Case study protective relaying over IP/MPLS: Myth to facts

The Lower Colorado River Authority (LCRA) is a public utility that operates in central Texas to manage the water supply in the Lower Colorado River basin and both generates and supplies electric power. LCRA Transmission Services Corporation (TSC) owns and operates more than 4,800 miles of transmission lines and 330 substations. IP/MPLS (Internet Protocol/Multi-protocol Label Switching) utilized primarily by the larger telecommunications service providers but has recently developed a presence in the public utility market. LCRA TSC has its own mission critical communications network supported by an 80-node SONET ring including over 170 IP/MPLS nodes. We have been migrating systems to IP/MPLS over the last 5 years. The MPLS network supports services that include SCADA, voice, security video, metering, and enterprise data. LCRA TSC is currently in the process of testing protective relay communications on its IP/MPLS network. In this paper, we will discuss the implementation of IP/MPLS technology for protective relaying. We will publish our test results using relays with DCB and LCD pilot schemes transported over the IP/MPLS network. Our IP/MPLS network is multivendor and uses various types of communication transport including microwave radio, direct fiber, SONET, and DWDM.