Missing Information Protection Considering Inrush Current and CT Saturation

When the measurement information is missing, the Kirchhoff synthetic current method is usually used to replace the current information at the missing measuring point. However, in some specific cases, the inrush current of the transformer and the saturation of the bus CT will occur, which affects the accuracy of the synthetic current, and then leads to the misjudgement of the differential protection using the equivalent current, which endangers the safety and stability of the smart substation and the power system. In this paper, an information loss protection is proposed to eliminate the influence of inrush current and CT saturation, and PSCAD / EMTDC simulation is carried out. The results show that the reliability of power system is effectively improved when the measurement information of transformer and bus connection line is missing.