Characterization of a Superconducting Power Filter for Embedded Electrical Grid Application

Stability issues exist in embedded electrical grids, mainly due to power electronics. One of the solutions is to use a superconducting power filter (SPF), made of a non-inductive superconducting coil. The DC losses are close to zero, the coil being in its superconducting state. The AC losses, proportional to the frequency, are weak but still exist and can be used to increase the stability of the DC grid. In this paper, different SPF prototypes are presented and experimental characterizations are exposed: measurements of the critical current, measurements of AC losses and measurements of AC+DC losses. This AC+DC loss measurement is unusual, tricky and especially developed for SPF application. Experimental results are discussed and compared to calculations obtained with the analytical Norris formulas. Strip model formula underestimates losses and elliptical section formula overestimates losses but both formulas give good approximation of the losses and are therefore useful tools to design a SPF.