Accurate Impedance Based Fault Location Algorithm Using Communication between Protective Relays

The reactance method with fault resistanceseparation has been developed in order to determine as preciselyas possible the impedance of a fault loop in a transmission ordistribution power system line. This method has commonly beenused for impedance calculation in case of a single phase-to-earthfault in diverse power system protection applications. Newdevelopments in this area have shown that the extension of themethod to multi-phase faults is not only possible but also ofpractical relevance. This research consists in an improvement ofthis calculation method using data from both the own and theremote line end. This approach uses communication between twomeasurement units e.g. protection relays, which have theadvantage of not requiring a precise synchronization with eachother. The additional time invariant parameters of the powersystem, acquired by each device and transferred to the remoteend, allow an exact computation of the fault reactance and faultresistance. In this paper, the derivation of this novel approach aswell as experimental results in a fault location application arepresented.