Smart transformer/large flexible transformer

Solid-state transformer-based smart transformer (ST) can provide the dc connectivity and advanced services to improve the grid performance and to increase the penetration of the power electronics interfaced resources (e.g., distributed generators and electric vehicle charging stations) in modern electricity distribution grids. Since the ST is a new and effective paradigm of the electricity grid evolution to well understand the ST, this paper systematically presents the basic architecture and the typical control schemes of the ST and then the advanced services that ST can provide to improve the electricity grids performances in terms of the power flow control, power quality improvement, active damping and active contribution to improve distribution grid resilience by means of enabling autonomous microgrids operation as well as launching a restoration procedure following a general blackout.