A novel adaptive dispersed phase current differential protection criterion

This paper indicates that the sensitivity of conventional dispersed phase current differential protection criterion using steady currents is impressed by the transient resistances and through currents. A novel adaptive dispersed phase current differential protection criterion is proposed in this paper, and an objective function with the independent variable of fault current component and through current is defined to revise the restraining ratio of differential protection criterion adaptively. The novel criterion possesses higher sensitivity at an internal ground fault with high transient resistances and heavy-loads. It can automatically decrease the restraint coefficients according to the transient resistances and improve the sensitivity at internal faults, while increase them at the external faults adaptively. The comparative analysis of the acting characteristic between the novel and conventional criterion is taken. Simulation results show the feasibility and effectiveness of the novel criterion proposed.