Research On Location Method Of Disturbance Source Units Caused By Low Frequency Oscillation

With the expansion of the internet-scale of the grid, the control method and operating characteristics of the network become increasingly complex. In recent years, two forms of low-frequency oscillation including negative damping mechanism and forced resonance mechanism have occurred many times in our country. because of the interference of the excitation system or the adjust control system in the generator, the phenomenon of forced resonance low frequency oscillation has seriously affected the stable and safety operation of power grid. When there was a low frequency oscillation in power grid, to fast find out the disturbance source of low frequency oscillation and remove it are worthy of study.Based on the attenuate voltage characteristics, by extracting disturbance variable voltages in different monitoring points and comparing the amplitude of each disturbance variable, then it can determine the low frequency oscillation disturbance source unit, then a new method of locating the disturbance source units caused by low frequency oscillation was proposed in the paper. Both results from theoretical analysis and simulation test show the correctness and veracity of the proposed method in this paper. The main research contents are as follows:When the forced resonance low-frequency oscillation occurred, The low-frequency characteristics of power line and transformer are analyzed, and mainly research the changes of individual components’ parameters in low frequency.A new method of locating the disturbance source units caused by low frequency oscillation was proposed in the paper. To collect the data installed in the power plant at the same time, and get the voltage data, the disturbance variable of voltage was obtained by the cubic spline interpolation method in each measuring point. Utilize the attenuation characteristic of the power system voltage in power system and compare the amplitude of each disturbance variable to locate the disturbance source units caused by low frequency oscillation.By MATLAB simulation software, three simulation models of locating the disturbance source of low frequency oscillation were built in this paper. By five generators and an infinite system on the same bus, six generators and an infinite system on the different bus and booster station location simulation model, I make the simulation verification of the location method. Utilizing the results of simulation tests to verify the correctness of the location method proposed in this paper,Compared with other positioning methods of forced resonance low frequency oscillation, the new method has a large advantage, less amount of computation and positioning time is much shorter. It has a more broad application prospects. At the same time, It provides a new idea and a reference value for other types of fault location.