Monitoring and suppression measures of transformer DC bias current

A real-time monitoring device of transformer DC bias current was presented in this paper, which can effectively improve the early warning capacity of transformer DC bias. It is consisted with compass module, GPRS module, Hall current sensor and so on. The main components, functions and technical specifications of this device are introduced. At present, there are some suppression measures of transformer DC bias, such as series capacitor, series resistance, and reverse compensation device of DC bias current, etc. By comparing the advantages and disadvantages of above suppression measures, an effective and practical measure for suppressing the DC bias current was advised. Series resistance in transformer neutral point can limit DC current. This measure is practical, economical, and easy to promote extensive application in the transformers near by the DC grounding electrode.