Research on Misoperation of Line Differential Protection Mixed with Different CT

摘要

With the development of information technology and the in-depth advancement of the ubiquitous power Internet of Things, a large number of power electronic devices have entered the power grid, and the types and quantities of devices which are connected to the power grid have also increased, making the shape of the power grid gradually change. In the current operation of the substation, intelligent substations and traditional substations are often present at both ends of the line. They use electronic current transformers and electromagnetic current transformers respectively in the differential protection. The malfunction of the line differential protection is caused by the difference between two transformers in characteristics. This paper proposes a method to detect the saturation point of electromagnetic current transformer by B-spline wavelet method to avoid the occurrence of protection malfunction.