Exploration of New Power System Protection Architecture

With the proposal of carbon peaking and carbon neutrality goals, the construction of a new power system dominated by new energy generation has become a key issue in the current energy structure transformation. With the introduction of new energy and power electronic equipment, power systems, fault diagnosis, and protection systems have become increasingly complex. The design of future protection urgently requires clear guidance on protection architecture. This article defines protection architecture as a series of abstract patterns aimed at achieving protection objectives. The significance of protection architecture lies in providing guidance for protection design in increasingly complex scenarios, while maintaining the rationality of the protection system's own design while clarifying the achievement of protection goals. The traditional power system protection architecture essentially protects the system by protecting equipment, utilizing three-phase electrical information and switch values to achieve pattern recognition-based assessment goals. The new power system has introduced new energy generation and power electronic equipment marked by converters, changing the operating characteristics of the system and proposing new protection requirements. Power electronic devices are quickly controlled and fragile. Rapid and controlled changes have altered the operational and fault characteristics of the protected equipment, blurred the boundary between faults and non-faults, and increased fault chain paths. Based on the protection requirements of the new power system, this article proposes that the new power system protection architecture should protect the system through protection equipment, while blocking fault chain and optimizing equipment protection through the protection system. By collecting and communicating electrical information and control status across all frequency bands, conducting fault analysis based on pattern recognition of modified electrical quantities, implementing coordinated protection between primary and backup protection, optimizing multi-interval control and electrical information interaction, the top-level goal of the protection architecture is achieved. Finally, this article proposes a typical protection scheme based on a new power system protection architecture, which adopts a control coordination method to expand the adaptability range of traditional protection. It provides a reference for the design of protection schemes and the integration of control and protection in future new power systems.