Substation architecture with protective relays using digital instrument transformers and digital interface technology

In this paper an integrated substation control and protection system is described. The system comprises both primary equipment and IEDs with digital interfaces connected via a process bus and station bus within the substation. Increased operational efficiency is achieved for both primary equipment and IEDs by sharing information between IEDs and providing access at remote locations. The system introduces a newly developed architecture using an internal parallel signal bus, instead of an external process bus, to transfer high speed/bulk process level data such as sampled data particularly for current and voltage signals for protective relays. This architecture can also satisfy the security and dependability expected from a protective relay with real-time performance.