What is the droop setting on the A4 governor set for during single unit operation?

The droop setting on the A4 governor during single unit operation is typically set to zero. This setting is crucial because it ensures that the governor can maintain a constant frequency and speed under varying load conditions. In a single unit operation, there is no need for load sharing among multiple units, so a zero droop setting is appropriate to maintain precise control over the generator's output.

In this configuration, the governor can respond quickly to changes in load without allowing the frequency to drop, as any adjustment to the load will require an immediate reaction from the governor to maintain stability. Thus, having no droop ensures optimal performance and efficiency of the single unit.