Characteristics Of Transient Powerangle Curve And Its Application In Searching DSR Critical Points

In recent years, the development of power system is more and more rapid.Because of the connection of large area, the scale and complexity of power system isincreasing day by day. Accordingly, the problem of transient stability analysisbecomes more and more important.Nowadays, dynamic security region is a hot subject of transient stability analysiswhich is made a series of important achievements. But the research of critical pointsin security region has been an important factor restricting the online application. Thejudgment standard of critical points is divided into two ways--fault clearing time andpower injection. Because of the corresponding of the concept of dynamic securityregion and the power injection, power injection is chosen as the critical judgmentstandard in this paper.Mean value method is widely used in the traditional research of critical points, inthis method，the search interval is halved step by step until small enough, whichmeans one of the critical points of dynamic security region is found. The convergencespeed is slow and only little information can be provided. After a lot of calculation,the curve of maximum power angle variation over time is deeply researched, and thesecondary fitting coefficient of the curve is extracted as the characteristic parameter.Taking WSCC4-11system as an example, the method provided in this paper isproved a practical one whose search time of every critical point is only30%of theoriginal algorithm without lowering the calculation accuracy. With the increase ofsecurity region’s dimension, the searching time will be greatly decreased. So thismethod provided in this paper will lead to a new direction for the development ofreal-time dynamic security region.