Super massive black hole (SMBH) winds, detected in the X-rays as blueshifted absorption troughs, are now considered a fundamental component in the overall understanding of active galactic nuclei (AGN), as they can provide the feedback required by galaxy evolution models. In this talk I will present the main results from the study of the luminous quasar PDS 456, which is host to one of the most powerful SMBH winds. I will show that the significant short-term X-ray spectral variability suggests that the outflow is characterized by a highly ionized component located closer to the SMBH, and a less ionized, colder and denser component located further out. I also investigated the physical origin of the observed prominent X-ray flares and their implications for the properties of the accretion disc corona. Finally, I will present a new result, where we find a direct correlation between the disc-wind outflow velocity and the luminosity in PDS456.