On the basis of analyzing the fault direction characteristics

a novel directional element based on amplitude comparison is proposed. The characteristics of the forward wave and backward wave are different in different directions. The difference between the forward wave and the backward wave is rather small under a forward fault while the difference is large under a backward fault. S-transform energy relative entropy is utilized to quantize the difference. In consideration of the inability of the capacitor voltage transducer (CVT)

to transform high frequency voltage signals

the lower frequency component is made use of to calculate the energy relative entropy. Then the criterion for fault direction is established. The simulation results based on PSCAD/EMTDC indicate that the proposed directional element is reliable and rapid and its performance is not affected by the fault inception angle， fault resistance， fault position， fault type and busbar configuration

and the arc fault.