Energy Function Method Analysis For Power System Transient Stability

Transient stability is the one important subject in power system. There have two main methods for transient stability analysis. One is time dominated simulation method, it has high precision and can calculate under the complex system model, but can't give stability margin and its calculation speed is too slow, so it only is an off-line method. Anther is direct method. Energy function method is the one important direct method. Its advantages lay in that it can give stability margin and has fast calculation speed. In recent years, energy function method has been studied greatly. These studies improve its precision, make it basically satisfy the demands of power system. It can be a fast on-line scanning method for transientstability.This paper summarized the studies of energy function method and BCU method (the Boundary of Stability Region based Controlling Unstable Equilibrium Point Method), expounded the basic theory of the energy method, detailedly studies the main contents of the energy function method, it includes: the system model, definition, calculation method and error analysis of the energy function in different coordinate, the transient stability criterion of the energy method, the basic theory, calculation steps of the BCU method and the BCU method analysis.Combined with the power dynamic surveillance system, this paper gives an on-line application project, it includes two main aspects: 1) under order operation, scanning analyze the transient stability of the real-time power condition in the given fault congregation by using energy function method; 2) under fault operation, use real-time measure data from the power dynamic surveillance system to forecast the generator's rotor angle and speed which used in the transient energy calculation,and analyze the transient stability.Some part programs of the energy function method were writed. This paper applied the energy function method and the BPA transient analysis software to analyze the transient stability of the 6 generators 22 points system in different faults. It proves the energy method can be a fast on-line scanning method for transient stability, and the forecast method is appropriate.Finally, this paper prospects the study's future of the transient stability, points out that the present energy function method only fits for the first swing transient stability analysis. With the energy function method's deep study, the energy function method for the fast transient stability has good on-line application future.