Source-independent Zone-1 protection for converter-dominated power networks

Growing penetration of converter-interfaced renewable energy sources with numerous control operations results in non-homogeneous fault characteristics in the network. Distance relay Zone-1 operation with such non-homogeneous situation may be vulnerable compromising both dependability and security aspects. In this work, vulnerability analysis is carried out to identify the factors influencing Zone-1 performance in a renewable integrated power network, and a method is proposed to ensure its correct operation. The method considers the homogeneity present in negative and zero sequence networks with converter-based sources to obtain the faulted loop current angle using local measurements and to derive correct decisions. The proposed method is tested for different renewable integrated systems, even with 100% converter-based sources and with variations in different vulnerable factors. Comparison with available distance relaying techniques demonstrates the superior performance of the proposed method.