# High Voltage Engineering Questions and Answers – Generation of Impulse Voltages

This set of High Voltage Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Generation of Impulse Voltages”.

1. The time taken by an impulse wave to reach its maximum value starting from zero value is called ______
a) wave front time
b) wave tail time
c) peak wave time
d) steepness time

Explanation: The time taken by an impulse wave to reach its maximum value starting from zero value is called wave front time. Generally, it is 0.5 μs to 10μs. It is also known as the rise time of the impulse voltage.

2. ______ is the impulse voltage developed without causing puncture or flashover.
a) normal impulse voltage
b) chopped impulse voltage
c) full impulse voltage
d) clean impulse voltage

Explanation: The full impulse voltage is the impulse voltage developed without causing puncture or flashover. It is characterized by its two time intervals and the peak value. The time intervals are wave front time and wave tail time.

3. ______is the impulse voltage developed by causing puncture or flashover by collapsing the impulse voltage.
a) normal impulse voltage
b) chopped impulse voltage
c) full impulse voltage
d) clean impulse voltage

Explanation: The chopped impulse voltage is the impulse voltage developed by causing puncture or flashover by collapsing itself. If chopping takes place on the front part of the wave, it is known as a front chopped wave. Otherwise, it is simply known as a chopped wave. The full impulse voltage is the impulse voltage developed without causing puncture or flashover.

4. Identify the following figure.

a) front chopped wave
b) chopped wave
c) full impulse wave
d) peak impulse wave

Explanation: The figure shows the front chopped wave. An impulse wave that is chopped at the front is known as front chopped wave. Otherwise, it is simply known as a chopped wave.

5. An impulse voltage is a bidirectional voltage.
a) True
b) False

Explanation: An impulse voltage is a unidirectional voltage. It does not have much oscillations. It rises to a peak value and decays to more or less a zero value.

6. Identify the following figure.

a) front chopped wave
b) chopped wave
c) full impulse wave
d) peak impulse wave

Explanation: The figure shows the chopped wave. An impulse wave which is not chopped at the front is known as chopped wave. The chopped impulse voltage is the impulse voltage developed by causing puncture or flashover by collapsing itself.

7. Which among the following represents standard lightning impulse?
a) 2/25 μs
b) 25/2 μs
c) 1.2/50 μs
d) 50/1.2 μs

Explanation: 1.2/50 μs represents standard lightning impulse. 1.2 μs is the rise time and 50μs is the decay time. A tolerance of 3% is allowed in the peak value.

8. What is the tolerance allowed in the peak value of the standard impulse?
a) ±3%
b) ±5%
c) ±6%
d) ±2%

Explanation: The tolerance allowed in the peak value of the standard impulse is ±3%.1.2/50 μs represents standard lightning impulse. 1.2 μs is the rise time and 50μs is the decay time.

9. The impulse ratio for flash over is the ratio of impulse flash over voltage to the _____
a) peak value of power frequency flash over voltage
b) minimum value of power frequency flash over voltage
c) mid value of power frequency flash over voltage
d) peak value of low frequency flash over voltage

Explanation: The ratio of impulse flash over voltage to the peak value of power frequency flash over voltage is known as the impulse ratio for flash over. It is not constant for any particular object. It depends on the characteristics and shape of the impulse wave.

10. Identify the following figure.

a) front chopped wave
b) chopped wave
c) full impulse wave
d) peak impulse wave

Explanation: The figure represents a full impulse voltage. It is the impulse voltage developed without causing puncture or flashover. It is characterized by its two time intervals and the peak value. The time intervals are wave front time and wave tail time.

Sanfoundry Global Education & Learning Series – High Voltage Engineering.

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