Estimation of fault currents in offshore wind power plants connected through HVdc links

A mathematical analysis is developed in this paper to estimate the value of short-circuit currents in HVdc links. The study allows to calculate the evolution of the fault currents, their maximum values and the time they are reached. Thus, it can help to select adequate protection systems for HVdc grids. The mathematical study is verified by means of PSCAD simulations where the theoretical and simulated results are compared for a point-to-point link interconnecting two HVdc links. Next the study is extended to HVdc links where one converter station is connected to a wind power plant and the influence of the wind farm control is analyzed. The results show a good agreement between the estimated and the simulated fault currents.