the sell mode

20

Considering ohms laws, on what type of day do PV watts decrease because of the relationship of volts to watts?

On a cloudy day

21

What do interactive systems offer?

Relatively simple calculations and allow the widest variance in component sizing

22

What is used to size the PV system during the critical design month in the worst case scenario?

Insolation data

23

What system offers relatively simple calculations and allows the widest variance in component sizing?

Interactive system

24

Where (which axis) is I on an I-V curve?

I is on the vertical y-axis

25

The appropriate size and material of the equipment grounding conductor between the inverter and the emergency is 10 AWG copper, the output of the inverter is connected to the optional standby system panel through a _____ circuit breaker.

30-A 

26

What is the measure of rate?

Amperes

27

When are the load and the insolation data used to size the PV system?

During the critical design month in the worst case scenario