Study On Automatic Identification Of Weak Feed Mode And Faulted Phase Selection Of Sequence Component

As power system developing, there are some changes in grid operation mode and parameters. That presents new requirements of weak feed identification and faulted phase selection. After analyzing the characteristic of week feed side fault, this paper proposes a new method which identifies weak feed mode by comparing zero and negative sequence current, and classifying negative sequence voltage. According to the characteristic of single and two-phase ground fault, this paper uses phase comparison of positive and negative sequence current to select fault phase, based on zero and negative sequence current division. That increases the ability of resisting transition resistance, and solves the problem that traditional impedance exclusive method may select error phase on heavy load line. Meanwhile, an intelligent power direction relay is put forward in this paper, which can adjust the motion interval automatically by inputting known line parameters. This relay enhances the reliability of direction distinguishing and the adaptability with weak feed identification elements. All methods proposed in this paper can help to increase the performance and adaptability of relay protection, which are simple and efficient, and have high value in theory and engineering application.