Simulation

General

The Proximal expected energy model converts measured weather conditions and the configured physical properties of a photovoltaic system into expected power at the point of interconnection. The model preserves the system hierarchy throughout the calculation, so results can also be reported for combiners, inverters, and transformers.

The simulation runs each model stage in order. Outputs from one stage become inputs to the next stage, while equipment assignments determine how values are mapped and combined between strings, combiners, inverters, transformers, and the project.

Acronyms

• POAI: Plane of Array Irradiance
• EPOAI: Effective Plane of Array Irradiance
• DC: Direct Current
• AC: Alternating Current
• POI: Point of Interconnection

Simulation Pipeline

The following flow diagram shows the major stages of the Proximal expected energy simulation. The flow chart is interactive. Clicking a documented model stage will take you to its detailed model chain.

Legend

flowchart LR

  classDef source fill:#6B7A8F, color:#CCCCCC
  classDef model fill:#202020, color:#CCCCCC
  classDef outputs fill:#B39245, color:#CCCCCC

  source[(Input Data)]:::source
  model_step[[Model Stage]]:::model
  model_outputs([Calculated Results]):::outputs

  source --> model_step --> model_outputs

Model Chain

flowchart TD

  classDef source fill:#6B7A8F, color:#CCCCCC
  classDef model fill:#202020, color:#CCCCCC
  classDef outputs fill:#B39245, color:#CCCCCC

  met_data[(
    --- MEASURED DATA ---
    irradiance
    ambient temperature
    relative humidity
    wind speed
    soiling
  )]:::source

  system_data[(
    --- SYSTEM DATA ---
    project location
    module parameters
    racking parameters
    electrical hierarchy
    inverter parameters
    transformer parameters
  )]:::source

  meteorological[[Meteorological Parameters]]:::model
  click meteorological "meteorological_parameters.html"

  rotations[[Tracker Rotation Angles]]:::model
  click rotations "tracker_rotation_angles.html"

  poai[[Plane of Array Irradiance]]:::model
  click poai "plane_of_array_irradiance.html"

  epoai[[Effective Plane of Array Irradiance]]:::model
  click epoai "effective_plane_of_array_irradiance.html"

  dc[[DC System Losses]]:::model
  click dc "dc_system_losses.html"

  ac[[AC System Losses]]:::model
  click ac "ac_system_losses.html"

  poai_output([POAI by combiner]):::outputs
  combiner_output([DC power by combiner]):::outputs
  inverter_output([AC power by inverter]):::outputs
  transformer_output([AC power by transformer]):::outputs
  poi_output([Expected power at POI]):::outputs

  met_data --> meteorological
  system_data --> meteorological
  meteorological --> rotations
  system_data --> rotations
  rotations --> poai
  meteorological --> poai
  system_data --> poai
  poai --> poai_output
  poai --> epoai
  met_data --> epoai
  system_data --> epoai
  epoai --> dc
  met_data --> dc
  system_data --> dc
  dc --> combiner_output
  dc --> ac
  system_data --> ac
  ac --> inverter_output
  ac --> transformer_output
  ac --> poi_output

Simulation Outputs

The model emits intermediate results as soon as each electrical level is complete:

1. Plane of array irradiance by combiner
2. DC power by combiner
3. AC power by inverter
4. AC power by transformer
5. Expected project power at the point of interconnection

Edits and Additions

If you would like to see support for another algorithm or would like to suggest edits or additions to this documentation page, please open an issue on the Proximal GitHub repository.