The phrase “Smart Grid” conjures up different images for different people. Advanced Meter Infrastructure, consumer energy portals, ubiquitous sensors, geospatial information systems, customer information systems and outage management systems all come to mind. But, whatever the Smart Grid is or will ever be, one thing is certain: a secure and reliable, real-time two-way, high-speed communications infrastructure is an essential part of the Smart Grid reality.
Driven by external and internal forces, the business of power utilities is changing. Regulatory bodies (such as NERC) are requiring better operational management and security. Market forces are putting pressure on operational expense and driving the need to increase efficiency and scalability. Our leaders (management and political) are responding to the demand for green initiatives and the need to deploy Smart Grid technologies. These drivers are forcing a modernization of the utility critical infrastructure. Specifically:
Bandwidth between the WAN and substations, generation and transmission facilities and control centers is limited.
There are still multiple legacy interfaces in use and now new IP-enabled devices (IEDs) coming on line.
NERC/CIP is requiring a move to parallel networks.
There is an increasing need for the security of physical assets.
Our future telecommunications networks must be ultra-reliable, act deterministically, and operate in harsh outside plant environments.
Critical Infrastructure Challenges in Supporting the Smart Grid
Utilities are in many different stages of critical infrastructure evolution. Some are aggressive in the adoption of new technologies while, overall, the industry is cautious. Regardless of where your network is, there is a common evolution path taking shape and manufacturers are designing and building solutions to help utilities along this path. This path has five important steps.
The future is too uncertain to bet on closed, proprietary solutions. Start migrating your network to standards-based technology solutions.
Standards are fully supported by equipment manufacturers, which mean a wide market base, short lead times, readily available spares and, most importantly, the lowest cost solution. Standards help make equipment future proof, instill feature roadmap confidence and lead to reasonable development timeframes. In addition, standards make equipment scalable, interoperable, provide state-of-the-art capabilities and usually provide easy-to-use operations models.
Benefits of a Standards-Based Solution
As network capabilities and applications become more sophisticated, interfaces tend come and go, appear and disappear. At the same time, basic transport evolves – growing in bandwidth and capacity, but fundamentally blind to the traffic that it carries. The best way to handle this dichotomy is to “factor” the transport functionality apart from access functionality.
Continue to support the legacy traffic (e.g., pilot wire, low-speed SCADA, FX lines) with embedded, purpose-built boxes but prepare for the future by deploying standards-based, next generation multiplexers.
Separate Transport and Access
Many in the telecommunications field are finding that: “packet services are not just different from TDM, they are really different.” With that said, everyone knows that Ethernet is the service interface of the future, so you need to understand its use and its place in your network. Pilot-test limited Ethernet functionality while you develop your organizational expertise and determine your true traffic needs. To do this, start with the basics: point-to-point and very limited multi-point. For capacities below 10 Gbps, Ethernet over SONET (on existing infrastructure) provides a cost-effective and easily managed entry point. Many utilities find that because of the hubbed nature of their traffic, there isn’t much value added with implementing large routed or switched networks.
Even small and mid-sized power utilities are finding the need for more than 10G Ethernet capabilities and are projecting growth past this in the near future. Most agree that Smart Grid projects are going to require an undefined, but certainly large, amount of bandwidth. For what you know, and more importantly what you don’t know, adding wave division multiplexing (WDM) helps future-proof your network.
WDM also helps with separation of critical infrastructure and corporate communications traffic, which can ride on separate WDM channels. In addition, WDM provides a high capacity vehicle for mission-critical IT traffic including disaster recovery and business continuity, inter-campus connectivity, disk replication/mirroring and basic corporate services.
WDM Future Proofs Your Network
WDM unlocks the potential of the fiber plant with scalability for additional bandwidth and new services, and Ethernet is the one growing service guaranteed to need this new bandwidth.
In general, almost all corporate traffic is evolving to IP/Ethernet. But, more importantly for a utility, new Smart Grid applications, such as substation modernization and AMI/AMR, are all based on Ethernet. However, these new applications require a higher quality of service than typical corporate traffic. These applications require predictability – they need consistent, deterministic communications under even the most inclement conditions.
The Ethernet that works best for utility communications networks uses Ethernet framing as transport while defining “circuits” to carry services over the transport layer. This Ethernet is known as Connection-Oriented Ethernet. Connection-Oriented Ethernet leverages the low cost of Ethernet technology while providing the reliability and performance demanded by mission-critical utility applications.
Connection-Oriented Ethernet Provides the QoS Required in Utility Networks
Currently, there are two competing “connection-oriented” technologies: Provider Backbone Bridging Traffic Engineering (PBB-TE) and Multiprotocol Label Switching Transport Profile (MPLS-TP). While PBB-TE is now standardized as IEEE 802.1Qay, the original proponent and many of the early adopters have backed away from it - leaving MPLS as the viable option.
MPLS is a mature technology that supports multi-cast and many forms of tunneling for reliable TDM support. In addition, MPLS is easily manageable with many vendors supporting GUI-based provisioning and tested inter-product compatibility.
In most networks, the last mile is the bandwidth bottleneck. Utility networks are no different – the bandwidth out to substations (and beyond) is often throttled-back by leased T1s or worse, dial-up lines. In addition, relying on third party’s (e.g., telcos) for critical infrastructure is at cross-purposes with the goals of the Smart Grid.
The best solution is fiber. While yielding the most bandwidth and flexibility, fiber is not always practical and often times expensive. Power Line Carrier (PLC) and Broadband over Power Lines (BPL) are attractive alternatives for substation communications because of the availability of transport media but are fraught with implementation and technology challenges due to the noisy environment in which they operate.
The other alternative is private wireless. There are several technology choices, each with their own benefits, including microwave, WiFi mesh and WiMAX. Private wireless provides a reliable, inexpensive, and arguably the best, broadband pipe out to substations.
Last Mile Options for Smart Grid
Fact:
The benefits of packet for utility critical infrastructure are just too appealing.
The Question:
How to make packet services provide the reliability and performance needed for mission-critical applications such as the Smart Grid?
The Answer:
MPLS
Over
WDM Optical Transport
And
Private Wireless in the Last Mile
MPLS finally delivers Ethernet QoS and OAM&P that is on par with SONET at a low price point. While WDM unlocks the potential of your fiber plant with high bandwidth transport that carries any service securely and reliably and private wireless provides practical and efficient access to substations and beyond.