Are Your Transformers Ready for the Smart Grid?

National challenges such as the aging power grid, increasing energy demands, spiraling cost of generating electricity and its cost on the environment all point toward the need for a grid that can produce and distribute energy more efficiently and reliably.

Oct 1st, 2010
52423

By Mike Dickinson

National challenges such as the aging power grid, increasing energy demands, spiraling cost of generating electricity and its cost on the environment all point toward the need for a grid that can produce and distribute energy more efficiently and reliably.

For years technologists have toyed with a smart grid, an electricity distribution system that uses digital technology to eliminate waste and improve reliability. Adoption of the smart grid is expected to enhance every facet of the electric delivery system, including generation, transmission, distribution and consumption. Advocates of the smart grid say it would open new markets for large- and small-scale alternative energy producers by decentralizing generation.

Transformers serve as a hub for collection and distribution of energy and are a key component of a successful transition to a smart grid. Some transformers are located where grid communication is mature enough to allow or require interaction, while others are not. Transformers used in power transmission are immediate candidates for integration into smart grid technology and immediately will benefit from reliability and efficiency improvements that result from some of the new online monitoring technologies. Transformers used mainly for distribution circuits probably will be affected more as the smart grid matures.

Most of today's transformers are not ready for the smart grid because they were placed into service years before the age of interactive information transfer. Building the next generation of transformers will require incorporating remote monitoring of a wide range of transformer and system parameters.

What is a Smart Grid?

Everyone is talking about the smart grid, but the actual definition is still fluid. The Department of Energy (DOE) notes that the smart grid will be an automated, widely distributed energy delivery network characterized by a two-way flow of electricity and information and able to monitor everything from power plants to customer preferences to individual appliances.

Figure 1 illustrates how the smart grid concept ties together all aspects of the power system, from the plug in the wall at a house or office to a factory, to the distribution system, to power plants of all kinds.

Distributed computing and communications technology will be incorporated to deliver real-time information and enable the near-instantaneous balance of supply and demand down to the device level. In short, the smart grid will deliver electricity from suppliers to consumers using digital technology to save energy, reduce cost and increase reliability and transparency.

Table 1 compares key features of today power distribution grid with that of a smart grid. Table 2 lists the key component technologies that are expected to be available to facilitate transition to the smart grid. Adoption of the smart grid is expected to enhance every facet of the electric delivery system, including generation, transmission, distribution and consumption.

To say there is much riding on a successful transition to a smart grid is a colossal understatement. The smart grid is expected to ensure the reliability of the power system, maintain its affordability, reinforce U.S. global competitiveness, fully accommodate both renewable and traditional energy sources, potentially reduce our carbon footprint, and be structured to facilitate the introduction of new advancements and efficiencies that have not yet been dreamed of.

Today's Transformers Not Ready for Tomorrow's Smart Grid.

Although just one piece of the smart grid puzzle, transformers serve a key role as the hub for energy collection and distribution. For the smart grid to work efficiently, there will be a need for smart transformers. As part of the distribution network, there are millions of transformers in the country; unfortunately, very few have any intelligence or communication capabilities that meet advanced metering infrastructure (AMI) standards or are parts of an advanced sensor infrastructure (ASI) network.

Transformer manufacturers are seeing increasing emphasis on online transformer monitoring, but today's transformers, for the most part, are not ready for tomorrow's smart grid.

The first reason for this is that transformers have a long, useful life expectancy–generally 20-30 years of service. Most were installed before the age of interactive information transfer, which is the foundation of a smart grid.

As they are replaced with contemporary technology, communication capability can be included as an upgrade. A product, however, with such a long projected useful life span only changes very gradually. When considering that all transformers have about a 25-year life span, each year only 0.04 percent of those installed likely would need to be replaced. Optimistically, that's only 4 percent per year for the next 25 years. That is a long time to wait for a smart grid, if typical replacement patterns apply.

A second reason is that the wide range of transformer applications means some transformers are in a position, location or application where grid communication is mature enough to allow or require interaction while others are not. Transformers used in the transmission of power are immediate candidates for integration into smart grid technology, while transformers used mainly for distribution circuits will be affected by a smart grid only after it matures to a greater degree.

Another key factor is the need for a change in how the industrial sector sees transformers. Their concern traditionally has focused on power continuity; heavy industrial users typically have not paid much attention to how their transformer can be used to affect power flow or load switching on a regional or national scale. The danger with this mindset is that industrial transformers purchased today, which will be in service for the next 20-30 years, might not contain the systems necessary for the monitoring of communication likely to be required within the next five years. Transition to the smart grid, clearly, will require a degree of re-education in the industrial sector.

Legislation, of course, might play a part in accelerating the change and transition to transformers that are compatible with smart grid concepts. That was recently seen as the DOE mandated higher efficiency ratings for all distribution transformers in 2010, and it was seen in the late 1980s when legislation mandated that polychlorinated biphenyl (PCB)-contaminated transformers be replaced.

There is already an increased use of digital monitoring in transformers. Vital statistics such as temperature, pressure and vacuum levels are being collected and transmitted in real time to a central clearinghouse. Many transformer manufacturers are recognizing this growing demand for online transformer monitoring products and diagnostic services and are investing in building them–especially for step-up transmission high-voltage transformers.

These technologies will be critical for improving grid reliability and helping utilities avoid transformer failures and resultant blackouts. They also will reduce maintenance costs and defer capital expenditures by extending a transformer's useful life.

In the past few years, for example, there has been a growing interest in conducting dissolved gas analysis (DGA) of the oil in transformers. With DGA, samples are taken of the oil's exhaust gases to determine if any events occurred that might be detrimental to the transformer and reduce its life. Both industrial transformer users and utilities are setting up these planned sampling programs using online devices that can monitor the oil for quality. This can greatly improve reliability because users will know in advance when something must be replaced–rather than risk an unscheduled outage. For food-processing plants and mills, which can lose millions of dollars if their power is interrupted, this type of sampling program is being undertaken to ensure reliable power.

Transformers in place already use smart devices for load switching. In the 21st century, the move will be toward monitoring systems that promote transformer reliability. Ensuring reliability on the grid by replacing equipment before it fails and anticipating upcoming problems is on what transformer manufacturers will focus.

Pacific Crest Transformers is responding to this growing demand for transformers that can be integrated into the smart grid as it matures. As the company builds next-generation transformers, it is incorporating remote monitoring of a wide range of transformer and system parameters. Table 3 shows typical monitoring parameters necessary for smart grid integration.

Though laudable, it must be said that the concept of using these smart grid concepts to ensure system reliability is still in its infancy. All parts of the system must work together to develop a system that monitors the transformer and other parts of the grid at all times. There is still a bit of an island mentality among those building system components, including switches, cabling and capacitors. Symbiosis among the components could happen, but it has not yet done so.

The answer to the question, "Is your transformer ready for the smart grid?" is complicated. Depending on where the particular transformer is used in the power generation and distribution system, the answer is yes, no or maybe. Pacific Crest Transformers is among those moving forward to develop transformers that can be part of smart grid initiatives to improve power reliability and efficiency.

About the author:
Mike Dickinson is the director of new business development, Pacific Crest Transformers.

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