基于故障分量综合阻抗的变压器保护新原理

A Fault Component Comprehensive Impedance Based Transformer Protection Principle

提出了一种基于故障分量综合阻抗的变压器保护新原理。利用故障分量综合阻抗在内部故障时符号为负,而外部故障、励磁涌流等情况下符号为正的特点,提出了综合阻抗方向元件,快速灵敏的识别内部故障。利用故障分量综合阻抗的幅值在外部故障时数值较大,而其他情况下数值较小的特点,可靠的识别空投于内部故障的情况。该原理不受励磁涌流的影响,EMTDC仿真验证了其可行性。

A novel fault component comprehensive impedance based transformer protection principle is proposed in this paper. The fault component comprehensive impedance is excitation impedance when external fault occurs, which magnitude is large and which sign is positive. In situation of internal fault, the fault comprehensive component impedance is the impedances of the transmission lines and equivalent sources of system. Which magnitude is smaller and which sign is negative. In situation of inrush current, the sign of fault component comprehensive impedance is positive and the magnitude is larger than that in internal fault situation. The proposed principle based on fault component comprehensive impedance can detect the internal fault from external fault and inrush current quickly. Simulation results show that it can immunize the maloperation when transformer is energized, and has high sensitivity and reliability.