By Gary Ockwell, Advanced Control Systems
You dread it–admit it! All of us in the utility industry can agree that it is no fun, after a big power outage, to be the person at the neighborhood cookout branded as an “electric power grid” person. While neighbors suffer frequent interruptions to their cable, internet and cell service–which are far less complex systems but for which they pay commensurately more than for their electrical service–their electrical supply is expected to be low cost while of high reliability. In fact, reliable electrical service is simply expected–like water.
Following an outage, we’re generally stuck in defensive mode while our neighbors ask why the local utility doesn’t improve its performance record and why their clocks always blink after lightning storms. Amidst our misplaced and mostly misunderstood explanations ranging from lightning arrestors and multi-phase service to fried squirrels and tree trimming, most of us have been conditioned over the years to accept our fate, shrug, and bear it with a stoic utility industry game face.
This is often the story unless you are one of the fortunate few who live in places like Cobb County, Ga., or areas around New Haven, Conn., to name two places where the neighborhood buzz after a storm or outage event is about “how many Mississippis” the kids counted before “the utility just switched the power back on–snap.” This author suggests you forget about explaining recloser programs, distributed intelligence and distribution management systems. Simply tell your neighbors they should thank the utility’s “smart grid” program. It’s finally happened, you are no longer the bane of the post-outage backyard barbeque.
And just think what will happen when the smart metering and smart thermostat programs are installed and your neighbors can actually manage energy better, save money and help the environment, too. You may yet win that best neighborhood lawn contest, or at least you won’t be the perennial victim of tricks rather than treats on October 31st.
Smart Grid Hits Main Street USA
While not yet as communal as neighborhood cookouts, the smart grid has reached Main Street USA in many tangible ways. Americans have officially sanctified energy efficiency as the de rigueur topic with regulators and government officials. With electric prices rising in many parts of the country, consumers are asking with renewed interest, “what am I actually paying for?” The HR6 Energy Bill signed by President Bush late last year includes important provisions for the smart grid. The smart grid was even the feature of a March 2008 Wall Street Journal advertisement. And, more recently, presidential candidates have been heard talking about the smart grid.
Utility executives have realized this smart grid movement underfoot isn’t a replay of the late ’70s fad around demand side management. On the contrary, most executives see the development and deployment of effective smart grid strategies as essential to future industry vitality in the face of increased power demand, inevitable CO2 legislation, rising fuel costs, and skyrocketing material and construction costs.
The logic is compelling: Presume consumers and regulators care primarily about end-bill cost and service reliability regardless of local or regional market constructs. This has been proved time and time again in research. Presume that the smart grid will, over time, increase aggregate plant asset utilization, capital allocation efficiencies, and reliability across the market. The conclusion you may reach is: “Why didn’t we start doing this 20 years ago when much of the necessary technology started emerging from work in other sectors, including telecommunications?” Moore’s Law has driven down the cost and increased the engineering feasibility of solid-state digitization of the power sector and, together with advancements in communications and positive consumer sentiment, the smart grid movement has finally passed its tipping point.
Emergence of the SubstationIntelligent Terminal Unit
Groundwork for the smart grid has been laid with the emergence of intelligent technologies that can support the grid and allow for an infrastructure that provides a multitude of energy services, integrated distributed energy resources and control programs. The smart grid’s objectives focus on enhancing customer satisfaction while improving security, economy, reliability and efficiency. To meet these objectives, an investment in an intelligent distribution technology roadmap is essential.
While implementing an updated infrastructure is a daunting challenge in scale and complexity, the benefits that some utilities are already achieving include opportunities to lower SAIDI, increase customer satisfaction ratings and increase return on assets. With utility industry requirements for 24x7x365 service as a backdrop, an incremental deployment plan that allows utilities to maintain existing infrastructure while deploying fully integrated “islands of intelligence” provides an optimal approach. Automation within the smart grid should ideally consider the deployment of multi-functional, vendor interoperable, open-standards solutions. This approach will minimize capital cost and maintenance, and it will provide a common information model-driven system strategy.
Smart grid technological evolution is occurring first at the customer meter and the distribution substation. The first evolution in the distribution substation is a network-based platform designed to meet local processing requirements for distributed feeder and substation automation. The need for autonomous distribution substations is amplified by ever-increasing security concerns and the sheer quantity of data that needs to be collected and processed. Factoring substation intelligent electronic device (IED) integration, the size of the substation database increases dramatically from the 100-point sizes common in legacy RTUs, to sizes as immense as 100,000 points in very large substations where each IED contributes 500 to 1,000 points. The next step toward automation is the addition of “substation intelligence.”
The “intelligent terminal unit” (ITU) as a substation computing platform is an independent server that supports local and remote access to achieve autonomous advanced command-and-control capabilities from the substation while providing a powerful local graphical user interface. This is what is often referred to as a “self-healing” grid in the trade and popular press.
