Electrical Power Transmission And Distribution

Typical Transmission and Distribution System Scheme Standard voltages for transmission. Advantages of high voltage transmission. Feeders, Distributors and Service mains.Overhead Transmission Lines Sag calculation in conductors -(a) Suspended on level supports (b) Supports at different levels. Effect of wind and ice tension and sag at erection. Stringing chart.Line Parameters Calculation of inductance of single phase, three phase lines with equilateral and unsymmetric spacing. Inductance of composite conductor lines. Capacitance - Calculation for two wires and three phase lines, capacitance calculation for two wires 3 phase lines with equilateral and unsymmetrical spacing.Characteristics and Performance of Power Transmission Lines Short transmission lines, medium transmission lines, Nominal T and representation of long lines, equivalent T and network representation of long transmission lines. ABCD constants. Power flow through a transmission line, P-V and Q-V coupling.Insulators Types, potential distribution over a string of suspension insulators. String efficiency and methods of increasing string efficiency and methods of increasing string efficiency, testing of insulators.Underground Cables Types, material used. Insulation resistance, thermal rating of cables, charging current. Grading of cables, capacitance grading and inter sheath grading, testing of cables.Corona Phenomena, expression for disruptive and visual critical voltages and corona power loss.Distribution Radial and ring main systems, AC to DC distribution : calculation for concentrated loads.