Patent ID: 6713998
Filing Date: 2004-03-30
Classification: G01R

Abstract:
A method for measuring the resistance R and the inductance L of a line, in which a voltage u across the line and a time derivative &igr; of a current through i through the line are measured at a rate 1/TA in order to obtain a series of N voltage values u0, u1, . . . uN and a series of N values &igr;0, &igr;1, . . . &igr;N of the differentiated current, wherein the first derivative of the current &igr; of the current i is measured using a Rogowski coil, N&gE;3 and the voltage values and the values of the differentiated current are substituted directly into an equation system with Nâˆ’1 equations of the formun=unâˆ’1+&agr;0Â·&igr;n+&agr;1Â·&igr;nâˆ’1, with parameters Î±0=RA+LÎ±1=RA-LwhereAâ‰…2/TA or A=Ï‰0&CenterDot;cot&it;(Ï‰02&CenterDot;TA2),and wherein the resistance R and the inductance L are found from the equation system.