Cable Parameters: Insulation Resistance,Charging Current, Dielectric Losses

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;
- 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 ω10-6   A/km

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 Uo2 tanδ 10-6   watt/km/phase

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.



Comments

Popular posts from this blog

Star Delta Starter Line Diagram and Its Working Principle

ELECTRICAL DISTRIBUTION BOARD DB WIRING

EARTH ELECTRODE RESISTANCE MEASUREMENT

SURGE ARRESTERS SPECIFICATION FOR 132 KV & 33 KV LINE

Why Purge System Is Required For Refrigerant and How Does It Operate in Chiller Compressor

STEP AND TOUCH POTENTIAL: REDUCE ELECTRICAL HAZARD AND IMPROVE SAFETY AWARENESS

CURRENT TRANSFORMERS –CT USING

ভুমিকম্পের কল্প কথা

How Economizer Works in Centrifugal Chiller

wazipoint

DMCA protected

The content is copyright protected to wazipoint and may not be reproduced on other websites.