# High Voltage Engineering Questions and Answers – High Voltage Testing of Electrical Equipment

This set of High Voltage Engineering Multiple Choice Questions & Answers (MCQs) focuses on “High Voltage Testing of Electrical Equipment”.

1. Cables are vital for transforming electrical energy through underground means.
a) True
b) False

Explanation: Cable is an important electrical apparatus that is used for transmission of electrical energy by underground means. They can transmit high voltage signals.

2. Which among the following is not a mechanical test?
a) bending test
b) dielectric test
c) dripping test
d) drainage test

Explanation: The dielectric test is a separate type of test which is carried in high voltage cables. The mechanical test includes bending, dripping, drainage, fire resistance and corrosion tests.

3. __________ is the normal length of the cable sample used for testing.
a) 1-50cm
b) 50cm-10m
c) 10-100m
d) above 100m

Explanation: The normal length of the cable sample used for testing usually lies between 50cm-10m. The cable samples have to carefully prepared and terminated to prevent excessive leakage and flashovers.

4. The terminations are provided to relieve the cable ends from __________
a) low electrical stress
b) low surface leakage
c) high electrical stress
d) high surface leakage

Explanation: The terminations are provided to relieve the cable ends from high electrical stress. They are usually made by shielding the end conductor with stress shields. It also prevents excessive leakage and flashovers.

5. The dielectric power test is carried using __________
a) low voltage Wheatstone bridge
b) low voltage Schering bridge
c) high voltage Wheatstone bridge
d) high voltage Schering bridge

Explanation: The dielectric power test is carried using a high voltage Schering bridge. The power factor also known as the dissipation factor is measured at each times the rated voltage. Of the cable. If breakdown occurs in the cable; the Schering bridge has to be given protection against over-voltages.

6. The voltage dip caused by a discharge at a fault remains as a standing wave.
a) True
b) False

Explanation: The voltage dip caused by a discharge at a fault is propagated as a travelling wave along the cable. These travelling waves are detected as voltage pulse across the terminals of the cable ends.

7. Cables are tested for high voltage using _________
a) power frequency voltage
b) ac-dc voltage
c) impulse voltage
d) power frequency, ac-dc and impulse voltage

Explanation: Cables are tested for high voltage using power frequency, ac-dc and impulse voltage. To check the continuity of the cable, the entire cable is passed through a high-voltage test at the time of manufacturing.

8. The weakness of the cable can be detected by __________
a) high-voltage tests
b) corrosion test
c) drainage test
d) partial discharge test

Explanation: The weakness of the cable can be detected by a partial discharge test. It is because the life of the insulation at given voltage stress it entirely depended on the internal discharges. Even the faults in the cables can be detected using the same test.

9. Middle electrodes are energized with high voltage in the scanning method.
a) True
b) False

Explanation: Four electrodes are used in the scanning method. They are mounted in the form of rings at both ends of the tube so that they have electrical contact with the water. The middle electrodes are energized with high voltage and the other two electrodes are grounded.

10. The following test is used in the factory site for isolating the defective insulation.
a) high-voltage tests
b) corrosion test
c) scanning test
d) partial discharge test

Explanation: The scanning method is used in the factory site for isolating the defective insulation. Four electrodes are used in scanning method. They are mounted in the form of rings at both ends of the tube so that they have electrical contact with the water. The middle electrodes are energized with high voltage and the other two electrodes are grounded.

Sanfoundry Global Education & Learning Series – High Voltage Engineering.

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