In this paper, the real-time boundary wavelet transform (RT-BWT) method is proposed for dc fault protection in multi-terminal high voltage dc (MTDC) grids. The proposed method is developed and tested in a real-time simulation platform. A wide range of test scenarios have been adopted considering ac and dc fault conditions, including variations in fault resistance, fault event distance, dc reactor inductance, external fault events, and changes in topology. The results and statistical analysis show the effectiveness and performance of the RT-BWT method in providing fast, sensitive, selective, and robust dc fault protection, even without the need for communications