中文摘要：

摘要：为了使振荡闭锁装置能在振荡中再故障时开放保护，就必须能区分振荡与故障，且故障相的单相阻抗继电器在振荡时也应能正确测量阻抗。但如何在振荡中快速正确地选出一个故障相进行阻抗测量是距离保护能否有选择性地切除振荡中故障的关键问题。在动模实验中发现：对于振荡中发生的故障，在一定情况下序分量选相元件会误选相。文中利用级联多分辨形态梯度变换（SMMG）提出了一种电力系统振荡中的故障检测和改进的故障选相方案：先利用一个SMMG滤波器对相电流进行处理，构成一个自适应的振荡中故障起动元件；检测到故障或扰动后，对接地故障，如果由现有的序分量选相方法判断出其为落在包含单相和相间2种故障类型的区域，则可利用故障后3个模电流分量的SMMG系数局部模极大值确定其故障相别。用EMTP在一个系统模型上进行了大量的仿真研究，其结果验证了该方案的有效性和易用性，该方法判别灵敏，结果可靠，所提出的算法易于实现，在现有的微机保护装置中可以直接采用。

英文摘要：

The blocked protective relays should be able to respond to internal fault occurring during power swing blocking state. Therefore, it is necessary to distinguish faults from swing. It is also desirable to identify the fault phase correctly and rapidly during power swing so that distance relay can measure the impedance correctly and trip the fault selectively. The conventional sequence component fault phase selector mal-operates in some cases during power swing according to dynamic simulation results. In order to overcome the disadvantage, a fault detector and improved fault phase selector during power swing based on series multi-resolution morphological gradient （SMMG） transform are proposed in this paper. First, a SMMG filter is used to detect fault inception. If the fault is either a single or a double phase（s） to ground one according to the sequence component fault phase selection scheme, another SMMG filter is then employed to process three modular current signals so as to distinguish between them. Using EMTP, an extensive series of simulations has been carded out on a model system to verify the efficiency and feasibility of the proposed scheme.