Factor affecting corona Loss in Power System

Atmosphere:

The voltage gradient for breakdown of the air is proportional to its density. In stormy weather (bad climate) the number of ions may be more than normal. As more number of ions present between the conductors means reduction of insulating property of the medium. So corona can occur at less voltage than critical breakdown voltage during bad climatic conditions than fair weather conditions.

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Conductor:

The corona is conserved to be affected by the Size(diameter), shape(stranded or smooth) and surface condition (dirty or clean) of the conductor.

Corona decreases with the increase in the conductor diameter. This is due to the fact that increase in the conductor diameter reduces the electric field intensity. 

For Stranded conductor corona is more compared to solid conductor. As the potential gradient of the stranded surface is more compared to the normal solid conductor for same power rating.

For dirty surfaced conductor the break down voltage required for corona formation is less than clean surfaced conductor. 

Spacing between Conductors:

With increase in the spacing between the conductors the electrostatic stresses reduces results in reduced corona effect

Line Voltage:

At low line voltage there will be no corona. When the voltage applied increases breakdown voltages then corona formation takes place