Updates June 2020

Electrical substation basic engineering and improved power station grouping algorithm

pvDesign - version 4.0.0


For the past year, we have been working to bring you the basic engineering of the step-up substation to which the PV plant is connected. This is the first release of this significant engineering project. Below, the main new features of this release are listed:

  • Basic engineering of the substation: The software automatically generates a solution for an electrical substation. The possible arrangements that can be obtained are a line to transformer substation, a single busbar substation and a double busbar substation. The software will select the best solution based on the medium voltage lines and the installed capacity of your PV plant.
  • Calculation of the insulation coordination: The procedure for insulation coordination is presented according to the IEC standards. The software calculates the highest voltage for the equipment together with a set of standard withstand voltages which define the insulation of the substation equipment.
  • Safety distances: The safety distances within the substation field are calculated and they are presented as the minimum distances that should be comply with to ensure the safety of workers.
  • Substation equipment: The components of the substation are sized in detail according to the electrical standards. The following elements are defined: power transformers, instrument transformers, circuit breakers, disconnectors, surge arresters, grounding devices, primary medium voltage cubicles, and high voltage busbars.
  • Size the switching and breaking station: It is possible to size the switching and breaking cubicles for those systems where rising the voltage is not required to connect the PV plant to the grid.
  • Short-circuit current calculations: The short-circuit currents that affect the substation are computed by introducing an equivalent voltage source at the short-circuit location.

    Choose the interconnection facility type in the Grid Point tab

Regarding the documents that pvDesign will generate for the basic engineering of the substation, the new ones are listed below:

  • Interconnection facility single line diagram: This new document is available for the line to transformer, single and double busbar substation, and for the switching cubicles. Furthermore, the diagrams are completed with detailed notes of the project.
  • Interconnection facility report: A design report where a descriptive memory of each substation component is found. Also, the number of transformer bays, output circuit bays, the type of arrangement, the short-circuit levels, the insulation coordination, the safety distances, and the dimensions of the busbar are included.

    Review the substation design in the SLD document

New features

We've released a new version of the power station grouping algorithm. The new algorithm produces better layouts, with reduced cable lengths and a more visually pleasing appearance. Below is a more detailed description:

  • Improved power station location: The power stations will be better aligned to the roads present in the layout. As a result, the power stations will usually be centered in their groups and the cable lengths will be reduced.
  • Squared power stations: We improved the grouping algorithm so that the power station shapes are closer to a square.
  • Improved specific capacity algorithm: When using specific capacity, the unused space in the layout is now selected in a smarter way. The new algorithm chooses which structures to leave unused so that smaller and unusable regions are excluded, and grouping unused structures away from the delivery point in a regular shape.
  • Layout preview enhancements: The layout preview results are now consistent with the final simulation results.

Improved power station location and shape.

Improvements and bug fixes

We made the following bug fixes and improvements:

  • The layout view in the DXF and PDF files is now rotated to counteract the UTM convergence. This does not affect the model space view.
  • Now when cloning a simulation, the name of the previous simulation is set in the create design dialog.
  • Updated the french translations for the bifacial simulation.
  • We improved the ground clearance calculation for the energy simulation when using trackers. Now the offset from the rotation axis to the modules is taken into account.
  • We changed the torque beam shading for 1V trackers in the energy simulation so that now the torque beam cross section is cylindrical.
  • We improved the specific capacity algorithm. Now, the rated power of the PV plant should always match with the user input in new design, as long as the area is big enough.
  • We re-enabled the NASA POWER meteorological data source.
  • We fixed a bug which caused some simulations to get stuck.
  • We changed the type of servers to take advantage of a faster CPU, which will result in slightly shorter simulation times.
  • We removed the irradiance losses in the summary in the Energy XLSX for bifacial simulations, as the loss values were not correct.