Test your knowledge with MCQ on Lightning Arresters. Practice important objective questions with answers and explanations for exams and interviews.
Lightning Arrester (20 Questions)
Question 1
MCOV stands for:
A.Maximum Current Operating Value
B.Maximum Continuous Operating Voltage
C.Minimum Continuous Over Voltage
D.Maximum Controlled Output Voltage
Hint: MCOV is the maximum voltage that can continuously appear across the lightning arrester under normal operating conditions without causing conduction.
Question 2
The primary purpose of a lightning arrester is to protect equipment from:
A.Overload current
B.Short circuit current
C.Lightning and switching surges
D.Power frequency voltage
Hint: Lightning arresters operate only during transient overvoltages like lightning or switching surges.
Question 3
MCOV stands for:
A.Maximum Current Operating Value
B.Maximum Continuous Operating Voltage
C.Minimum Continuous Over Voltage
D.Maximum Controlled Output Voltage
Hint: MCOV is the maximum voltage that can continuously appear across the arrester without conduction.
Question 4
MCOV must always be slightly higher than:
A.Line Voltage
B.Phase Voltage
C.Residual Voltage
D.BIL
Hint: Since arrester is connected between line and earth, phase voltage appears across it continuously.
Question 5
In an effectively earthed system, healthy phase voltage during fault rises up to approximately:
A.100% of line voltage
B.√3 times phase voltage
C.80% of line voltage
D.120% of phase voltage
Hint: Solid grounding limits voltage rise of healthy phases to about 80% of line voltage.
Question 6
132 kV and 220 kV systems are generally:
A.Non-effectively earthed
B.Effectively earthed
C.Unearthed
D.Isolated neutral
Hint: High voltage transmission systems are normally solidly grounded.
Question 7
In a non-effectively earthed system, healthy phase voltage during fault may rise up to:
A.0.8 times line voltage
B.√3 times phase voltage
C.50% of line voltage
D.Zero
Hint: Neutral shift during fault causes voltage rise up to √3 times phase voltage.
Question 8
For effectively earthed systems, rated voltage of lightning arrester is generally:
A.1.2 × Line Voltage
B.1.0 × Line Voltage
C.0.8 × Highest System Voltage
D.0.5 × Line Voltage
Hint: Rated voltage is approximately 0.8 times the highest system voltage.
Question 9
The standard waveform for nominal discharge current is:
A.4/10 µs
B.8/20 µs
C.10/350 µs
D.1/50 µs
Hint: Nominal discharge current is tested using 8/20 microsecond impulse waveform.
Question 10
Nominal discharge current for distribution class arrester is typically:
A.20 kA
B.10 kA
C.5 kA or below
D.100 kA
Hint: Distribution class arresters typically have 5 kA nominal discharge current.
Question 11
For 132 kV and 220 kV systems, station class arresters generally have nominal discharge current of:
A.5 kA
B.10 kA
C.20 kA
D.65 kA
Hint: Station class arresters for transmission systems typically use 10 kA nominal discharge current.
Question 12
Residual voltage develops across the arrester due to:
