# Documentation

 Symbol Name Unit S $s_{air}$ Axial spacing between objects m $s_{b1}$ Thickness of surface layer m $s_{b2}$ Thickness of middle layer m $s_{b3}$ Thickness from object to top of bedding layer m $s_{b4}$ Thickness from object to bottom of bedding layer m $s_c$ Separation of conductors in a system mm $s_{cm}$ Separation of conductors in a system m $S_G$ Apparent power at injecting point kVA $S_{gas}$ Sutherland's constant K $s_{ij}$ Spacing between object i and j $S_k$ Cross-sectional area of current carrying component mm$^2$ $s_{S1}$ Spacing between phases in 1st section p.u. $s_{S2}$ Spacing between phases in 2nd section p.u. $s_{S3}$ Spacing between phases in 3rd section p.u. $SI$ Surge Impedance $\Omega$ $\sigma$ Stefan Boltzmann constant W/m$^2$K$^4$ $\sigma_{ab}$ Volumetric heat capacity of armour bedding J/K.m$^3$ $\sigma_{ab,1}$ Volumetric heat capacity of 1st armour bedding J/K.m$^3$ $\sigma_{ab,2}$ Volumetric heat capacity of 2nd armour bedding J/K.m$^3$ $\sigma_{ar}$ Volumetric heat capacity of armour material J/K.m$^3$ $\sigma_c$ Volumetric heat capacity of conductor material J/K.m$^3$ $\sigma_d$ Volumetric heat capacity of duct material J/K.m$^3$ $\sigma_{d,fill}$ Volumetric heat capacity of duct filling J/K.m$^3$ $\sigma_{encl}$ Volumetric heat capacity of enclosure material J/K.m$^3$ $\sigma_f$ Volumetric heat capacity of filler J/K.m$^3$ $\sigma_{fluid}$ Volumetric heat capacity of fluid J/K.m$^3$ $\sigma_i$ Volumetric heat capacity of insulation material J/K.m$^3$ $\sigma_{ins}$ Volumetric heat capacity of insulation J/K.m$^3$ $\sigma_j$ Volumetric heat capacity of jacket material J/K.m$^3$ $\sigma_{k2}$ Specific isobaric volumetric heat capacity of layer located below J/K.m$^3$ $\sigma_{k3}$ Volumetric heat capacity of layer located above J/K.m$^3$ $\sigma_{kc}$ Volumetric heat capacity of metallic component J/K.m$^3$ $\sigma_{ki}$ Volumetric heat capacity of adjacent material J/K.m$^3$ $\sigma_{pipe}$ Volumetric heat capacity of fluid-filled pipe J/K.m$^3$ $\sigma_{prot}$ Specific isobaric volumetric heat capacity of protective cover J/K.m$^3$ $\sigma_{sc}$ Volumetric heat capacity of screen material J/K.m$^3$ $\sigma_{scb}$ Volumetric heat capacity of screen bedding J/K.m$^3$ $\sigma_{scs}$ Volumetric heat capacity of screen serving J/K.m$^3$ $\sigma_{sh}$ Volumetric heat capacity of sheath material J/K.m$^3$ $\sigma_{shj}$ Volumetric heat capacity of sheath jacket material J/K.m$^3$ $\sigma_{skid}$ Volumetric heat capacity of skid wires J/K.m$^3$ $\sigma_{sp}$ Volumetric heat capacity of steel pipe material J/K.m$^3$ $\sigma_{sun}$ Absorption coefficient of solar radiation