HVE_Module-1 quiz

According to Townsend current growth processes the current (I) in a uniform electric field gap is

• Io e^-ad

• Io e^ad

• Io e^yd

• Io e^-yd

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 the 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

• alpha and gamma depends on E/p

• electronegative gases have high breakdown voltage

Conduction and breakdown in commercial liquids is affected by

• solid particles

• vapour or air bubbles

• electrode material

• all the above three factors

The usual mechanism of breakdown in solid dielectrics is

• intrinsic breakdown

• electromechanical breakdown

• thermal breakdown

• chemical breakdown

paper insulation is mainly used in

• cables and capacitors

• transformers

• rotating machines

• circuit breakers

Breakdown is permanent in

• gases

• liquids

• solids

• composite insulation

breakdown due to internal discharges develops

• in milliseconds

• in few seconds

• over a long duration of several days

• all of the above

which of the following gas is a electronegative gas ?

• air

• O2

• SF6

• Both O2 and SF6

Stressed oil volume theory is applicable when

• small volume of liquid is involved

• large volume of liquid is involved

• large gap distance is involved

• pure liquids are involved