Control-Based Faulty Phase Detection Methods for Lines With Converter-Interfaced Sources

Unequal sequence superimposed impedance angles of converter-interfaced renewable energy sources (CIRESs) may lead to the maloperation of traditional phase selectors based on relative angles of sequence superimposed currents. To solve this problem, two control-based schemes are proposed to make original phase selectors operate correctly. In the first method, the negative-sequence superimposed impedance angle of converter-interfaced RES (CIRESs) is adjusted to respectively track positive- and zero-sequence superimposed impedance angles by calculating suitable negative-sequence current references, but this method cannot ensure that two phase selectors operate simultaneously. To achieve this aim, the second method is proposed to adjust positive- and negative-sequence superimposed impedance angles close to 90° together. Two methods can be applied to different fault types, fault points, weak grids, and high-resistance faults. Moreover, typical fault ride-through requirements can be performed strictly in the first method, and reactive power can be also provided in the second method while a large active power is maintained. PSCAD simulation and hardware-in-the-loop testing verify the proposed method.