Research On Local Damping Promotion Strategy Of Low Frequency Oscillation Based On Active Power Modulation Of Unit

In recent years,with the addition of new energy sources and the complication of operation modes,low-frequency oscillations occur frequently.Preventing the occurrence of low-frequency oscillations is of great significance for maintaining the safe and stable operation of power systems.Generator damping is the main component of system damping,and the online evaluation and online improvement of its damping characteristics is of practical significance for maintaining the stable operation of the system.Therefore,this paper uses a large number of easily available environmental excitation data to explore the relationship between the dissipated energy at the generator port and the dissipated energy flow,expounds the components of the dissipated energy at the generator port,and studies the refined damping analysis of the system.method,the local damping evaluation of the generator is carried out,a new local active power sensitivity index is defined,and local power flow regulation is carried out to eliminate the hidden danger of low frequency oscillation of the system.The damping performance of the potential weak damping mode of the online lifting system provides a new idea for the prevention and control of the low-frequency oscillation of the power system.The specific research contents are as follows:Firstly,based on the analysis of the mathematical model,the random response model of the load under environmental excitation is established,and the time domain analytical expression of the system state variable is deduced.It is theoretically proved that the random response data contains the power system stability analysis.The required modal information,and the method of dynamic mode decomposition combined with Morlet wavelet filtering to extract a single electromechanical oscillation mode under environmental excitation is introduced,and the consistency of dynamic mode decomposition and eigenvalue analysis to identify modal frequencies and Morlet wavelet filtering are verified in the simulation.Feasibility of extracting electromechanical oscillation modes.Secondly,under the environmental excitation,the dissipated energy expressions of generators and load ports are derived from the perspective of frequency domain,and the concept of local damping index of generators is derived according to the physical meaning of the internal variables,and the online damping of generators in power systems is further explored.The evaluation method realizes the online monitoring of the damping change of the generator during the normal operation of the power system.Finally,in order to improve the damping level of the system,this paper studies the precise modulation measures of generator active power based on local active power sensitivity.In this paper,the local active power sensitivity of the generator is calculated based on the generator damping results of the generator port dissipative energy flow identification.Increases the damping level of the system’s potential weakly damped oscillatory modes,eliminating the possibility of low-frequency oscillations.