To improve the reliability of conventional protection using traveling waves， a wide area protection method based on polarity comparison of the first traveling wave is proposed. According to the transmission lines configuration and traveling wave protection relays（TWPRs） positions in a power grid， the line/TWPR associated matrices can be obtained. When a fault occurs in the power grid， fault associated matrices can be formed based on the first traveling wave polarity recorded by TWPRs and line/TWPR associated matrices， and then the fault line can be identified by the wide area traveling wave protective system based on the above information. It is worth noting that such protection can also be achieved even if certain TWPR breaks down， failure in start， or null traveling wave is recorded. Analysis and simulation results show that the proposed wide area traveling wave protection algorithm is simple and feasible.