WorksheetsHVE Breakdown in Insulating Materials
Total questions: 15
Worksheet time: 8mins
What is the primary outcome of ionization in an insulating material?
Creation of free electrons and positive ions.
Formation of an insulating layer around the material.
Neutralization of the electric field.
Decrease in the conductivity of the material.
Which of the following best describes the de-ionization process?
The separation of ions in the gas.
The neutralization of ions by recombination with electrons.
The generation of free electrons from neutral molecules.
The breakdown of the insulating material due to high voltage.
Which type of discharge occurs when ionization is limited to a thin layer near an electrode, often seen in power lines?
Corona discharge
Townsend discharge
Spark discharge
Streamer discharge
According to Townsend's theory, the multiplication of electrons during breakdown occurs primarily through which process?
Secondary electron emission from the cathode.
The formation of ion pairs through collisions.
The absorption of thermal energy by gas molecules.
The recombination of free electrons and ions.
Which gas is most commonly used for insulation in high-voltage applications due to its low ionization potential?
Oxygen
Nitrogen
Argon
Hydrogen
What happens to the breakdown voltage in a uniform gap as the distance between the electrodes increases?
Breakdown voltage decreases.
Breakdown voltage remains constant.
Breakdown voltage increases.
Breakdown voltage fluctuates.
In the context of gas insulation, which of the following factors most affects the breakdown strength of the material?
The density of the gas.
The molecular weight of the gas.
The temperature of the gas.
The purity of the gas.
What distinguishes a non-uniform gap from a uniform gap in terms of electrical breakdown?
Non-uniform gaps require higher voltage to break down.
Non-uniform gaps have an uneven electric field, leading to easier breakdown.
Uniform gaps break down more easily because of consistent ionization.
Non-uniform gaps do not ionize at all.
Which of the following statements about Townsend's theory is correct?
It is applicable only to non-uniform breakdown.
It assumes a constant electric field in the breakdown region.
It explains the breakdown of insulating materials in the presence of a uniform magnetic field.
It is based on the concept of ionization by collision in gases.
In the streamer mechanism, what is primarily responsible for the rapid increase in the ionized region?
The sudden increase in temperature within the insulating material.
The avalanche effect from the free electrons.
The creation of high-energy photons in the discharge process.
The formation of a highly localized electric field that accelerates electrons.
In a corona discharge, what typically causes the ions to remain near the electrode?
The high temperature of the gas.
The weak electric field around the electrode.
The low voltage applied to the system.
The high density of the gas near the electrode.
Which of the following conditions is necessary for a streamer discharge to occur?
A low electric field strength.
A sufficiently high voltage to generate free electrons.
A uniform distribution of ions.
A strong magnetic field.
What factor is critical in preventing breakdown in uniform gaps?
The purity of the gas.
The shape and smoothness of the electrodes.
The ionization rate of the gas.
The presence of impurities in the insulating material.
Which of the following is a common consequence of corona discharge in high-voltage transmission lines?
Significant power loss.
Reduced insulation efficiency.
Increased stability of the system.
Decrease in the ionization of surrounding air.
Which of the following gases is generally NOT used as an insulating material due to its high ionization potential?
Nitrogen
Oxygen
Sulfur hexafluoride (SF₆)
Xenon
