Patent ID: 6336059
Filing Date: 2002-01-01
Classification: H02H

Abstract:
A reach-measurement method for use in connection with a series-compensated line of a power system, the series-compensated line including an installed series capacitance having a bus side and a line side, and a non-linear protection device parallel to the installed series capacitance, the series-compensated line having a line current, a bus side voltage, and a line side voltage, the series capacitance and the non-linear protection device having a capacitance voltage thereacross equal to the bus side voltage minus the line side voltage, the method comprising the steps of:measuring a number (n) of line current samples representative of values of a line current waveform at successive instants of time on the series-compensated line; computing capacitance voltage values based on the measured line current samples in accordance with an equation which takes into account the non-linear protection device parallel to the installed series capacitance; and performing a prescribed power system function based on the computed capacitance voltage values, wherein the computed capacitance voltage values are determined in accordance with the following equation: Vk+1=Vk+Î”&it;â€ƒ&it;tC&it;(Ik-INLP&af;(Vk));wherein Vk=V(tk), the capacitance voltage at time tk: Ik=I(tk), the line current at time tk; INLP(Vk) is the current through the non-linear protection device at voltage Vk; C is the installed series capacitance; &Dgr;t represents the time period separating successive samples and tk=k &Dgr;t for k=0, . . . , n.