ENIT Enhances Renewable Hosting Capacity with Real-Time Simulation

The customer

ENIT (National Engineering School of Tunis) is a leader in energy systems research and education in Tunisia. Its MICROGRID platform supports Tunisia’s transition toward smart grids by enabling testing, validation, and innovation in renewable energy integration and power electronics. The platform includes two 15 kVA microgrids (single- and three-phase), 16 kW PV capacity, and 7.2 kWh lithium-ion storage, along with load, PV, battery, and network emulators.

ENIT has been partnering with OPAL-RT since 2020 to drive innovation in power systems through rapid control prototyping and CPU-FPGA co-simulation.

The challenges

With photovoltaic (PV) and battery storage systems growing rapidly in Tunisia, the distribution grid faces new challenges:

• IBR Impact on Grid Quality: Understanding the impacts of inverter-based resources (IBRs) on power quality and stability
• Hosting Capacity Limits: Increasing hosting capacity for renewable and electric vehicle (EV) chargers on existing distribution networks.
• Advanced Control Validation: Developing and validating advanced control strategies under realistic conditions—from LCL resonances to EV load surges.
• Physical Testing Limitations: Physical testing alone was limited by cost, complexity, and flexibility. ENIT needed a scalable, precise way to simulate diverse scenarios while accelerating prototyping.

The OPAL-RT solution

ENIT integrated OPAL-RT’s real-time simulation platform into its MICROGRID research facility:

• Hardware: The OPAL-RT real-time simulator serves as the core platform, enabling FPGA-CPU co-simulation for high fidelity and low latency.
• Software: eHS (FPGA-based Power Electronics Toolbox) and ARTEMiS (Advanced Real-Time Electro-Mechanical Simulator) toolchains provide detailed switching-level simulation of power electronics and grid dynamics.
• Testing Modes: Supports real-time simulation, HIL, C-HIL, SIL, and PHIL testing in a single unified environment.
• Integration: Seamless integration with physical equipment including Imperix, Cinergia, and TeknoCEA converters for hybrid testing configurations.

The results

ENIT achieved impactful research outcomes across multiple use cases:

• Adaptive Inverter Control: Developed adaptive virtual impedance control for mitigating LCL filter resonances, improving power quality and system stability.
• Digital Twin for Prosumers: Created a SIL-based digital twin simulating a PV-powered prosumer microgrid, enabling rapid validation of control strategies.
• Voltage Stabilization via Electric Spring: Modeled and validated Electric Spring (ES) devices to stabilize voltage under varying grid conditions, enhancing demand-side management.
• EV Charger Co-Simulation: Simulated a 3.7 kW onboard EV charger with power factor correction, ensuring accurate transient behavior under variable loads.

Key research projects supported:

• PV-NeTE: A PHIL-based platform for exploring new PV technologies
• IRoN: Research on rooftop PV integration and its grid impacts
• N-TeQ: Development of microgrid strategies for dynamic power quality

Looking Ahead: ENIT plans to integrate Imperix 20 kVA converters with OP4512 for advanced PHIL experiments, testing BESS, PQID, and PV emulators in real time within the Pla-NeTE platform.

Read the full story