Neutral Current Characteristics and Suppression Strategies of Transformers in Urban Substations

In urban substations near the rail transit, abnormal cases appear frequently in the grounding transformers, which can cause negative effects in the operation of the power system. This phenomenon attracts the attention of the researchers, and ultimately points to the invading stray current leaked from the rail transit nearby. Based on the measurement results in the substation, the characteristics of the neutral current in the grounding transformer are analyzed. In this way, the relationship between the change of transformer neutral current and the operation of rail transit is presented. Then the cause of harmonics in the current is modeled and analyzed. At last, a new suppression strategy for the current is proposed. For verification, the simulation proves the effectiveness of the whole research.