基于波形非正弦度分形估计的励磁涌流识别方法

电力变压器作为输变电关键主设备,在电力系统中占有极其重要的地位,纵差保护是变压器的主保护之一,正确识别变压器励磁涌流和内部短路故障是变压器保护的关键问题。提出了一种基于波形非正弦度分形估计的励磁涌流识别方法,应用网格分形技术计算差流波形的非正弦度,利用励磁涌流波形非正弦度增大的特点,鉴别励磁涌流和故障电流。仿真结果表明,该方案能很好满足继电保护要求的有效性和可靠性。

Novel Method of Identifying Inrush Current based on Non-sinusoidal Fractal Estimation

Power transformer is the vital important electric installation equipment in power system. As longitudinal differential protection is one of the main transformer protection, the correct identification of transformer magnetizing inrush current from internal short-circuit fault current is a key issue of transformer protection. A non-sinusoidal fractal estimation method is proposed to identify inrush current. It employs grille fractal technique to compute non-sinusoidal degree of differential current waveform. The inrush current and fault current can be distinguished by the sign that the non-sine degree of inrush current will increase. The simulation in ATP shows that this scheme can greatly satisfy the demands on effectivity and reliability.