Featured post

What Is Fluid and Its Properties?

Science helps to understand things in a better way. We know about fluid but science helps to understand different aspects of it in a better ...

09/12/2020

Insulation Resistance of Single Core Cable


  • The insulation of proper thickness over the conductor is provided in order to prevent leakage current. 
  • The leakage current is a current which flows in a path that don’t intend to provide to it. As the conductor is circular, the path of leakage current is radial.

Let us

  • Radius of the single core conductor of cable = r1
  • Internal sheath radius = r2
  • Length of cable = L
  • Resistivity of cable insulation = ρ

insulation-resistance-of-single-core-cable.png


Let us consider very small thickness of insulation dx at radius x distance.

  • Area of leakage current flows = 2πxL
  • Length through leakage current flows = dx
  • Insulation resistance of layer dx = ρ ( dx / 2πxL )

Insulation resistance of cable

insulation-resistance-of-cable.png






       

    

 R α ( 1 / L )

  • The insulation resistance is inversely proportional to length of cable. If the length of cable decreases, its insulation resistance increases and vice versa.

You may also like : 

Right of way ( ROW ) in the Transmission line

Disadvantages of low power factor

Effect of frequency on skin effect

Minimum clearance between transmission line conductor and ground 


No comments:

Post a Comment