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Definition for flat with/without transposition is according to IEC 60287-1-1.The same definition can also be found in 'General Calculations Excerpt from Prysmian Wire and Cable Engineering Guide' (2015), the parameter is called $X_M$ instead of $X_s$.
Definition for variation of spacing is according to IEC 60287-1-1.
Definition for PAC/GIL is analog to cables without transposition.
| $\omega \frac{\mu_{0}}{2\pi} \ln\left(\frac{2s_{c}}{d_{s}}\right)$ | cables without transposition |
| $\omega \frac{\mu_{0}}{2\pi} \ln\left(\frac{2a_{m}}{d_{s}}\right)$ | cables with regular transposition |
| $\omega \frac{\mu_{0}}{2\pi} \ln\left(2\sqrt[3]{2} \frac{s_{c}}{d_{s}}\right)$ | cables with regular transposition in equidistant flat formation (special case of the above) |
| $1.25X_{e}$ | unknown variation of spacing between sheath bonding points |
| $\frac{a_{S1} X_{e1}+a_{S2} X_{e2}+a_{S3} X_{e3}}{a_{S1}+a_{S2}+a_{S3}}$ | known variation of spacing between sheath bonding points |
| $F_{lay,3c} X_{e}$ | CIGRE TB 880 Guidance Point 44, three-core cables |
| $\omega \frac{\mu_{0}}{2\pi} \ln\left(\frac{2.3s_{c}}{d_{s}}\right)$ | CIGRE TB 880 Sample case 3, pipe-type cables cradled |
| $\omega \frac{\mu_{0}}{2\pi} \ln\left(\frac{2S_{m}}{D_{encl}-t_{encl}}\right)$ | PAC/GIL |