With the increasing penetration of inverter-interfaced distributed generators (IIDGs) and energy storage systems (ESS) in distribution networks

conventional pilot protection faces challenges such as difficult setting coordination

insufficient selectivity and reliability. To address these issues

this paper proposes a pilot protection scheme based on positive-sequence fault component impedance characteristics. Firstly

combined with the output characteristics of IIDG and ESS under different operating conditions and considering the influence of an improved low-voltage ride-through control strategy

the equivalent positive-sequence impedance expressions and their magnitude-phase characteristics for IIDGs and ESS are derived and analyzed. Secondly

the characteristic differences of positive-sequence fault component impedance measured by protections at both ends of distribution lines with IIDG and ESS under internal and external faults are investigated. On this basis

a pilot protection scheme based on positive-sequence fault component impedance characteristics is designed combined with 5G communication technology. Simulation results show that the proposed scheme is immune to the types and access modes of IIDG as well as the operating states of ESS

has favorable performance against transition resistance

and can identify internal and external faults accurately and reliably.