The Design to Downsize a Conduction-Cooled LTS Pulse Coil for UPS-SMES as Protection From Momentary Voltage Drops

The stability margin of a conduction-cooled LTS pulse coil with stored energy of 1 MJ, which is used for UPS-SMES as protection from momentary voltage drops, is estimated from thermal analyses using the two-dimensional finite elementary method. How much the 1 MJ coil is able to be downsized is discussed. The winding conductor of this coil is a NbTi/Cu Rutherford cable, which is extruded with aluminum. Dyneema FRP and Litz wires are used as the spacers of this coil. In the design of this 1 MJ coil, the effects of spacers were neglected. In order to estimate the stability margin, thermal analyses was carried out by taking into account the thermal effects of spacers, for the coil during overload operation. And it was checked whether the maximum temperature The results showed that the 1 MJ coil has a large stability margin of 8 times the rated ac loss. In addition, new coils with a stability margin of about two times were designed. Possibilities for reducing the size and the cost of a 1 MJ LTS pulse coil are also shown.