Application of MPLS-TP for transporting power system protection data

Power utilities are increasingly dependent on the use of communications networks. These networks are evolving to be packet-based, rather than using conventional Time-Division Multiplexing (TDM) technologies. Transporting current differential protection traffic over a packet network is especially challenging, due to the safety-critical nature of protection, the strict requirements for low delay and low asymmetrical delay, and the extensive use of legacy TDM-based protocols. This paper highlights the key technical characteristics of Multi-Protocol Label Switching-Transport Profile (MPLS-TP), and demonstrates its application for transporting current differential protection traffic. A real-time hardware-in-the-loop testing approach has been used to thoroughly validate the technologies in various configurations. It is demonstrated that MPLS-TP technologies can meet the requirements of current differential protection and other, less critical applications. In particular, it is shown that delay and asymmetrical delay can be controlled through the inherent use of bi-directional paths---even when “hitless” link redundancy is configured. The importance of appropriate traffic engineering, clocking schemes, circuit emulation methods is also demonstrated

IP/MPLS and MPLS/TP teleprotection latencies over high voltage power lines

Power utilities dependent on communication networks to deliver critical power services continue to increase. These time-critical networks have evolved to use packet-based technologies such as Internet Protocol Multi-Protocol Label Switching (IP/MPLS) and Multi-Protocol Label Switching Transport Protocol (MPLS/TP). Both packet-based technologies are efficient traffic routing protocols for critical applications like teleprotection with challenging low propagation and asymmetrical latency requirements. This paper presents the findings of IP/MPLS and MPLS/TP hitless teleprotection applications over high voltage power lines. The performance of both technologies is compared based on specific network parameters using test equipment. The major results highlighted include base case tests of propagation and symmetrical latencies following latency injections, event response, bit error, path switching, Quality of Service (QoS), and IEC 61850 proof of concept test. While the result demonstrates that IP/MPLS and MPLS/TP - if configured properly - can meet the strictest requirements of teleprotection latencies over high voltage power lines, their performance varied across the hitless technology test metrics. These findings are not only relevant for unravelling deployment decisions between both packet-based technologies in the energy sector but are also useful for the long-term infrastructural planning of power utilities