TRANSMISSION LINES DESIGN and ELECTRICAL ENGINEERING HUB

Porcelain insulators (bell type) were first created in 1849 by Werner von Seimens. Porcelain Insulators was originally used for insulation of telephone lines. Since then, porcelain insulators have evolved and has found vast usage especially in the transmission lines system acting as insulators. Porcelain Insulators have two basic purposes on transmission lines: 1.To support conductors and attache them to structures 2.To electrically isolate conductors from other components on a transmission line The second purpose is very important to operation since without some form of insulating material, electrical circuit cannot operate. To be able to isolate conductors, insulators must be made of materials that offer a great deal of resistance to the flow of electricity. Porcelain is one of the most highly used insulator type along with glass and other synthetic materials. Porcelain is a multiphase ceramic material that is obtained by heating aluminum silicates until a mullite phase is f...

The Right of Way Before we are going to discuss the classification of power lines, it is good to be acquainted with the concept of the Right-of-Way. Transmission lines are normally constructed on a tract of land known as right-of-way. In most cases, only one type of structure is used on a right-of-way. But there are also instances wherein different types of structures and different types of lines are being put. A right-of-way may follow a straight path, or may change direction in order to avoid obstacles, which happen in many cases. This change in direction causes strain on structures, and the need to compensate from these strains causes the emergence of much type of Transmission Line Structures. The general types of structures used on transmission lines are wooden poles, concrete poles, metal or steel poles, and lattice towers. These structures can be classified as tangent, angled, or dead-end structure, depending on how it is used in a line. Dead-End Structures Dead-...

Power Cable Capacitance (C) Formula Single Conductor Shielded Cable         C = 0.024113 x e/ [log (d2/d1)]   microfarad/ kilometer where: e = dielectric constant for XLPE = 2.3, PVC = 5.0-7.0 d2 = diameter under insulation d1 = diameter over the insulation Power Cable Insulation Resistance (IR) Formula According to ICEA Specification IR @ 15.6 degrees C = K log (d2/d1)    Megaohm - 1000ft According to JIS Specification IR @ 20.0 degrees C = 3.665 x 10^-12 x p x log (d2/d1)    Megaohm - km where: d2 = diameter under insulation d1 = diameter over the insulation K = constant (XLPE = 20,000; PVC = 500) p = volume density (ohm-cm) ; XLPE = 2.5 x 10^15, PVC = 1 x 10^13 Power Cable Inductance (L) Formula Multiple conductor cable or single conductor cable arranged in parallel and three single conductor arranged in triangular           L = 0.46 log (S/d) + 0.19   ...