Analysis of Earth Fault Experiments in Actual Distribution Network

Experiments performed in a real network represent an efficient means to verify theoretical calculating methods for fault and transient analysis. One of the most common faults in distribution networks is a single-phase earth fault. It is also a fault whose location is very complicated. Therefore, research concerning the characteristics and the behaviour of compensated networks represents an important step towards efficient tools for the protection of such networks as well as the control of their operation. This paper presents the results of the analysis of fault records obtained during numerous experiments performed from 2008 to 2011 in real resonant-earthed distribution networks. The purpose of these experiments was to provide data either for verifying distribution network safety during earth faults or for testing methods of earth fault location or elimination. This is why the measurements were performed during earth faults at various points in the network and for various operating conditions concerning the size of the network, the off-resonant degree (undercompensation, overcompensation and full compensation) and the fault resistance (including arc earth faults) and the network load. A detailed analysis of the obtained measurement records having been completed, its results could be evaluated with respect to the dimensioning of network components, ground fault protection setting and particularly as a base for a further development of the earth fault location methods. This paper presents the results of the analysis of a vast fault records database.