Cody's Utility Specialist Class > Electrical Knowledge > Flashcards

Electrical Knowledge Flashcards

(89 cards)

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1
Q

What is voltage?

A

The electrical potential difference or pressure that drives current through a conductor.

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2
Q

What is current?

A

The flow of electric charge through a conductor measured in amperes.

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3
Q

What is resistance?

A

The opposition to current flow in an electrical circuit measured in ohms.

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4
Q

What does Ohm’s law state?

A

Voltage equals current times resistance (V = I × R).

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5
Q

Define conductor in electrical systems.

A

A material that allows electricity to flow with low resistance.

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6
Q

Define insulator in electrical systems.

A

A material that resists electrical flow and prevents unintended current paths.

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7
Q

What is grounding?

A

Connecting equipment or systems to earth to prevent dangerous voltages and provide a safe fault path.

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8
Q

What is bonding?

A

Connecting conductive parts to maintain equal electrical potential and reduce shock hazard.

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9
Q

What is induction?

A

The transfer of electrical energy from an energized line to a nearby object through electromagnetic fields.

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10
Q

Which type of induction occurs when a nearby energized line induces voltage into a parallel de-energized line?

A

Static induction.

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11
Q

Which type of induction occurs due to magnetic fields from current flow in adjacent lines?

A

Magnetic induction.

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12
Q

What is step potential?

A

Voltage difference between a worker’s feet caused by current traveling through the ground after a fault.

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13
Q

What is touch potential?

A

Voltage difference between a grounded object the worker touches and their feet during a fault.

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14
Q

Which hazard is greater: step or touch potential?

A

Touch potential.

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15
Q

What is the purpose of grounding a line during maintenance?

A

To prevent hazardous voltages and provide a low-resistance path for induced or fault current.

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16
Q

What does MAD stand for?

A

Minimum Approach Distance.

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17
Q

What determines minimum approach distance?

A

System voltage, altitude, and worker insulation factors.

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18
Q

Multiple choice: Which increases MAD? A) Higher voltage B) Lower voltage C) Moisture only D) Conductor size

A

A) Higher voltage.

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19
Q

What is a distribution line typically energized at?

A

4 kV to 35 kV.

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20
Q

What is a transmission line typically energized at?

A

69 kV to 765 kV.

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21
Q

What is a substation?

A

A facility where voltage is transformed, controlled, or switched within the electrical grid.

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22
Q

Name three major substation components.

A

Transformers, circuit breakers, and bus structures.

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23
Q

What is a transformer?

A

A device that changes voltage levels using electromagnetic induction.

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24
Q

What is a circuit breaker?

A

A protective device that interrupts fault current automatically.

