Topics Covered

Inductance of transmission lines: Flux linkage, Inductance due to internal flux, Inductance of single phase two wire lines, Flux linkage of one conductor in a group, Inductance of composite conductor lines. GMD examples; 3 phase lines with equilateral spacing and unsymmetrical spacing. Parallel circuit 3 phase lines. Use of tables. Electrical field; potential difference between points due to a charge, capacitance of a two-wire line. Group of charged conductors. Capacitances of 3 phase lines with equilateral and with unsymmetrical spacing. Effect of earth, parallel circuit lines. Resistance and skin effect: Resistance and temperature, skin effects, influence on resistance, use of table, Current and voltage relation on a transmission line, T-  and pi-  representation, exact solution. Equivalent circuit of a long line. Mechanical characteristics of transmission line: Sag and stress analysis; Wind and ice loading, supports at different elevation conditions at erection; effect of
temperature changes. Generalized line constant: General line equation in terms of A, B, C, D constants. Relation between constants, charts of line constants, constants of combined networks, measurement of line constants. Circle Diagrams: Receiving end and sending end power circle diagrams. Voltage and power factor control in transmission systems. Tap changing Transformers; on load tap changing. Inductance regulators. Moving coil regulators; Boosting transformers. Power factor control; static condensers; synchronous condenser. Insulators for overhead lines; types of insulators, their construction and performance. Potential distribution in a string of insulators, string efficiency. Methods of equalizing potential distribution; special types of insulators, testing of insulators. Insulated cables, cables versus overhead lines, insulating materials. Electrostatic stress grading. Three core cables; dielectric losses and heating. Modern development; oil filled and gas filled cables. Measurement of capacitance. Cable testing. Introduction to transmission line
protection: over current relay and time grading, reverse power relays. Differential protection. Distant relays. Distribution: Distributor calculation, ring mains and interconnections.