Transient monitoring function-based pilot protection for inverter-based resource-dominated power systems

With the increasing penetration of renewable energy sources (RESs) in generation portfolios, the fault characteristics of power systems are changing significantly. In particular, inverter-interfaced distributed generators (IIDGs) driven by RESs, which have a limited overcurrent carrying capacity, render overcurrent protection ineffective. Although this ineffectiveness can be addressed by conventional pilot protection, which is a mature scheme in transmission systems, it may still maloperation under conditions of high IIDG penetration. In this paper, a protection scheme based on the transient monitoring function (TMF) is proposed to enhance the protection of distribution systems integrated with IIDGs. The proposed scheme can accurately locate faults while remaining unaffected by non-fault events. It demonstrates higher sensitivity compared to conventional pilot protection, addressing the challenge of pilot protection maloperations. The performance of the proposed scheme has been validated through simulations conducted under various scenarios, such as different fault locations and types, as well as the effects of harmonics, sampling frequency, and data window length, using the MATLAB/Simulink platform. • The scheme accurately distinguishes internal faults from external faults. • The proposed scheme is more sensitive than conventional pilot protection. • The scheme remains effective when the IIDG-side fault current is zero. • The scheme remains secure under harmonics and frequent switching events. • The scheme is validated under different fault locations and fault types.