Angular characteristic of a synchronous generator operating over a long line in the dead time of single-phase auto-reclosing
This article discusses the problem of calculating an angular characteristic of a synchronous generator related to the elimination of arcing single phase-to-ground faults in the lines of ultrahigh voltage (UHV).Due to a long length of UHV lines such accidents cause the vast majority of them (98 %). At the same time, a significant part (70 %) of single phase-to-ground faults (SPGF) represents unstable arc accidents, which can be successfully eliminated in the single-phase automatic reclosing (SPAR) cycle. The SPAR dead time depends on the value of the secondary arc currents and is in the range of 0.5…3.0 s. Therefore, it is of interest to analyze the nature of dynamic transitions when using SPAR of different duration and to assess the capacity level of very long power transmission lines in terms of dynamic stability. The features of dynamic transition in determining the accident can be traced using angular characteristics of the normal, SPGF and SPAR modes. However, in the literature there is no exact way to simulate the angular characteristic in the dead time, when the emergency phase is disconnected on both sides at the ends of the line. The article proposes an original exact algorithm for calculating an angular characteristic of a synchronous generator operating over the UHV line in the dead time, in order to estimate an error of simplified modeling of the angular characteristic, when the two-way phase opening is replaced by a single gap either at the beginning or at the end of the line.