Research On Disturbance Source Locating Of Power System Low Frequency Oscillation

With the development of the national economy, the scale of power network is gradually expanding and its interconnection is being strengthened. Meanwhile, the system often works near its limit. The low frequency oscillation caused by local small disturbance posed a great threat to the stable operation of the system in the case of poor damping characteristic of the system and even cause severe accidents as power system blackout. Therefore, the study of development mechanism of low frequency oscillation and the accurate disturbance source locating has an important practical significance. The main work of this paper is to establish the connection between the mechanism of low frequency oscillation and the energy function. According to the generator classical model, the disturbance source of low frequency oscillation can be located to the power plant or its outlet lines by the cutest-energy based method. Then the disturbance source can be located accurately to the generator according to the comprehensive oscillation characteristic index which is based on multiple attribute decision making.This paper research the current disturbance source locating methods and prevention and control measures of low frequency oscillation through the analysis of the generator classical model. This paper describes a new method of locating disturbance source based on the existing research and the energy function. In this method, the disturbance source is located through the direction of the formed pivotal cutsets’ energy flow.Then, this paper proposes the comprehensive oscillation energy of generator, maximum amplitude, relative maximum amplitude, oscillation energy, normalized vibration moment as the oscillation indexes, according to generator parameter which is detected by the wide area measurement system. The preliminary judgment of the disturbance source can be obtained through the inherent relationship between the indexes and disturbance source. At the same time, the comprehensive evaluation index of oscillation characteristics which is based on the principle of multiple attribute decision making can located the disturbance source of power system low frequency oscillation effectively and accurately.Finally, the power network of Sichuan Province in Central China is used as an example to verify the rationality and validity of the proposed in this paper.