Study for the Wide-area Protection Schemes Coping with Abnormal Trip Phenomenon

Several severe power failures occurred in recent years, the reason of which are common fault-trip-cased flow transferring. This phenomenon can lead to abnormal trip of load flow protection, and at worse result in intertripping. To prevent potential power failures, wide area protection based on wide area measurement was proposed. Wide area protection systems can be divided into two parts: wide area backup protection and wide area emergency control. The first part of the paper introduces the development process of cascading outages, principles, characteristics and classification of wide area backup protection. The second part of the paper focuses on structure and control mode of wide area backup protection system and the improvement of various structures to the performance of the traditional back up protection. In the last part, three kind of wide area backup protection which bases on current differential principle, direction comparison principle and multi-Agent is introduced. They are the major forms of centralized protection and distributed protection respectively.