Short Answer:

Weather conditions have a major impact on corona loss in transmission lines. When the weather is humid, rainy, or foggy, the air’s ability to resist electrical breakdown decreases, making it easier for corona discharge to occur. As a result, corona loss increases under such conditions compared to dry, clear weather.

In dry and clean air, corona loss is usually lower because the air provides better insulation. However, in wet or polluted weather, water droplets and dust particles reduce the breakdown voltage of air, increase ionization, and lead to higher energy loss. That’s why power systems often experience more corona-related issues in bad weather.

Detailed Explanation:

Effect of Weather on Corona Loss

Corona loss refers to the energy lost in the form of light, heat, sound, and chemical reaction due to corona discharge around high-voltage conductors. This discharge happens when the electric field near a conductor becomes strong enough to ionize the surrounding air. Weather conditions play a key role in determining how easily this ionization happens, and how much energy is lost through corona.

In dry weather, the air is a good insulator, and higher voltage is required to initiate corona. But in humid or rainy conditions, the air’s insulation strength weakens due to moisture or dust, making corona discharge easier and more intense. As a result, corona loss increases during bad weather.

Weather Conditions That Increase Corona Loss

1. High Humidity
   Moisture in the air reduces the dielectric strength of the air. Water particles make it easier for air molecules to break down and become ionized, leading to increased corona discharge and greater power loss.
2. Rainfall and Wet Conditions
   Raindrops or a thin layer of moisture on the conductor surface create irregularities that concentrate the electric field at certain points. These irregular spots act like sharp edges, enhancing corona formation and resulting in higher loss.
3. Fog and Mist
   In foggy weather, tiny water droplets suspended in air lower the air’s breakdown voltage. This makes the corona appear more frequently, and the energy loss becomes significantly higher.
4. Dust and Pollution
   Dust particles, smoke, and industrial pollution in the air also reduce its insulating capacity. These contaminants provide a path for ionization, increasing the chances and intensity of corona discharge.
5. Cold Weather with Frost
   Sometimes, frost or ice can form on conductors. When this melts unevenly, it may leave wet patches or irregular surfaces, which increase corona activity temporarily.

Weather Conditions That Reduce Corona Loss

1. Dry and Clean Air
   When the weather is dry, the air remains a good insulator. The voltage required to initiate corona is much higher, so corona discharge is reduced. As a result, the energy loss is also minimal.
2. Cool but Non-humid Conditions
   If the temperature is low but there is no moisture in the air, corona remains under control. The electric field does not easily reach the breakdown level of air, and corona loss remains low.

Impact of Increased Corona Loss

• Power Wastage: Energy is lost that could have been used by consumers.
• Voltage Drop: Excessive corona causes voltage drop along the transmission line.
• Noise and Interference: Corona noise becomes louder and radio/TV interference increases during rainy nights.
• Ozone and Nitric Acid: Wet air increases the formation of ozone and other chemicals due to corona, which can damage insulation and metal parts.

Preventive Measures in Bad Weather

1. Use of Bundled Conductors
   Reduces the surface electric field intensity, minimizing corona discharge even during bad weather.
2. Larger Diameter Conductors
   Bigger conductors have less corona effect because of lower surface field strength.
3. Regular Cleaning
   In polluted areas, regular maintenance helps remove dust and pollutants from insulators and conductors.
4. Improved Surface Coating
   Applying special coatings or using weather-resistant materials on conductors can help reduce moisture absorption and prevent corona spots.

Conclusion

Weather has a strong influence on corona loss in transmission lines. Bad weather conditions like humidity, rain, fog, and pollution lower the air’s insulation strength and increase corona discharge, leading to higher energy losses and electrical disturbances. Dry and clean weather helps reduce corona effect naturally. To protect the power system and maintain efficiency, engineers use design strategies such as bundled conductors, large-diameter wires, and proper maintenance to manage corona loss under all weather conditions.