A series multiresolution morphological gradient-based criterion to identify CT saturation

作者：Lin XN^*; Zou L; Tian Q; Weng HL; Liu P

来源：IEEE Transactions on Power Delivery, 2006, 21(3): 1169-1175.

DOI：10.1109/TPWRD.2005.861338

• current-transformer (CT) saturation
• differential protection
• mathematical morphology
• series multiresolution morphological gradient

The differential relay possibly mal-operate due to the inconsistent transforming characteristics of current transformers (CTs) when experiencing heavy through fault. According to the investigation of CTs of differential protection, the time interval between the occurrence of differential current and the sudden change of phase current can be utilized to distinguish between the external faults and the internal faults. A new CT saturation-blocking scheme for differential protections, which aims at identifying this time interval by virtue of series multiresolution morphological gradient (SMMG) is proposed. Using the excellent singularity detecting together with the noise-repressing abilities of SMMG, this time interval can be identified in real time with high accuracy. The EMTDC-based simulation results show that the scheme can effectively prevent the differential protection from mal-operating meanwhile guarantee the high-speed response to the internal fault.

• 出版日期2006-7
• 单位华中科技大学