Enhancing BESS Performance and Reliability with C-HIL Simulation

The company

NHOA Energy is a global leader in the supply of energy storage systems, making green energy reliable and competitive. Operating across five continents with over 2.6 GWh of systems either in operation or in advanced stages of construction, NHOA Energy develops, manufactures, and delivers Battery Energy Storage Systems (BESS) for large-scale industrial applications.

At the core of its offering is NHEXUS, a plug-and-play platform that seamlessly integrates conversion, control, and energy management systems. Engineered for performance, reliability, and cost-effectiveness, NHEXUS delivers optimized storage solutions tailored to the evolving needs of grid operators, utilities, and energy developers.

The challenges

• Complex Multi-Device Coordination: BESS control systems involve multiple Devices Under Test (DUTs)—including plant controllers, distributed Power Island controllers, and PCS control boards—requiring precise debugging and optimization across hardware interfaces and communication delays.
• Commissioning Risk: Predicting system performance before on-site Site Acceptance Tests (SAT) is critical to reduce risk and accelerate deployment timelines.
• Post-Deployment Management: After delivery, managing change requests, troubleshooting malfunctions, and supporting O&M tasks (such as high-voltage switching operations) require a safe, representative testing environment.
• Grid-Code Compliance: Validating performance under various market and grid conditions—including single-phase, three-phase, and line-to-line faults—demands high-fidelity, real-time simulation capabilities.

The OPAL-RT solution

NHOA Energy implemented a comprehensive C-HIL architecture designed to maximize simulation accuracy and fidelity across the full project lifecycle:

• Hardware: The flagship OPAL-RT OP5707XG real-time simulator serves as the core platform, modeling the grid and power systems with ultra-high time resolution.
• Software: The eHS (FPGA-based Power Electronics Toolbox) solver executes the BESS power model—including DC/AC conversion, transformer losses, auxiliary loads, and Thevenin-equivalent grid representation—with dedicated IO interfaces for direct PCS control board integration.
• Control Hardware Integration: All relevant BESS control hardware is physically interfaced with the simulator, including the NHOA Power Plant Controller (PPC), PEMS Battery (Power Island distributed controller), PCS Control Board, and Power Meters.
• SCADA Interface: A custom Simulink-based SCADA within RT-Lab enables real-time control of simulation parameters, TCP-based communication with DUTs, and execution of standardized automated test procedures under various market and grid fault conditions.
• Grid Fault Simulation: A configurable grid fault simulator emulates various fault types with adjustable short-circuit impedance, validating system response under extreme scenarios.

The results

The OPAL-RT C-HIL solution transformed NHOA Energy’s engineering workflow across all project phases:

• Accelerated Development: Enabled early identification of issues, refinement of hardware interfaces, and fine-tuning of system parameters in a safe simulated environment—before physical deployment.
• De-Risked Commissioning: C-HIL simulations accurately predict system performance before SAT, significantly reducing on-site risk and accelerating the commissioning process.
• High-Fidelity Validation: Post-SAT comparison of actual plant data with simulation outputs confirmed the framework’s accuracy in both transient and steady-state conditions.
• Digital Twin for After-Sales: The C-HIL simulation serves as a digital twin of the delivered plant—enabling safe testing of updates, troubleshooting of malfunctions, and support for O&M operations.
• Full Power Envelope Testing: Automated test procedures push the system to its power capability limits, validating overall performance under predefined active/reactive power setpoints.

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