### Cable Parameters: Insulation Resistance,Charging Current, Dielectric Losses

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**Cable Parameters: Insulation Resistance,Charging Current, Dielectric Losses
**

Before we formulated cable basic parameters resistance, inductance and capacitance, now we will try to 3 more parameters like Insulation Resistance, Charging Current and Dielectric Losses.

**Insulation Resistance:**

Using the following formula you can calculate insulation resistance in mega-ohm per kilo-meter of cable, to do this you consider the insulation material, diameter of cable including semiconductor layer, diameter of insulated core.

**R =K In (D/d )**MΩ/km

Where

**R**= Insulation resistance in MΩ/km;

**K**= Constant depends on the insulation material;

**d**= Diameter of the conductor in mm including the semiconducting layer;

**D**= Diameter in mm of the insulated core;

**MΩ**- mega ohm,

**km**- kilo meter,

**mm**- mili meter.

**Charging Current:**

The charging current is the capacitive current which flows when AC voltage is applied to the cables as a result of the capacitance between the conductor and earth, and for a multi-core cable in which cores are not screened, between conductors. The value can be calculated from the following equation.

**IC = Uo**

**ω**

**C**

**10**

**A/km**

^{-6}
Where

**IC**

**= Charging current in Ampear/km;**

**Uo**=Voltage in volt between phase and earth;

**ω**= 2 π f (π=22/7, f= frequency in hertz) Hz;

**C**= Capacitance in micro-farad per kilo-meter to neutral;

**Dielectric Losses:**

To calculate the dielectric losses of an AC cable are proportional to the Capacitance, the frequency, the phase voltage and the power factor. The value in watt per kilo-meter per phase can be calculated from the following equation.

**WD = 2 π f C Uo**

^{2}**tan**

**δ 10**

**watt/km/phase**

^{-6}
Where

**WD**

**= Dielectric losses in watt/km/phase;**

**f**= Frequency in hertz;

**C**= Capacitance in micro-farad per kilo-meter to neutral;

**Uo**

**= Voltage in volt between phase and earth;**

**tanδ=**Dielectric power factor.

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