The protocols driving smart grid interoperability

Paul Boughton

Efforts are underway to create a smarter power grid by adding intelligence to the electrical infrastructure that connects energy generation, distribution, transmission, and consumption. Tony Paine reports.

The US Department of Energy calculates that the current grid consists of 300,000+ miles of transmission lines and about 10,000 generating units with a capacity of 1,000,000+ megawatts of energy. It is arguably the best creation of the past century. However, due to an increasing environmentally-conscious population and a rising demand for energy, this incredible infrastructure must be revamped in preparation of future requirements.

With so much invested in the current power grid, utility companies and technology providers must reuse as much of the existing infrastructure as possible. The renovations are estimated to cost trillions of dollars, even without closing and replacing existing generation plants and distribution facilities. It is impractical to start over; instead, we must retrofit the existing systems for interoperability so that they can provide the information needed to make smarter decisions. The smart grid must evolve organically from the current power grid.

Proprietary protocols have historically forced utility companies to standardise on a brand of equipment for both the central system and consumer endpoint. Fortunately, a shift is underway to utilise open protocols for interoperability between different vendors. The Internet Protocol Suite (which is a group of globally-accepted protocols used over the Internet) will be the foundation for communications. Internet Protocols provide lower-level communications interoperability at the network and transport layers, thus allowing vendors to select and incorporate standardised components like Ethernet or Wi-Fi into their systems. These components can be plugged into the existing infrastructure that is already connecting parts of the Smart Grid ecosystem. Systems and devices can then build application-level requirements on top of these layers, specifying the data and structures that will be exchanged. [Page Break]

Protocol requirements

The power, building automation, and manufacturing markets are not new to creating application-level protocol requirements. For example, the power industry utilises distributed network protocol (DNP3) heavily in process automation for electric utilities in North America. Built on top of the Internet Protocols, DNP3 supports two-way communications for exchanging information between control centres, remote terminal units (RTU), and intelligent electronic devices (IED). It can also operate over IP and Ethernet networks. The content is not modified during transfer, but changes how it operates during transport to allow existing DNP3 serial devices to work seamlessly over the same network. This flexibility reduces the need to buy new devices when switching from serial to ethernet networks.

The IEC61850 protocol adopted by the power industry in Europe has similar characteristics and functionality as DNP3. Although there are other protocols being used in electric systems, these two technologies are the most established and relevant in evolving the existing infrastructure into tomorrow's grid.

There are established protocols in the building automation market, as well. One such standard is BACnet, which is used in heating, ventilation, and air conditioning (HVAC) systems and lighting, security, and fire detection applications. It supports two-way communications, has built-in plug-and-play capabilities, and defines a security model for user and message authentication and encryption. In order to turn a building into a smarter building, the existing control and automation systems must interoperate with the smart grid.

In the manufacturing industry, automation reduces human error and efficiently produces high-quality goods. It also consumes large amounts of energy, with typical manufacturing processes running 24 hours a day, seven days a week. Facilities contain many sub-systems and components that are often procured from different vendors at different times. Each component utilizes its own protocol (open or proprietary), much like the different components in a Smart Grid.

To achieve interoperability, the manufacturing industry collaborated and created the open connectivity (OPC) standard. OPC is an abstraction layer between the different components and their underlying protocols. OPC unified architecture (UA) is the newest version that is built on top of the Internet Protocols and provides secure and reliable communications between endpoints. It functions as the glue for industrial automation, where application-based gateways transform OPC requests into the appropriate underlying device-level protocols. This technology allows proprietary-based systems to be retrofitted into a more open-based system, thus enabling parties to communicate, share data, and make intelligent real-time automated decisions.

The success of interoperability in the manufacturing industry is a lesson for the power market. According to the National Institute of Standards and Technology (NIST), DNP3 is one of the standards needed to support an interoperable power infrastructure. NIST calls DNP3 a new IEEE standard: its synergistic relationship with IEC61850 will help support greater connectivity within power infrastructures, saving utility customers time and expense.

It stands to reason that the power, building automation, and manufacturing markets' standards and protocols will be closely evaluated as the smart grid is built. These three industries constitute a large part of the smart grid ecosystem through energy generation, distribution, transmission, and consumption. Applying existing protocols and building interoperable gateways will accelerate the creation and adoption of the new smart grid by leveraging new technology with proven connectivity and reducing expenses in national and global markets.

Tony Paine is President and CEO, Kepware Technologies, Portland, Maine, USA.

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