A Novel Hierarchical Protection System for Power Grids with High Penetration of Renewable Energy Integration

To address the issue that traditional protection principles based on power‑frequency phasors and their stepwise backup protection coordination are no longer fully applicable under large‑ scale integration of renewable energy, this paper proposes a novel hierarchical relay protection system framework based on information exchange between electrically direct ‑ connected substations. This protection system is structured into three layers: local, stationarea, and wide-area. Each layer employs the new principle of time domain protection to resolve adaptability challenges of traditional power frequency protections in the scenario of high proportion of new energy access. A fault‑scenario identification scheme is also presented, which utilizes abnormal signals such as channel alarms to identify fault scenarios and activate corresponding protection functions, thereby greatly simplifying the coordination settings of backup protection. This hierarchical system breaks through the constraints of conventional stage ‑ wise coordination, successfully mitigating protection ‑ miscoordination risks in grids with high renewable energy penetration while accelerating backup protection response, thus comprehensively enhancing substation protection performance and demonstrating broad prospects for engineering application.