Which term refers to a planned outage for maintenance that is coordinated by the grid owner?

The term that refers to a planned outage for maintenance, which is coordinated by the grid owner, is "Scheduled Maintenance." This term encompasses the proactive measures taken to ensure the reliability and efficiency of the power substation. Scheduled maintenance involves planning and executing tasks during an outage to minimize disruption to the power supply while ensuring that equipment is serviced properly.

This type of maintenance typically includes inspections, repairs, component replacements, and upgrades, all scheduled in advance to align with operational requirements and grid management strategies. By coordinating these outages, the grid owner can effectively manage resources and communicate with stakeholders about the operational status of the grid, hence maintaining the balance between reliable power delivery and necessary upkeep of infrastructure.

The other terms, while they may sound relevant, do not capture the same specific intent of a coordinated maintenance effort. Maintenance Shutdown might suggest an abrupt halt without the planning context. Scheduled Inspection refers mainly to the assessment phase rather than the overarching maintenance activities. Coordinated Outage can imply various types of outages, not exclusively tied to maintenance, making scheduled maintenance the most accurate descriptor for the planned effort described in the question.