Dependence of dielectric loss tangent on the parameters of multilayer insulation materials cable

In an alternating electric field ( )0E exp current flows through the dielectric, which is the sum of current density through iCKB and a bias current density iCM:

i i i i E i+CKB CM CKB CM= d dDγ τ=; (1)

The dielectric permittivity is a complex function of frequency:

ε ε ε( )ω ( )ω ( )ω= ′ + ′′i (2)

The total current is divided into active ia and reactive ir cleaving:

i i i E i E+ = = ′a r a ri ;i ( )+ ′′ ε ε ω0 (3)

Thus, a real insulator besides purely reactive current, is the effect of the alternating electric field causes the conduction current through or current leakage caused by a purely resistive conductive dielectric.