Slip Transient Energy Function And Its Application

This paper reviews the history of the development of the power system transient stability and analyzes the deficiency of the present methods of transient stability research, then develops the branch transient energy function-based the actual fault trajectory. This function that only needs the dynamic observation information of part network can be applied to study power system transient stability problem on the level of the whole system, the local system or a branch.Firstly, this paper analyzes the distribution in the network of difference of the total kinetic energy under different coordinates and proves that it is feasible to analyze the power system transient stability in terms of branches. The method can avoid setting up the models of the generator and load.Secondly, this paper proposes the conception of the smallest topography trees, which makes that the analyzing of power system transient stability can be processed on the least branches and reduces the calculation and the actual network information of the transient stability.Thirdly, this paper studies the distribution characteristic of the system transient energy in network branches,and analyzes the relationship of the branch transient energy distribution and system transient stability, and explains that the system instability is as a result of the unbalance of transient energy of part network.Furthermore, this paper analyzes the characteristic of the difference of angle frequency of branch ends, the branch power different from pre-fault and the branch transient energy. Then the power system instability criterion is set up which is appended branch transient energy condition. Using this criterion, power system transient stability will be judged more exactly and quickly because it is only depended on the branch dynamic measure information.Finally, this paper develops the branch transient energy analytic method, thus the system transient stability can be quantitatively analyzed. This paper also probes into its practical application in power system.