The related information of different power system element may be collected by line IED and bus IED for wide-area backup protection, then the fault recognition network of line and bus based on PSO-LIBSVM is established and the information collected by IED is taken as input vector for establishing the training sample matrix of the fault recognition network. PSO algorithm is used to search optimal parameter combination to train the fault identification network. The line and bus identification network is tested by the testing sample matrix of random failure, and the fault component IED is identified and the fault components are determined. A large number of experiments are made to simulate the fault identification under a variety of inaccurate information. Experiment results show that wide area backup protection based on PSO-LIBSVM has good accuracy and good fault-tolerance.