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
