Synchronous generator voltage regulation
Maintaining the terminal voltage of the generator equal to the given value is the main means of regulating the voltage of the power system. How to ensure that the terminal voltage of the synchronous generator is a given value?
We say that in the case of load changes, it is necessary to adjust the way of excitation. The following is a detailed analysis of the specific principle of the generator with a simplified phasor diagram.
From the above picture:
Where: Eq——the no-load potential of the generator; Uf——the terminal voltage of the generator; If—the ratio of the load current of the generator. The above formula shows that in the case where the generator no-load potential Eq is constant, the generator terminal voltage Uf will decrease as the load current If increases. To ensure that the generator terminal voltage Uf is constant, it must follow the generator load current If. Increase (or decrease), increase (or decrease) the no-load potential Eq of the generator, and Eq is a function of the generator excitation current Ifq (if the saturation is not considered, Eq is proportional to Ifq), so the generator is running In the process of changing the load current of the generator, the excitation current must be adjusted to make the voltage at the generator terminal constant.