Calculation principles for a superconducting inductive FCL and a current-limiting transformer

We present general principles of the parameters calculation and application of two power devices: an inductive fault current limiter and a current-limiting transformer. Both the devices are based on the superconducting - normal state transition in a superconducting switching element magnetically coupled with a primary winding. The relationships between the design parameters of the devices and the limited current, losses and temperature in the superconducting element were investigated. It is shown that, in spite of similarity, the devices have distinctive features manifested in different depths of the fault current limitation. The case of performance of the superconducting winding in the form of HTS BSCCO hollow cylinders is analyzed. Basic parameters of the devices are evaluated for their application in 45 MVA power circuit. Problems of the transition into the normal state and recovery of the superconducting state in the switching element are discussed.