The ITU as a platform for distributed smart grid applications can provide greater reliability, improved performance, distributed computing, and maximized reliability supported as needed by a powerful substation GUI. This distributed architecture allows the substation to serve as an independent processor in a network of computers, in essence, moving the computing power from the master station to the substation. The substation is autonomous and maintains service reliability within the system. As a distributed platform located at the substation, besides performing its local automation duties, it is a powerful processing node in a network of computing platforms sharing the distributed data it has with a master station distribution management system (DMS). In a hierarchical architecture, the utility has the option to apportion whatever functions should be performed at each level in the hierarchy. For example, the “island of intelligence” may be responsible for the self healing and loss minimization control of the substations and feeders within its island, while the master station is responsible for overall monitoring, control and optimization of feeders between islands. In such a hierarchy, the master station can inhibit, override or re-enable any degree of automation within the island on a per feeder basis. The key to development of a cost-effective distribution intelligence roadmap is an approach that leverages installed infrastructure, open standards, and flexible approaches to localized and master station automation. The ITU, the logical evolution of the RTU, is a part of this approach.
Advantages of Distributed, Neighborhood-Based Substation Intelligence
This architecture is advantageous from many viewpoints. Perhaps most importantly, this enables the distribution automation portions of the smart grid to “get off the ground.” The most popular deployment of new smart grid technologies involves a phased or pilot project approach. The island of intelligence is self sufficient, low cost and easy to deploy and evaluate. As “islands” increase in size and number the distributed architecture, which implies both platforms and database using a common model, is hierarchically able to support master station monitoring, authorization, optimization and control without interfering with basic self-healing functions that are performed locally within the island. The big payback is not the reduced communications to control centers, which ultimately will be required, nor the avoidance of fork lift replacement of existing facilities, or the reusability of the infrastructure; it is in the common daily model maintenance of the network as a whole, which is distributed to the islands of intelligence.
Since the platform may be located in a single substation within its island of intelligence it is essentially a rugged open-computing platform that meets the substation’s harsh environmental requirements. As an open-computing platform, it supports advanced applications and feeder network automation that can increase reliability, improve power quality, provide advanced monitoring, optimize efficiency and lower network cost. A principal “self-healing” feeder application operates autonomously using a real-time network model that is able to rapidly collect fault data and determine fault location. It can then isolate the fault, analyze and choose the switching options, and restore power both upstream and downstream from the fault. The network is reconfigured to maximize service availability to the customers with a restoration time of less than 20 seconds. The system is no longer hindered by the control center’s protracted network analysis, and the risk of delays or communication losses between the master and substation is eliminated with this type of approach.
The advantage of an intelligent substation platform is its ability to support any application from a common substation database and model. The data is central to the substation and not the application, as is the case with feeder automation solutions that are not network based and rely on pre-planned switching schemes. The application is capable of adapting to the real-time network topology, regardless of whether it is in the normal or abnormal state, and able to handle very complex solutions including load transfer schemes to restore the maximum number of unfaulted feeder sections to service. The intelligent substation platform is easily expandable to an unlimited number of feeders or devices, and the feeder automation solution is able to operate with existing protection schemes and switches of various manufacturers. Although the system can function without supervision, it can be configured for supervised operation.
Given that deployment of autonomous islands of intelligence will in themselves multiply as substations and feeders are automated, the system will also evolve to a hierarchical architecture involving users, at least at the master station level. The question then becomes twofold: How can any user view the complexity of the island’s feeder network operation–even for post fault analysis, time tagged reports and local remote control–without a powerful local user interface, and how can the master system also receive the information it needs? For this reason, it is ideal for the substation-based automation island to incorporate its own user interface which is maintained once and shared by all including the master station operators.
For these reasons, the island’s user interface should support a network diagram with topology and colorization for each feeder automated, as well as the substation, and it should also provide control, security, and safety functions such as user authorization log-in, event reporting, and device tagging. Since many users outside of the island, such as the master station, will have different graphics needs and capabilities and could actually be using various legacy SCADA systems, the user interface and its information should be obtainable over any type of communications such as a network, or using serial communications within a window or browser.
Operator Intervention & Monitoring
Since the accuracy of the model is of primary importance for the proper operation of the applications, the substation user or master station operator must have the ability to make whatever changes are necessary in seconds. This includes not only performing control or updating of pseudo points, or model parameter changes using the substation GUI, but they should also be able to perform temporary real-time “redline” changes to the network connectivity model itself. These redline additions have to reflect emergency changes such as a cut in a circuit or placement of a jumper in order for the smart grid applications to be able to adapt to the real-time network. No matter how automated and computer-driven the smart grid becomes, operators should always have the ability to provide local control and the tools to monitor and maintain intelligent automation programs, both locally and at the master.
The intelligent distribution substation can help effectively transition today’s utility to the “utility of the future” through its support of advanced applications with a real-time database and model capable of consolidating network information. The development and implementation of these technologies will advance the capabilities of a powerful independent processing unit that can implement and coordinate dynamic changes to the network. A multiphase plan that includes the evolution of the automated distribution substation is crucial to improving reliability and launching the distribution operations elements of the smart grid.
Awareness of smart grid opportunities is growing across Main Street USA. Consumer support will be required for long-term success. Ultimately, educating consumers will be easier as neighbors, friends and relatives experience the benefits of the distribution automation programs gaining momentum in pilots across North America.
Gary Ockwell, a 30 year veteran of the utility and automation industry, is director of strategy at Atlanta-based Advanced Control Systems, an EFACEC Company. He can be reached at Gary.Ockwell@acsatlanta.com.