A lot of parameters affect your electrical configuration. In pvDesign this is no exception! Would you like to know more about these parameters?
pvDesign will automatically size your PV plant's cables according to the International Electrotechnical Commission (IEC) standard, the National Electrical Code (NEC) standard, the Australian standard, or the National Standard of the People's Republic of China. All these standards will apply the Maximum Rated Current (Ampacity) criterion, the Voltage Drop Limit criterion, and the Short-Circuit Temperature Rise criterion and will make sure that the cables are sized based on the most restrictive one.
Users can also define the maximum voltage drop limit for both the low voltage and the medium voltage systems.
A maximum of two cable cross-sections will be used for each subsystem to reduce the total installed cable volume.
This section will tackle all the parameters that affect the Low Voltage configuration, from the number of modules per string all way to the power stations.
The first step is to select the inverter. pvDesign offers both central and string inverters. You can select an inverter from our public database or opt to upload your own equipment (How to upload your own equipment) to your private database. pvDesing also permits you to select a secondary central inverter if needed.
Modules per string
You have just selected the PV module and the inverter that you want, now what? pvDesign will recommend the optimal number of modules per string and set an interval of allowed values (all found in the Equipment tab). This interval depends on the minimum historical temperature found in the Site tab (this parameter can be modified). For more information on how we calculate this, please refer to our Electrical Methodology.
If you select a central inverter, the power station will be defined by the number of central inverters inside it (and secondary inverters as well if selected). These power stations will be distributed throughout the layout and smaller ones will be used once no more can fit.
When it comes to the low voltage electrical configuration, you can select one of four: String Box, DC Bus System, String Box L2 (Field), and String Box L2 (Power Station). String box L2 won't be available if a secondary central inverter is selected.
You can also specify your preferred number of strings per string box / DC bus system. This value will be used to generate a list of 30 different electrical configurations from which you need to select one.
Now if you opt for string inverters, the power station will be defined by the preferred and the minimum number of these inverters.
Two different low voltage electrical configurations are available for string inverters: String Inverter (Field), and String Inverter (Power Station).
To define the size of the blocks of structures that will be installed in our design, we must select one of the following alternatives:
- Regular Blocks: big blocks of structures with a shape as squared as possible will be installed. This will lead to a regular design that may not optimize the available area.
- Adaptive Design: smaller blocks of structures will be installed. Blocks of structures starting from 1x1 will be installed, fitting to the perimeter as much as possible.
The last input that we must define is the DC/AC ratio. This DC/AC ratio will be used to generate the List of Electrical Configurations.
List of Electrical Configurations
So I have just selected all the right equipment and modified some of the electrical parameters, now what? How will pvDesign define the final electrical configuration for my PV plant?
Since some electrical parameters depend on each other, some values may need to be slightly adapted to the rest of the configuration. With this purpose in mind, pvDesign facilitates a list of electrical configurations where you can decide the electrical configuration that will be used in the final design.
So does this mean that the parameters that I selected will not be taken into consideration?
Of course, they will be. This list is ordered in a way that gives more priority to your preference DC/AC Ratio and your preferred number of strings per string box / DC bus system. It then uses them to offer you possible outcomes that would make sense electrically.
With pvDesign, you can size your PV plant's cables following the IEC, NEC, the Australian, or the Chinese standard, choose a central or string Inverter, and define your Low and Medium Voltage systems with a reduced number of inputs, obtaining an optimized layout that will be adapted to fit your requirements.
For any other questions or for more information, you can contact us at the following email: email@example.com