Accurate measurement and calculation method for parameters of power transmission line

The invention discloses an accurate measurement and calculation method for parameters of a power transmission line. In the method, the parameters of the power transmission line are accurately calculated according to short-circuit impedance ZS and open-circuit impedance ZO of the power transmission line. The method comprises the following steps of: measuring the short-circuit impedance ZS and the open-circuit impedance ZO of the power transmission line with length of D; acculate calculating characteristic impedance zc and propagation coefficient gamma of the power transmission line according to a calculation formula provided by the invention; further, calculating impedance z and admittance y under the condition of unit length of the line through the formulas of z=zc gamma and y=gamma/zc; and accurately calculating impedance Z' and admittance Y' of an equivalent pi circuit of the power transmission line according to the calculation formula provided by the invention. By adopting the measurement and calculation method provided by the invention, the accuracy for the parameters of the power transmission line can be greatly improved, manpower and material resources are saved, tide current of a power system is stably analyzed; protection setting is performed; and fault positioning is more accurate.