Research on Braking Strategy of Current Differential Protection for Flexible DC Distribution Network

In view of the lack of effective braking measures in the current differential protection of flexible DC distribution networks, a protection method is proposed that takes the differential of the current as the action amount and the modulus of the current differential as the braking amount. Use the cooperation of the upper and lower levels to complete the identification of specific fault locations. Through theoretical analysis, the relationship between the direction and magnitude of the action amount and the braking amount is summarized so as to construct the protection criterion. Through simulation verification, when an internal fault occurs, the action amount of the current level line is greater than the braking amount, and the braking amount of the lower levels line is greater than the action amount, and the protection is sensitive. The reliability and selectivity of the protection algorithm. At the same time, the protection combines the fault component algorithm, and the sensitivity and the ability to withstand excessive resistance are also improved to a certain extent.