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Utility Test > Ch 5 electrical knowledge > Flashcards

Ch 5 electrical knowledge Flashcards

1
Q

a series of power interruptions on a transmission system whereby one interruption increases vulnerabilities and causes additional interruptions, which in turn cause further interruptions, potentially resulting in widespread
blackouts.

A

cascading outage

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2
Q

electric distribution configuration with three phases, but no common neutral wire. There is no fixed difference between phase-to-phase and phase-to-ground voltages.

A

delta construction

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3
Q

inrush of electricity caused when electrical devices, such as motors or transformers, are first switched on, at which time they can draw several times their normal operating electrical load; often occurs when circuits are first re-energized following an outage.

A

Current surge

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4
Q

Electro motive force

A

Voltage

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5
Q

the sum of resistance-inductive resistance and capacitive resistance.

A

impedance

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6
Q

electrification of a wire by passing through a moving electromagnetic field.

A

inductance

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7
Q

amperages in a conductor that are larger than those for which it is rated.

A

overcurrent

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8
Q

protective device mounted on distribution poles or crossarms that isolates line sections or protective zones in order to limit the number of customers who lose service as the result of a fault. They cut off current when an up stream recloser operates, isolating a fault in the line beyond the sectionalizer.

A

line sectionalizer

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9
Q

stationary part of an electrical generator.
Contains field windings.

A

stator

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10
Q

electric facility that does not change voltage but is used to route power through various circuits. May be strategically designed to compensate for portions of a system that are experiencing power failures, protecting circuits through disconnect switches, circuit breakers, relays, and communications systems (compare to substation).

A

Switch yard

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11
Q

wire connection between energized conductors and other electrical equipment, such as transformers.

A

taps

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12
Q

fault that affects the dielectric properties of a system for an instant, and no longer exists after the power has been restored.

A

transient fault

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13
Q

ratio between the two wire coils in a transformer; identical to voltage ratio.

A

turns ratio

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14
Q

electrical potential over a specified distance. In the context of tree-caused electrical faults, it is determined by the voltage and spacing of the lines, as well as stem diameter and species of tree. Greater branch diameter and closer phase spacing create higher gradients. The higher the gradient, the more likely a tree is to cause a fault.

A

voltage gradient

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15
Q

Luminous discharge of electricity through a gap btw 2 conductive objects

A

Spark over

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16
Q

Electricity is generated by industrial _____ through ____

A

Magnets, induction

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17
Q

Each of the 2 coils in a transformer has a different number of turns. The ratio of one to the other is ___ratio, while the proportion of the primary to secondary voltage is the ___ratio

A

Turns, voltage

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18
Q

Which type of current is typically used in power supplies

A

Alternating current

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19
Q

Ivm is an ___-based systematic process

A

Ecosystem

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20
Q

____ ____ the principal protective devices in distribution substations are designed to operate in as little as 10hz

A

Circuit breakers

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21
Q

2 examples of protective equipment

A

Circuit breakers, lighting arrestors

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22
Q

A grid based scheduling system is most likely to be used by highly ______ utilities

A

Urbanized

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23
Q

Why is utility pruning done

A

Maintain safety and right of way

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24
Q

A challenge with grid based scheduling is that circuits may traverse many grids, allowing for a variety of _____ _____

A

Tree conditions

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25
Q

What is the max amount of foliage that should be removed in one growing season?

A

25%

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26
Q

The ____ has been adopted by most states as the document providing safety provisions for those working with or near electric supply equipment

A

Nesc (national electrical safety code)

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27
Q

Utility pruning removes the leaves and reduces a trees _______ growth, but remaining _____ may grow more

A

Overall, shoots

28
Q

Research has shown that trees are more likely to cause outages on ______ -phase lines than on _____-phase lines

A

Three, single

29
Q

Ohm’s Law describes the relationship between:

A

voltage, current, & resistance

30
Q

Formula for power

A

Power = Volts × Current
(P = V x I)

31
Q

____amps may cause cardiac arrest & organ damage, &____
amps will likely kill outright. High voltage
contact usually kills outright regardless of amperage.

A

2, 15-20

32
Q

Protective equipment for electricity is designed to shield the system from:

A

faults, short circuits, & current surges

33
Q

The potential between live conductors & the ground is
known as ___-to-__ _ _ potential

A

phase-to-ground

34
Q

____ ____provide defense against inadvertent re-
energization.

A

protective grounds

35
Q

An interruption in the flow of electricity that could lead to
fire or an outage

A

electrical shorts

36
Q

Amps in a conductor that are larger than those for which it is rated

A

Overcurrent

37
Q

electric generation, the number of magnet revolutions per
second:

A

Hertz

38
Q

A point at which the level of incompatible plant species, density, height, location, condition threatens the stated management objectives and requires implementation of a control method

A

Action thresholds

39
Q

Transmission circuit breakers operate in response to
abnormally high_______ , abnormally low______ , & unequal ________

A

amperage,
voltage,
current

40
Q

The value which if exceeded could expose a widespread
area to instability or cascading outages:

A

interconnection reliability operating limit (irol)

41
Q

electric facility that is used to route power through
various circuits (it does not change voltage):

A

Switchyard

42
Q

Graphical representation of alternating current:

A

Sine wave

43
Q

Inrush of electricity:

A

Surge

44
Q

System that automatically collects data & enables remote
control switching operations

A

supervisory control and data acquisition (scda)

45
Q

Electricity is usually generated at distribution voltage
typically between__-_kV

A

7.5-13.8 kV

46
Q

Volt is also called

A

Electromotive force

47
Q

Region where transmission or extra high transmission lines are connected.

A

Transmission interconnect

48
Q

Used to manage the electrical network

A

Switches

49
Q

Ratio btw the 2 wire coils in a transformer, similar to voltage ratio

A

Turns ratio

50
Q

The proportion of primary to secondary voltage of a transformer

A

Voltage ratio

51
Q

Utility system _____ allows the efficient transmission of electricity to areas of greatest need at a particular moment, which also makes system more susceptible to ______

A

Interactivity, blackouts

52
Q

In an electric transmission or distribution system, the activation of a protective devise

A

Operations

53
Q

In an electric utility system a high priority electric distribution supply line carries electricity from distribution substations to other primary distribution supply lines or transformer

A

Feeder

54
Q

unintentional and undesirable conducting
path or blockage of current in an electrical system

A

Fault

55
Q

Sustained service interruption

A

Outage

56
Q

Current that is bypassing a designed conducting path

A

Short circuit

57
Q

common return path for an electri-
cal circuit or physical connection to the earth

A

Ground wire

58
Q

disruption
of electrical supply.

A

Interruption

59
Q

transient faultin an elec-
trical system, lasting
from 33 to 133 milliseconds.

A

Momentary interruption

60
Q

Electrically operated swich

A

Relay

61
Q

designed for use on overhead electricity distribution networks to detect and interrupt transient faults. Resets quickly

A

Recloser

62
Q

Total duration of customer interruptions/total number of customers. Measures number of minutes average customer is out of power over a year

A

SAIDI/System average interruption duration index

63
Q

It is a measure of the number of outages experienced by the average customer over a year

A

SAIFI/System average interruption frequency index

64
Q

electrically connected to the earth, pro-
viding a path for the flow of electricity to prevent
accidental energizing.

A

Grounded

65
Q

Caused by load lost whenever a current flows into a coil (transformer)

A

Inductive reactance

66
Q

A charge that builds up between long parallel conductors. Portion of load slightly impeded current

A

Capacitive reactance

Utility Test (7 decks)

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