Simply input basic module criteria along with a few key system details to determine string design and inverter selection recommendations in a simple, easy-to-use and printable format.This customized assessment can be printed for customer presentations or as a reference during installation.
Topics include solar technology, photovoltaics and renewable energy. My Hobbies: Running, backpacking, spending time outdoors and the occasional game of hockey. You can enter your equipment type and it will give you string sizing based on your project location. I am an electrical engineer and a renewable energy consultant but am new into the use of SMA product. You can participate in these online trainings from Ghana and there are ways to interact just as actively as in our face-to-face trainings. You can look at the PV System Logbook on your Portal plant to see if there are errors being reported by the inverter. That is to prevent dangerous situations from arising if the array is upgraded in the future. Voltage drop due to warm temps just brings us further under the danger zone. Sma String Sizing Calculator How To Size AWeve written guides on how to size a grid-tied system, as well as sizing a battery bank for off-grid systems, which give you a pretty good idea of how much solar energy you need to produce to offset your energy consumption. Our goal is to equip you with accurate information to make informed decisions during your research and design process. String sizing describes the calculations we make to determine how many panels we should plug into one input for optimal efficiency. The inverter (appropriately called a string inverter) has three string inputs. Your panel strings must output a voltage that falls within that range. In this range, your inverter will turn on and deliver power to your appliances. This is the sweet spot in which your inverter runs at the peak efficiency listed on its spec sheet. This is the sweet spot for ideal operation that I mentioned in the last section. Were especially concerned about this, because if you exceed the max operating voltage, youll overload the inverter and potentially fry the equipment. Typically this wont be an issue, since we want our strings to operate well above the minimum, up in the MPP range where it works at higher efficiency. Lets use that 9 kW grid-tied system I linked earlier as an example. The operating range is 100-600 volts (look for minimum and maximum DC voltage on the spec sheet ). So your minimum string size is 7 panels before temperature compensation. We want to double check that this falls within our peak efficiency range as well. Since 471V is below our target 480V, everything checks out here. But this doesnt take temperature into account, which can have a significant impact on our figures (colder temperatures lead to a rise in voltages and hotter temperatures will lower voltage). I want to find the coldest ever day on record (to account for the absolute worst-case scenario). We take the difference between the NOCT and the coldest day on record (-33.3 C) for a value of 77.3 C below the standard conditions. Take the array voltage (701.83V) and subtract the true panel voltage (58.486V). Since weve removed 2 panels from our starting point, we arrive at a final max string size of 10 panels. Under these conditions, your string size should be capped at 10 panels. Any larger has the potential to permanently damage your array in extreme temperatures. Most places dont peak above this, although it certainly happens in some areas, especially close to the Equator. Again, our primary concern is staying below the max input voltage so we dont damage the inverter.
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