What are transmission lines made of
Bare, steel-cored- aluminum overhead lines
What is the range of transmission voltages
60kv to 765kv
Hydro max is 500kv
What is installed to prevent Transmission Line Galloping
Dampers
Benefits of HV
Reduce line current, reduce power loses, reduce weight
What are the three ways to get power to us
Generation, transmission, distribution lines
How to reduce corona
Bundle cables with spacers, use Corona rings at weak points
What effect does corona have
Power losses interferes with radio signals
What is corona
Ionized air
What causes tracking
Contamination x moisture x high voltage
An electrostatic field is due to what
Voltage
Medium voltage is determined by the IEEE standards as
2400v to 69,000v
What effect does electric stress have on insulation
Weakens the insulation
What does BIL stand for and what significance does it have for the insulation of Hv equipment?
Basic impulse insulation level.
Requires higher levels of insulation than rated volts would increase
What is a sub station
Area that controls circuit, breakers, disconnects, transformers, lightning, arresters, and other associated equipment
What is a unit sub station
Modular construct enclosure, housing HV terminations, bus bars, circuit breakers, Transformers, low-voltage circuit breakers
HV equipment must always be installed in a vault
False
What is the primary purpose of a series reactor in a HV system?
Limit The magnitude of fault current
How come the use series reactors reduce the cost of substation installation?
By allowing the use of circuit breakers with lower interrupting capacity
What are the main parts of a surge arrestor
Airgap and thyrite material
What are the five general steps to be taken in a safe testing
Disconnect
Lockout.
Test
Ground.
Screen off nearby live parts if needed
What is the minimum safe distance to be maintained when work is to be done in the vicinity of a 25kv line
3 m
What is likely to be higher step voltage or touch voltage
Touch voltage
What fuses have a replaceable cartridge
Boric acid fuse
What fuse are you least likely to encounter
Liquid fuse
