Real-time analysis of transient voltage security based on off-line database and data fitting

In recent years, because of the interconnection of large grids and the accession of HVDC, real-time analysis approach is needed for transient voltage security (TVS) analysis. Traditional simulation analysis is time-consuming and the transient energy function approach is difficult to analyze large scale power systems. In this paper, an approach for real-time TVS analysis is proposed based on off-line database. A new transient voltage security index (TVSI) is defined in this paper. Firstly, a lot of operation modes that meet the constraints of steady state operation are generated. Then the TVSIs under these operation modes are computed to form an off-line database. Next, the TVS analysis of current operation mode can be carried out based on data fitting of current operation mode using the off-line database. At last, two case studies based on the New England 39 bus test system are presented to verify the effectiveness of the approach.