In a power system, what is the purpose of a droop governor?

A droop governor serves a vital role in power systems by maintaining system stability, particularly in regulating frequency. The droop control mechanism allows a generator to automatically adjust its output power in response to changes in system frequency. When frequency drops—indicating that generation is less than demand—the droop governor will reduce the generator's output, which helps to balance the power system by automatically declining generation output according to how far the frequency is from its nominal value. This response is proportional and is determined by the droop setting of the governor.

Although the other choices relate to power system operations, they do not accurately represent the primary function of a droop governor. For example, while governors contribute indirectly to frequency regulation, their specific purpose during frequency drops involves limiting output as described. Similarly, droop governors do not directly increase voltage or enhance output during peak demand; rather, those functions are typically handled by different system components and strategies such as voltage regulation equipment or load forecasting mechanisms.