变压器外部故障切除后恢复性涌流的研究

Study of Transformer Recovery Inrush After Clearance of External Faults

长期以来,变压器区外故障切除后的电压恢复过程被认为与空载合闸一致,其实变压器在此 期间的电磁暂态过程有其自身的特点。文中考虑了断路器在电流过零时开断短路电流的约束条 件,分析了变压器从外部故障发生到被切除的电磁暂态全过程,提出了故障传递剩磁的概念,说明 了影响变压器外部故障切除后恢复性涌流的4个参数。在此基础上,以数字仿真和动模录波数据 分析说明恢复性涌流本身不会造成变压器差动保护误动。

The transient of transformer voltage recovery after clearance of external faults has been considered to be the same with that of transformer switching-on without load. In fact, the transient during transformer voltage recovery has its own characteristic. Taking into account the constraint that a breaker opens at the fault zero-crossing current, this paper analyzes the transformer magnetic-electric transient during the entire period of external faults. The fault transferring residual flux is firstly presented and four variables influencing the transformer recovery inrush current are studied. Furthermore, The digital simulation results and dynamic simulation data indicate that transformer recovery inrush itself cannot result in mal-operation of differential protection.