How do synchronous generators increase and decrease power generation?

Increasing the amount of air intake results in more work being done, thereby generating more electricity; reducing the air intake means less work is done, and less electricity is generated. A turbine drives the generator, with the turbine serving as the prime mover.

Increasing or decreasing the amount of intake air is a way to alter the power generation amount. The key issue is that after increasing or decreasing the intake air volume, the rotational speed does not remain constant; so how can the power generation amount be changed?

Yes, for synchronous generators, the speed of 3000/1500/1000/750 remains constant; turbine generators typically operate at 30,000 revolutions per minute

What I mean is, with a constant rotational speed, where does the work done come from as a result of an increase in air intake, so as to increase power generation?

Copied: Therefore, as a steam turbine that serves as the prime mover for a generator, any change in the amount of steam supplied is used solely to overcome the electromagnetic torque of the generator; as a result, it only alters the generator’s output power by converting mechanical energy into electrical energy, without increasing its rotational speed. (First of all, it should be understood that it is the load on the generator that changes, which in turn causes the output of the turbine to adjust. The reason is that when the load on the generator increases, the current flowing through its coils also increases, and thus the magnetic force that resists the rotation of the rotor increases as well. At this point, the turbine needs to slow down; in order to maintain its normal speed, it must increase the amount of air intake in order to counteract the opposing torque generated by the generator. The end result is that the two torques balance each other out, and the amount of air intake into the turbine increases. This increase is caused by the increased load on the generator.) To reiterate, when the air intake to the turbine is increased, the power generation load rises, and the electrical engineers will correspondingly increase the excitation current. In their technical terminology, this is referred to as adding reactive power, while the load as perceived by the turbine is called active power in electrical engineering terms.

By changing the excitation current, the generator’s magnetic field is altered, which in turn changes the power generated. The turbine speed remains constant, ensuring the generation of 50-hertz electricity.

Adjusting the excitation does not cause any change in power generation; it only affects reactive power