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Aamir Ejaz
12-30-2013 10:51 PM

Interview related to solar systems

An electrical engineer needs assistance for interview related to solar systems? What can be the expected questions related to electricity generation from solar energy?
12-31-2013 01:07 AM
Top #2
John Capella
12-31-2013 01:07 AM
Without knowing the company and the role you are interviewing for, I would just be guessing...so here is my best guess:
1) show that you understand the basic I-V curve of a PV module, Voc, Isc, max power point.
2) given a typical I-V curve, sketch the new curve if there is less irradiance
3) understand temp coefficient (voltage rise with temp decrease)
4) explain the role of other system components such as charge controllers, batteries, and inverters and sketch how you would connect them, with/without battery etc.
5) Understand the impact of shading and how micro-inverters can help.
6) know as much as possible about your national electrical codes (wire sizing, circuit breaker sizing)
7) assuming your company will do commercial work, understand 3 phase power and wiring.
Good Luck!
12-31-2013 03:30 AM
Top #3
Aamir Ejaz
12-31-2013 03:30 AM
Thanks alot John. The company, where I shall be interviewed, deals only in installation of solar cells. They are not the manufacturers. So kindly assist me more related to installation of solar cells.
12-31-2013 06:17 AM
Top #4
Ping Xi
12-31-2013 06:17 AM
if the company deals only with the installation, pay attention to
1) electrical stuff like @John Capella mentioned, as well as,
2) mechanical stuff like, ground work/roof preparation; solar module v.s. mounting structure test & compatibility; wind/snow load provision; etc.
Good luck, man~
12-31-2013 08:49 AM
Top #5
Aamir Ejaz
12-31-2013 08:49 AM
thanks, ping.
12-31-2013 11:27 AM
Top #6
Bailey Liu
12-31-2013 11:27 AM
Hi Aamir, could you please tell me your email address? Thanks.
12-31-2013 02:11 PM
Top #7
John Capella
12-31-2013 02:11 PM
Just to clarify, my first 3 points mentioned earlier are some basic PV module characterics that are pretty important for any PV system designer working for an installer company. I am an electrical engineer and I was recently working for a solar installer here in the USA. I was responsible for roof layout design, string-sizing (how many PV panels to connect in series to match the central inverter), and creating the "one-line" system schematic showing the connection of the components I mentioned earlier, as well as the connection to the utility. If you work for a company with many engineers these duties may be split among various people but if you can gain knowledge in all these areas you are more valuable.
As far as "string-sizing", if you can find out what brand of inverter the company likes to use, you can go to the website of the inverter manufacturers and practice string-sizing using the free interactive tools that most provide. The tools calculate for you the sum of voltages of the series connected PV modules including the effect of temperature coefficient and also the power totals. I think all of these manufacturers have such website tools:
Satcon (for higher power systems)
Again, best of luck.
12-31-2013 04:24 PM
Top #8
Anatoli Naoumov
12-31-2013 04:24 PM
Aamir, you might like to clarify for yourself the difference between a solar cell and a solar panel.
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