Single-ended backup protection method and system based on line model parameter matching

The invention discloses a single-ended backup protection method and system based on line model parameter matching, and the method comprises the steps: substituting voltage and current information collected in a unit data window of a protection device into a line resistance-inductance equation according to the voltage and current corresponding to a system fault, forming a difference equation set, and obtaining a matrix equation of a line resistance-inductance model; fitting solution is carried out on the matrix equation by using a least square method, fitting error calculation in all unit data windows in a cycle is completed, and the fault distance is a first element of a fitting coefficient matrix beta r until the fault distances in all unit data windows in the cycle are obtained; and completing fault judgment according to fault distance calculation results and fitting error calculation results in all unit data windows in a cycle. Compared with the prior art, a backup protection scheme for protecting the full