Wind energy is projected to become a leading source of electricity worldwide, driving rapid expansion in wind turbine (WT) deployment onshore and offshore. Ensuring compliance with evolving grid codes is essential for successful operation of these turbines. Traditional field-based testing is constrained by site conditions, lengthy timelines, and specialized equipment, while the increasing scale and complexity of turbines make them costly and, in some cases, technically unfeasible. At the same time, new grid-forming requirements demand advanced WT capabilities—including inertial response, fault ride-through and islanded operation—that are difficult to demonstrate in the field.

This paper presents a co-simulation-based Controller Hardware-in-the-Loop (CHiL) approach for verification of grid-forming capabilities of WTs. Designed to complement field measurements, the test enables verification of advanced grid-forming capabilities that are otherwise impractical to test on site. Aerodynamic and mechanical subsystems are modeled in DNV Bladed®, while the permanent magnet synchronous generator, converter, and grid are simulated in real time. Actual turbine and converter controllers are integrated as hardware replicas. The testbed enables realistic assessment of electromechanical interactions under grid disturbances and supports validation of inertial support and other advanced services. Results demonstrate a practical path to reduce testing time and cost while accelerating deployment of grid-forming WTs.