PHEP 31 Flashcards
Transmission lines are used for the purpose of…
- transmitting the highest voltage circuits on any given system
- Tying together the major generating stations and primary sub stations
- Interconnecting major electrical systems for the interchange of power
In discussion related characteristics of transmission lines, it can be said that the higher the voltage…
The lower the I^2R losses
The energy stored in the magnetic fields of conductors is…
Called wattless energy.
Electrostatic and electromagnetic imbalance between phases in a three phase transmission system is reduced by…
Transposing, or rotating the conductors.
The steel core of a ACSR conductor does not…
Carry any appreciable amounts of load current
Transmission line losses due to corona, may be reduced by all of the below, except…
- increasing Voltage value
- Increasing the diameter of the conductor
- Keeping the surface of the conductor as clean and smooth as possible
- Increasing the spacing between the conductors
Increasing the voltage value
What is a characteristic of bundled conductors?
They reduce inductive reactance
An electrical transmission system may be caused to drop out of step, or become unstable by…
- A sudden increase in load
- A sudden decrease in load
- A short circuit
Switching performed under short circuit conditions is apt to be most disturbing to transmission lines when…
Done on low voltage side
The voltages induced in the lead sheath of underground cables may be eliminated by…
- installing porcelain insulators to sectionalize the sheath
- Transposing
- Cross-bonding
Material such as Thyrite would most likely be used in…
A valve type lightning arrester
What is not an advantage in the transmission of HVDC as compared to AC except for…?
The overall insulation requirements may be based on the peak rather than actual voltages
HVDC transmission lines cannot…
Be protected from faults by using conventional circuit breakers
In a HVDC transmission system…
The quantity and direction of power flow may be controlled with high accuracy and extreme rapidity
Suspension type insulators…
-Must be able to accept flashover without shattering
-Are designed to resist thermal shock
-Should be able to accept some amount of mechanical impact
