Electric power transmission moves large amounts of electricity from generating plants to substations, where it can be sent onward to customers. Understanding the purpose of transmission and why voltage is raised helps explain how electricity can travel efficiently over long distances.
Electric power transmission is the bulk movement of electrical energy from a generating site to an electrical substation. A long conductor that carries this energy is a transmission line. Connected transmission lines form a transmission network.
All flashcards
What does a transmission matrix relate?
Sending-end voltage and current to receiving-end voltage and current on a transmission line.
What is subtransmission?
The movement of power at lower voltages from the main network across an area to smaller substations.
What is thermal sag in an overhead line?
The downward movement of a conductor as heating causes it to expand.
Why are transmission networks often considered natural monopolies?
Building competing parallel networks may be inefficient.
What is single-wire earth return (SWER)?
A system that supplies single-phase power using one conductor and an earth return path.
Quiz questions
Why can an HVDC link connect two AC grids that are not synchronized?Answer: It controls DC power transfer independently of the grids’ phase angles.
Why can long underground AC cables have limited useful power transfer?Answer: Their capacitance becomes significant over long distances.
What is a benefit of bundling conductors in a high-voltage line?Answer: It can increase capacity and reduce corona-related losses.
Which resources are commonly suited to serving base load?Answer: Plants suited to steady operation, such as nuclear, coal, or hydroelectric facilities.
What do protective relays do when a transmission fault occurs?Answer: They detect faults and signal circuit breakers to isolate damaged sections.