In order to increase the tolerance, a novel wide-area backup protection algorithm with sections weighed fault matching is proposed in the paper. Firstly, it is analyzed that there is differences on relative protection components of faulted and adjacent lines under different sections. Using redundant wide-area backup protection components, the real protection vector and fault expectation protection vector of each section are constructed. The weighed fault matching function is defined. The fault criterions are given to detect the fault component. The simulation test illustrates the effectiveness of proposed algorithm. It has 100% accuracy rate under five protection information errors. The factors that include the choice of wide-area backup protection components and their weighted coefficients are analyzed, as well as topological structure of power grid and its change.