Real-Time Operational Assessment Of A Hybrid AC-DC Grid With Wind Integration Under Normal And Faulted Conditions

The increasing penetration of offshore wind generation introduces significant operational challenges due to its stochastic and intermittent nature. The rapid growth of renewable energy penetration, along with the increasing requirement for efficient long-distance bulk power transfer, has driven strong interest in hybrid AC-DC power grid architectures. This paper investigates the application of a multi-terminal high-voltage direct current (MTDC) system embedded in a hybrid AC-DC grid for assessing real-time operating behavior, with the objective of improving overall system stability. The study is carried out by implementing a hybrid grid model derived from the CIGRE B4.57 benchmark in DIgSILENT PowerFactory. Wind generation and load demand are modeled as time-varying signals. Both steady-state and time-domain simulations are performed under normal operation and contingency conditions, including an AC line outage three-phase fault. The results show that the MTDC grid maintains bus voltages more effectively than a conventional AC network. Although the power flows on the transmission lines fluctuate as the generation and load vary over time, they remain within acceptable operating limits. In particular, when temporary faults occur on both the DC and AC lines, the system voltage experiences only a short-term deviation and is quickly restored to a stable post-fault condition. These findings indicate that the MTDC-based grid not only enhances power transfer flexibility but also significantly improves voltage stability and overall system operational reliability.