Simulation Research on UHV Transformer DIFP Based on Different Fault Conditions

The actual configuration and parameters of UHV transmission under construction in China are introduced, and the corresponding dynamic simulation experiment model is established. According to the structure and operation characteristics of the 1000kV UHV transformer, the differential protection scheme is proposed based on the divided structure and large capacity of UHV transformer. Simulation results show that when voltage regulation winding and voltage compensation winding inter turn faults happen, individual DIFP configuration of voltage regulation winding and voltage compensation winding can improve the sensitivity, the fault component DIFP can improve the sensitivity of the main winding's slight fault under the condition of heavy load, the split side DIFP can avoid the influence of over excitation and magnetizing inrush, and the zero sequence DIFP can improve sensitivity when single phase earth faults happen, especially for slight grounding fault whose grounding point is close to the neutral point.