Which of the following best describes 'overexcited' generators?

'Overexcited' generators are those that supply reactive power, also known as VARs (volt-amperes reactive), to the electrical grid in order to increase the system voltage. This process is essential for maintaining stable voltage levels across the power network, especially in scenarios where voltage support is needed.

When a generator is in an 'overexcited' state, it means that it is operating in a manner that adds more reactive power to the system than it consumes. This is typically achieved by increasing the exciter output, which enhances the magnetic field in the generator, thus allowing it to deliver additional VARs. This characteristic is particularly beneficial during periods of high demand when voltage levels may drop, because overexcited generators help to stabilize the voltage and maintain system reliability.

In contrast, other options do not accurately describe the role of overexcited generators. For example, while generators that consume VARs would be recognized as 'underexcited' and are not the focus of this description, generators that operate at maximum load or are used solely during peak demand periods do not sufficiently capture the reactive power contributions that define the 'overexcited' state.