Who is responsible for ensuring the changes to the tap settings of a generator's step-up transformer are implemented?

The generator owner holds the responsibility for ensuring that any changes to the tap settings of a generator's step-up transformer are implemented. This is due to their direct control and ownership of the generator and its associated equipment. The tap settings on a transformer can significantly affect voltage levels and overall system stability, thus it is crucial for the generator owner to manage these settings in line with system requirements and operational needs.

Furthermore, while other roles such as the transmission operator and system planner play important parts in the overall coordination and management of electrical grid operations, they do not have the direct authority or responsibility to execute changes to a generator's equipment settings. The regulatory authority, meanwhile, oversees compliance and safety regulations but does not engage in the operational tasks related to specific equipment adjustments. Therefore, the generator owner is the correct choice as they retain the accountability for the operational integrity of their generating units, including the transformers.