An Automatic Shedding Decision System for the Backup Protection of a Transmission Network

In recent years, many wide spread blackouts is caused by incorrect operations of the backup protection relays that result from the overloading of some transmission lines after one faulted transmission line is tripped. This paper gives a new solution to this event. A new conception of RCTL(relative cluster of the transmission line ) is introduced firstly in this paper. Then the method for searching RCTL based on decision tree theory and the method for calculating distribution coefficient of RCTL is introduced in detail, among them the key techniques are emphasized in the paper. On this basis, an automatic shedding decision system for the backup protection is proposed to prevent cascading outages. The simulation of CEPRI standard model shows that the automatic shedding decision system for the backup protection against cascading outages works well.