On-line impedance meter to measure the impedance of a distribution line using inverter

Abstract

To tackle the harmonic problem in a distribution line system, it is important that we are able to measure the impedance of the distribution line in a simple way. In addition, it is desirable that we make the measurement without service interruption. Under such circumstances, a novel measurement method for determining line impedance using an inverter circuit is proposed in this paper. In the case where we are determining the inductance, the line inductance can be measured relatively accurately. Moreover, we also propose the measurement method of the line capacitance. Finally, in the case where we are determining the resistance, the line impedance is measured by a technique derived from fundamental measurement theory, in which only passive elements such as inductors or resistors are used.