Principles of Transformer Differential Protection and Existing Problem Analysis

As the main protection for most power transformers, the performance of differential protection affects the continuous and stable operation of the whole power system. This chapter firstly studies fundamentals of transformer differential protection and introduces common differential protection schemes. Since it may mal-operate in the presence of transformer inrush currents, various schemes in current differential protection principles and inrush current blocking schemes based on different mechanisms are then proposed and discussed. By comparative research, the future of the transformer main protection technology is pointed out.