Why MPLS-TP is the Best Option for Smart Grid Evolution
Utilities are adopting smart grid technology in order to improve the sustainability, efficiency, and reliability of the electricity network, while also enabling customer-generated supply and smarter time-of-day based energy usage. The adoption of this technology is being enabled by the European Technology & Innovation Platform (ETIP) Smart Networks for Energy Transition (SNET) in Europe and its US equivalent. The result is over $50B of global investment in smart grids in 2017, which is forecast to grow to $70B by 2020.
But what does this mean for the communications network electrical utilities use to control and operate the electricity distribution network? At a high level, electricity networks consist of generation, transmission, substations, and consumers. High voltage from generators goes across the transmission network to the primary substations where medium voltage goes to secondary substations and heavy industry, and then low voltage is delivered to residential properties, light industry, and everyone else.
Electricity Network Overview
This network requires a communications network for monitoring and control, protection, and utility office applications. Historically, SONET/SDH has been used to provide this mission-critical communications network due to its reliability and quality of service, transparency to unique electricity industry control protocols (DNP3, Modbus), and support for now legacy serial (RS232, RS485) and TDM (E1, T1) interfaces. The need for extremely accurate time and frequency synchronization has traditionally been met by a Global Navigation Satellite System (GNSS) such as GPS.
However, SONET/SDH lacks the bandwidth and flexibility required for smart grid communications. It is also inherently point-to-point and cannot natively meet the mesh and multicast requirements of many smart grid applications. Furthermore due to component obsolescence, finding replacement parts for failed SONET/SDH equipment is becoming increasingly challenging. So what is the alternative?
Fortunately, the legacy protocols (DNP3, Modbus) are evolving to IEC 61850, an international standard defining communication protocols for intelligent electronic devices at electrical substations. It uses Ethernet (Layer 2) for synchronization (IEEE 1588v2), protection (Generic Object Oriented Substation Events [GOOSE]) and the multicast of analogue measurements of the electrical signal, and IP (Layer 3) for configuration and reporting (Manufacturing Message Specification [MMS]). This will reduce the requirement for legacy protocol and interface support, however, this transition will not happen overnight.
Therefore, what is required is a scalable solution that can support both Ethernet and IP transport while still providing support for legacy TDM and serial interfaces through circuit emulation. The solution must deliver the high availability and the sub 5 ms transmission latency required for sub 50 ms protection of the electrical network. Comprehensive synchronization support including IEEE 1588v2 is also required.
SONET/SDH vs. MPLS-TP
MPLS-TP provides an ideal technology to meet these requirements with support for point-to-point (VPWS) and mesh (VPLS/H-VPLS) Ethernet, transparent IP, and legacy interfaces through circuit emulation. Platforms like the Coriant® 7090 M/CEM also provide 50 ms network protection and hard quality of service, ultra-low latency, and comprehensive synchronization including IEEE 1588v2 support, making them an excellent option for evolving electricity networks from legacy SONET/SDH to a smart grid enabling packet infrastructure. And the bonus? Excess capacity on this network can be monetized by selling MEF E-Line, E-LAN, E-Tree, E-Transit, and E-Access services to enterprise and wholesale customers.