ALFC and AVR are used to maintain grid frequency and grid voltage constant w.r.t. changes in real and reactive power. Real power has a direct effect on frequency while reactive power has a direct effect on the grid voltage. Consider a power system running at normal grid volage with rated freauency of 50Hz, with generators equipped with AVR and ALFC. If the load demand increased, the primary ALFC loop will operate (free governor operation) and governor will increase the mechanical input according to its % droop. Let's say the new frequency settles down to 49.7Hz. Then central LFC will send signal to the generator's speed changer and its reference power setting will be increased by a suitable amount, which will bring back the frequency to 50Hz (for the increased demand). But before the central LFC changes the reference power setting of the generator, the generator is operating at reduced frequency (49.7Hz) for some time (small time). Does this reduction in frequency affect terminal voltage? Generated emf in the generator is proportional to the speed of rotation. Will the reduction in frequency reduce the terminal voltage? Does AVR respond to this change? Or does it only operate during reactive power changes in the system?