Determination of the Value of the Capacitive Earth-Fault Current in Distribution Networks Operated with Isolated Neutral Point

Abstract

The new indirect method of measurement
and calculation of the phase-earth capacity in networks with
isolated neutral point is based on creation of a short-term
phase capacity asymmetry in the network. The value of the
phase earth capacity in the network can be determined
using the voltage ratio in the network and the capacity value
of the connected capacitor. When expanded, the method can
be also used for the leakage current estimation.
Furthermore, this method can be applied to periodic
controls of the earth capacitive current value. For the
evaluation of the phase earth capacity, a single-purpose
automation can be used and thus the whole process of
measurement and evaluation is conducted at a defined
period (at a given hour, day, month…) or on operator’s
command.