Analysis And Localization Of Forced Power Oscillation Caused By Impact Load

The power grid interconnection can greatly improve the energy allocation capability and the power supply security level.However,with the increase of load,the increase of transmission distance and the operation of a large number of HVDC transmission lines,the dynamic characteristics of power system are becoming more and more complicated.In the real power system,a series of forced power oscillation problems appear.The existing researches on the mechanism of forced oscillation and the localization of oscillation sources mostly focus on the power supply side.There are few researches on forced oscillation of load side.It is very important to study the generation mechanism of forced oscillation on load side and how to monitor forced oscillation and locate the oscillation sources on load side.It is of great significance for the safe and stable operation of power system.In this paper,the impact load disturbance is decomposed into the superposition of several sine waves by Fourier decomposition,which improves the theoretical derivation of the mechanism of forced power oscillation caused by non-sinusoidal continuous periodic impact load.The differences between the forced oscillation induced by the impact load disturbance and sinusoidal load disturbance are compared.The main factors affecting the amplitude of forced oscillation are analyzed.These works provide more engineering guidance for the research on forced oscillation induced by load side,and lays the foundation for further research on the propagation and suppression of forced oscillation caused by load side.Aiming at the problem of forced oscillation source localization caused by periodic load disturbances in power system,a phasor measurement unit(PMU)optimization placement method is proposed for forced oscillation monitoring at load side.By analyzing the typical characteristics of impact load,the PMU monitoring strategy is obtained and the monitoring range is reduced to ensure the economy of PMU configuration.Establish a binary logic tree for PMU optimization configuration analysis,and use the network connectivity algorithm and network topology identification to obtain digitized information.This method ensures the economy of the PMU configuration and the monitoring of forced oscillations on load side.And last through the PMU measurement data and the principle of the spread of forced oscillation in power system,a method is obtained to locate the oscillation source.The validity of this method is verified by three power system models.