Fault identification algorithm applied in regional backup protection based on fault condition set

A fault identification algorithm based on the fault condition set (FCS) is proposed, which is applied in the regional backup protection system. Firstly, the element action factor (AF) is defined to indicate the operation state of protection elements. With the help of the AF, the fault condition set is presented for estimating the fault situation of a studied transmission line. Secondly, the element relationship factor (RF) is defined to show the relevance of the protection elements to the corresponding lines. By using the AF and RF, the line fault factor (FF) is formed. The function of the FF is to convert the FCS to a fault identification criterion which can be directly disposed by the backup protection system. Hence the fault identification criterion also has the capability to determinate a fault line. Finally, simulation results demonstrate that no incorrect judgment happens, even in the situations that any two messages are lost or one message is misjudged. The proposed algorithm is concise and reliable with great information error tolerant ability.