HVE QUIZ-1_2025

Beyond breakdown voltage, dielectrics become insulating.

• True

• false

• partial

• None of the above

In which type of breakdown, an avalanche of electrons is formed?

• Defect breakdown

• thermal breakdown

• Intrinsic breakdown

• electrochemical breakdown

The breakdown criterion in a uniform field electrode gap is

• α –γd =1

• α = 𝜂

  (1−𝛾)

• γeαd = 1

• γe-αd = 1

Time lag for breakdown is

• time difference between instant of applied voltage and occurrence of breakdown

• time taken for the voltage to rise before breakdown occurs

• time required for gas to breakdown under pulse application

• none of the above

Paschen’s law states that

• breakdown voltage is a function of electric field

• breakdown voltage is a function of pd

• α and γ depends on E/p

• electronegative gases have high breakdown voltage

The requirement of gases for insulation purpose is

• high dielectric strength and thermal stability

• high dielectric strength only

• high thermal stability

• high thermal stability and low temperature condensation

The breakdown voltage in gases depends on

• distance between the electrodes

• relative air density

• humidity

• all of the above

Townsend’s first ionization coefficients define as

• Maximum number of ionizing collisions made by an electron per centimeter travel in the

  direction of field

• Minimum number of ionizing collisions made by an electron per centimeter travel in the

  direction of field

• Average number of ionizing collisions made by an electron per centimeter travel in the

  direction of field

• Maximum number of ionizing collisions made by an electron per millimeter travel in the

  direction of field

For high voltage transmission line, Corona is responsible of

• Power losses and deterioration of insulation

• Improve receiving end voltage

• Create fault condition

• Improve reliability

What are the physical conditions governing ionization mechanism in gases dielectrics?

• Nature of electrode surface

• temperature

• pressure

• all of them