What is isochronous governing?

Isochronous governing refers specifically to the control method where the speed of a generator remains constant regardless of fluctuations in load demand. This is achieved by utilizing a governor that adjusts the fuel input or steam flow to maintain a constant frequency (or speed) output.

The concept of zero % droop is essential in isochronous governing, as it allows the engine or turbine to respond immediately to changes in load without experiencing a decrease in speed. In systems utilizing other governing methods, like droop control, the output speed would vary slightly with changing loads, reflecting a predetermined percentage drop, which would not be the case in isochronous operation.

In contrast, the other options describe governing methods that are not focused solely on maintaining speed at a constant level without drift. Governing with variable speed suggests the system would intentionally allow speed fluctuations, while governing with variable pressure relates to maintaining pressure rather than speed. Finally, governing based on load demand implies an adjustment in output proportional to load changes, which contradicts the fundamental characteristic of isochronous governing that maintains a steady speed regardless of changes in demand.