Abstract: It is important to equip all the 220 k V transmission lines with travelling wave devices economically and feasibly, and realize the full coverage of the fault location method, since there are more substations and lines, and the topology is also more complex in 220 k V power grid. In this paper, the observability of fault induced current traveling waves of the transmission lines was analyzed, and extended adjacency matrix was used to describe the relationship among the lines and substations in power grid. The optimal placement of traveling wave devices was expressed as linear 0-1 integer programming model including inequality and equality constraint conditions, considering the limitation of practical engineering and results of the observability analysis. The parameters and solution method of the model can be determined and the static optimal placement of the global power grid can be obtained by solving the model. Based on the static optimal solution, the dynamic sequence of the each device installation can be determined, according to the minimum decreasing weighted observable length of the lines by single and double ended fault location principles caused by each device retreat. The proposed method is proven to be feasible and effective by tests considering certain actual 220 k V power grid optimal placement.