Research on Intelligent Transformer Differential Protection System Based on "Plug and Play"

In order to realize the differential protection of transformer better, the research of intelligent transformer differential protection system based on "plug and play" is put forward. In the aspect of hardware, "plug and play" is used to realize the connection of differential protection. According to IEC 60870-5-104 transmission protocol, the communication between transformer and differential protection device is established to realize the mutual transfer of information after verification. In the aspect of software, the information automatic checking service from main station to substation and from substation to differential device is accomplished by information automatic checking. On the basis of the basic principle of current differential protection, the brake quantity is introduced and the criterion of ratio differential protection is analyzed. The differential protection device is used to collect the checked information, and the secondary harmonic of the inrush current is calculated after A/D conversion to complete the differential protection. The test results show that the system has higher information automatic check efficiency and ratio differential protection operation efficiency, and can better complete the differential protection of intelligent transformer.