Abstract

A Hardware-in-the-Loop (HIL) test bench is presented for real-time validation of photovoltaic plant simulations. The setup integrates an electrical model of the converter and grid in OPAL-RT, along with a digital model of the photovoltaic array exported as a Functional Mockup Unit (FMU). The photovoltaic model, developed in Modelica based on the single-diode scheme, is executed on a set of virtual machines (VMs) with varying CPU, RAM, and storage configurations to emulate embedded platforms with limited resources. The system architecture communicates using the IEC 61850 standard, employing a publisher/subscriber scheme. A weather station sends reference data on irradiance, temperature, and DC voltage -defined by an electrical grid model also simulated in OPAL-RT -to interact in closed loop with the photovoltaic array. The computational requirements of the virtual machines are characterized based on the actual resources of the selected embedded platforms, and their performance is evaluated in terms of communication, execution times within the simulation time step, RAM usage, and processor load. Results shown that CPU resources have a significantly greater impact on simulation stability than RAM availability. Furthermore, performance anomalies were linked to periodic Disk I/O spikes and virtualization-induced latencies, confirming that hypervisor overhead poses a significant challenge to maintaining real-time operation. © 2025 IEEE.