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21 Cards in this Set
- Front
- Back
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When are standalone PV systems needed? |
rural areas |
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What are the three types of grid connected systems? |
residential rootop commercial rooftop PV plant |
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Why do we connect modules in series? |
To get the voltage high enough for the inverter input, and we have multiple strings connected in parallel. Each string is connected to an inverter |
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What is the middle ground between having one inverter and inverter for every module |
String inverters |
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When can having separate inverters come in handy? |
Multiple modules at different angles |
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What is a central inverter |
One massive inverter, where all PV arrays feed into. Disadvantage - lots of DC cabling, especially with high voltage. Typically used in PV power plants |
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What safety mechanism is used for Grid Tie inverters? |
Grid tie inverters follow the grid i.e. if grid disconnects, inverter stops working. |
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What is islanding? |
PV cannot run when there is a fault on the distribution network supplying power to an "island" |
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How can loss of grid be detected? |
Too high or too low voltage (240-250V) or frequency (as close to 50 Hz as possible, not much fluctuation |
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How can we prevent nuisance tripping due to transients? |
Introducing a time delay for thresholds |
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What is the capacity factor? |
Energy system actually provides vs energy system would provide at rated output during entire time period |
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What is net metering? |
When you sell to the govt when you're producing energy and buying from the govt when your PV cells aren't producing |
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What is a demand charge/ |
Considers how much power you draw at any given time (usually per month). Helps supplier maintain infrastructure |
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What is time of use? |
Highter tarriff during "peak" demand and lower during "off peak" |
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What does reserve capacity charge consider? |
it is a form of demand based tariff that also considers when system demand is hgih |
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What kind of solar battery can we use? |
$13000 for 7kWh powers home for 3 hours warranty 10 years not yet economical useful for peak times |
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What does the size of the system depend upon? |
annual energy to be displaced availability of storage DC layout self consumption or export? |
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List some practical design considerations |
Account for pre-existing buildings and electrical systems Roof orientation Roof angle (flat panels more aesthetically pleasing) Inverter placement and numbers |
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What factors will influence economics of system? |
Cost of grid electricity cost of technologies tariff structures Size of PV plant |
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What does PPA stand for? |
Power Purchase Agreement |
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How much per watt is a PV system? |
$2 per Watt |
