AC superconducting cables are usually to be bundled by many strands to make
large current capacity for AC power applications. Superconducting strands
composing multistage cables have twisted structure in each stage for lower
AC loss and higher stability. So, when transport currents flow in a cable,
each strand is exposed to longitudinal and azimuthal magnetic fields produc
ed by transport current flowing in strand itself and longitudinal and trans
verse magnetic fields by transport current flowing in twisted cable. In thi
s paper, we calculate the self field loss generated in second stage superco
nducting cable considering twist of strands in cables and filaments in stra
nds. Also, we describe the influence on self field loss by twist direction
of filaments and strands.