← All revision guidesSEMESTER 3 · DI03000101
6FLASHCARDSTransmission and Distribution
Line parameters, substations, feeders and distribution performance.
Transmission
Q1Why is electrical power transmitted at high voltage?
For the same power, higher voltage reduces current, I²R losses and conductor size.
Q2What causes corona?
Ionisation of air around a conductor when the electric field exceeds the critical value.
Q3Define voltage regulation of a line.
The change in receiving-end voltage from no load to full load, expressed as a percentage of full-load voltage.
Distribution
Q1Differentiate feeder and distributor.
A feeder carries power without normal tapping and is sized by current; a distributor has taps and is designed for voltage drop.
Q2What is a ring-main system?
A distributor forming a closed loop and fed at one or more points for better reliability and voltage profile.
Q3Why is a substation earthing grid used?
It provides a low-impedance fault path and controls touch and step potentials.