Which action is appropriate for mitigating heavy power transfer on a transmission line?

Using a parallel line in service is a common method to mitigate heavy power transfer on a transmission line. When the load on a transmission line exceeds its safe capacity, utilizing a parallel line helps to distribute the power more evenly across multiple pathways. This reduces the stress on any single line and can prevent overheating, voltage drops, and potential failures associated with overloading.

On the other hand, putting a capacitor in service typically serves to improve reactive power support and voltage stability but may not effectively address the issues arising from heavy power transfer. Similarly, introducing a reactor into the system primarily helps with limiting short-circuit currents and managing reactive power, which does not specifically alleviate the burden of heavy power transfer. Increasing generation might seem effective in some scenarios, but it could lead to additional strain on the existing infrastructure or exacerbate the overload situation. Therefore, deploying a parallel line is the most effective and appropriate approach for managing heavy loads on transmission lines.