The following losses
take place in the Cable.

**Heating of cable**- The heating of cable depends upon dielectric loss, copper loss and inter sheath loss.

__Copper Loss__- The copper loss depends upon current passing through conductor and resistance of the cable.

__Inter sheath loss__- The inter sheath loss occurs due to circulating current flows in between the sheaths.

__Dielectric loss__- The capacitor is formed between core and sheath.
- There is no dielectric loss if the capacitor is pure but this is not possible.
- The capacitor is represented by parallel combination of resistance and capacitor.
- The Phasor diagram is shown in the Figure.
- The current in the cable leads voltage by an angle less than 90 degree due to presence of resistance.
- The losses occur in the capacitor because the cable is not perfect dielectric.

The capacitor current I

_{C}flows
I

_{C}= V / X_{C}
= ωVC

tan δ = I

_{R}/ I_{C}
= ( V / R ) / ωVC

= V / ωVC R

= 1 / ωCR

R = 1 / ωC tan δ

The dielectric loss P =
V

^{2 }/ R
=

**V**^{2}ωC tan δ
Where δ = Dielectric
Loss angle

- As the dielectric loss
angle is very small, it is considered as tan δ ≈ δ The dielectric loss P = V
^{2}ωC δ

*Parameters affecting Dielectric Loss*- The dielectric loss is directly proportional to square of applied voltage and directly proportional to frequency.

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