发电厂送出线重合闸时刻的在线优化研究

摘要

重要输电线路的重合闸时间对系统运行的稳定性有较大影响,传统的定时限重合闸方式可能使系统在重合后振荡幅度短时变大,当重合于永久性故障时,可能使原本稳定的系统失稳.根据暂态能量函数理论和发电厂接线特点,提出了基于正序电流幅值的发电厂送出线重合闸时刻在线优化方法.理论分析和BPA软件仿真表明,发电机机组与其并网的系统之间具有明显的两机系统特征,注入系统的正序电流幅值能够准确反映暂态能量的变化规律,很好地对最佳重合时刻进行实施捕捉,对系统在重闸后的振荡过程进行有效抑制,提高了发电厂运行的稳定性.同时该方法还具有只需要采集少量站内数据,计算量较小,易于实现的优点,具有很高的实用价值.%It's proved that the stability of power system can be affected by reclosing time of important transmission lines; the traditional fixed-time reclosing scheme could enlarge the oscillation magnitude of system after reclosing operation, and cause the loss of stability when reciosed to permenant faults.In this paper, an online optimization scheme of reclosing-time of power plant transmission lines based on positive sequence current magnitude is proposed under the study of transient energy function and power plants main connection characteristics.Theoretical analysis and BPA simulation have proved the two-machine characteristics between the power plant and the system it is connected to, and that the positive sequence current magnitude can accurately reflect the transient energy and capture the best reclosing time, restrain the oscillation of power system after reclosing operation, and improve the stability of the power plant.The proposed scheme also has advantages of less computation and easy realization, and is of great practical value.