Grid appliances, based on superconducting materials, can reduce the threats to power grids posed by lowered grid impedances due to decentralization in grid topology and offer further advantages. This book introduces superconducting materials, the functionality of a superconducting current limiting transformer and the design and optimization process behind such a device. It further presents the manufacturing of a superconducting hybrid transformer of the 1 MVA-class and its experimental testing. ...