大型调相机惰速同期并网可靠性研究

静止变频器（SFC）输出侧不配升压变可减少加装调相机的整体成本,但并网前SFC退出后调相机转子转速将不再可控,同期条件差。为提高惰速同期并网可靠性,首先建立了冲击电流与频差和角差间的关系,其次对同期点存在概率进行了研究,然后提出了在正频差时选择滞后系统的一个小角度、负频差时选择超前系统的一个小角度并网,正频差允许值设定较小、负频差允许值设定较大等提高并网可靠性的方法。结合算例,对调相机惰速运行中不同惰速率和不同允许频差下的同期点存在概率进行了计算分析,验证了所提方法可有效减小并网冲击电流,增加同期点存在概率,提高并网可靠性。

Reliability Research on Idle Speed Synchronization of Large Condenser

The output side of the static frequency converter (SFC) which is not equipped with step-up transformer can reduce the overall cost of installing the condenser, but then the conditions of grid connection will become harsh when the rotor speed is no longer controllable. In order to improve the grid-connected reliability of synchronization, firstly the relationship is established between the inrush current, frequency difference and angular difference, secondly the existence probability of synchronous point are researched on, then some suggestions that select a small lag angle in the positive frequency difference, a small advanced angle in the negative frequency difference and so on are put forward to improve the reliability of synchronization. Based on the example, the existence probabilities and permissible frequency differences are studied that verify the proposed methods can effectively improve the reliability of synchronization.