A new algorithm to compute fault synchrophasor from transient state synchrophasor in PDC

Synchrophasors are increasingly used in the wide area monitoring applications. Computational window lengths of the practical synchrophasor estimation filters are often multiple fundamental cycles long to achieve robustness. In many situations, the window length of the synchrophasor estimation filter is greater than the fault clearing time. In this case, there are not enough fault samples within the window to compute a synchrophasor corresponding to the fault condition. So, transient state synchrophasors are only available for use in this case. A fault transient synchrophasor is computed over a window consisting of pre-fault and fault samples. Currently, these transient synchrophasors are discarded and generally not used in the applications. In this paper, an algorithm is proposed to compute fault voltage/current synchrophasor from a fault transient synchrophasor value. The novelty of the proposed algorithm is that this algorithm can be used in a Phasor Data Concentrator (PDC). The proposed algorithm is simple, noniterative and performs satisfactorily in presence of noise. One possible application of the proposed algorithm is in the fault location on transmission lines where the fault clearing time is lower than the estimation filter window length.