Recent questions tagged power-system-transmission

Description : What is kelvin's economy law?

Last Answer : Most economical cross section area of conductor is that which makes annual cost of energy loss equal to annual interest & depreciation on capital cost of conductor.

Description : What is skin effect?

Last Answer : If DC is passed through lines, current density is uniform over cross-section If AC is passed total inductance in inner portion > outer portion. Therefore more current flows in outer portion.Hence I² R losses increase

Description : What is long transmission line?

Last Answer : Length is more than 150 km Voltage level is above 100 kV Line constants are considered as distributed over the length of the line.

Description : What is Medium transmission line?

Last Answer : Length is about 50km to 150km Operational voltage level is from 20 kV to 100 kV Capacitance effect is present Distributed capacitance form is used for calculation purpose.

Description : What is short transmission line?

Last Answer : Length is about 50 km. Voltage level is up to 20 kV Capacitance effect is negligible Only resistance and inductance are taken in calculation.

Description : What are the types of transmission line?

Last Answer : Short Transmission Line Medium Transmission Line long Transmission Line

Description : What is transmission line?

Last Answer : Transmission line is the long conductor with special design (bundled) to carry bulk amount of generated power at very high voltage from one station to another as per variation of the voltage level.

Description : Why 3 phase power is used and not 6 phase or 12 phase?

Last Answer : There are two reasons: (1) using three phases results in the lowest conductor cost/watt to transmit power; (2) using three phases displaced in space around a cylinder by 120 degrees results ... degrees - this is a fundamental energy conversion principle for the operation of AC motors and generators.