Study on the improved transformer protection method based on the magnetic flux characteristics

For the problem of discrimination between inrush current and internal fault current, this paper is to put forward a new method for distinguishing magnetizing inrush based on the characteristics of voltage and differential current. The principle is simple and the implementation is easy. None of anticipated internal parameters are needed. The advantages of the method are convenient data acquisition, fewer computations and a reliable and quick operation. ATP simulation tests show that the method is reasonable. The results of dynamic analog testing and analysis of transformer operation data in the field confirmed that the method is able to clear the internal fault reliably and quickly.