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WorksheetsQuiz II PS-I
Total questions: 10
Worksheet time: 5mins
The over-voltage surges in power system may be caused by
Lightning
Resonance
Switching
All of these
The protection against direct lightning strokes and high voltage steep waves is provided by
Ground wire
Lightning arresters
Lightning arresters and ground wires
Earthing of neutral
Lighting arresters are used in power system to protect electrical equipment against
Direct stokes of lightning
Over-voltages due to indirect lightning stroke
Power frequency Over-voltages
Over-currents due to lightning
Surge absorbers are used for protection against
High voltage low frequency oscillations
High voltage high frequency oscillations
Low voltage high frequency oscillations
Low voltage low frequency oscillations
Surge absorber ____________ the energy of travelling waves
Absorbs
Reflects
Diverts
Partly absorbs and partly doverts
The method of neutral grounding affects the
Positive-sequence network
Negative-sequence network
Zero-sequence network
Both Positive- and Zero-sequence network
Switching over-voltages are more hazardous than lightning surges in case of
Low voltage system
33 kV system
EHV and UHV systems
All of these
For protection of rotating machines against lightning surges ___________ is used.
Lightning arrester.
Capacitor
Combination of lightning arrester and capacitor
Lightning conductor and arrester
Which of the following is the protective device against lightning over-voltages?
Rod gaps
Surge absorbers
Horn gaps
All of the above
Overhead ground wires are used to protect a transmission line against
Line-to-ground faults
Arcing earths
Voltage surges due to direct lightning stroke
High voltage oscillations due to switching
