基于测后模拟原理的半波长输电线路暂态量纵联保护

针对特高压半波长超长的输电距离带来的继电保护难题,提出基于测后模拟原理的半波长输电线路暂态量纵联保护方法。特高压半波长交流输电具有传输距离远、输送容量大、全线无功自平衡等优点,可以作为未来清洁能源电力输送的一种可选方案。通过分析现有输电线路保护方法对于半波长交流输电线路的不适用性,对特高压半波长输电线路在区内外故障情况下,推导至中点的暂态量电流和的绝对值在短时窗内积分方向的不同进行理论分析;以贝杰龙模型为基础,利用测后模拟原理构成输电线路暂态量纵联保护方法,进行仿真实验;进而判别输电线路单相接地故障时故障初始角、故障位置和过渡电阻对故障判据的影响。仿真实验证明,此方法构成的保护计算精度高,相较于工频量构成的保护其动作速度更快且几乎不受过渡电阻、故障距离及故障初始角变化的影响,理论分析与实际的仿真结果相一致。

Transient longitudinal protection of half-wavelength transmission line based on post-test simulation principle

Aiming at the relay protection problems caused by ultra long transmission distance of UHV half wavelength,a transient pilot protection method based on post-test simulation principle was proposed.UHV half-wavelength AC transmission has the advantages of long transmission distance,large conveying capacity,and full-line reactive power self-balancing,which can be used as an option for future clean power transmission.By analyzing the inapplicability of the existing transmission line protection method to the half-wavelength AC transmission line,the UW half-wavelength transmission line was deduced to the midpoint of the transient current and the absolute value in the short-time.The theoretical analysis of the difference was conducted in the direction of integration in the window;based on the Bergeron model,using the post-test simulation principle to construct the transient protection method for the transmission line transients,the PSCAD/EMTDC simulation experiment was carried out;and the single-phase ground fault of the transmission line was determined.The effect of fault initial angle,fault location and transition resistance was judged on the fault criteria.The simulation experiment proves that the protection calculation of this method is high,and the action speed is faster than that of the power frequency,and it is hardly affected by the transition resistance,the fault distance and the initial angle of the fault.Theoretical analysis are consistent with actual simulation results.