Based On Network-based Peer-to-peer Communication With The Study Of The Electrical Protection System

Fault-location and protection is one of the most important parts of distribution automation system. Protection in distribution has been a difficult problem for a long time, because distribution lines are relatively shortor in distribution network and there are more cascade switches than the electrical transmission system. So traditional protection methods, such as over-current protection and distance protection, are not all applicable in this case in the distribution system.With the application of communication in the distribution automation, digital logical protection has come into use. Digital logical protection is a kind of protection based on the centralized communication. A sub-master station for protection is set up to collect fault information from FTUs on the lines, analyse and locate fault, then give order to the FTU near the fault spot to trip the switch instantly. The centralized logical protection is fast and accurate, however it's so dependent on the submaster station that the whole protection system fails if the substation has any failure.To overcome the defect of the protection based on the centralized communication, based on the peer-to-peer communication network protection, a new protection method, is brought forword in this paper. The network protection is a kind of distributed protection. Via peer-to-peer communication network, each FTU locates the fault and judges whether the switch ought to act with the fault information it collects from other FTUs in the network. The network protection, combining modern communication technology with dependable distribulized algorithms, makes the switches in the network cooperating more rapidly and efficiently. Network protection is a new conception. It realizes high-speed and selective action without the dependence on the submaster station, and shows more advantages than the centralized protection.