Research On The Method Of Low Frequency Forced Oscillation Source Location By Using Disturbance Power

Forced resonance low frequency oscillation caused by the interconnection of power systems and small interfering stability has become an important factor which endangers the safe and stable operation of power grid. The most effective way to suppress such oscillations is to analyze the characteristics of online data, track the propagation path of oscillation, identify the initial starting point, and remove the disturbance source. The key problem in the low frequency oscillation control technology is the search and location of the low frequency oscillation range. The wide-area measurement system provides a new technology platform for the electric power system fault analysis and low frequency oscillation source location. Using the wide-area measurement data for oscillation source has become a hot research issue.However, the relevant results have not taken into account the shortcomings of mass measurement data location and the phasor measurement unit (PMU) is still unable to fully configure. By analyzing the distribution of low frequency disturbance variable in the power grid, a new method of locating the source of low-frequency oscillation which uses the minimum number of PMU is proposed. Theoretical analysis and simulation results verify the correctness and accuracy of the proposed forced vibration frequency method.The main contents and achievements of this paper are as follows:(1) A new method of locating the generation units as the disturbance source of low frequency oscillation is proposed in the paper. The specific methods are as follows. The low frequency oscillation disturbance variables of each measurement point are extracted by interpolation fitting. Low frequency oscillation suspicious area is divided by comparing the disturbance power of node line . And the low frequency oscillation source is accurately identified by the relationship between the voltage difference and the line length in the suspicious region.(2) By MATLAB simulation software, three simulation models of locating the disturbance source of low frequency oscillation are built in this paper, including: a five-machine infinite system with radial structure, a seven-machine infinite system with ring structure, and a low-frequency oscillation source localization model for different power systems. The results of simulation tests show the correctness of the location method proposed in this paper.Theoretical analysis and simulation results show that the method proposed in this paper can determine the disturbance source of low frequency oscillation in large-scale power grid rapidly. Thus the duration of low frequency oscillation in power grid can be evidently shortened, and the further deterioration of the accident is prevented. The new method for locating low frequency oscillation source in power grid lay the foundation to establish the corresponding control measures and guarantee the safety and stable operation of power grid.