Study of the Causes of Zonal Low Frequency Oscillation in the Electric Power Network

At any disturbances in the electric energy system (EES), various types of low-frequency oscillations (LFO) are recorded at the observation points. In the oscillograms of grid frequency observed on the busbars of stations at the same type of disturbances, oscillations of at least two frequencies can be distinguished. Higher frequency oscillations are local oscillations, the parameters of these oscillations mainly depend on the parameters of the grid closest to the point of application of the disturbance. Fluctuations of a lower frequency are zonal oscillations; their parameters depend on the entire scheme of the EES. It is very important to determine the cause of the appearance of zonal oscillations, since they spread over a section of the power system. In the course of modelling in this work, one of the reasons for their appearance was identified.