Chap 5 Questions Flashcards
A/an ____ is a measure of electrical current.
Amp
Voltage used by North American utilities generally ranges from ____V for end users (customers) to ____kV for the largest transmission lines.
120, 765
A ____ is a blocked current or a bypass of an intended conducting path.
fault
Transmission lines terminate at ____, where voltages are changed using transformers to step up or step down the voltage in the lines.
substations
Primary distribution lines have lower ____ than transmission lines, which is safer and easier to work with.
voltage
Fiberglass, glass, polymers and porcelain are good ____; aluminum and copper are good ____.
insulators, conductors
____ ____ is used on distribution lines in densely forested areas to provide some protection from faults caused by branches.
tree wire
____ ____, the principal protective devices in distribution substations, are designed to operate in as little as 10 cycles.
circuit breakers
Electrical flow in an unintended direction is called ____ ____.
back feed
Three tree and electrical system characteristics that influence the likelihood of a tree-related service interruption are ____ ____, ____ ____, and ____.
voltage gradient, stem diameter, spieces
Two indices used to quantify reliability are SAIFI and SAIDI which measure the ____ and ____ of interruptions experienced by the average customer over a given period.
frequency, duration
The most common cause of tree related service interruptions is ____ ____ failure.
mechanical tear down
The utility system’s ____ allows the efficient transmission of electricity to areas of greatest need at a particular moment, which also makes the system more susceptible to ____.
interactivity, blackouts
The ____ ____ ____ ____ or MVCD is a calculated distance inside of which vegetation may not encroach.
minimum vegetation clearance distance
The capacity of a material to transmit electricity is referred to as
A) electrical fault
B) electromagnetic field
C) conductivity
D) inductance
C) conductivity
A transformer that is intended to reduce voltage is known as
A) capacitor
B) step down transformer
C) step up transformer
D) voltage regulator
B) step down transformer
Which of the following is not true of aluminum wire?
A) it is lightweight
B) it is low cost
C) it has more conductivity than copper
D) it can span longer distances than copper.
C) it has more conductivity than copper
Which of the following is true of guy wires?
A) they are intended for support rather than electrical conduction
B) they are made of steel and are therefore conductive
C) they can become energized by direct or indirect contact with energized wire
D) all of the above
D) all of the above
Electricity seeks the path of least resistance to the ground.
A) true
B) false
A) true
Transmission circuit breakers operate in response to all of the following irregularities, except
A) abnormally high amperage
B) abnormally high voltage
C) abnormally low voltage
D) unequal current.
B) abnormally high voltage
