Power quality (PQ) regulation is of great importance due to the economical consequences associated with the presence of the disturbances in power systems. Regulations should provide interventions at the system level (transmission and distribution networks) and the local level at the point of common coupling between utilities and customers. This paper proposes an integrated approach for overall voltage quality regulation; in particular, it focuses on regulation at the system level, which seems to be widely applicable. The regulation structures proposed for system regulation use global indices to characterize the voltage quality. A numerical application supports the theoretical considerations.