Efforts are underway to create a smarter grid by adding intelligence to the electrical infrastructure that connects generation, distribution, transmission, and consumption. According to calculations, the current US electrical grid consists of roughly 10 000 generating units with a generation capacity in excess of 1 000 000 megawatts of energy and over 300 000 miles of transmission lines. It is arguably the best creation of the past century, and has kept consumer costs relatively low over the years. With a growing environmentally-conscious population and an increasing demand for energy, however, this incredible infrastructure needs to be revamped in preparation of future requirements.
The keyword here is revamp. With 100 years invested, utility companies and technology providers will want to reuse as much of the existing infrastructure as possible. The cost is estimated to be in the trillions of dollars once completed, and would be even more expensive if it required that existing generation plants and distribution facilities be shut down and replaced. Consumers will not want to tear down buildings and homes to take advantage of the smart grid. Because it is impractical to start from the beginning and create a single standard or protocol to unify the elements of this ecosystem, we must observe what is already in place and retrofit those pre-existing systems so that they may interoperate and provide us with information to make smarter decisions.
The first step
The first step in creating a smarter grid was investing in an advanced metering infrastructure (AMI). An AMI contains a smart meter that enables near real-time two-way communications to the distributor when connected to a building or home. This technology enables utility companies to monitor energy usage in hourly intervals, which in turn provides them with the ability to base charges on whether energy is consumed during peak or non-peak times. This technology also enables consumers to determine the price of energy at any point in time. Before smart meters, readings were done manually and consumers were charged a fixed rate regardless of when the energy was consumed. Consumer opinion of smart meters likely depends on when and how much power they utilise; however, smart meters are more than billing machines. They also have the ability to report power outages and quality of service. Such an exchange of information between utility companies and consumers would not be possible without the use of a protocol, which defines the structure and transfer of information between entities.
The need for open protocols
At first, these protocols were proprietary and forced utility companies to standardise on a brand of equipment to install at the central system and consumer endpoint. Fortunately, a shift is currently underway to utilise open protocols to provide interoperability between different vendors. The Internet Protocol Suite (a group of protocols used over the Internet) is globally accepted and will be the foundation for communications. Internet Protocols only provide lower-level communications interoperability at the network and transport layers. This in itself is important, because it allows vendors to select standardised components (such as Ethernet or Wi-Fi) to incorporate into their systems. These components can then be plugged into an existing infrastructure that is already connecting different players in the smart grid ecosystem. It is on top of these layers that systems and devices must build their application-level requirements, specifying the data and corresponding structure that will be exchanged. The practice of creating application-level protocol requirements is not new to the power and building automation space.
The power industry also has its share of protocols that are utilised for interoperability. In North America, DNP3 (distributed network protocol) is used heavily in process automation for electric utilities. DNP3 is built on top of the Internet protocols and supports two-way communications for exchanging information between control centres, remote terminal units (RTUs), and intelligent electronic devices (IEDs). It can operate over IP and Ethernet networks, typically known as DNP3 over IP. The content is not modified when transferred over IP but changes as to how it operates over the transport – allowing existing DNP3 serial devices to work seamlessly over the same network. This provides the flexibility needed for customers to cut costs by reducing the need to buy new devices when switching from serial to Ethernet networks.
It defines the security model that will be used between the different endpoints to ensure proper message authentication and encryption. In Europe, the IEC 61850 protocol has been adopted and has similar functionality and characteristics as DNP3. Although there are other protocols being used in electric systems, these two technologies appear to be the most established and will be looked at closely when integrating existing infrastructure with tomorrow’s grid.
Existing protocols are also present in the building automation and control networks space. One such standard is BACnet, which is widely used in heating, ventilation, and air conditioning (HVAC) systems, lighting, security, and fire detection applications. This protocol also supports two-way communications systems, has built-in discovery capabilities that provide 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.
Manufacturing and OPC
Manufacturers are one of the largest consumers of energy: a typical manufacturing process runs 24 hours a day for 7 days a week. The manufacturing process has been automated for years in order to eliminate human error and produce high quality goods in the shortest amount of time possible. A typical facility usually consists of many sub-systems and parts, not all of which are procured from the same vendor. In order to automate the manufacturing process, communications must occur among these various components. Much like the different components in a smart grid, each component utilises its own protocol (which may be open or proprietary). In order to achieve interoperability, the manufacturing industry collaborated and created a well-known standard called OPC (open connectivity). OPC is an abstraction layer between the different components and their underlying protocols. The latest version of OPC is known as OPC Unified Architecture (UA), and provides some of the same features that are required of the smart grid. UA is built on top of the Internet protocols and provides secure, reliable two-way communications between endpoints. OPC and UA can be thought of 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, enabling all parties to communicate, share data, and make intelligent real-time automated decisions.
Convergence and the need for secure communications
Given our dependence on power, security requirements must be considered as the smart grid is developed. In addition to protecting against physical attacks, security needs to be built into the communications infrastructure to protect against cyber attacks through the system. Leading the way in defining the security requirements is the National Institute of Standard and Technology (NIST). NIST has developed guidelines for security requirements, risk assessment, privacy protection and the prevention of other types of vulnerabilities that must be adhered to by utility and technology providers. Any protocols selected for standardisation will be mapped out against these guidelines before they are considered and eventually accepted.
The NIST organisation recently released a report called The NIST Framework and Roadmap for Smart Grid Interoperability Standards, Release 2.0, where they included DNP3 as part of their list of standards needed to support an interoperable power infrastructure. NIST refers DNP3 as a new IEEE standard. And it is DNP3 synergistic relationship with IEC 61850 which will support more connectivity within power infrastructures. By not having to replace one protocol (DNP3) with another (IEC 61850), utility customers will save substantial time and potential difficulties. NIST defines IEC 61968/61970 Suite as an application-level energy management system interface and deems it as an acceptable approach for conducting the messaging for distribution grid management in the utility space.
It stands to reason that the power, building, and manufacturing markets’ standards and protocols will be evaluated closely as the smart grid is built. All three of these spaces constitute a large piece of the smart grid ecosystem, whether through generation, distribution, transmission, or consumption. Leveraging these protocols or building interoperable gateways will accelerate creation and adoption while saving costs and reusing the technology with proven connectivity
For more information contact Neil Upfold, eTX Data Services, +27 (0)83 325 4139, [email protected], www.kepware.com
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