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25
What is a recloser?
A device that interrupts momentary faults and automatically restores power if the fault clears.
26
What is a fuse?
A protective device that melts when current exceeds its rating.
27
Which device recloses automatically: breaker
fuse, or sectionalizer? , A recloser.
28
What is a sectionalizer?
A device that counts fault operations and opens during a breaker's open interval.
29
What is a fault?
An abnormal electrical connection resulting in excessive current flow.
30
Name three common fault types.
Phase-to-phase, phase-to-ground, and tree contact.
31
How does vegetation cause outages?
By contacting energized conductors or causing faults between phases or ground.
32
Multiple choice: What does fault current depend on? A) Conductor color B) Soil moisture C) System voltage and impedance D) Tree species
C) System voltage and impedance.
33
What is arc flash?
A dangerous release of energy caused by an electrical arc during a fault.
34
What determines arc flash severity?
Voltage, available fault current, distance, and exposure time.
35
What is a conductor sag affected by?
Temperature, loading, and tension.
36
What increases conductor sag?
Higher temperature.
37
Why is sag important in UVM?
Sagging conductors can reduce clearance to vegetation and increase outage risk.
38
What is a neutral conductor?
A grounded conductor used to carry unbalanced current in distribution systems.
39
What is a phase conductor?
An energized conductor carrying voltage to customers.
40
What is a guy wire?
A support wire used to stabilize poles.
41
What must be done to guy wires for safety around vegetation?
They must be properly grounded to prevent hazardous touch potential.
42
What is a capacitor bank used for?
Improving system voltage and power factor.
43
Why should vegetation inspectors identify capacitor banks?
They create switching hazards and elevated ground-level voltage gradients.
44
What is a regulator?
A device that maintains consistent voltage on distribution lines.
45
What is an overhead switch?
A device used to disconnect or reroute power in a circuit.
46
What is a pad-mount transformer?
A ground-level transformer in a locked metal cabinet used in underground distribution.
47
Why do padmount transformers present ground potential hazards?
Faults or internal failures can energize the surrounding soil and metal surfaces.
48
What is an underground distribution system?
A system using buried cables, padmount transformers, and switchgear.
49
Why are UG systems risky during vegetation work?
Damaged cables can be unseen and faults can energize the ground.
50
Define circuit load.
The amount of electrical demand placed on a conductor.
51
Define short circuit.
A low-resistance connection between conductors causing excessive current.
52
What is a load tap changer (LTC)?
A device that adjusts transformer output voltage under load.
53
What is a right-of-way (ROW) in electrical systems?
A defined corridor that provides space for electrical equipment and safe vegetation clearance.
54
Why is understanding electrical equipment important in UVM?
To identify hazards, maintain clearances, and prevent outages.
55
Multiple choice: What increases induction risk? A) Parallel lines B) Wet vegetation only C) Birds D) Wood poles
A) Parallel lines.
56
Why can vegetation become energized without touching a line?
Through induction or energized conductor leakage.
57
Define energized vegetation.
A tree or branch carrying electrical potential due to contact or induction.
58
Define potential gradient.
The change in voltage over distance, especially during faults.
59
Why must grounds be placed on both sides of a worksite?
To protect workers from backfeed or induced voltages.
60
What is backfeed?
Unexpected electrical energy flowing from alternate sources such as generators or other circuits.
61
What is tagging and locking out?
A system to prevent re-energization of electrical equipment during work.
62
Why should vegetation workers know basic switching procedures?
To recognize switching hazards and avoid energized equipment.
63
What are high-impedance faults?
Faults where current is limited by soil, vegetation, or other resistance.
64
Why are high-impedance faults dangerous?
They may not trip protection devices but can energize the ground surface.
65
Which type of line is more likely to be affected by tree contact: distribution or transmission?
Distribution.
66
Why do transmission lines require wider ROWs?
Higher voltage creates larger electrical fields and greater required clearances.
67
What is a shield wire?
A grounded conductor above phase conductors that protects against lightning strikes.
68
Why should workers avoid touching grounded equipment during storms?
Ground potential rise can cause touch hazards.
69
What is stray voltage?
Low-level voltage present on grounded objects due to normal system operation or faults.
70
What is equipotential bonding?
Creating a zone where all conductive objects share the same electrical potential.
71
Why is equipotential important?
It reduces the risk of touch and step potential during faults.
72
What is a switching surge?
A temporary spike in voltage caused by switching operations.
73
Multiple choice: Which scenario increases arc flash risk? A) Low voltage B) High available fault current C) Dry soil D) Cold weather
B) High available fault current.
74
Why must UVM personnel understand electrical phase identification?
To report hazards accurately and assist utilities in assessing outage risk.
75
What is a phase-to-phase fault?
A short between two energized phase conductors.
76
What is a phase-to-ground fault?
A short between a phase conductor and earth or grounded equipment.
77
What is an insulator string?
A series of insulator units supporting high-voltage conductors on transmission towers.
78
Why can dirty or damaged insulators cause outages?
They allow leakage current or flashovers.
79
What is a right-of-way encroachment?
Vegetation or structures intruding into required electrical clearance space.
80
Why is vegetation clearance especially critical after rain?
Wet vegetation increases conductivity and flashover risk.
81
Define electromagnetic field (EMF).
A field produced by voltage (electric field) and current (magnetic field).
82
What affects EMF strength?
Voltage, current, and distance from the conductor.
83
Do EMFs energize trees?
No, but they can contribute to induction under certain conditions.
84
What is leakage current?
Small amounts of current that escape from conductors due to contamination or moisture.
85
Why is leakage current dangerous?
It can energize nearby vegetation or equipment unexpectedly.
86
What is a ground grid in a substation?
A network of buried conductors that controls ground potential rise.
87
Why is entering substations dangerous for vegetation workers?
High fault currents can create lethal ground potential gradients.
88
What is a bus (electrical)?
A rigid conductor carrying current within substations or switchgear.
89
Why is it important to recognize energized vs. grounded equipment?
To avoid accidental contact and assess vegetation hazards.
Cody's Utility Specialist Class
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