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WorksheetsEMJ42003 Chapter 7 - Quiz 2 - Set 1
Total questions: 20
Worksheet time: 14mins
What is an overvoltage?
A voltage that is always safe
A voltage that exceeds normal levels
A constant voltage level
A voltage below the normal level
Which type of overvoltage is caused by lightning discharges?
Permanent overvoltage
Temporary overvoltage
External overvoltage
Internal overvoltage
What does TOV stand for?
Transient Overvoltage
Temporary Overvoltage
Tension Overvoltage
Total Overvoltage
Which of the following is a cause of Slow Front Overvoltage (SFO)?
Switching of inductive currents
Load rejection
Fault initiation
All of the above
What is the primary purpose of a lightning arrester?
To store energy
To measure current
To protect against lightning surges
To increase voltage
What is the typical peak current for a first stroke of lightning?
10 kA
30 kA
100 kA
200 kA
What is the main effect of Temporary Overvoltage (TOV)?
Increased efficiency
Equipment damage
Reduced power consumption
Improved insulation
Which of the following is NOT a type of overvoltage classification?
Very slow overvoltage
Slow front overvoltage
Fast front overvoltage
Temporary overvoltage
What is the primary cause of Fast Front Overvoltage (FFO)?
Load rejection
Fault initiation
Lightning strokes
Switching operations
What is the effect of SFO on power system equipment?
Improved performance
Insulation stress
Increased lifespan
No effect
What is the purpose of surge protective devices (SPDs)?
To increase voltage levels
To absorb transient overvoltage
To measure electrical current
To reduce power loss
What is the main characteristic of Very Fast Front Overvoltage (VFFO)?
Low peak voltage
Gradual rise time
Long duration
High-frequency content
Which overvoltage increases with the system's operating voltage?
External
Lightning
Internal
Direct Stroke
What is the keraunic level used to measure?
Lightning flash density
Insulation strength
Ground resistance
Lightning current
What is the main factor affecting grounding systems?
Cable length
Load resistance
Soil resistivity
Conductor material
What is the standard waveform of lightning impulse voltage?
8/20 µs
250/2500 µs
1.2/50 µs
30/80 µs
What is the standard waveform of switching impulse voltage?
8/20 µs
250/2500 µs
1.2/50 µs
30/80 µs
What is the name of the common cloud that is related to lightning?
Stratus clouds
Cumulonimbus clouds
Cirrus clouds
Altostratus clouds
What percentage of lightning strikes result from negatively charged clouds compared to positively charged clouds?
13%
50%
87%
97%
Identify the type of lightning-ground flash depicted.
Upward positive
Downward positive
Upward negative
Downward negative
