During a short circuit condition, core of a Current Transformer (CT) may become saturated due to large primary current containing a significant DC component. The saturation of the core distorts the secondary current which may cause malfunction of the protective devices connected to the CT. As a result of significant advances in the technology and deployment of digital relays in the last decade, the distorted secondary current can be reconstructed in a very short time. Several methods, which take into account the non-linear behavior of the CT, have been researched in the recent past. Processing time, accuracy, and online implementation are of prime importance while selecting a particular algorithm. In this paper, a comprehensive review of the different algorithms used for the detection of saturation as well as reconstruction of the distorted secondary current is presented.
©2011 Walter de Gruyter GmbH & Co. KG, Berlin/Boston
