Disturbance Source Locating Of Low Frequency Oscillation Based On Network Topology Data

With the development of the electric power industry,the scale of the interconnected power grid is gradually expanding.The dynamic stability of the power grid is becoming more and more complicated.Low-frequency oscillation sometimes occurs,which threatens the safety and stable operation of the power grid and limits the power transmission capacity.Quickly and accurately locating of low-frequency oscillation disturbance source has an important significance for suppressing oscillation diffusion and preventing the spread of the accident.Based on the previous studies,this paper combines the oscillation energy distribution characteristics with the topology of the power grid,and proposes a new method of disturbance source location based on network topology data.The simple system model is used to research the negative damping mechanism and the forced oscillation mechanism.Then,it take the oscillision energy as the basis of disturbance source location.By analyzing the energy distribution characteristics of the oscillation,the thought that the graph theory can be applied to disturbance source location is proposed.On the basis of the cutset energy,the concept of the maximum oscillation energy flow cutset is proposed.Disturbance source location is transformed into searching for the maximum oscillation energy flow cutset.Due to the large scale of the power grid,it is difficult to search for the maximum oscillation energy flow cutset by the common cutset search method.In this paper,we propose two ways to improve the search speed:1、 Reduce the search space;2、Improve the search validity.In order to reduce the search space,it analyzes the energy distribution characteristics and finds the distribution law of the maximum oscillation energy flow cutset.The locating method of oscillation source based on K shortest paths is proposed,which limits the search space into the K shortest paths and improves the search efficiency.Furthermore,Experience-Correction method is put forward to assign a value to K,which makes the locating method more practicable.For the purpose of improving the search validity,it applies the 01 codes to the network branch in the light of the characteristics of large-scale network cutset search.And the genetic algorithm is applied to lead the search of the maximum oscillation energy flow cutset.Besides,according to the specific characteristics of the disturbance source locating,pre-selecting chromosomes is proposed to accelerate the genetic evolution.So the locating method of low frequency oscillation source based on genetic algorithm is formed.The above two locating methods of low frequency oscillation source are applicable to both local and inter-area oscillation modes,and only use the line information when generator real-time information of the regional grid is incomplete.Finally,The West Inner Mongolia Power Grid is used to verify the effectiveness and practicability of the locating methods...