Electrical Plus Notes

CONTENTS > Line Supports : > Properties for LIne Supports : > Types of Line Supports : > Advantages and Disadvantages of Line Supports : Line Supports Line support palys a major role in power transmission. Line support (like Poles and Towers) are used for supporting the overhead lines or wires. Desired properties for lIne Supports:   1) High mechanical strength to withstand the weight of conductors and wind load etc 2) Light in weight without the loss of mechanical strength. 3) Cheap in cost and economical to maintain. 4) longer life. 5) Easy accessibility of conductors for maintenance. Line Supports Types:   1) Wooden Poles 2) Steel Poles 3) R.C.C. Poles 4) Lattice steel towers   1) Wooden Poles :   These supports are cheap, easily available , provide insulating properties and widey used for distribution purpose in rural areas.  # Span upto 50 meters. # Made of seasoned wood (sal and chir)   Advantages  1)...

Causes of insulation Failure :   (a) Cracking of Insulator - Porcelain insulator mainly consists of three different materials  like main porcelain body, steel fitting arrrangement and cement   to fix the steel part with porcelain. The unequal expansion and contraction  of porcelain, steel and cement are the chief cause of cracking of insulator .   (b) Defective Insulation Material -  If the material used for insulator is defective then it gets easily punctured. (c) Porosity in the Insulation Materials -  When porcelain insulator is manufactured at low temperature then it will make insulator porous and it willl absorb moisture from air which reduces insulation. (d) Improper glazing of Insulator surface - If the surface of porcelain insulator is not properly glazed ,moisture can stick over it and cause insulation reduction. (f)   Mechanical Stresses on Insulator - If insulator has any weak portion due to manufacturing defe...