Learn how to set up electrical parameters, choose placement options, and run automatic or semi-automatic device generation across your PV areas.
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Electrical devices
We start by opening the Electrical devices menu.
Before proceeding further, we must select our PV area’s boundary line and press Space or Enter on the keyboard.
Having done so, we are now presented with the total available and used string amount.
Our next step will be to define the type of electrical system we will be using. By clicking on the drop-down menu, we are presented with seven system types:
(String) Inverter - Transformer;
(String) Inverter - AC combiner - Transformer;
DC Combiner - Central Inverter (Transformer included);
DC Combiner - (String) Inverter - Transformer;
Trunk - ISO - Central Inverter (Transformer included);
Additionally, for each type of system, one of the three harness types (End, Parallel, and Motor) can be selected.
For this example, we will utilize the (String) Inverter and Transformer option (without Harness).
Our next step is to define the number of strings per inverter and the number of inverters per transformer. Tthe AC Power - the power in kW of the inverter, can also be inputted so once we link the strings to the inverter, we can see the DC/AC ratio on the Electrical Overview.
As we can see, the software takes the string count and inverter count and provides us with the number of strings per transformer. It also calculates the number of inverters and transformers for our system, as well as the number of leftover strings.
It should be noted that the number of devices per transformer or Central inverter you specify will be the hard limit when using Auto (for Semi the user will be prompted on the go, if those limits need to change). This will prevent unused strings from being assigned to electrical devices, should you reach the string limit for the devices.
We also have the option to choose the device placement type from either of the four options:
Trench adjacent - devices are placed next to the alignment line. The alignment line is defined by the user;
Row clustering - devices are distributed in the selected rows and placed as close as possible to the alignment line;
String adjacent - places electrical devices at the end of the frame which ends this particular device's connection and as close as possible to the alignment line;
Centralized - place all the DC/AC combiners and string inverters together in a centralized location.
In the Device Configuration Section you also have the ability to:
Choose whether you would like to mount the electrical device to the frame at a specific height, or if the position should speficic X,Y, and Z offsets.
Decide your electrical device dimensions: width, height, and depth.
Note: Not all placement types are available for every electrical configuration
In our example, we will use the Trench Adjacent device placement. All subsequently placed electrical devices will be placed on the frame as close as possible to the user-defined alignment line. The alignment line can be defined beforehand or during the electrical generation process.
Having established our device alignment line, we must now define our transformer station objects and their positions. In this case, we will use the RECTANG function and draw a rectangle that will serve as a transformer station object. The rectangle must be converted to a Block Reference object for it to serve its purpose. This can be done by typing BLOCK and pressing Space or Enter on the keyboard, which will open the Block Definition menu. There, we assign the name to our rectangle, and using the Select objects button, we select the rectangle. After that, we click OK and our rectangle was transformed into a Block reference which can now be used as a transformer.
Note: you may also make copies of this object and place them into the drawing as necessary.
The transformer (or central inverter block) can also be created directly from the Electrical devices generation button, as shown below.
Having established our alignment line and our transformer, we now have everything necessary to start our electrical device placement.
There are two ways of placing electrical devices in PVcase:
Automatic generation - the software will place the devices according to the orders defined in the Device numbering and String numbering sections.
Semi-auto generation - the user has finer control over how the software assigns strings and frames to string inverters, DC combiner boxes, or DC harnesses. This mode gives full control over specific strings and the way they are numbered in a sub-device. Devices and strings will be numbered in the order in which they were selected (For example, the first device you select will be labeled as number 1).
If we start the Auto-generate mode, we will be prompted to select a transformer. Once we click on the transformer block object, we press Space or Enter on the keyboard. Then we are prompted to select the alignment line for the device placement - just like before, we select the line and press Space or Enter on the keyboard. We are now able to select the strings we want to use for this transformer.
As can be seen in our example, we have partially-filled inverters. In Auto Generate mode, PVcase will only connect fully populated inverters - any unused strings will be left out of the generation.
Note: the above example will only place 16 Inverters, leaving excess strings unused.
Once we have selected our strings, we press Space or Enter on the keyboard. As the image below showcases, the software has placed the devices next to the alignment line. In the case that some strings were not assigned to an inverter and transformer, they can be resolved by using Semi-Auto generation.
We select the Semi-Auto generate function from the drop-down menu, and the procedure is similar to automatic generation:
We are prompted to select our transformer - just like before, we select the rectangle and press Space or Enter on the keyboard. Similarly, for the alignment line - we select the line and press Space or Enter on the keyboard. We are now able to select the remaining strings we want to use for this transformer.
Once we have selected our strings, we press Space or Enter on the keyboard.
If applicable, we could be presented with a pop-up asking if we want to string these inverters with values differing from our initial configuration.
If we click “No”, the string will not be connected, and we are prompted to reselect again. If we choose “Yes” only this inverter will be connected with an alternate string count. If we click on “Yes to all” then this and future differing selections will be executed without asking for confirmation (until a new Semi order is executed. In our case, we want to choose“ Yes”.
Just like before, the software has placed our inverter next to the alignment line.
In addition to the above, we can enter the Numbering and Labeling menus to modify how the string numbers and names are assigned.
You an find out more about the labeling tool here.
Electrical Overview
We also have the Overview menu, which allows us to view the entire device chain in an expandable tree menu. Here, we can view each electrical device in greater detail, with the ability to toggle on and off devices and see the DC/AC ratio, voltage drop, and cable cross-section (after cable generation).
It is also possible to right-click on each device to Locate objects, Edit number, Add strings, Export SLD for this device, Select cables (after the cabling design), Change parent device, Change AC power Delete devices, and copy a pattern.
1. Match system - matches the selected system type and configuration inputs that were used for a particular transformer or central inverter.
2. Locate object - locates a specific device or string inside a drawing. Simply right-click on the component in the overview tab and click locate object or double-click.
3. Hide objects - the ability to hide objects so that you can better track progress, identify easily which parts belong to which device, and, of course, vastly improve the performance on large-scale sites by hiding parts that are already finished.
4. Renumbering - you can use the overview tab to change the numbering of transformers, central inverters, and other devices.
5. If there is a necessity to move a device to a different Transformer/Central inverter, Change parent device function can be used. Example below:
6. Add string allows the user to add strings to a connected box, as can be seen below:
7. In the overview menu, after the strings are assigned to a specific device, you can see the DC/AC ratio, which is calculated automatically according to DC and AC power per device.
8. The AC power can be changed if necessary, even after the devices were placed. By using the Change AC power function. Example below:
9. Export SLD for this device allows exporting a reduced SLD for a specific component. In the Overview menu, right-click on a device to generate the SLD for that device only.
10. Copy - Paste of strings and electrical devices
If you have optimized your strings, inverters, and transformer placement and would like to replicate the same pattern in other parts of your drawing, you can use this function.
After copying a configuration, just use Ctrl+V or Paste to replicate it in the desired place:
Limitations:
- Strings connecting different frames might not work.
- Frames that are not 100% strung will not work.
- The positioning of the frames can vary slightly. The pasted string has to touch the frame to be adapted to it.
In addition to using these options from the Overview, most of them can also be used by right-clicking on the device (transformer, combiner, inverter, string) in the drawing and then selecting PVcase: