In high-voltage lines protections, directional elements based on negative sequence voltages available can not work well when negative voltages protection equipments capture are relatively low, which may lead to malfunctions or failure to actuate. A new directional element based on negative sequence reactance is presented in this paper. The negative sequence reactance is negative and then it is less than the line negative sequence reactance when a forward fault occurs. And when a reverse fault occurs, the negative sequence reactance is greater than the line negative sequence reactance. Hence, which direction a fault occurs can be distinguished according to the sign and the magnitude of the reactance. The direction element based on the negative sequence reactance has high sensitivity with no influence by transition resistances. The directional element proposed can work well when the negative sequence voltage is very low or even close to be zero and it is easy to realize.
