Study on designing high current density rotor windings of superconducting generator and relation of the stabilities in static and rotating conditions

It is critically important to realize high current density superconducting rotor windings to make a superconducting generator economically competitive to a conventional one. High current density rotor windings inevitably suff er from instability problems. Therefore, the rotor windings should be desig ned for the quench currents to surely exceed the maximum operational curren ts in the rotating condition. In the next step of the Super-GM project, the current density required is 30% higher than that of the rotor winding deve loped in the former Super-GM project. To test the stability of the rotor wi ndings, usually quench tests are conducted in a static and pool-cooled cond ition for the simplicity of the test but presently the relation between the stabilities in the static and rotating conditions is not clear. In the pap er, we study what information can be obtained and how the stability in the rotating condition can be estimated from the static test. Based on this stu dy, we investigate a method to design quench currents of high current densi ty rotor windings to exceed a required value and discuss what level for the quench current to exceed in the static condition to satisfy the requiremen t in the rotating condition.