Lack of dynamic reactive power compensation result in power system transient voltage instability. To improve the transient voltage stability, an optimization strategy for setting the excitation system difference coefficient of the generator is presented in this paper. The concept of the excitation system difference coefficient is introduced. Then the impacts of difference coefficients of generator excitation system on generator stability are analyzed and adjustment range is proposed. The calculation results of Guangdong province system show that the transient voltage stability level is enhanced effectively after optimizing the excitation system difference coefficient.

Features of different kinds of wind power generators worldwide are firstly overviewed. Then the latest development trend and research progress of modeling and simulation for wind power generator are analyzed and compared. Finally, the developing directions of the modeling and simulation technology for wind power generator are presented, hoping to offer study idea and reference for deeply researches.

HVDC technology is more and more common in practical projects, of which reliability will affect the whole power system. As different evaluation methods, FTA and FD method had their own advantages and disadvantages, this paper combined FTA method with FD method. Firstly FTA method was used to get basic parameters of each subsystem, then combined each subsystem to a whole equivalent model with FD method. What's more, different capacities of AC filters were also under consideration. Finally, an actual example was given to demonstrate validity of the method that this paper proposed. Compared with Zusim software, the result is more accurate.