LV WIRES: PVFARM vs PVCASE

PVCASE

In PVCASE, it is possible to define the positive and negative outputs of a string either:

• on opposite sides of the string (Daisy-Chain)
  
• on the same side of the string (Leapfrog)
  
  

PVFARM

In PVFARM, a string is formed from modules in a bottom-to-top direction, and the positive and negative outputs of the string are always located on opposite sides of the string (Daisy-Chain). For example, the distribution of 56 modules on a fixed-tilt into two strings of 27 modules each (an odd number), arranged in two rows, would look like this:

Electrical Devices Configuration

PVCASE

In PVCASE, one of the following equipment configurations is selected:

PVFARM

1. First, on the Layout panel, you choose whether the configuration will use a String Inverter (PVCASE configurations: 1, 2, 6) or a Central Inverter (PVCASE configurations: 3, 4, 5, 7).

   

2. Then, on the LV Wiring panel, you define the position of the Combiner Boxes. The "Clustered" option places all combiner boxes directly next to the SKID with the transformer. In this case, the combiner boxes can be considered part of the transformer station, which corresponds to PVCASE configurations without combiner boxes (configurations 1, 3, 6).

   

   Additionally, PVFARM offers:

   1. Middle of Row option – places the combiner boxes in the middle of the row with SAT / Fixed-tilt trackers;
   2. End of Row option – places them at the end of the row.
   3. Single array – the row contains only one SAT / Fixed-tilt tracker.
   4. Multi array – the row consists of several SAT / Fixed-tilt trackers.

3. Next, on the LV Wiring panel, you select the type of wiring used to connect the strings to the inverter: Harness, Trunk Bus, or a combination of both (Harness + Trunk Bus).

   

   If you choose the following chain: Harness → Extender → Whip → CB → DC Feeder → SKID, it corresponds to PVCASE layout 5.

   If you choose: Harness → Extender → EW Trunk → LBD → DC Feeder → SKID, it corresponds to PVCASE layout 7.

   By combining various Combiner Box placements, wiring schemes, and the type of inverter (String or Central), it becomes possible to analyze and configure far more than the seven predefined PVCASE layouts. This flexibility allows you to select the most cost- and loss-efficient electrical configuration for a specific layout.

Wire routing

PVCASE

Cable trenches must be manually drawn on the layout to define where the wires will be routed.

PVFARM

Wire routing is fully automatic — it traces all cables from the strings to the transformer, through all equipment automatically placed on the layout. The system builds the shortest possible path, while avoiding all restricted cable areas.

Conclusion

To configure Daisy-Chain String → String Inverter → Inverter Transformer Station in PVFARM, follow these steps:

1. In the Layout panel, select a configuration with a String Inverter

   

2. In the LV Wiring panel, under LV equipment configuration, set the Combiner Boxes location to Clustered

   

   In the LV Wiring panel, under LV equipment configuration, set the String Inverter location to Distributed

   

3. In the LV Wiring panel, under Wiring scheme, select the appropriate wiring method

   

To configure Daisy-Chain String → Combiner Box → Inverter Transformer Station in PVFARM, follow these steps:

1. In the Layout panel, select a configuration with a Central Inverter

   

2. In the LV Wiring panel, under LV equipment configuration, set the Combiner Boxes location to Distributed

   

3. In the LV Wiring panel, under Wiring scheme, select the appropriate wiring method.