Argus PV simulator electrical simulation

Overview

The electrical simulation follows directly after the optical simulation in the Argus PV simulation chain. It takes the spectrally and optically corrected GTI per PV cell — the output of the optical simulation — and converts it into electrical power output, tracking losses at every stage from the PV cell level through to the grid connection.

This stage is essential for accurately quantifying the energy that a PV power plant will deliver under real operating conditions. The Argus electrical simulation achieves high fidelity by combining De Soto's single diode model with the cell-level raytracing results from the optical stage, enabling precise simulation of partial shading effects without simplifying assumptions. Inverter performance, DC and AC cabling losses, transformer losses, and auxiliary consumption are all modeled explicitly using component-specific parameters from the PV Components Catalog (PVCC) and the Energy system designer.

The final output of this stage — power delivered to the grid (PVOUT_AC_GRID) — feeds directly into the post-processing stage, where system unavailability and long-term degradation are accounted for.

Processes included in this stage

The following processes are applied sequentially during the electrical simulation:

• Conversion of irradiation to DC electricity (De Soto single diode model, transient thermal correction model, IV curve addition)

• Inverter clipping losses

• Grid power limitation losses

• DC losses (cabling and combiner boxes)

• Inverter DC/AC conversion (MPP calculation, Sandia inverter model)

• Auxiliary losses

• Transformer losses (variable and constant losses models)

• AC losses (low, medium, and high voltage cabling)

Electrical simulation

Conversion of irradiation to DC electricity 

For each time step, Argus converts the cell-level GTI heatmap into DC electrical output using the De Soto Single Diode Model, which derives the IV curve for each cell from five physical parameters extracted from the module datasheet.

For full details on the Single Diode Model, cell temperature model, and IV curve aggregation, see PV conversion model.

Inverter clipping losses

At each time step, Argus identifies the optimal working point on each inverter input IV curve using the MPPT algorithm, subject to voltage, current, and power constraints. Power exceeding the inverter's rated limit is reported as clipping loss. DC power is then converted to AC using the Sandia Inverter Model.

For full details on the MPPT algorithm, Sandia model, and complex output working point, see Inverter model — Maximum Power Point Tracking.

Grid power limitation losses

Grid power limits are applied by capping the MPPT algorithm at each inverter. Both static limits (fixed for the simulation period) and dynamic limits (time-slot-specific) are supported.

For full details, see AC power transmission model — Grid limits.

DC losses

DC losses in the direct current path from PV modules to inverters are a crucial factor in energy yield simulations. These losses occur due to the electrical resistance in the DC cables, and other DC components such as combiner boxes.

Default value used in Solargis Evaluate is 2%.

Inverter DC/AC conversion

An inverter is an electronic device that converts direct current (DC) generated by PV modules into alternating current (AC). The output can be either a one-phase or a three-phase voltage. Simulation of inverters is based on inverter parameters taken from PV Components Catalog.

Note: The energy losses in inverters (including night losses) are specified in the PV Components Catalog, and are applied in the simulation.

In Solargis Evaluate, the inverter conversion calculation consists of two main stages:

• Maximum power point (MPP) calculation: The Maximum power point (MPP) calculation utilizes the IV curve at the inverter input, which is derived from the previous simulation steps.

• DC/AC conversion model: Solargis Evaluate uses the Sandia inverter model which considers operational and environmental conditions in determining the inverter efficiency and its AC output. It also calculates the active and reactive power components, considering the user-specified power factor and inverter capabilities.

Auxiliary losses

Auxiliary losses account for the energy consumed by plant support systems (cooling, HVAC, motor drives, lighting, security). They are applied as night constant losses, day constant losses, and day proportional losses relative to inverter output.

For full details on each loss type and default values, see Inverter model — Auxiliary losses.

Transformer losses

Transformer losses are modeled using either the variable losses model (separating iron/no-load and copper/load losses) or the constant losses model (a percentage reduction). Both LV/MV and MV/HV transformer stages are covered.

For full details on both models and the calculation method, see AC power transmission model — Transformer model.

AC losses

AC cabling losses occur in the low-voltage, medium-voltage, and high-voltage cable segments between inverters and the grid connection point, modeled via Joule resistance (inductive/capacitive effects excluded).

For full details, see AC power transmission model — AC losses.

Further reading

• Improvement and validation of a model for photovoltaic array performance. W. De Soto, S.A. Klein, and W.A. Beckman.

• Transient Weighted Moving-Average Model of Photovoltaic Module Back-Surface Temperature. M. Prilliman, J. S. Stein, D. Riley, G. Tamizhmani