The 10 MW Dynamic Nacelle Testing Laboratory of Fraunhofer IWES provides a controlled environment for performing electrical and mechanical tests on a wind turbine nacelle. Apart from physical testing, system level simulations are another paradigm in the framework of nacelle testing. In this contribution, the development of a dynamic model of the load application system for the 10 MW nacelle test bench is presented. The test bench load application system controls are integrated in the model via co-simulation in Simulink. The model is evaluated using experimental results. By utilizing the modal strain recovery method, a direct comparison of the strain results of the model with the experimental results is achieved. Moreover, it is shown that the actual applied loads on the device under test can be estimated by analysing the strain readings. The developed model provides a platform for developing a high fidelity virtual nacelle test bench.