Power Frequency Variations:
It is defined as the deviation from the normal value of the operating frequency of the energy system (50Hz, 60Hz). Permanently, the network frequency is proportional to the rotational speed of the generators in the system. The frequency depends on the dynamic equilibrium between the load and the production, and there is little change in frequency due to this balance. The magnitude and duration of these oscillations in frequency depend on the load characteristic and the response of the generator to load changes. Small, instantaneous frequency changes are observed during almost any switching. These changes in frequency can affect the operation of the rotating machines and the electronic circuits that derive the processing time from the basic frequency.