Integrating current differential relaying communications into an IP based infrastructure

Current differential relaying is a proven and time tested method for line protection. One of the main benefits is its simplicity. While having been displaced by distance protections for transmission line protection, current differential relays have regained their popularity thanks to increased access to digital communications media. The present design of numerical current differential relays is made for synchronous communications, such as Tl/El and SONET/SDH. However, there is nothing in the relaying principle that prevents the use of packetized communications (Ethernet), and this paper has presented several alternatives for how this can be realized. With telecommunications inevitably moving towards Ethernet, conventional synchronous pilot relaying channels may quickly become obsolete. Relay manufacturers will have to address the need for new communications solutions for relaying, providing native Ethernet protective relay devices.