Multi-criteria relaying strategy for single phase to ground fault in MV power systems

This paper devotes research to the single phase to ground fault line detection problem in neutral nondirect earthed power systems. A concept of fault measures is introduced to quantitatively describe the degree of the fault indication in each line for flexible and reasonable fusion of multi criteria. A wavelet based transient method is proposed to extend the use of fault information. Fault measure algorithms for transient, steady state magnitude and steady state phase angle are formulated respectively. D-S evidence theory is introduced to deal with the fusion of multi criteria. An example obtained from a practical fault is provided to verify the effect of the fault measures, the transient detection method and the D-S combination. The example shows that the novel resorts proposed in this paper can really improve the performance of fault line detection.