Stranded and Bundled Conductors: Key to Reducing Corona Loss in High Voltage Lines

The design of high voltage transmission lines plays a crucial role in minimizing power loss and maintaining system efficiency. Stranded and bundled conductors have found significant application in this regard, as they offer a promising solution to reduce corona loss. In this article, we explore the concept of corona and how stranded and bundled conductors can be utilized to mitigate this issue in high voltage power transmission.

Understanding Corona in High Voltage Power Transmission

Corona is a phenomenon that occurs near high voltage transmission lines, leading to the formation of violet light or a hissing noise due to the ionization of air molecules. This ionization results in a loss of power, which can significantly impact the efficiency and reliability of the power transmission system. Corona primarily manifests in high voltage (HV) lines where the electric field intensity near the conductors is sufficient to ionize the surrounding air molecules.

The Role of Stranded and Bundled Conductors in Minimizing Corona Loss

One common method to reduce corona loss is the use of stranded and bundled conductors, which are designed to reduce the voltage gradient in the vicinity of the transmission line. By distributing the electric field over multiple conductors, these configurations can minimize the likelihood of air ionization, thereby reducing corona discharge.

Stranded Conductors

Stranded conductors are made up of numerous individual wires that are twisted together to form a single conductor. This construction increases the overall surface area of the conductor. While the increased surface area might intuitively suggest a higher corona loss, it is important to understand that the key factor in minimizing corona is not the surface area itself, but rather the distribution of the electric field. The multiple strands in a stranded conductor distribute the electric field more evenly, thus reducing the instantaneous electric field intensity and minimizing the risk of air ionization.

Bundled Conductors

Bundled conductors involve the use of multiple single conductors per phase, typically three or four. Each conductor carries a portion of the total current, and they are arranged close to each other. Similar to stranded conductors, this arrangement helps in reducing the electric field intensity in the immediate vicinity of the conductors. By spreading the electric field across multiple conductors, the potential for air ionization is significantly reduced, leading to a decrease in corona loss. This configuration is widely used in high voltage systems to enhance system performance and reliability.

Comparison and Analysis

While both stranded and bundled conductors aim to reduce corona loss, they do so through slightly different mechanisms. Stranded conductors rely on the distribution of the electric field over multiple individual wires, whereas bundled conductors utilize multiple single conductors arranged closely together. Both methods effectively reduce the instantaneous electric field intensity near the conductors, thereby minimizing the risk of air ionization and reducing corona discharge.

Misconception Clarified: Stranded or Bundled Conductors Increase Corona Loss

A common misconception is that stranded or bundled conductors increase corona loss due to their increased surface area. However, this is not the case. The key factor in reducing corona loss is the distribution of the electric field, rather than the surface area. By spreading the electric field across multiple conductors, the risk of air ionization is significantly reduced, leading to a decrease in corona loss.

Conclusion

In conclusion, the strategic use of stranded and bundled conductors is a critical approach to minimizing corona loss in high voltage power transmission lines. By effectively reducing the voltage gradient and distributing the electric field, these conductors can enhance the performance and reliability of power transmission systems. For more detailed insights into the factors affecting corona loss and the methods to mitigate it, please refer to the provided link.