# Photovoltaics

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1. List three types of configurations of the solar array and the most common type. PP 4
Utility supplemental and standalone. The most common configuration is a utility connected system
2. Find the inverse square law as relates to photovoltaics. Pp 31
A physical law that states that the amounts of radiation at points are proportional to the inverse of the square of their distances from the source.
3. Defined distributed generation. PP 26
A system in which many smaller powergenerating systems create electrical power near the point of consumption.
4. PV systems operating in parallel with the utility system, referred to as what systems? WB PP 1
Multimodal, distributed, interactive, or stand alone?
interactive
5. PV systems operated independently of other power systems are, referred to as what type of systems? WB PP 1
stand-alone
6. While PV cells produce only _______ power, PV systems can produce ______ power. WB PP 2
Cells produced DC power and PV systems can produce AC power
7. Balance of system (BOS) components typically include all but what? WB PP 2
PV modules and inverters.
8. List of three main components of the electric utility system. WB PP 3 photovoltaics
Generation, transmission, and distribution
9. The first practical Silicon solar cell was made in what year? WB PP 4
1954
10. Solar power and solar energy is commonly expressed in what units? WB PP 5
Solar power is commonly expressed in watts per square meter  Solar energy is commonly expressed in watt hours per square meter.

Note: solar power is used to estimate the output of the PV modules and arrays over time.
11. What is the formula for solar radiance on the surface involving time? WB PP 6 (Photovotaic notecard set)
• H = (E average) x T
• Where H = solar radiation in watt hours per meter squared
• E average = average solar radiation and watts per meter squared and
• T = time in hours
12. The peak solar radiance incident on the earths surface is approximately what percentage of extraterrestrial irradiance? WB PP 7 (Photovotaic notecard set)
73%
13. List three atmospheric effects on solar radiation. WB PP 7 (Photovotaic notecard set)
Scattering, reflection, and absorption
14. Air mass is a representation of what? WB PP 8 (Photovotaic notecard set)

What value of Air mass is considered representative of average terrestrial conditions in United States and used as a reference condition rating modules and arrays?
Relative distance of atmosphere that radiation must travel through to reach the earth's surface

AM 1.5
15. What three components of the electromagnetic spectrum are contained in solar radiation? WB PP 9 (Photovotaic notecard set)
Ultraviolet, invisible, and infrared.
16. The orientation of PV arrays is defined by their what? WB PP 15 (Photovotaic notecard set)
Array tilt and array azimuth
17. To maximize wintertime output PV arrays are generally tilted at an angle close to what? WB PP 15 (Photovotaic notecard set)
Lattitude + 15 degrees
18. What is the formula for roof slope angle? WB PP 23 (Photovotaic notecard set)
Theta (angle) = Tan-(Rise/ Run)
19. What is a monopole array? PP 155 (Photovotaic notecard set)
An array that has one positive terminal and one negative terminal
20. What is a bipolar array? PP 155 (Photovotaic notecard set)
A bipolar array is an array tha has two terminals, one positive and one negative, and a third terminal connected at a center tap.
21. What is a Photovoltaic effect? PP 154 (Photovotaic notecard set)
A photovoltaic effect is the movement of electrons within a material when it abords photons with energy above a certain level.
22. The maximum power voltage (Vmp) and maximum power current (Imp) both share what definition? PP 155 (Photovotaic notecard set)
is the operating voltage/ current on an I-V curve where the power output is at maximum.
23. A p-type semiconductor is a semiconductor that has what? PP 154 (Photovotaic notecard set)
A p-type semiconductor is a semiconductor that has electrond voids.
24. An N-type semiconductor is a semiconductor that has what? PP 154 (Photovotaic notecard set)
An N-type semiconductor is a semiconductor that has free electrons.
25. Bypass diodes do what for a PV device and under what condition or why? PP 154 (Photovotaic notecard set)
Bypass diodes protect PV devices form damage and excessive loss of power by directing current around shaded or damaged devices. Remember: Voltage is additive in series and thus current is constant, and since sunlight is directly proportional to current production then a shaded panel would have lower current and would become a load. resulting in damage.
26. What affects the magnitude and postion of the I-V curve? PP 154 (Photovotaic notecard set)
27. Bypass diodes are typically installed around groups of _____ to ______ series-connected cells. PP 148 (Photovotaic notecard set)
• Bypass diodes are typically installed around groups of 12 to 18 series-connected cells.
• Note: bypass diodes must be able to handle the maximum operating voltage for the number of cells or modules bypassed, and must be rated in excess of the maximum circuit current.
28. Define a bypass diode. PP 148 (Photovotaic notecard set)
A bypass diode is a diode used to pass current around, rather than through, a group of PV cells.
29. A bypass diode allows a reverse bias of only ______ volts. PP 148 (Photovotaic notecard set)
.7 volts
30. Most modules are rated for a maximum system voltage of ______, though some are rated as high as _______. PP 148 (Photovotaic notecard set)
• 600v
• 1000v
31. What should be remembered about PV devices and thier current rating regarding connection in series? PP 144 (Photovotaic notecard set)
It should always be remembered that PV devices of different current rating should never be connected is series since "...the current output for a circuit of disssimilar devices in series is limited to the current of the lowest-current output devide in the entire string."
32. What should you remember about the juction box on a PV module if available? PP 144 (Photovotaic notecard set)
That the PV module may be configured for the ability to change the series or parallel configuration with certain jumper arrangements.
33. The top and bottom surface of a PV cell or module is of what type of silicon junction and polarity? PP 144 (Photovotaic notecard set)
The top is negative (N type) and the bottom is positive (p type). PP 126
34. Concerning the photo voltaic effect, what is associated with shorter wavelengths and higher freqeuncies? PP 125 (Photovotaic notecard set)
Higher energy.
35. Finish the sentence: The absence of a negative charge is considered a ___________. PP 124 (Photovotaic notecard set)
positive charge carrier.
36. A rectifier converts? PP 120 (Photovotaic notecard set)

