What would be a necessary action if a transformer shows signs of overheating?

When a transformer shows signs of overheating, powering down the transformer is crucial for several reasons. Overheating can lead to irreversible damage to internal components, including insulation breakdown, which may result in equipment failure or even fire hazards. By powering down, you allow the transformer to cool and prevent further damage from occurring.

If a transformer's temperature rises beyond safe limits, immediate action is required to protect both the transformer and the overall electrical system. This process also allows for an assessment of the cause of overheating, which could include overloaded circuits, insufficient cooling, or malfunctioning components.

While other options may be relevant in different contexts, they are inappropriate when dealing with overheating issues. For example, adjusting the tap changer could potentially worsen the situation, as it might increase the load or alter voltage levels that could exacerbate the overheating problem. Increasing the load would directly contribute to higher temperatures, and activating the automatic voltage regulator might not address the underlying issue causing the transformer to overheat. Thus, powering down the transformer is the most effective course of action to ensure safety and facilitate the evaluation of the situation.