TEPCO and Furukawa have been developing a compact 66 kV-class high-T c superconducting (HTS) cable that employs two new important technologies. One technology reduces AC losses of HTS cable. In our studies, we found that using twisted filaments in the HTS tapes in the multi-layer conductor and adjusting winding pitches of layers dramatically reduces AC losses. Another technology is related to the mass production of HTS cable. To facilitate mass production, we improved the cable design. A three-phase prototype HTS cable was then successfully fabricated with machines at Furukawa Electric. The results of the performance testing of the cable demonstrated that the proposed design and the production method were appropriate.