Full scale earth fault experiments on 10 kV laboratory network with comparative measurements on conventional CTs and VTs

In this paper, the authors present a result of a full-scale earth fault test carried out on the 10 kV research/laboratory distribution network at Kyndbyvaerket Denmark in May 2001. The network is compensated through a Petersen-Coil and current and voltage measurements were measured on conventional current transformers (CTs) and voltage transformers (VTs) by an optical link. Comparison with a similar earlier performed experiment carried out autumn 1998, where current and voltage measurements were measured with high bandwidth Rogowski coils and high voltage Tektronix probes, gave remarkable results. The necessity of high bandwidth measurement equipment for earth fault measurements on compensated distribution networks can be undermined, since it will be shown that the transient signal transfer through conventional CTs and VTs for further signal analysis is sufficient. Caused by the inadequacy three phase conductor cable models in PSCDAD/EMTDC^® V3, the simulations of the whole laboratory network shows more or less good identity with the measurements.