A converter....

An inverter....
A rectifier converts AC to DC.

A converter converts a AC voltage to a different voltage level.

An inverter converts DC power to AC power.
37. Define a type of standalone system where the output of the PV module or array is directly connected to the DC load. PP 120 (photovoltaic notecard set)
A direct coupled PV system.
38. Define an electro-chemical device that uses electricity to split water into hydrogen and oxygen PP 120 (photovoltaic notecard set)
An electrolyzer
39. What is Islanding? PP 120 (Photovotaic notecard set)
Islanding is the undesirable conditions where a distributed generation power source, such as a PV system, continues to transfer power to the utility grid during a utility outage.
40. Define a multi-mode system. PP 120 (Photovotaic notecard set)
A multi-mode system is a PV system that can operate in either utility interactive or standalone mode and uses battery storage.
41. Concerning net metering, using this system, energy supplying the utility PV system is? PP 113 (Photovotaic notecard set)
effectively credited to the customer.
42. What type of PV system is the simplest and least expensive PV system that produces AC power because they require the least components and do not use batteries? PP 113
The utility interactive system that operates in parallel with and is connected to the electric utility grid.
43. Utility interactive inverter output is determined by what?  Whereas the output from battery based inverters,  is determined by what? PP 102 (Photovotaic notecard set)
Utility interactive inverter output is determined by the DC input from the array unlike the output from battery based inverters, which is determined by the load.
44. What type of inverter is used exlusively in PV systems?
think of what type of UPS is used with DC batteries
static inverters. PP 224 (Photovotaic notecard set) A static inverter is a device that converts a dc voltage to a stable ac voltage for use in an uninterruptible power system.
45. inverters for PV systems are broadly classified as what? PP 226 (Photovotaic notecard set)
Think one grid tied or not
either stand alone or interactive.
46. What size are String inverters, central inverters, and utility scale inverters? PP 227 (Photovotaic notecard set)
• String inverters: small 1kw to 12 kw residential
• central inverters: large utility interactive 30kw-500kw
• utility scale inverters: very large 500kw-1MW and bigger
47. For a stand alone PV system what determines the inverter's power rating? PP 226 (Photovotaic notecard set)
The AC load rather than the DC power source.
 Author: johnbowens ID: 189649 Card Set: Photovoltaics Updated: 2018-02-02 04:52:26 Tags: photovoltaics JATC IBEW solar Folders: Description: from Photovoltaic Systems: 3rd edition, James P Dunlop Show Answers: