Improved time domain distance protection method based on error weight matrix

The invention discloses an improved time domain distance protection method based on an error weight matrix. The method comprises the steps of: 1, reading a voltage and current sampling sequence in a power transmission line, constructing a calculation matrix; 2, judging singular points which affect fitting calculation, and eliminating the singular points; 3, performing parameter identification on the power transmission line based on the calculation matrix of which the singular points are removed; 4, according to fitting error corresponding to each fitting calculation result, judging whether the calculation result enters a steady state or not; 5, after judging that the calculation result enters the steady state, performing weight accumulation on the historical calculation results according to the fitting error, and meanwhile, ensuring the rapidity and stability of the fitting calculation results; 6, after judging that the calculation result does not enter the steady state, outputting a fault distance calculatio